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Some new developments for modelling the geological compaction of fine-grained sediments: introduction
Marineand PetroleumGeology ELSEVIER
Marine and Petroleum Geology 15 (1998) 105-I 08
Some new developments for modelling the geological compaction of fine-grained sediments : introduction Andrew C. AplirP*, Guy Vasseurb aFossil Fuels and Environmental Geochemistry Postgraduate Institute : NRG, University of Newcastle, Newcastle upon Tyne, NE1 7RU, U.K. b GBE, UMR CNRS-CIA42 W 5569. C.057. Universitk de Montpellier 2, 34095 Montpellier Cedex 5, France
Received 12 December 1996; revised 3 1 December 1997; accepted 5 January 1998
Abstract From 1992-1995 the European Union supported a programme of research entitled “Interdisciplinary Basin Studies”. One objective of the programme was to develop a better understanding of the compaction of fine-grained sediments. Some of the results of the research are presented in the subsequent four papers, which are introduced and summarised in this contribution. 0 1998 Elsevier Science Ltd. All rights reserved.
1. Background
Over the past seventy years a large body of work has accumulated concerning the compaction of fine-grained sediments (important examples include Terzhagi, 1925 ; Athy, 1930 ; Hedberg, 1936 ; Gibson, 1958 ; Parasnis, 1960; Roscoe and Burland, 1968 ; Skempton, 1970; Smith, 1971 ; Rieke and Chilingarian, 1974 ; Perrier and Quiblier, 1974; Magara, 1978 ; Jones and Addis, 1985 ; Burland, 1990 ; Audet and McConnell, 1992 ; Maltman, 1994). Much of the intellectual development has been achieved by those working within the realms of Soil Mechanics and Civil Engineering. Geological applications have commonly been based on the principles established in Soil Mechanics, the most obvious example being the common assumption that compaction is driven by changes in vertical effective stress (Terzhagi, 1925) and that time, temperature and chemical changes are of minor importance. Whilst it seems likely that the Terzhagi model is reasonably robust for sediments buried to less than 2 km (Skempton, 1970; Aplin et al., 1995), it is important to bear in mind the model’s potential limitations: firstly, that it was developed for sediments experiencing much lower levels of stress than those common in sedimentary basins; secondly, that it assumes vertical effective stress to be the sole driving force ; and thirdly, that it is a one dimensional model attempting to describe a three dimensional phenomenon.
*Corresponding 5431. SO264-8172/98 PII: SO264--8
author.
Tel.
: 0044 191 222 6852; fax: 0044 191 222
$19.00 ‘$2 1998 Elsevier Science Ltd. All rights reserved I72(98)00007 5
In many cases within sedimentary basins it may be sufficient to treat compaction as a one dimensional process. In some cases, however, for example where there is significant lateral tectonic stress, steeply dipping sediment bodies or strongly anisotropic sediments, a three dimensional approach is required. A full description of sediment compaction requires a three dimensional mechanical model which relates the deformation and stress tensors of the porous medium. With this information it would be possible to calculate stress fields within sedimentary sequences and assess the possibility of lateral deformation, differential compaction and failure. In the Civil Engineering literature, the most common mechanical models for soils and sediments, such as the CamClay model, are based on an elastoplastic rheology (e.g. Roscoe and Burland, 1968). However, except for the deformation of shallow sediments in accretionary prisms (Tom Chang et al., 1990), the use of such tensorial rheology for computing the full stress tensor at basin scale does not seem to have been tested so far. Sophisticated models and computer programs have been developed to describe the coupled mechanical, thermal and hydraulic evolution of sedimentary basins, following the work by Sharp and Domenico (1976), Yukler et al. (1978), Bethke (1985), Ungerer et al. (1990), Lerche (1990) and others. In these programs, the effect of compaction is generally accounted for by two basic relations : the first, mechanical relation links porosity $ to vertical effective stress, assuming only vertical deformation. The second, hydraulic relation links permeability to porosity during compaction. For the mechanical aspects, various empirical laws are
used. For example, Athy’s law (Athy, 1930) states that porosity decreases exponentially with increasing effective stress. In Soil Mechanics, another type of law was proposed in which the void ratio e (e = $/( 1 - 4)) is written as :
Here c* is a reference void ratio at a reference effective stress o’* and e and (r’ are the current values. For the hydraulic aspects, the compaction induced permeability variation can be related to porosity (or void ratio) according to a law somewhat similar to that shown below :
where k,, and c,, are the reference permeability and void ratio of the sediment, (1is the current void ratio and c an exponent factor. One of the major difficulties with these descriptions is assigning accurate values to these coefficients, especially to p, the compression coefficient of the sediment, and to c, the exponent relating permeability and porosity. The compression coefficient varies with detailed mudstone lithology (defined. for example, by grain size; Skempton, 1970; Burland, 1990; Aplin et al., 1995) and in one of the following papers it is shown that lithology is a pivotal relationships exhicontrol on the porosity : permeability bited by mudstones. Basin models come with a wide choice of porosity : permeability functions for ‘standard shales’ which span a permeability range of many orders of magnitude at a single porosity value. The situation is worse when one considers the lithological diversity of ‘shales’.
2. Forthcoming papers The four papers in this series are based on closely related work supported by the European Union’s Joule programme. The EU funded the Interdisciplinary Basin Studies programme, one of whose aims was to develop a fuller understanding of the compaction of fine-grained sediments. Some of the IBS work has been presented previously in Marine and Petroleum Geology (Volume 12). Three approaches to the problem were followed and are all represented in this volume. Firstly, Djeran-Maigre et al. describe the results of experimental, oedometric compaction of natural muds and mineralogically pure clays. These experiments were conducted in a novel oedometric cell designed to measure lateral stresses and permeability at vertical stresses up to 50 MPa. Furthermore, the samples were carefully characterised by Transmission Electron Microscopy both before and after loading, thus allowing the study of the evolution and linkage of the sediments’ macroscopic and microscopic properties with
increasing load. The results of the study confirm that the soil mechanics (‘Terzhagi’) approach to compaction is robust at geological stress levels and provides an important dataset describing the way that porosity, permeability, axial and radial thermal conductivity evolve with increasing vertical stress in exceptionally well characterised materials. A surprising result is the fact that pure clay samples are less deformable (larger void ratio or smaller compaction coefficient) than clays containing an appreciable coarse fraction. The mechanical behaviour appears to be related to the size of clay particles and to their organization in aggregates. The reorientation of clay particles during their compaction is observed directly and appears to explain qualitatively the increasing anisotropy of thermal conductivity measured on compacted kaolinite paste. Also, the measured permeabilities are generally different- up to two orders of magnitude different-- to those calculated by the Kozeny-Carman equation and a power law c’ with c from four to six seems relevant. In the second paper. Pouya et al. use Djeran-Maigre et al.‘s data to verify that the elasto-plastic Can~Clay model is an acceptable three dimensional mechanical model for fine-grained sediments subjected to geological stresses. Pouya et al. develop a methodology which allows the parameters within the Cam Clay model to be derived from an oedometric dataset which includes lateral stress measurements. An important result from the work of both Pouya et al. and Djeran-Maigre et al. is that the elastoplastic CamClay rheology, which was developed for civil engineering purposes. appears to be robust at vertical stress levels up to 50 MPa. This means that in principle, the commercially available computer models which utilise the Cam--Clay rheology and which are commonly used in civil engineering to describe sediment deformation, might be used to describe sediment deformation in sedimentary basins. Luo et al. have tested two such models, CESAR and FLAC. both of which allow the use of Cam- Clay elastoplastic rheology but which operate in numerically distinct ways. Neither proved to be wholly satisfactory as tools to describe sediment deformation on geological timescales. Although CESAR is able to account for coupled hydro-mechanical phenomena and is thus a potentially powerful basin modelling tool, the computing power which would be required to model relevant geological processes is currently prohibitive. FLAC was adapted to allow modelling on a geological timescale and is used to illustrate the potential importance of lateral deformation during the development of basin margins. However it was not possible to couple the hydraulic and mechanical phenomena. Luo et al. also develop a I-D, incremental mechanical model which is able to solve completely the hydro-mechanical problem with continued sedimentation. The model gives sensible results but has limited application since it
A.C. Aplin,
G. VusseurlMarine
and Petroleum
is unidimensional. Nevertheless, future work may generalise this mechanical model to two or three dimensions. The final paper by Yang and Aplin is more concerned with mudstone permeability than porosity. Mudstone permeability is a major unknown in basin modelling and published data range over three orders of magnitude at a single porosity value (Neuzil, 1994). A new permeability model is presented based on a size distribution of pores which flatten with increasing effective stress. Using measured pore size distributions, the model is used to show that porosity :permeability :effective stress relations in mudstones are highly influenced by lithology, defined in this case by a measure of grain size. If, as seems likely, permeability is a strong function of both porosity and lithology, then the definition of detailed mudstone lithology from wireline log data might allow a rapid assessment of mudstone permeability from wireline logs. The body of work in the following pages presents some new approaches to the way we might model deformation, loss of porosity and loss of permeability in sedimentary basins. Just as current modelling approaches are based on techniques developed by engineers, the future approaches described here are also based on techniques developed by civil engineers. The novelty is that experimental work has shown that the techniques are applicable to geological levels of stress and that, at least in principle, existing codes could be applied to geological settings. Three difficulties remain (at least!). Firstly, the development of adapted algorithms for geological boundary conditions and timescales. Secondly, the derivation of the parameters required to model what is a highly heterogeneous and disparate sediment type. And thirdly, current models are based on an elastoplastic rheology which does not account for effects related to time (‘creep’) or chemical effects such as pressure solution and mineral recrystallisation. These are known to be potentially important in carbonate sediments (e.g. Meyers, 1980) and may also be relevant to mudstones (Bjorlykke and Hoeg, 1997) since mudstones also undergo significant mineralogical changes during burial diagenesis (e.g. Hower et al., 1976). Some initial efforts have been made in this area; for example, Schneider et al. (1994) have proposed a more complex viscoplastic rheological model for fine-grained sediments which accounts for irreversible chemical processes such as pressure solution.
Acknowledgements
This work was supported by the IBS project (Interdisciplinary Basin Studies), part of the Joule research programme funded by the Commission of the European Communities (contract no. JOU2-CT-92-0110). Thanks to Mervyn Jones and an anonymous reviewer for their efforts on the manuscript.
Geo1og.v 15 (1998)
105- 108
107
References
Aplin, A. C., Yang, Y.. & Hansen, S. (1995).
Assessment of p, the compression coefficient of mudstones and its relationship to detailed lithology. Marine and Petroleum Geology, 12,955-963. Athy. L. F. (1930). Density, porosity and compaction of sedimentary rocks. Am. Assoc. Pet. Geol. BUN., 31, 241-287. Audet, D. M.. & McConnell, J. D. C. (1992). Forward modelling of porosity and pore pressure evolution in sedimentary basins. Basin Rrseurck,
4. 147 -162
Bethke C. M. (1985). A numerical model of compaction driven goundwater flow and heat transfer and its application to the paleohydrology of intracratonic sedimentary basins. J. G‘ro@z~:v. Rex.. YO. 6817-6828.
Bjarlykke, K.. & Hoeg. K. (1997). Effects of burial stresses. compaction and fluid flow in sedimentary Petrol.
GwI.,
diagenesis on basins. Mur.
14, 267-276
Burland. J. B. (1990). On the compressibility and shear strength of 40. 329-378. natural clays. GPo/&mique, Gibson. R. E. (1958). The progress of consolidation in a clay layer increasing in thickness with time. G‘Por~clrniyur. N. I7 I -I 81. Hedberg, H. D. (1936). Gravitational compaction of clays and shales. Am. J. Sci.. IN4, 241-287. Hower, J. E., Eslinger, E. V.. Hower, M. E.. & Perry. E. A. (1976). Mechanism of burial metamorphism of argillaceous sediments : I. Mineralogical and chemical evidence. G‘eol. Sot. An!. Bull.. 87. 725 737. Jones. M. E.. & Addis. M. A. (1985). On changes in porosity and volume during burial of argillaceous sediments. Mar. Pcrrol. Grol.. 2, 247-253. Lerche, 1. ( 1990). Brr.sr/t .4ncr/~~.ri.s.Quuntitcrti~ .Me/hodv. Vol. 12. San Diego, CA: Academic Press. Magara. K. (1978). Compaction and fluid migration; practical petroleum geology. L)c~~~c,lc)/)~?rc,rrr,s in Pcfrolc~unr .%irnc~e. 0. p. 3 I Y. Amsterdam: Elsevier. Maltman, A. ( 1994). ed.. Talc G~~oIoqi~~uI Drfbrmcrliorr
of’S~~c/in~c~nts. p.
362. London: Chapman and Hall. Meyers. W. E. (1980). Compaction in Mississippian limestones southwestern New Mexico. J. Sedim. Petrol.. 50. 457.-474. Neuzil. C. E. (1994). How permeable are clays and shales? M’u/. Rr.your. RPJ.. 30. l45m 50. Parasnis, D. S. (1960). The compaction of sediments and its bearing on some geophysical problems. Geopi~.r.s. J. R~F. As/ro~. Sot,.. 3, I-28. Perrier. R.. & Quiblier. J. (1974). Thickness changes m sedimentary layers during compaction history. AAPG Bull., 52, 57 ~65. Rieke, H. H., & Chilingarian. G. V. (1974). Con.vo/idutinn of’ Aryillucc~u.v Sedimcn~s.
~rc.clopr,~rnt.c.
itr S~,~linzc,tltolo,~~. Ih.
424.
New
York: Eisevier. Roscoe. K. H.. 8i Burland. J. B. (1968). On the gencrahsed stressstrain behaviour of wet clay. Engincvring P/u.\/ic,irJ, (pp. 535--609). Cambridge: Hetman Leckie. Schneider, F., Poitevin, J. L.. Wolf, S., & Faille, I. (1994). Modele de compaction Clastoplastique et viscoplastique pour simulateur de bassins sedimentaires. Rev. de I’lnsrimr Frcrqoi.t hr Pc/r.ole. 49. I4 I148. Sharp, J. M., & Domenico. A. (1976). Energy transport in thick seqences of compacting sediment. Geol. Sot,. Am. Bull., X7. 39&400. Skempton, A. W. (1970). The consolidation of clays by gravitational compaction. Q. J. Gcol. Sot. London. 125. 37341 I. Smith, J. E. (1971). The dynamics of shale compaction and evolution of pore pressures. Moth. Geol.. 3, 239-263. Terzhagi, K. (1925).Erdhuumecllanik uuf hodenpll~sikulisc,ilt~r Grundluge. p. 399. Leipzig: Deuticke. Tom Chang, T.. Lennon, G. P., Pamuksu. S., & Carson, B. (1990). A coupled fluid expulsion model of dewatering sediments. In R. H. Bennett. W. R. Bryant and M. H. Hulbert (Eds), Mic,rostruc/urc of Fine Gruitred .%dimet~ts (pp. 273 -280). Springer Verlag.
108
A.C. Aplin, G. VasseurjMarine and Petroleum Geology 15 (IWS)
Ungerer, P., Burrus, J., Doligez, B., Chenet, J. Y., & Be&, F. (1990). Basin evaluation by integrated two-dimensional modeling of heat transfer, fluid-flow, hydrocarbon generation and migration. Am. Assoc. Pet. Grol. Bull., 74, 309-355.
105-108
Yukler, M. A., Cornford, C., & Welte, D. H. (1978). One dimensional model to simulate geologic, hydrodynamic and thermodynamic development of a sedimentary basin. Grol. Rundsch., 67, 96C979.
Marine and Petroleum Geology 15 (1998) 105-I 08
Some new developments for modelling the geological compaction of fine-grained sediments : introduction Andrew C. AplirP*, Guy Vasseurb aFossil Fuels and Environmental Geochemistry Postgraduate Institute : NRG, University of Newcastle, Newcastle upon Tyne, NE1 7RU, U.K. b GBE, UMR CNRS-CIA42 W 5569. C.057. Universitk de Montpellier 2, 34095 Montpellier Cedex 5, France
Received 12 December 1996; revised 3 1 December 1997; accepted 5 January 1998
Abstract From 1992-1995 the European Union supported a programme of research entitled “Interdisciplinary Basin Studies”. One objective of the programme was to develop a better understanding of the compaction of fine-grained sediments. Some of the results of the research are presented in the subsequent four papers, which are introduced and summarised in this contribution. 0 1998 Elsevier Science Ltd. All rights reserved.
1. Background
Over the past seventy years a large body of work has accumulated concerning the compaction of fine-grained sediments (important examples include Terzhagi, 1925 ; Athy, 1930 ; Hedberg, 1936 ; Gibson, 1958 ; Parasnis, 1960; Roscoe and Burland, 1968 ; Skempton, 1970; Smith, 1971 ; Rieke and Chilingarian, 1974 ; Perrier and Quiblier, 1974; Magara, 1978 ; Jones and Addis, 1985 ; Burland, 1990 ; Audet and McConnell, 1992 ; Maltman, 1994). Much of the intellectual development has been achieved by those working within the realms of Soil Mechanics and Civil Engineering. Geological applications have commonly been based on the principles established in Soil Mechanics, the most obvious example being the common assumption that compaction is driven by changes in vertical effective stress (Terzhagi, 1925) and that time, temperature and chemical changes are of minor importance. Whilst it seems likely that the Terzhagi model is reasonably robust for sediments buried to less than 2 km (Skempton, 1970; Aplin et al., 1995), it is important to bear in mind the model’s potential limitations: firstly, that it was developed for sediments experiencing much lower levels of stress than those common in sedimentary basins; secondly, that it assumes vertical effective stress to be the sole driving force ; and thirdly, that it is a one dimensional model attempting to describe a three dimensional phenomenon.
*Corresponding 5431. SO264-8172/98 PII: SO264--8
author.
Tel.
: 0044 191 222 6852; fax: 0044 191 222
$19.00 ‘$2 1998 Elsevier Science Ltd. All rights reserved I72(98)00007 5
In many cases within sedimentary basins it may be sufficient to treat compaction as a one dimensional process. In some cases, however, for example where there is significant lateral tectonic stress, steeply dipping sediment bodies or strongly anisotropic sediments, a three dimensional approach is required. A full description of sediment compaction requires a three dimensional mechanical model which relates the deformation and stress tensors of the porous medium. With this information it would be possible to calculate stress fields within sedimentary sequences and assess the possibility of lateral deformation, differential compaction and failure. In the Civil Engineering literature, the most common mechanical models for soils and sediments, such as the CamClay model, are based on an elastoplastic rheology (e.g. Roscoe and Burland, 1968). However, except for the deformation of shallow sediments in accretionary prisms (Tom Chang et al., 1990), the use of such tensorial rheology for computing the full stress tensor at basin scale does not seem to have been tested so far. Sophisticated models and computer programs have been developed to describe the coupled mechanical, thermal and hydraulic evolution of sedimentary basins, following the work by Sharp and Domenico (1976), Yukler et al. (1978), Bethke (1985), Ungerer et al. (1990), Lerche (1990) and others. In these programs, the effect of compaction is generally accounted for by two basic relations : the first, mechanical relation links porosity $ to vertical effective stress, assuming only vertical deformation. The second, hydraulic relation links permeability to porosity during compaction. For the mechanical aspects, various empirical laws are
used. For example, Athy’s law (Athy, 1930) states that porosity decreases exponentially with increasing effective stress. In Soil Mechanics, another type of law was proposed in which the void ratio e (e = $/( 1 - 4)) is written as :
Here c* is a reference void ratio at a reference effective stress o’* and e and (r’ are the current values. For the hydraulic aspects, the compaction induced permeability variation can be related to porosity (or void ratio) according to a law somewhat similar to that shown below :
where k,, and c,, are the reference permeability and void ratio of the sediment, (1is the current void ratio and c an exponent factor. One of the major difficulties with these descriptions is assigning accurate values to these coefficients, especially to p, the compression coefficient of the sediment, and to c, the exponent relating permeability and porosity. The compression coefficient varies with detailed mudstone lithology (defined. for example, by grain size; Skempton, 1970; Burland, 1990; Aplin et al., 1995) and in one of the following papers it is shown that lithology is a pivotal relationships exhicontrol on the porosity : permeability bited by mudstones. Basin models come with a wide choice of porosity : permeability functions for ‘standard shales’ which span a permeability range of many orders of magnitude at a single porosity value. The situation is worse when one considers the lithological diversity of ‘shales’.
2. Forthcoming papers The four papers in this series are based on closely related work supported by the European Union’s Joule programme. The EU funded the Interdisciplinary Basin Studies programme, one of whose aims was to develop a fuller understanding of the compaction of fine-grained sediments. Some of the IBS work has been presented previously in Marine and Petroleum Geology (Volume 12). Three approaches to the problem were followed and are all represented in this volume. Firstly, Djeran-Maigre et al. describe the results of experimental, oedometric compaction of natural muds and mineralogically pure clays. These experiments were conducted in a novel oedometric cell designed to measure lateral stresses and permeability at vertical stresses up to 50 MPa. Furthermore, the samples were carefully characterised by Transmission Electron Microscopy both before and after loading, thus allowing the study of the evolution and linkage of the sediments’ macroscopic and microscopic properties with
increasing load. The results of the study confirm that the soil mechanics (‘Terzhagi’) approach to compaction is robust at geological stress levels and provides an important dataset describing the way that porosity, permeability, axial and radial thermal conductivity evolve with increasing vertical stress in exceptionally well characterised materials. A surprising result is the fact that pure clay samples are less deformable (larger void ratio or smaller compaction coefficient) than clays containing an appreciable coarse fraction. The mechanical behaviour appears to be related to the size of clay particles and to their organization in aggregates. The reorientation of clay particles during their compaction is observed directly and appears to explain qualitatively the increasing anisotropy of thermal conductivity measured on compacted kaolinite paste. Also, the measured permeabilities are generally different- up to two orders of magnitude different-- to those calculated by the Kozeny-Carman equation and a power law c’ with c from four to six seems relevant. In the second paper. Pouya et al. use Djeran-Maigre et al.‘s data to verify that the elasto-plastic Can~Clay model is an acceptable three dimensional mechanical model for fine-grained sediments subjected to geological stresses. Pouya et al. develop a methodology which allows the parameters within the Cam Clay model to be derived from an oedometric dataset which includes lateral stress measurements. An important result from the work of both Pouya et al. and Djeran-Maigre et al. is that the elastoplastic CamClay rheology, which was developed for civil engineering purposes. appears to be robust at vertical stress levels up to 50 MPa. This means that in principle, the commercially available computer models which utilise the Cam--Clay rheology and which are commonly used in civil engineering to describe sediment deformation, might be used to describe sediment deformation in sedimentary basins. Luo et al. have tested two such models, CESAR and FLAC. both of which allow the use of Cam- Clay elastoplastic rheology but which operate in numerically distinct ways. Neither proved to be wholly satisfactory as tools to describe sediment deformation on geological timescales. Although CESAR is able to account for coupled hydro-mechanical phenomena and is thus a potentially powerful basin modelling tool, the computing power which would be required to model relevant geological processes is currently prohibitive. FLAC was adapted to allow modelling on a geological timescale and is used to illustrate the potential importance of lateral deformation during the development of basin margins. However it was not possible to couple the hydraulic and mechanical phenomena. Luo et al. also develop a I-D, incremental mechanical model which is able to solve completely the hydro-mechanical problem with continued sedimentation. The model gives sensible results but has limited application since it
A.C. Aplin,
G. VusseurlMarine
and Petroleum
is unidimensional. Nevertheless, future work may generalise this mechanical model to two or three dimensions. The final paper by Yang and Aplin is more concerned with mudstone permeability than porosity. Mudstone permeability is a major unknown in basin modelling and published data range over three orders of magnitude at a single porosity value (Neuzil, 1994). A new permeability model is presented based on a size distribution of pores which flatten with increasing effective stress. Using measured pore size distributions, the model is used to show that porosity :permeability :effective stress relations in mudstones are highly influenced by lithology, defined in this case by a measure of grain size. If, as seems likely, permeability is a strong function of both porosity and lithology, then the definition of detailed mudstone lithology from wireline log data might allow a rapid assessment of mudstone permeability from wireline logs. The body of work in the following pages presents some new approaches to the way we might model deformation, loss of porosity and loss of permeability in sedimentary basins. Just as current modelling approaches are based on techniques developed by engineers, the future approaches described here are also based on techniques developed by civil engineers. The novelty is that experimental work has shown that the techniques are applicable to geological levels of stress and that, at least in principle, existing codes could be applied to geological settings. Three difficulties remain (at least!). Firstly, the development of adapted algorithms for geological boundary conditions and timescales. Secondly, the derivation of the parameters required to model what is a highly heterogeneous and disparate sediment type. And thirdly, current models are based on an elastoplastic rheology which does not account for effects related to time (‘creep’) or chemical effects such as pressure solution and mineral recrystallisation. These are known to be potentially important in carbonate sediments (e.g. Meyers, 1980) and may also be relevant to mudstones (Bjorlykke and Hoeg, 1997) since mudstones also undergo significant mineralogical changes during burial diagenesis (e.g. Hower et al., 1976). Some initial efforts have been made in this area; for example, Schneider et al. (1994) have proposed a more complex viscoplastic rheological model for fine-grained sediments which accounts for irreversible chemical processes such as pressure solution.
Acknowledgements
This work was supported by the IBS project (Interdisciplinary Basin Studies), part of the Joule research programme funded by the Commission of the European Communities (contract no. JOU2-CT-92-0110). Thanks to Mervyn Jones and an anonymous reviewer for their efforts on the manuscript.
Geo1og.v 15 (1998)
105- 108
107
References
Aplin, A. C., Yang, Y.. & Hansen, S. (1995).
Assessment of p, the compression coefficient of mudstones and its relationship to detailed lithology. Marine and Petroleum Geology, 12,955-963. Athy. L. F. (1930). Density, porosity and compaction of sedimentary rocks. Am. Assoc. Pet. Geol. BUN., 31, 241-287. Audet, D. M.. & McConnell, J. D. C. (1992). Forward modelling of porosity and pore pressure evolution in sedimentary basins. Basin Rrseurck,
4. 147 -162
Bethke C. M. (1985). A numerical model of compaction driven goundwater flow and heat transfer and its application to the paleohydrology of intracratonic sedimentary basins. J. G‘ro@z~:v. Rex.. YO. 6817-6828.
Bjarlykke, K.. & Hoeg. K. (1997). Effects of burial stresses. compaction and fluid flow in sedimentary Petrol.
GwI.,
diagenesis on basins. Mur.
14, 267-276
Burland. J. B. (1990). On the compressibility and shear strength of 40. 329-378. natural clays. GPo/&mique, Gibson. R. E. (1958). The progress of consolidation in a clay layer increasing in thickness with time. G‘Por~clrniyur. N. I7 I -I 81. Hedberg, H. D. (1936). Gravitational compaction of clays and shales. Am. J. Sci.. IN4, 241-287. Hower, J. E., Eslinger, E. V.. Hower, M. E.. & Perry. E. A. (1976). Mechanism of burial metamorphism of argillaceous sediments : I. Mineralogical and chemical evidence. G‘eol. Sot. An!. Bull.. 87. 725 737. Jones. M. E.. & Addis. M. A. (1985). On changes in porosity and volume during burial of argillaceous sediments. Mar. Pcrrol. Grol.. 2, 247-253. Lerche, 1. ( 1990). Brr.sr/t .4ncr/~~.ri.s.Quuntitcrti~ .Me/hodv. Vol. 12. San Diego, CA: Academic Press. Magara. K. (1978). Compaction and fluid migration; practical petroleum geology. L)c~~~c,lc)/)~?rc,rrr,s in Pcfrolc~unr .%irnc~e. 0. p. 3 I Y. Amsterdam: Elsevier. Maltman, A. ( 1994). ed.. Talc G~~oIoqi~~uI Drfbrmcrliorr
of’S~~c/in~c~nts. p.
362. London: Chapman and Hall. Meyers. W. E. (1980). Compaction in Mississippian limestones southwestern New Mexico. J. Sedim. Petrol.. 50. 457.-474. Neuzil. C. E. (1994). How permeable are clays and shales? M’u/. Rr.your. RPJ.. 30. l45m 50. Parasnis, D. S. (1960). The compaction of sediments and its bearing on some geophysical problems. Geopi~.r.s. J. R~F. As/ro~. Sot,.. 3, I-28. Perrier. R.. & Quiblier. J. (1974). Thickness changes m sedimentary layers during compaction history. AAPG Bull., 52, 57 ~65. Rieke, H. H., & Chilingarian. G. V. (1974). Con.vo/idutinn of’ Aryillucc~u.v Sedimcn~s.
~rc.clopr,~rnt.c.
itr S~,~linzc,tltolo,~~. Ih.
424.
New
York: Eisevier. Roscoe. K. H.. 8i Burland. J. B. (1968). On the gencrahsed stressstrain behaviour of wet clay. Engincvring P/u.\/ic,irJ, (pp. 535--609). Cambridge: Hetman Leckie. Schneider, F., Poitevin, J. L.. Wolf, S., & Faille, I. (1994). Modele de compaction Clastoplastique et viscoplastique pour simulateur de bassins sedimentaires. Rev. de I’lnsrimr Frcrqoi.t hr Pc/r.ole. 49. I4 I148. Sharp, J. M., & Domenico. A. (1976). Energy transport in thick seqences of compacting sediment. Geol. Sot,. Am. Bull., X7. 39&400. Skempton, A. W. (1970). The consolidation of clays by gravitational compaction. Q. J. Gcol. Sot. London. 125. 37341 I. Smith, J. E. (1971). The dynamics of shale compaction and evolution of pore pressures. Moth. Geol.. 3, 239-263. Terzhagi, K. (1925).Erdhuumecllanik uuf hodenpll~sikulisc,ilt~r Grundluge. p. 399. Leipzig: Deuticke. Tom Chang, T.. Lennon, G. P., Pamuksu. S., & Carson, B. (1990). A coupled fluid expulsion model of dewatering sediments. In R. H. Bennett. W. R. Bryant and M. H. Hulbert (Eds), Mic,rostruc/urc of Fine Gruitred .%dimet~ts (pp. 273 -280). Springer Verlag.
108
A.C. Aplin, G. VasseurjMarine and Petroleum Geology 15 (IWS)
Ungerer, P., Burrus, J., Doligez, B., Chenet, J. Y., & Be&, F. (1990). Basin evaluation by integrated two-dimensional modeling of heat transfer, fluid-flow, hydrocarbon generation and migration. Am. Assoc. Pet. Grol. Bull., 74, 309-355.
105-108
Yukler, M. A., Cornford, C., & Welte, D. H. (1978). One dimensional model to simulate geologic, hydrodynamic and thermodynamic development of a sedimentary basin. Grol. Rundsch., 67, 96C979.