Amidocyanogen silanol as a high-temperature-resistant shale inhibitor in water-based drilling fluid

Applied Clay Science 184 (2020) 105396

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Research paper

Amidocyanogen silanol as a high-temperature-resistant shale inhibitor in water-based drilling fluid

T

⁎

Qi Chua,b, , Ling Linc, Junlin Suc a

State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100101, China Sinopec Research Institute of Petroleum Engineering, Sinopec, Beijing 100101, China c School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China b

A R T I C LE I N FO

A B S T R A C T

Keywords: Amidocyanogen silanol Shale inhibitor Adsorption Wettability Water-based drilling fluid

To meet the technical requirements of high-temperature deep wells, highly inhibitive, high-temperature-resistant shale inhibitors are essential. This paper reports for the first time the use of amidocyanogen silanol (ANS1), a newly developed oligomer with an amino siloxane structure, as a potential shale inhibitor. Its inhibitive properties were evaluated by linear swell testing, cutting dispersion testing, bentonite inhibition testing, and mud pellet disintegration testing, and the results were compared with the properties of other current conventional inhibitors. The inhibition mechanism was investigated by X-ray diffraction, adsorption, Fourier transforms infrared spectroscopy, contact angle, zeta potential and transmission electron microscope. The results indicated that ANS-1 can inhibit the hydration swelling and dispersion of water-sensitive clay minerals effectively, performing better than other inhibitors. Furthermore, ANS-1 provides reliable thermal stability as high as 140 °C and has potential application in high-temperature deep wells. ANS-1 can adsorb into the surface of clay, which changes the wettability of the clay surface and increases the resistance of water molecules to bond with the clay. In addition, ANS-1 can intercalate into the clay interlayer, occupying water adsorption sites, and into the interlayer channel, thus inhibiting the hydration swelling of clay. The introduction of siloxane groups in the ANS-1 molecular chain led to a firm chemical adsorption between ANS-1 and clay, which increased the adsorption capacity of ANS-1 at high temperature, thus improving its inhibition performance.

1. Introduction Wellbore stability is the primary problem that affects the safety and progress of drilling engineering (Fuh et al., 1988; Nguyen et al., 2009; Zeynali, 2012). The key technology to maintain wellbore stability is inhibiting hydration swelling and dispersion of water-sensitive clay minerals in the shale formation (Liu et al., 2004; Jain et al., 2015; Villada et al., 2017). Compared with water-based drilling fluids, oilbased drilling fluids can more effectively inhibit hydration swelling and dispersion of water-sensitive clay mineral, but they are expensive and contribute to environmental pollution, limiting their application (Tan et al., 2002; Fadairo et al., 2012). To mitigate the damage caused by water-based drilling fluids, shale inhibitors are widely used to minimize or even prevent the hydration of water-sensitive clay minerals in the formation (Peng et al., 2013; An et al., 2015; Ma et al., 2017). Shale inhibitors can be chemically divided into two types: inorganic shale inhibitors (e.g., KCl, NaCl, CaCl2, and NH4Cl) (Balaban et al., 2015; Ferreira et al., 2016) and organic shale inhibitors (potassium

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formate (Ofei and Bendary, 2016), cesium formate (Lv et al., 2018), potassium humate (Jiang et al., 2016a, 2016b), polyacrylamide (Liu et al., 2014), ionic liquid (Luo et al., 2017; Yang et al., 2017; Ren et al., 2019), cationic starch derivative (Cescon et al., 2018), polymeric alcohol (Jiang et al., 2011; Villabona-Estupiñan et al., 2017), and polyamines (Zhang et al., 2016). At present, owing to their outstanding effects, the polyamines have been recognized as the inhibitor of waterbased drilling fluids with most potential. Polyether diamine (Qu et al., 2009; Zhong et al., 2011), poly(oxypropylene)-amidoamine (Zhong et al., 2012), polyamidoamine (Zhong et al., 2015), and polyethyleneimine (Jiang et al., 2016a, 2016b) are all polyamine inhibitors and have been investigated in the literature. In alkaline condition, the primary amine group in the chain of polyamine inhibitors is protonated and converted into a quaternary ammonium group. The polyamine inhibitor with positive charge enters the clay layer space and adsorbs with negative charge clay through electrostatic interaction. Therefore, the adjacent clay lamellar structure is bound together, which hinders the invasion of water molecules, and finally achieves the purpose of

Corresponding author at: Sinopec Research Institute of Petroleum Engineering, Beijing 100101, China. E-mail address: [email protected] (Q. Chu).

https://doi.org/10.1016/j.clay.2019.105396 Received 14 May 2019; Received in revised form 26 November 2019; Accepted 30 November 2019 0169-1317/ © 2019 Elsevier B.V. All rights reserved.

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inhibiting the hydration of clay (Billingham et al., 1997; Patel et al., 2007; Wang et al., 2011; Xie et al., 2017). The polyamine inhibitors have weak temperature resistance, generally < 120 °C, which has become a technical bottleneck, restricting their application in deep oil and gas exploration and development. The reason for this weak temperature resistance is that polyamine inhibitors are desorbed with clay easily at high temperature. Reports from the literature suggest that the introduction of siloxane into the polymer molecular chain can improve the adsorption capacity effectively and revolutionize performance (Xu et al., 2009; Krumpfer and McCarthy, 2011). Chu et al. (2013) proposed that organosilicon polymer as a fluid loss additive in a water-based drilling fluid, which was obtained from the silane coupling agent acrylanidypropyl tris (triethyl siloxy) silane as one of the raw materials, could effectively improve its adsorption capacity on the clay surface and enhance temperature resistance. In this work, we are committed to the development and evaluation of an oligomer with an amino siloxane structure, amidocyanogen silanol, as a shale inhibitor in a water-based drilling fluid. The inhibition properties of amidocyanogen silanol were evaluated by cuttings dispersion test, linear swell test, bentonite inhibition test and mud pellet disintegration test. In addition, temperature resistance was compared with other polyamine inhibitors. In order to further investigate the mechanism of amidocyanogen silanol as shale inhibitor for water-based drilling fluid, X-ray diffraction, adsorption, contact angle and transmission electron microscope analyze were performed to explore the interaction between amidocyanogen silanol and clay.

Table 1 Mineralogical and clay composition of shale cuttings. Mineralogical composition

Content (wt %)

Clay composition

Content (wt %)

Quartz Potassium feldspar Plagioclase Calcite

24.18 5.72 18.57 14.11

Kaolinite Chlorites Illite Illite/smectite mixed layer

2.92 14.83 30.61 51.64

Dolomite Siderite Hematite Clay minerals

3.19 0.90 0.76 32.57

Shadizadeh et al. (2015). A higher linear swelling rate indicated a high potential of hydration swelling. 2.2.2. Cutting dispersion test The cutting dispersion test was intended to evaluate the effect of the inhibitor on the hydration and dispersion of shale cuttings that have been invaded by the drilling fluid. Testing solutions (350 mL) containing different inhibitors were prepared and poured into a stainlesssteel aging jar, which contained 50 g of shale cuttings sorted with a 6–10 mesh. After sealing, the stainless-steel aging jar was put into a GW300-type frequency conversion rolling oven (Qingdao Jiaonan Tongchun Machinery Plant, China) for hot rolling aging for 16 h. After cooling, the shale cuttings were screened through a 40 mesh and washed with a saturated KCl solution. The shale cuttings were then dried to into constant weight in a vacuum drying oven at 105 °C. Finally, the shale cuttings were weighed and recorded. The shale cutting recovery (R) was calculated using the formula

2. Experimental 2.1. Materials Pristine sodium montmorillonite (NaeMt) was a commercial product from Xinjiang Xiazijie Bentonite Co., Ltd., China, and had a cation exchange capacity of 118.4 cmol(+)/kg. KCl and HCOOK were obtained from Chengdu Changzheng Chemical Reagent Co., Ltd., China. Ultrahib, a commercial polyamine shale inhibitor, was provided by M-I SWACO in America. Amidocyanogen silanol (ANS-1) was obtained from the Beijing Shengxin Chemical Reagent Co., Ltd., China. The possible molecular general formula is shown in Fig. 1. The shale cuttings were obtained from well YP14 of the Yaoyingtai gas field in the Songliao basin, China. The main mineralogical compositions are listed in Table 1.

R=

W × 100% 50

where W is the weight. Obviously, the stronger the ability of the inhibitor to inhibit water-sensitive shale hydration and dispersion, the more the integrity of shale cuttings can be maintained and the greater the R value is. 2.2.3. Bentonite inhibition test This test simulates the invading process of water-sensitive clay minerals from the formation in drilling engineering, which is similar to the drilling condition in the water-sensitive formation, and aims to evaluate the ability of inhibitors to inhibit the hydration and dispersion of watersensitive clay minerals dispersed in the drilling fluid. The yield point (YP) of NaeMt with different concentrations in inhibitor solutions was determined with a ZNN-D6-type rotating viscometer (Qingdao Tongchun Petroleum Instrument Co., Ltd., China). The test was conducted according to a procedure previously described by Chen et al. (2017). The stronger the ability of inhibitors to inhibit water-sensitive clay minerals, the stronger the ability of inhibitors to inhibit watersensitive clay minerals in drilling fluids from pulping, and the lower the YP of testing solutions.

2.2. Methods 2.2.1. Linear swell test A linear swell test simulates the environment in which the rock in the formation is immersed in the drilling fluid and evaluates the extent of hydration swelling of water-sensitive clay minerals of shale inhibitor. The linear swelling rates of NaeMt in water and inhibitor solutions were determined with an M4600-type high-temperature, high-pressure linear shale swelling instrument (Grace Instrument, USA). The test was conducted according to the procedure previously described by

Fig. 1. Molecular structure of ANS-1. 2

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Ltd., China) and set the temperature to 160 °C. 6 h later, the filter loss channel of the apparatus was opened to filter out all the liquid from the mixture. The solid phase on the filter paper was NaeMt adsorbed with ANS-1. After drying at 105 °C to a constant weight, the solid phase was extracted with soxhlet extractor for 24 h with anhydrous ethanol as solvent to remove ANS-1 physically adsorbed on NaeMt. By drying the eluted solids to a constant weight, the Na-Mt/ANS-1 hybrid for FT-IR spectra analysis was obtained. FT-IR spectra were recorded using an Agilent Cary 670 spectrometer (Agilent, USA) on powder-pressed KBr pellets. In accordance with the mass ratio of 1:100, mix Na-Mt/ANS-1 hybrid with KBr and grind evenly in agate crucible. The sample to be tested was placed in BL6170-C-type tablet press (Dongguan Bolon Instrument Co., Ltd., China) and pressed for 2 min under the pressure of 20 MPa to obtain a 2 mm thick circular slice, which was then put into the infrared spectrometer for testing. In order to investigate the adsorption model between ANS-1 and clay, the FT-IR spectra of NaeMt was also recorded according to above preparation steps.

2.2.4. Mud pellet disintegration test This test simulates the disintegration process of rock around the borehole wall during the circulation of drilling fluid in the wellbore. The integrity of the mud pellet reflects the degree of influence of hydration on borehole wall stability directly; that is, it reflects the effect of the inhibitor in the drilling fluid to improve water-sensitive rock strength. 10 g of NaeMt was prepared and loaded into the mold of the hydraulic press. The pressure was stabilized at 41.38 MPa for 30 min, and a mud pellet with a diameter of 1 cm was obtained. The mud pellets were put into test bottles containing water and inhibitor solutions one by one. After sealing, the mud pellets were put into an HZ-9613Y-type high-temperature oil bath oscillator (Changzhou Jintan Liangyou Instrument Co., Ltd., China). The mud pellets were shaken for 4 h at an oscillation rate of 25 rpm, and the disintegration of the mud pellets was observed. 2.2.5. Rheological measurements The rheological parameters (apparent viscosity (AV), plastic viscosity (PV) and YP were determined according to the relation between shear rate and shear stress, where the shear rate was read in the dial in degree of a circle. According to American Petroleum Institute, these rheological parameters obtained with ZNN-D6-type rotating viscometer at room temperature before and after thermal aging experiments were calculated from 300 and 600 rpm readings (Φ300 and Φ600) as follows:

2.3.4. Contact angle 50 g of NaeMt was added to 2500 mL of water and ANS-1 solutions with different concentrations, and then each suspension was divided into an average of six parts. Each sample was stirred at 5200 rpm for 60 min and reached adsorption equilibrium after hot rolling aging at different temperatures for 16 h. The samples were dripped onto clean glass sheets and air-dried under natural conditions. A smooth film then formed on the surface of the glass sheets. About 5 μL of water droplets was added to the surface of the film and the contact angle was measured with an SL200L-type contact angle meter (KINO Industry Co., Ltd., USA).

AV = Φ600 /2 (mPa⋅s )

PV = Φ600 − Φ300 (mPa⋅s ) YP = 0.511(Φ300 − PV ) (Pa) 2.3. Mechanism analysis

2.3.5. Zeta potential Zeta potential was measured with a 90Plus-type Zetasizer Nano ZS instrument (Brookhaven instrument, USA). 5 g of NaeMt was added to 250 mL of water and ANS-1 solutions with different concentrations. After hot rolling aging at different temperatures for 16 h, the dispersions were shaken for 24.0 h at room temperature and then allowed to settle for 2 h. After settling, the zeta potentials of the dispersions were measured.

2.3.1. X-ray diffraction 5 g of NaeMt was added to 250 mL of water or ANS-1 solutions with different concentrations. After stirring at 5200 rpm for 60 min, the samples were centrifuged with JIDI-50D type centrifuge (Guangzhou Jidi Instrument Co., Ltd., China) for 30 min. The lower precipitate was vacuum dried at room temperature until a constant weight was obtained. In addition, six dispersions containing 5 g NaeMt in 0.5% ANS1 were prepared. After hot rolling aging at different temperatures for 16 h, we repeated the above steps of agitation, centrifugation and drying. Finally, a series of Na-Mt/ANS-1 hybrids were obtained by grinding to a fine powder. X-ray diffraction (XRD) patterns of Na-Mt/ANS-1 hybrids were measured with a D8 Advance-type X-ray polycrystalline diffractometer (Bruker AXS GmbH, Germany) with Cu Kα radiation (λ = 0.154 nm) operating at a voltage of 45 kV and a current of 35 mA. Scans were run in the 2θ range of 3° to 15° at a step size of 0.0167° and a scan rate of 0.197°/s. The interlayer spacing was analyzed using Bragg's equation. The value for n = 1 was calculation from 2dsinθ = nλ.

2.3.6. Transmission electron microscope Transmission electron microscopy (TEM) analyses were performed with a Tecnai transmission electron microscope (FEI Co., USA). 5 g of NaeMt was added to 250 mL of water and 0.5% ANS-1 solution. After stirring at 5200 rpm for 60 min, the latter suspension was divided into three equal parts, two of which were hot aged for 16 h at 140 and 160 °C, respectively. The samples were prepared by dipping the prepared aqueous dispersion onto the amorphous carbon-coated copper TEM grids and dried under an infrared lamp. 3. Results and discussion

2.3.2. Adsorption The amounts of ANS-1 with a concentration of 0.5% adsorbed onto NaeMt in a dispersion of 2 wt% NaeMt were measured with a vario TOC total organic carbon analyzer (Elementar Analysensysteme GmbH, Germany) using a thermal filtration method. The test was conducted according to the procedure previously described by Chu et al. (2018). The amount of ANS-1 molecules adsorbed by NaeMt at a high temperature can be measured accurately by thermal filtration.

3.1. Inhibition evaluation 3.1.1. Linear swell test The linear swelling curves of NaeMt immersed in water and ANS-1 solutions with different concentrations at 20 °C are presented in Fig. 2. For all testing solutions, the linear swelling curves exhibited a similar trend. At the initial stage of water invasion, the linear swelling curves increased rapidly, and then the slope decreased significantly, which follows the typical swelling behavior of NaeMt in aqueous solution. It can be clearly seen that, compared with the linear swelling curve of NaeMt in water, the linear swelling rates of NaeMt in ANS-1 solutions were notably lower, with higher concentrations yielding lower linear swelling rates. After testing for 24 h, the linear swelling rate of NaeMt in water reached 140.63%, while the linear swelling rate of NaeMt in

2.3.3. Fourier transforms infrared spectroscopy (FT-IR) 2 g ANS-1 was added to 400 mL dispersion of 2 wt% NaeMt and stirred for 6 h to reach adsorption equilibrium. The mixture was transferred to a GGS42-type high-temperature and high-pressure filtration apparatus (Qingdao Tongchun Machinery Petroleum instrument 3

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Fig. 2. Linear swelling curves of NaeMt in water and ANS-1 solutions with different concentrations.

Fig. 4. Shale cutting recoveries of water and ANS-1 solutions with different concentrations.

0.1% ANS-1 was only 68.85%, demonstrating the good inhibiting effect of ANS-1 as a shale inhibitor on the hydration swelling of water-sensitive clay minerals. When the concentration of ANS-1 in the testing solution was increased to 0.5%, the linear swelling rate of NaeMt was further reduced to 29.24%. Therefore, we can conclude that a strong inhibition performance was obtained with ANS-1. To investigate the advantages of ANS-1 in terms of inhibition performance at high temperature, linear swelling tests were performed at different temperatures in different inhibitor solutions. Fig. 3 shows the linear swelling rates of NaeMt in different inhibitor solutions at different temperatures after testing for 16 h. With an increase in temperature, the linear swelling rate of NaeMt in different inhibitor solutions gradually increased, which was mainly because high temperature promoted the hydration swelling of NaeMt. In the test temperature range from 20 to 160 °C, the linear swelling rate of NaeMt in 0.5% ANS-1 was always at the lowest level and was less affected by the temperature. When the temperature was 20 °C, the linear swelling rate of NaeMt in 0.5% ANS-1 was 29.22%, which was slightly lower than the linear swelling rate of NaeMt in 7.0% KCl, 3.0% HCOOK and in 0.5% Ultrahib. When the temperature was increased to 160 °C, the linear swelling rate of NaeMt in 0.5% ANS-1 increased to 62.52%, while the linear swelling rate of NaeMt in 7.0% KCl, 3.0% HCOOK, and

0.5% Ultrahib increased to 115.36%, 108.24%, and 147.04%, respectively. Hence, at high temperatures, in comparison with the other inhibitors, the ability of ANS-1 to inhibit hydration swelling of NaeMt was more stable. The high-temperature resistance of ANS-1 was related to the interaction between inhibitor molecules and clay, which will be discussed in the following section. 3.1.2. Cutting dispersion test The shale cutting recoveries of water and ANS-1 solutions with different concentrations after hot rolling aging at 100 °C for 16 h are presented in Fig. 4. Compared to the shale cutting recovery in water (17.23%), the shale cutting recovery in ANS-1 solutions improved significantly. When the concentration of ANS-1 in solution was 0.1%, the shale cutting recovery reached 54.36%, which was 37.13% higher than that in water. As the concentration of ANS-1 in the solution increased, the shale cutting recovery gradually increased. When the concentration of ANS-1 in solution increased to 0.5%, the shale cutting recovery reached 81.45%. The temperature resistance of shale inhibitors plays a key role in wellbore stability, and it is also an important factor affecting the application range of shale inhibitors. Therefore, it is necessary to study the ability of shale inhibitors to inhibit hydration and dispersion. The shale cutting recoveries of different inhibitor solutions at different hot rolling aging temperatures are presented in Fig. 5. With the increase of hot rolling aging temperature, the shale cutting recoveries decreased gradually because high temperature prompts hydration and dispersion of shale cuttings. The shale cutting recovery of 0.5% ANS-1 was significantly higher than that of 7.0% KCl, 3.0% HCOOK, and 0.5% Ultrahib in the range of 60 to 160 °C. When the aging temperature was 60 °C, the shale cutting recoveries of 0.5% ANS-1, 7.0% KCl, 3.0% HCOOK, and 0.5% Ultrahib were 88.63%, 73.65%, 70.58%, and 85.36% respectively, indicating that ANS-1 had a strong but not obvious ability to inhibit hydration and dispersion of shale cuttings. When the temperature increased to 160 °C, the shale cutting recoveries of 0.5% ANS-1, 7.0% KCl, 3.0% HCOOK, and 0.5% Ultrahib were 56.75%, 38.97%, 40.21%, and 17.53% respectively, indicating that ANS-1 could still effectively inhibit hydration and dispersion of shale cuttings at high temperature. Therefore, we can conclude that the interaction between ANS-1 and shale cuttings remains relatively stable at high temperature. 3.1.3. Bentonite inhibition test The YPs of a series of water and inhibitor solutions with different concentrations were measured after hot rolling aging at 60 °C for 16 h. As shown in Fig. 6, for the control sample without any inhibitor, the YP

Fig. 3. Effect of temperature on linear swelling rate of NaeMt in different inhibitor solutions. 4

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Fig. 5. Shale cutting recoveries for water and inhibitor solutions at different hot rolling aging temperatures.

investigate the temperature resistance of inhibitors. The YP of 7.0% KCl, 3.0% HCOOK, 0.5% Ultrahib, and 0.5% ANS-1 as testing solutions were measured after hot rolling aging at different temperatures when the NaeMt concentration was set to 15 wt%. As can be seen from Fig. 7, compared with 7.0% KCl, 3.0% HCOOK, and 0.5% Ultrahib testing solutions, 0.5% ANS-1 solution can inhibit the trend of increasing YP with increasing temperature, indicating that ANS-1 more effectively inhibits hydration and dispersion of water-sensitive clay minerals. According to the above results, we can conclude that ANS-1 can bind the water-sensitive clay minerals with a lamellar structure in the testing solution together at high temperature, which prevents a three-

increased greatly after addition of NaeMt. When the concentration of NaeMt reached 20 wt%, the control sample without any inhibitor was too viscous and had exceeded the detection range of the rotating viscometer. However, the testing solutions containing inhibitor inhibit the trend effectively such that the YP of the testing solution increased with the increase of NaeMt concentration, indicating that inhibitor is effective in inhibiting hydration and dispersion of water-sensitive clay minerals. Higher concentrations had a stronger inhibitory effect, conforming to the performance expression rule of conventional inhibitors. As temperature is one of the important factors affecting hydration and dispersion of water-sensitive clay minerals, it is necessary to

Fig. 6. Bentonite inhibition test comparing the YP of different inhibitors: (a)KCl; (b)HCOOK; (c)Ultrahib; (d)ANS-1. 5

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drilling fluid properties and wellbore stability in water-sensitive formations. The inhibitive property of ANS-1 and conventional inhibitors at high temperature was further assessed by mud pellet disintegration tests. Fig. 9 shows the morphologies of mud pellets in inhibitor solutions after shaking at temperatures from 60 to 160 °C. Especially in 7.0% KCl and 3.0% HCOOK, the disintegration of mud pellets in different inhibitor solutions was particularly prominent, indicating that high temperature can promote hydration of water-sensitive clay minerals. In comparison, the integrity of the mud pellets in 0.5% Ultrahib and 0.5% ANS-1 was good relatively. In the range of 60 to 100 °C, the contour of the mud pellets soaked in 0.5% Ultrahib and 0.5% ANS-1 was still clear, and the core part of the pellets exhibited no obvious disintegration. When the temperature rose to 120 °C, the edges of the mud pellet in 0.5% Ultrahib became blurred and cracks began to appear in the core, indicating that Ultrahib had failed to effectively prevent water molecules from invading into the mud pellet. However, the mud pellet in 0.5% ANS-1 maintained a perfect appearance. It was not until the temperature was increased to 140 °C that the outer edge of the pellet in 0.5% ANS-1 began to blur, indicating that disintegration had begun to occur. At this temperature, the mud pellet had disintegrated in 0.5% Ultrahib, indicating that Ultrahib had failed to completely prevent the hydration of water-sensitive clay minerals. When the temperature rose to 160 °C, the core part of the mud pellet in 0.5% ANS-1 exhibited obvious signs of hydration, which was consistent with the results of the cutting dispersion tests. According to the above appearance changes of the mud pellets at different temperatures, compared with conventional inhibitors, ANS-1 can more effectively maintain the integrity of rock cuttings composed of water-sensitive clay minerals at high temperatures, which is beneficial for using solid control equipment to remove shale cuttings from clay-rich shale formations in drilling engineering. As a low molecular weight inhibitor, ANS-1 can firmly adsorbed on the surface of the mud pellet, which is similar to the surface modification of inorganic mineral materials by silane coupling agent reported in the literature (Sayilkan et al., 2004; Yurhan et al., 2008; Duarte-Silva et al., 2014; Varadwaj et al., 2016). The long carbon chains distributed in the ANS-1 molecular have significant hydrophobicity, which can transform the surface of the mud pellet from hydrophilic to hydrophobic. This is equivalent to the formation of a hydrophobic film on the surface of the mud pellet, which is very effective in preventing water molecules from invading into the mud pellet.

Fig. 7. Effect of temperature on YP of different inhibitors in the bentonite inhibition test.

dimensional network structure from being formed by the bridging of water-sensitive clay minerals. This is significant for maintaining the stability of the rheological properties of water-based drilling fluids in the water-sensitive formation in deep wells. 3.1.4. Mud pellet disintegration test The disintegration morphology of a mud pellet in ANS-1 solutions with different concentrations at room temperature is illustrated in Fig. 8. The overall structure of the mud pellet in water has disappeared, and it had been dispersed in the water and could not be recognized, indicating that the mud pellet had been hydrated fully in water and disintegrated completely. The overall structure of the mud pellet could be maintained to a certain extent. The higher the ANS-1 concentration was, the clearer the contour of the mud pellet was, indicating that ANS1 as a shale inhibitor was effective in improving the integrity of the mud pellet. The results revealed that ANS-1 can effectively prevent water molecules from invading into the interior of the mud pellet, which is beneficial to preventing hydration of fresh shale cuttings from water-sensitive formations in drilling engineering. Therefore, we can conclude that ANS-1 plays an active role in maintaining water-based

Fig. 8. Status of mud pellets immersed in water and ANS-1 solutions. 6

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Fig. 9. Status of mud pellets immersed in inhibitor solutions after shaking at different temperatures.

3.1.5. Rheological The rheological properties of water-based drilling fluid with 5 wt% NaeMt were measured before and after hot rolling aging at 100 °C for 16 h. As shown in Table 2, with concentration increasing, AV, PV and YP of water-based drilling fluid with 5 wt% NaeMt increased, but the increasing trend is not significant. This is mainly due to the small molecular weight of ANS-1, which is not enough to have a great impact on the rheological properties of drilling fluid. Compared with the values before hot rolling aging tests, the rheological parameters of water-based drilling fluid did not change significantly, showing good rheological stability. As shown in Table 3, the rheological parameters of 0.5% ANS-1 in water-based drilling fluid with 5 wt% NaeMt were presented after hot rolling aging tests at different temperatures for 16 h. When the hot rolling aging temperature was lower than 140 °C, the AV, PV and YP of water-based drilling fluid decreased slowly as the temperature increased. As the hot rolling aging temperature continued to rise to 180 °C, the rheological parameters of water-based drilling fluid showed a cliff fall, which was because the high temperature destroys the

Table 3 Rheological properties of ANS-1in water-based drilling fluid with 5.0% NaeMt after hot rolling aging tests at different temperatures. Temperature (°C)

AV (mPa·s)

PV (mPa·s)

YP (Pa)

60 80 100 120 140 160 180

12.0 10.5 8.0 7.5 7.5 7.0 2.0

8.0 8.0 6.0 6.0 6.0 6.0 2.0

4.0 2.5 2.0 1.5 1.5 1.0 0

All rheological parameters were measured at 20 ± 0.5 °C.

colloidal stability of water-based drilling fluid. 3.2. Mechanism analysis 3.2.1. XRD The variations of XRD patterns of Na-Mt/ANS-1 hybrids with

Table 2 Rheological properties of ANS-1 in water-based drilling fluid with 5.0% NaeMt before and after hot rolling aging tests. Concentration (%)

0 0.10 0.20 0.30 0.40 0.50

Before

After

AV(mPa·s)

PV(mPa·s)

YP(Pa)

AV(mPa·s)

PV(mPa·s)

YP(Pa)

5.5 6.5 6.5 7.0 7.5 8.0

4.0 4.5 4.5 5.0 5.5 5.5

1.5 2.0 2.0 2.0 2.0 2.5

5.0 6.5 6.5 6.5 7.5 8.0

4.0 4.5 4.5 4.5 5.5 6.0

1.0 2.0 2.0 2.0 2.0 2.0

All rheological parameters were measured at 20 ± 0.5 °C. 7

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Fig. 11. XRD patterns of Na-Mt/ANS-1 hybrids after hot rolling aging at different temperatures.

Fig. 10. XRD patterns of pristine NaeMt and Na-Mt/ANS-1 hybrids with different ANS-1 concentrations.

1.32, 1.39, and 1.82 nm, respectively, showing that the interlayer spacing increases gradually with the increase of temperature. Obviously, when the temperature reached 160 °C, the interlayer spacing of NaeMt (1.82 nm) was close to that of NaeMt (1.85 nm) without any inhibitor at room temperature, indicating that ANS-1 can no longer effectively inhibit hydration swelling of water-sensitive clay minerals at 160 °C. According to the above experimental results, it can be inferred that ANS-1 can be embedded into the lamellar structure of water-sensitive clay minerals and bind the adjacent lamellar structures together firmly, thus effectively preventing water molecules in water-based drilling fluid from invading the lamellar structure of water-sensitive clay minerals and causing hydration swelling. ANS-1 has a resistance of 140 °C, which was significantly stronger than that of polyamine inhibitors.

different ANS-1 concentrations in comparison with that of pristine NaeMt are presented in Fig. 10. For pristine NaeMt, the XRD pattern displayed interlayer spacing of 1.18 nm, corresponding to a monolayer hydration stage. The NaeMt swelled naturally in the absence of inhibitor in the water, and its interlayer spacing increased to 1.85 nm. The modification of NaeMt with ANS-1 effectively reduced the interlayer spacing of NaeMt, indicating that the degree of hydration of NaeMt was reduced. When the concentration of ANS-1 was 0.1%, the interlayer spacing of NaeMt decreased to 1.58 nm. The interlayer spacing of NaeMt continued to decrease with increasing concentration of ANS-1. When the concentration of ANS-1 was increased to 0.4%, the interlayer spacing of NaeMt decreased to 1.28 nm. When the concentration of ANS-1 was increased further, the interlayer spacing of NaeMt remained almost constant as a consequence of saturation adsorption of ANS-1. As one of the important factors affecting the hydration of watersensitive clay minerals, the influence of temperature on interlayer spacing of NaeMt is obvious. Fig. 11 presents the XRD patterns of NaMt/ANS-1 hybrids with 0.5% ANS-1 after hot rolling aging at different temperatures for 30 min. When the temperature was 60, 80, 100, 120, 140, and 160 °C, the interlayer spacing of NaeMt was 1.30, 1.30, 1.31,

3.2.2. Adsorption As with most other drilling fluid treatment agents, the desorption of inhibitors on water-sensitive clay minerals is an important reason for reducing their effectiveness at high temperature. Therefore, the determination of the adsorption of ANS-1 on water-sensitive clay minerals at high temperature has profound significance for revealing the 8

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Fig. 14. FT-IR spectra of NaeMt and Na-Mt/ANS-1 hybrid. Fig. 12. Dynamic adsorption curves for ANS-1.

According to Silva et al. (2011) and Lv et al. (2014), the hydroxyl group on the clay surface appears about 3600 to 3630 cm−1. At around 3602 cm−1, the characteristic stretching vibration of surface νsSi-OH and νsAl-OH was found. The FT-IR spectrum of NaeMt was a characterized by double bond stretching vibration at 1092 cm −1 and 1035 cm−1 which could be assigned to νsSi-O-Si. The band due to stretching vibration at 916 cm−1 corresponded to δAl-OH. The band due to bending vibration at 516 cm−1 corresponded to δSi-O-Si. This is consistent with the previously reported absorption peaks assigned to the characteristic groups of clay (Shanmugharaj et al., 2006; Park et al., 2009; Khosravi and Eslami-Farsani, 2016). In comparison with the spectrum of Na-Mt/ANS-1 hybrid，the stretching vibration (1092 and 1035 cm−1) of νsSi-O-Si and the bending vibration (516 cm−1) of δSi-O-Si were still significant. In addition, absorption peaks, ascribed to the CeH asymmetrical and symmetrical stretching vibrations of the methyl (2956 and 2874 cm−1) and the methylene (2920 and 2852 cm−1) of ANS-1 appeared. The asymmetric and symmetric bending vibration assigned to methyl at 1456 and 1376 cm−1, respectively, further proved the existence of ANS-1. The area under the broad band corresponding to amino at 3446 cm−1 increased in intensity. Obviously, the strength of the bending vibration peak belonging to δAl-OH decreased at 916 cm−1. Similar results have been reported in previous work on silane coupling agent modified clays (Herrera et al., 2005; Hao et al., 2017). Since the FT-IR spectrum of NaeMt and Na-Mt/ANS-1 hybrid were measured under the same conditions, this meant that the number of Al-OH in Na-Mt/ANS-1 hybrid decreased significantly. The disappearance of signal at 3602 cm−1 t corresponding to νsSi-OH and νsAl-OH together with the appearance of signals in the aliphatic region argued for the covalent attachment of the ANS-1 molecules to the clay surfaces via Si-O-Si bond formation.

mechanism of ANS-1 as a shale inhibitor at high temperature. The dynamic adsorption curves for ANS-1 in Na-Mt-based drilling fluid at 25 °C are shown in Fig. 12. The adsorption reaction of ANS-1 reached equilibrium after 60 min, and the equilibrium-adsorbed amounts were 54.49 mg/g clay particle. Fig. 13 shows the adsorbed amount of ANS-1 at the same high temperature after aging for 2 h at different temperatures (from 60 to 160 °C). With the increase of temperature, the adsorption amount of ANS-1 on NaeMt decreased gradually. When the temperature was 160 °C, the adsorbed amount of ANS-1 was 7.28 mg/g clay particle. The results demonstrate that ANS-1 exhibited obvious desorption on NaeMt above 140 °C, which is consistent with the good inhibitory ability of ANS-1 within 140 °C shown in the above studies. It can be inferred from the influence of temperature on the adsorbed amount that the force between ANS-1 and NaeMt is the valence bond force with stronger temperature resistance; that is, ANS-1 has a chemical adsorption on NaeMt. 3.2.3. FT-IR The FT-IR spectrum of NaeMt and Na-Mt/ANS-1 hybrid is shown in Fig. 14. The spectrum of NaeMt exhibited two bands due to the presence of physisorbed water, namely the νOH stretching vibration at around 3446 cm−1 and δOH deformation band at 1633 cm−1.

3.2.4. Contact angle The variation of the contact angle of water and ANS-1 modified NaeMt after hot rolling aging at different temperatures is depicted in Fig. 15. After hot rolling aging at 60 °C, the contact angle of water was 26.62° measured on NaeMt film, demonstrating a hydrophilic property. The higher the concentration of ANS-1 was, the larger the contact angle of water on NaeMt film. When the concentration of ANS-1 reached 0.5%, the contact angle for water was as high as 80.16°, close to that of 90°. The more hydrophobic the clay surface, the lower the affinity between clay and water, and the lower the degree of hydration of clay in water-based drilling fluids, which is beneficial for maintaining the stability of water-sensitive clay minerals. At higher hot rolling aging temperature, the contact angle becomes smaller and the affinity between clay and water becomes stronger. When the hot rolling aging temperature reached 160 °C, the difference

Fig. 13. Effect of temperature on adsorbed amount of ANS-1. 9

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NaeMt was −36.24 mV, which was equivalent to the zeta potential of NaeMt in water after hot rolling aging at 60 °C for 16 h, indicating that ANS-1 had excellent adsorption at high temperature. After adsorption, the surface of NaeMt was covered with a hydrophobic film, thus resulting in shielding effect. The shielding can decrease the thickness of the electrical double layer of NaeMt, thus making NaeMt had lower mobility. At the same temperature, the higher the concentration of ANS-1, the more significant the shielding effect on NaeMt surface, and the smaller the thickness of the electrical double layer, resulting in the lower the absolute value of zeta potential of NaeMt particles. 3.2.6. TEM The dispersion state of NaeMt in water and in ANS-1 solutions can be demonstrated by TEM visually. As shown in Figs. 17(a) and (b), NaeMt presented a typical lamellar structure in both water and ANS-1 solutions, but the lamellar structure of NaeMt in ANS-1 solutions was relatively thick. As seen in Fig. 17(c), after aging at 140 °C for 16 h, the lamellar structures of NaeMt in the ANS-1 solutions attracted each other and bound together without obvious dispersion, indicating that ANS-1 could enter the lamellar structures of clay and bind the adjacent lamellar structures together, which played a positive role in inhibiting hydration and dispersion of clay. As seen in Fig. 17(d), after aging for 16 h at 160 °C, NaeMt did not present lamellar structure in ANS-1 solutions, but the particles were finer and aggregated together to form a larger structure, indicating that NaeMt had undergone obvious and irreversible hydration dispersion.

Fig. 15. Contact angles of water and ANS-1-modified NaeMt after hot rolling aging at different temperatures.

in the contact angle of water on NaeMt film modified with ANS-1 at different concentrations decreased significantly, indicating that ANS-1 could not effectively reduce the affinity of clay and water, which was mainly due to the adsorption of ANS-1 on the surface of the clay.

3.2.7. Mechanism investigation From the results obtained in this study and those available in the literature, a probable inhibition mechanism by which ANS-1 prevents the hydration of water-sensitive clay minerals would be expected to emerge. Fig. 18 shows a schematic of the ANS-1 adsorption process on a clay-rich shale formation during drilling. During drilling, ANS-1 molecules dispersed in the drilling fluid are distributed on the borehole wall and cutting surface composed of water-sensitive clay minerals by adsorption. The presence of hydrophobic groups distributed in the ANS-1 molecules changes the hydrophilicity of the borehole wall and cutting surface, increases the resistance to combination of water molecules and water-sensitive clay minerals, and slows the hydration process of the water-sensitive clay minerals, which plays a positive role in maintaining the stability of the borehole wall and inhibiting hydration and dispersion of cuttings. Microscopically, ANS-1 not only adsorbs on the outer surface of the lamellar structure of water-sensitive clay minerals but also intercalates into the interlayer of clay. As shown in Fig. 19, as ANS-1 intercalates into the interlayer of clay, not only does it occupy the adsorption site of water molecules, but also the hydrophobic groups in ANS-1 occupy the interlayer channel, preventing water molecules in the aqueous phase from entering the space between lamellar structures, thus inhibiting the hydration swelling of water-sensitive clay minerals. The adsorption modes between ANS-1 and clay include physical adsorption and chemical adsorption. The amine groups distributed in the ANS-1 molecule can be physically adsorbed to the clay by sharing hydrogen bonds, which is the same as the adsorption mode of conventional amine inhibitors. In addition, Si–OCH2CH3 groups in the ANS-1 molecule are converted into Si–OH groups under alkaline conditions. Si–O–Si groups are formed by condensation polymerization of Si–OH groups present in the ANS-1 molecule and Si–OH groups distributed on the surface of the lamellar structures of clay. That is, chemical adsorption of ANS-1 on clay minerals occurs by covalent bonding, which is equivalent to the formation of a strongly adsorbed molecular film on the surface of the lamellar structures of clay. The bond energy of SieO bonds is as high as 460 kJ/mol, and hence it is difficult to break SieO bonds, which thus increases the adsorption capacity for ANS-1 at high temperatures. As a poly-amine-modified polyether polyols shale inhibitor, Utrahib is adsorbed to clay by hydrogen bonding (Qiu et al.,

3.2.5. Zeta potential The zeta potentials of NaeMt particles dispersed in water and ANS1 solutions with different concentrations were presented in Fig. 16. The zeta potential of NaeMt in water was −36.12 mV after hot rolling aging at 60 °C for 16 h, indicating that the dispersion is stable. The adsorption of ANS-1 changed the zeta potential in absolute value to different degrees with the increase of concentration. The higher the concentration of ANS-1, the greater the adsorption, and the smaller the absolute value of zeta potential of NaeMt in the dispersion, indicating the weaker dispersing ability. When the concentration of ANS-1 reached 0.5%, the zeta potential of NaeMt in the dispersion was −20.36 mV after hot rolling aging at 60 °C for 16 h. High temperature promoted the hydration and dispersion of NaeMt, thereby increasing the absolute value of zeta potential of NaeMt. Although ANS-1 could not completely hinder the hydration and dispersion of NaeMt at high temperature, it could effectively hinder the hydration and dispersion of NaeMt. After hot rolling aging at 160 °C for 16 h, the zeta potential of

Fig. 16. Zeta potential of NaeMt in water and ANS-1 solutions after hot rolling aging at different temperatures. 10

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Fig. 17. TEM images of NaeMt in water (a) and in ANS-1 solutions at (b) room temperature, (c) 140 °C and 16 h, and (d) 160 °C and 16 h.

high temperature will increase the interlayer spacing between adjacent clay lamellar structures to a certain extent, which weakens the electrostatic adsorption and finally weakens the inhibition performance. The adsorption of ANS-1 to the lamellar structure of clay is achieved through covalent bonds and the adsorption strength and desorption of inhibitor molecules are less affected by temperature. Therefore, ANS-1 can still inhibit hydration and dispersion of shale at high temperatures.

2011). This type of adsorption belongs to the physical adsorption with weak binding force. With the increase of temperature, the desorption rate between Utrahib and clay increases gradually, thus reducing the inhibition performance of Utrahib. Potassium ions in KCl and HCOOK are intercalated into the interlayer of clay, and the hydration swelling and dispersion of clay are prevented by the electrostatic adsorption between potassium ions and the lamellar structure of clay. The effect of

Fig. 18. Schematic of ANS-1 adsorption process on the clay-rich shale formation during drilling. 11

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Fig. 19. Conceptual illustration showing the interaction between ANS-1 and the lamellar structure of clay.

4. Conclusions

References

In this work, ANS-1 was introduced and its inhibitory performance was investigated. Based on the obtained research results, the following conclusions can be drawn: ANS-1 can effectively inhibit hydration swelling of water-sensitive clay minerals, hydration and dispersion of shale cuttings, and slurry formation, as well as the collapse of mud blocks in drilling fluids. Compared with the conventional inhibitors KCl, HCOOK, and Ultrahib, ANS-1 has the ability to resist temperature up to 140 °C, exhibiting a strong temperature resistance. Mechanism analysis showed that, on the one hand, the surface of clay with adsorbed ANS-1 exhibited altered surface wettability, inhibiting hydration and dispersion of the borehole wall and cuttings. On the other hand, ANS-1 can intercalate into the interlayer of clay, occupying the adsorption site of water molecules, with its hydrophobic groups occupying the interlayer channel, inhibiting the hydration swelling of clay. The introduction of siloxane groups in the molecular chain of ANS-1 can effectively improve the adsorption capacity of ANS1 in clay, so that ANS-1 can still maintain stable inhibition performance at high temperature. On the other side, the mechanism ANS-1 as a shale inhibitor needs further research. In particular, more evidences need to be explored to prove that the interaction between ANS-1 and clay minerals is through covalent bonds. The next work is in progress.

An, Y.X., Jiang, G.C., Ren, Y.J., Zhang, L.Y., Qi, Y.R., Ge, Q.Y., 2015. An environmental friendly and biodegradable shale inhibitor based on chitosan quaternary ammonium salt. J. Pet. Sci. Eng. 135, 253–260. Balaban, R.C., Vidal, E.L.F., Borges, M.R., 2015. Design of experiments to evaluate clay swelling inhibition by different combinations of organic compounds and inorganic salts for application in water base drilling fluids. Appl. Clay Sci. 105–106, 124–130. Billingham, J., Breen, C., Yarwood, J., 1997. Adsorption of polyamine, polacrylic acid and polyethylene glycol on montmorillonite: an in situ study using ATR-FTIR. Vib. Spectrosc. 14 (1), 19–34. Cescon, L. dos S., Quartarone, P., Ribeiro, S.P. da S., Nascimento, R.S.V., 2018. Cationic starch derivatives as reactive shale inhibitors for water-based drilling fluid. J. Appl. Polym. Sci. 135 (33), 46621–46632. Chen, G., Yan, J., Li, L.L., Zhang, J., Gu, X.F., Song, H., 2017. Preparation and performance of amine-tartaric salt as potential clay swelling inhibitor. Appl. Clay Sci. 138, 12–16. Chu, Q., Luo, P.Y., Zhao, Q.F., Feng, J.X., Kuang, X.B., Wang, D.L., 2013. Application of a new family of organosilicon quadripolymer as a fluid loss additive for drilling fluid at high temperature. J. Appl. Polym. Sci. 128 (1), 28–40. Chu, Q., Li, T., Liu, K.X., Li, Z.J., Song, Z.H., Xue, Y.Z., 2018. Determination of adsorption properties of organic additives for drilling fluids. CN 105277657. Duarte-Silva, R., Villa-García, M.A., Rendueles, M., Díaz, M., 2014. Sturctural, textural and protein adsorption proterties of kaolinite and surface modified kanlinite adsorbents. Appl. Clay Sci. 90, 73–80. Fadairo, A.A., Adeyemi, G.A., Ameloko, A., Ogidigbo, E., Airende, O., 2012. Environmental impact evaluation of a safe drilling mud. In: SPE Middle East Health, Safety, Security, and Environment Conference and Exhibition, 2–4 April, Abu Dhabi, UAE, (SPE 152865–MS). Ferreira, C.C., Teixeira, G.T., Lachter, E.R., Nascimento, R.S.V., 2016. Partially hydrophobized hyperbranched polyglycerols as non-ionic reactive shale inhibitors for water-based drilling fluids. Appl. Clay Sci. 132–133, 122–132. Fuh, G.F., Whitfill, D.L., Schuh, P.R., 1988. Use of borehole stability analysis for successful drilling of high-angle hole. In: SPE/IADC Drilling Conference, 28 February–2 March, Dallas, Texas, (SPE 17235–MS). Hao, N., Wu, J., Wan, J., Liu., Z., 2017. Morphology and mechanical properties of UVcurable castor oil-based waterborne polyurethane/organic montmorillonite nanocomposites. Plast. Rubber Compos. 46(8), 346–354. Herrera, N.N., Letoffe, J.M., Reymond, J.P., Bourgeat-Lami, E., 2005. Silylation of laponite clay particles with monofunctional and trifunctional vinyl alkoxysilanes. J. Mater. Chem. 15 (8), 863–871. Jain, R., Mahto, V., Sharma, V.P., 2015. Evaluation of polyacrylamide-grafted-polyethylene glycol/silica nanocomposite as potential additive in water based drilling mud for reactive shale formation. J. Nat. Gas Sci. Eng. 26, 526–537. Jiang, G.S., Ning, F.L., Zhang, L., Tu, Y.Z., 2011. Effect of agents on hydrate formation and low-temperature rheology of polyalcohol drilling fluid. J. Earth Sci. 22 (5), 652–657. Jiang, G.C., Qi, Y.R., An, Y.X., Huang, X.B., Ren, Y.J., 2016a. Polyethyleneimine as shale inhibitor in drilling fluid. Appl. Clay Sci. 127–128, 70–77. Jiang, G.C., Xuan, Y., Wu, X.Z., Chen, J.B., Ouyang, W., Luo, T.T., 2016b. Biomimetic polymer for stabilizing wellbore and method for preparation of the same and drilling fluid. US 611086. Khosravi, H., Eslami-Farsani, R., 2016. Enhanced mechanical properties of unidirectional basalt fiber/epoxy composites using silane-modified Na+-montmorillonite nanoclay. Polym. Test. 55, 135–142. Krumpfer, J.W., McCarthy, T.J., 2011. Rediscovering silicones: “unreactive” silicones react with inorganic surfaces. Langmuir 27 (18), 11514–11519.

Declaration of Competing Interest The authors declare that they have no known competing financialinterestsor personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments The authors cordially acknowledge the financial support of the National Key Technology Research and Development Program of China during the Thirteenth Five-year Plan Period (2016ZX05021004-002), National Science and Technology Major Project (2016ZX05061), Major Program of National Natural Science Foundation of China (51490650) and the Science and Technology Department Project of Sinopec (P16095). Our special thanks to the State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms Effective Development of China for providing the necessary facilities to carry out this research work. 12

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Shanmugharaj, A.M., Rhee, K.Y., Ryu, S.H., 2006. Influence of dispersing medium on grafting of aminopropyltriethoxysilane in swelling clay materials. J. Colloid Interf. Sci. 298 (2), 854–859. Silva, A.A., Dahmouche, K., Soares, B.G., 2011. Nanostructure and dynamic mechanical properties of silane-functionalized montmorillonite/epoxy nanocomposites. Appl. Clay Sci. 54, 151–158. Tan, C.P., Wu, B., Mody, F.K., Tare, U.A., 2002. Development and laboratory verification of high membrane efficiency water-based drilling fluids with oil-based drilling fluidlike performance in shale stabilization. In: SPE/ISRM Rock Mechanics Conference, 20–23 October, Irving, USA, (SPE 78159–MS). Varadwaj, G.B.B., Parida, K., Nyamori, V.O., 2016. Transforming inorganic layered montmorillonite into inorganic–organic hybrid materials for various applications: a brief overview. Inorg. Chem. Front. 3, 1100–1111. Villabona-Estupiñan, S., de Almeida Rodrigues, J., Nascimento, R.S.V., 2017. Understanding the clay-PEG (and hydrophobic derivatives) interactions and their effect on clay hydration and dispersion: a comparative study. Appl. Clay Sci. 143, 89–100. Villada, Y., Gallardo, F., Erdmann, E., Casis, N., Olivares, L., Estenoz, D., 2017. Functional characterization on colloidal suspensions containing xanthan gum (XGD) and polyanionic cellulose (PAC) used in drilling fluids for a shale formation. Appl. Clay Sci. 149, 59–66. Wang, L., Liu, S.Y., Wang, T., Sun, D.J., 2011. Effect of poly(oxypropylene)diamine adsorption on hydration and dispersion of montmorillonite particles in aqueous solution. Colloids Surf. A Physicochem. Eng. Asp. 381 (1–3), 41–47. Xie, G., Luo, P.Y., Deng, M.Y., Su, J.L., Wang, Z., Gong, R., Xie, J.N., Deng, S.J., Duan, Q., 2017. Intercalation behavior of branched polyethyleneimine into sodium bentonite and its effect on rheological properties. Appl. Clay Sci. 141, 95–103. Xu, Y.J., Yin, H., Yuan, S.F., Chen, Z.R., 2009. Film morphology and orientation of amino silicone adsorbed onto cellulose substrate. Appl. Surf. Sci. 255 (20), 8435–8442. Yang, L.L., Jiang, G.C., Shi, Y.W., Yang, X., 2017. Application of ionic liquid and polymeric ionic liquid as shale hydration inhibitors. Energ. Fuel. 31 (4), 4308–4317. Zeynali, M.E., 2012. Mechanical and physico-chemical aspects of wellbore stability during drilling operations. J. Pet. Sci. Eng. 82–83, 120–124. Zhang, S.F., Qiu, Z.S., Huang, W.A., 2016. Water-adsorption properties of Xiazijie montmorillonite intercalated with polyamine. Clay Miner. 50 (4), 537–548. Zhong, H.Y., Qiu, Z.S., Huang, W.A., Cao, J., 2011. Shale inhibitive properties of polyether diamine in water-based drilling fluid. J. Pet. Sci. Eng. 78 (2), 510–515. Zhong, H.Y., Qiu, Z.S., Huang, W.A., Cao, J., 2012. Poly (oxypropylene)-amidoamine modified bentonite as potential shale inhibitor in water-based drilling fluids. Appl. Clay Sci. 67–68, 36–43. Zhong, H.Y., Qiu, Z.S., Huang, W.A., Sun, D., Zhang, D.M., Cao, J., 2015. Synergistic stabilization of shale by a mixture of polyamidoamine dendrimers modified bentonite with various generations in water-based drilling fluid. Appl. Clay Sci. 114, 359–369.

Liu, S.Y., Mo, X.G., Zhang, C.G., Sun, D.J., Mu, C.H., 2004. Swelling inhibition by polyglycols in montmorillonite dispersions. J. Disper. Sci. Technol. 25 (1), 63–66. Liu, X.J., Liu, K., Guo, S.H., Liang, L.X., Luo, C., Guo, Q.P., 2014. Water-soluble acrylamide sulfonate copolymer for inhibiting shale hydration. Ind. Eng. Chem. Res. 53 (8), 2903–2910. Luo, Z.H., Wang, L.X., Yu, P.Z., Chen, Z.X., 2017. Experimental study on the application of an ionic liquid as a shale inhibitor and inhibitive mechanism. Appl. Clay Sci. 150, 267–274. Lv, B., Duan, X.B., Gao, D.G., Ma, J.Z., 2014. Preparation and properties of montmorillonite modified by silane coupling agent. J. Shanxi Uni. Sci. Tech. 32 (3), 9–14. Lv, K.H., Sun, J.S., Liu, J.P., 2018. Water-based drilling fluid for protecting high-permeability reservoirs, and preparation method and use thereof. US 809707. Ma, F.J., Pu, X.L., Wang, B., Li, J., Cao, C., 2017. Preparation and evaluation of polyampholyte inhibitor DAM. RSC Adv. 7, 49320–49328. Nguyen, V.X., Abousleiman, Y.N., Hoang, S., 2009. Analyses of wellbore instability in drilling through chemically active fractured-rock formations. SPE J. 14 (2) (SPE 105383). Ofei, T.N., Bendary, R.M.A., 2016. Formulating water-based muds for high temperature wellbores using potassium formate brine and synthetic polymers: a design of experiment approach. In: IADC/SPE Asia Pacific Drilling Technology Conference, 22–24 August, Singapore, (SPE 180520–MS). Park, S.J., Kim, B.J., Seo, D.I., Rhee, K.Y., Lyu, Y.Y., 2009. Effects of a silane treatment on the mechanical interfacial properties of montmorillonite/epoxy nanocomposites. Mater. Sci. Eng. 526 (1–2), 74–78. Patel, A., Stamatakis, E., Young, S., Friedheim, J., 2007. Advances in inhibitive waterbased drilling fluids-Can they replace oil-based muds? In: International Symposium on Oilfield Chemistry, 28 February-2 March, Houston, Texas, USA, (SPE 106476–MS). Peng, B., Luo, P.Y., Guo, W.Y., Yuan, Q.Y., 2013. Structure–property relationship of polyetheramines as clay-swelling inhibitors in water-based drilling fluids. J. Appl. Polym. Sci. 129 (3), 1074–1079. Qiu, Z.S., Zhong, H.Y., Huang, W.A., 2011. Properties and mechanism of a new polyamine shale inhibitor. Acta Petrol. Sin. 32 (4), 1074–1079. Qu, Y.Z., Lai, X.Q., Zou, L.F., Su, Y.N., 2009. Polyoxyalkyleneamine as shale inhibitor in water-based drilling fluids. Appl. Clay Sci. 44 (3–4), 265–268. Ren, Y.J., Wang, H.N., Ren, Z.C., Zhang, Y., Geng, Y.R., Wu, L.S., Pu, X.L., 2019. Adsorption of imidazolium-based ionic liquid on sodium bentonite and its effects on rheological and swelling behaviors. Appl. Clay Sci. 182, 105248. Sayilkan, H., Erdemoǧlu, S., Sener, S., Sayilkan, F., Akarsu, M., Erdemoǧlu, M., 2004. Surface modification of pyrophyllite with amino silane coupling agent for the removal of 4-nitrophenol from aqueous solutions. J. Colloid Interf. Sci. 275 (2), 530–538. Shadizadeh, S.R., Moslemizadeh, A., Dezaki, A.S., 2015. A novel nonionic surfactant for inhibiting shale hydration. Appl. Clay Sci. 118, 74–86.

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