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Behaviour of hydraulically induced fractures in oil sands
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816018 E~:2~TS OF FRICTION ON HYDRAULIC FRACTURE GROWTH NE&~ UNSDNDED I~I'~FACES IN ROCKS Anderson, G D Soc Pet Engr J, V21, NI, Feb 1981, F21-29 Laboratcry experiments using samdstone and limestone were performed to study the effects of the frictiomal l~Ol~-rties of unbodied interfaces on the growth of hydraulically driven fractures. The purpose was to evaluate umder which conditions the hydraulic fractures would cross the interface. Additional experiments were performed to evaluate the coefficient of friction for different interface surface preparations. 816019 STUDY OF INCLINED HYDRAULIC F R A C ~ I N G IN ERI'I~ AND I I ~ ROCK Mizuta, Y; Kobayashi, H In: Ur~lergrouni Rock Emgineering (Papers to 13th Camadian Rock Mechanics Symposi~n, Toronto, 28-29 May 1980), P17-23. Publ Montreal: CD44, 1980 Laboratory hydraulic fracturing tests were conducted on granite to investigate the effect of borehole inclination with respect to in situ stress field amd flow rate. The specimens were fractured hydraulically under blaxial loading and fractures were reopened by cycling the pressure at different flow rates. Fir~te element analyses were also carried out to suVport experimental data. 816020 BEHAVIOUR OF HYDRAULICALLY INDUCED FRACTURES IN OIL SANDS Dusseault, M B In: Und~rgrouni Rock Engineering (Papers to 13th Canadian Rock Mechanics Symposium,
Toronto, 28-29 ~a~ ~980), F36-41. ~u~l Montreal: CI~M, 1980 Presents a fracturing effects of llthologic
geomechanical model of hydraulic in oil sands anl discusses the injection on principal stress, amd control of fracture propagation.
816021 REVIEW OF FRAC%K~E TOUGHNESS TESTING ON ROCK Ouchterlor~, F Swedish Detonic Research Foundation, Report DS 1980:15, 30 Dec 1980, 80P A comprehensive review of crack growth resistance measurements on rock is made. Its accent is on the plane-strain fracture toughness as origirmlly defined for metals. The influence of the metals testing criteria and other factors on establishing a material property for rock are discussed in detail. Of the former, specimen thickness and loading rate appear to have little effect for example. Other crack resistance measures are included too, such as the specific work of fracture, the fracture e n e r ~ const~mption rate based on Griffith, amd the critical J-integral value. The review comprises a substantial llst of repc~ted crack resistance values for rocks ar~ the need for test method standardization is eml~hasized. Further development of core based test specimens is also outlined. 85 refs. Avail: The Foundation, Box 32058, S-126 !i, Stockholm, Sweden
816022 FRACTURE OF ~WMENTS IN PAR~T;~ Lumdborg, N Swedish Detonic Research Four~tion, Report DS 1980:9, ! Sept 1980, 12P Analyses mathematically the probability of tensile fracture of a n~m~0er of samples connected in parallel. The principle of the solution is shown for the case of 3 elements. The general solution for n elements is given ~ the terms specified for 4 and 5 parallel elements. A comparison is made between serial and parallel connection with up to i0 elements. An approximate solution where the number of terms is highly reduced is described. Finally the asymptotic value for large n is calculated. Avail: The Fomndation, Box 32058, S-126 ii, Stockholm, Sweden
Strength characteristics 816023 SHEAR STRENGTH OF ROCKFILL Barton, N; K4aernsll, B J Oeotech Er~ng Div ASCE, riO7, NGTT, July 1981, P873-891 A practical method for estimatin~ the shear strength of rockfill is developed. The peak drained friction angle is found to be closely related to that of rock Joints, in both cases dependent on saml~le size, stress level, surface roughness, and on the unlaxial compression stremgth of the rock. Friction =-r~/lesare therefore higher for smaller samples, and very high where stresses are low, as at the toe or near the face of a rockfill dam. Test data reviewed shows that the value of the peak drained friction angle for rockfill can be quantified by an equivalent roughness (R), and an equivalent particle strength (S). The value of R depends on the porosity following compaction, amd on the degree of particle roumdedmess and surface smoothness. A practical method is proposed for ~ysically measurimg the full-face shear strength of in-place compacted rockfill. 816024 C~ENTED SANDS UNDER STATIC LO~3~I~.~ Clough, O W; Sitar, N; Bachus, R C J Geotech Emgng Div ASCE, VI07, NGT6, June 1981, P7 99-817 Relx~-ts a test programne to define the nature of t h e cementation of cemented s-~_a=Is f r o m the San Francisco Bay area, and its effect on soil behaviour. A total of 137 laboratory compression a~i tension load tests were performed on undisturbed samples of naturo_lly cemented sands and artificially prepared cemented sands. The materials exhibited friction angles similar to uz~nted saris, but had a cementation strength intercept and a tensile strength. The primary cementir~ agents of the sands tested were silicates and iron oxides. The strengths of the cemented sands were found to be a function of density, amount of cementing agent, grain shape and grain arrangement.
816018 E~:2~TS OF FRICTION ON HYDRAULIC FRACTURE GROWTH NE&~ UNSDNDED I~I'~FACES IN ROCKS Anderson, G D Soc Pet Engr J, V21, NI, Feb 1981, F21-29 Laboratcry experiments using samdstone and limestone were performed to study the effects of the frictiomal l~Ol~-rties of unbodied interfaces on the growth of hydraulically driven fractures. The purpose was to evaluate umder which conditions the hydraulic fractures would cross the interface. Additional experiments were performed to evaluate the coefficient of friction for different interface surface preparations. 816019 STUDY OF INCLINED HYDRAULIC F R A C ~ I N G IN ERI'I~ AND I I ~ ROCK Mizuta, Y; Kobayashi, H In: Ur~lergrouni Rock Emgineering (Papers to 13th Camadian Rock Mechanics Symposi~n, Toronto, 28-29 May 1980), P17-23. Publ Montreal: CD44, 1980 Laboratory hydraulic fracturing tests were conducted on granite to investigate the effect of borehole inclination with respect to in situ stress field amd flow rate. The specimens were fractured hydraulically under blaxial loading and fractures were reopened by cycling the pressure at different flow rates. Fir~te element analyses were also carried out to suVport experimental data. 816020 BEHAVIOUR OF HYDRAULICALLY INDUCED FRACTURES IN OIL SANDS Dusseault, M B In: Und~rgrouni Rock Engineering (Papers to 13th Canadian Rock Mechanics Symposium,
Toronto, 28-29 ~a~ ~980), F36-41. ~u~l Montreal: CI~M, 1980 Presents a fracturing effects of llthologic
geomechanical model of hydraulic in oil sands anl discusses the injection on principal stress, amd control of fracture propagation.
816021 REVIEW OF FRAC%K~E TOUGHNESS TESTING ON ROCK Ouchterlor~, F Swedish Detonic Research Foundation, Report DS 1980:15, 30 Dec 1980, 80P A comprehensive review of crack growth resistance measurements on rock is made. Its accent is on the plane-strain fracture toughness as origirmlly defined for metals. The influence of the metals testing criteria and other factors on establishing a material property for rock are discussed in detail. Of the former, specimen thickness and loading rate appear to have little effect for example. Other crack resistance measures are included too, such as the specific work of fracture, the fracture e n e r ~ const~mption rate based on Griffith, amd the critical J-integral value. The review comprises a substantial llst of repc~ted crack resistance values for rocks ar~ the need for test method standardization is eml~hasized. Further development of core based test specimens is also outlined. 85 refs. Avail: The Foundation, Box 32058, S-126 !i, Stockholm, Sweden
816022 FRACTURE OF ~WMENTS IN PAR~T;~ Lumdborg, N Swedish Detonic Research Four~tion, Report DS 1980:9, ! Sept 1980, 12P Analyses mathematically the probability of tensile fracture of a n~m~0er of samples connected in parallel. The principle of the solution is shown for the case of 3 elements. The general solution for n elements is given ~ the terms specified for 4 and 5 parallel elements. A comparison is made between serial and parallel connection with up to i0 elements. An approximate solution where the number of terms is highly reduced is described. Finally the asymptotic value for large n is calculated. Avail: The Fomndation, Box 32058, S-126 ii, Stockholm, Sweden
Strength characteristics 816023 SHEAR STRENGTH OF ROCKFILL Barton, N; K4aernsll, B J Oeotech Er~ng Div ASCE, riO7, NGTT, July 1981, P873-891 A practical method for estimatin~ the shear strength of rockfill is developed. The peak drained friction angle is found to be closely related to that of rock Joints, in both cases dependent on saml~le size, stress level, surface roughness, and on the unlaxial compression stremgth of the rock. Friction =-r~/lesare therefore higher for smaller samples, and very high where stresses are low, as at the toe or near the face of a rockfill dam. Test data reviewed shows that the value of the peak drained friction angle for rockfill can be quantified by an equivalent roughness (R), and an equivalent particle strength (S). The value of R depends on the porosity following compaction, amd on the degree of particle roumdedmess and surface smoothness. A practical method is proposed for ~ysically measurimg the full-face shear strength of in-place compacted rockfill. 816024 C~ENTED SANDS UNDER STATIC LO~3~I~.~ Clough, O W; Sitar, N; Bachus, R C J Geotech Emgng Div ASCE, VI07, NGT6, June 1981, P7 99-817 Relx~-ts a test programne to define the nature of t h e cementation of cemented s-~_a=Is f r o m the San Francisco Bay area, and its effect on soil behaviour. A total of 137 laboratory compression a~i tension load tests were performed on undisturbed samples of naturo_lly cemented sands and artificially prepared cemented sands. The materials exhibited friction angles similar to uz~nted saris, but had a cementation strength intercept and a tensile strength. The primary cementir~ agents of the sands tested were silicates and iron oxides. The strengths of the cemented sands were found to be a function of density, amount of cementing agent, grain shape and grain arrangement.