DEM Modeling of Interaction Between the Propagating Fracture and Multiple Pre-existing Cemented Discontinuities in Shale
- 157 Downloads
It is known that pre-existing discontinuities can act as planes of weakness that divert the propagating fractures in rocks, but previous studies have mostly focused on the interaction between the propagating fractures and a single pre-existing discontinuity. The influences of multiple pre-existing cemented discontinuities, such as calcite veins and bedding planes, on the fracture propagation still remain poorly understood. In this study, particle-based discrete element method was used to characterize the fracturing behavior of shale containing multiple cemented veins and bedding planes through numerical semi-circular bend (SCB) tests. Model results show that geometrical and mechanical properties of multiple pre-existing cemented discontinuities can significantly affect the interaction modes between the induced tensile fractures and pre-existing cemented discontinuities, as well as the mode I fracture toughness of shale. The typical mechanical interaction modes between the induced tensile fractures and the multiple pre-existing cemented discontinuities and the corresponding conditions are given. The effect of pre-coexisting discontinuities on the peak loads for shale during SCB tests is also discussed.
KeywordsDEM Shale Pre-existing cemented discontinuities Semi-circular bend tests
Z.L. and H.X. are financially supported by National Natural Science Foundation of China (No. 41502190) and Science Foundation of China University of Petroleum, Beijing (No. 2462014YJRC055). Z.Z. is financially supported by the National Natural Science Foundation of China (No. 51509138 and No. 51779123).
- Blanton TL (1982) An experimental study of interaction between hydraulically induced and pre-existing fractures. In: Paper SPE 10847 presented at the SPE unconventional gas recovery symposium, Pittsburgh, Pennsylvania, USAGoogle Scholar
- Gu H, Weng X (2010) Criterion for fractures crossing frictional interfaces at non-orthogonal angles. In: Paper ARMA 10–198 presented at the 44th US rock mechanics symposium and 5th US-Canada rock mechanics symposium, American Rock Mechanics Association, Salt Lake City, UtahGoogle Scholar
- Gu H, Weng X, Lund J, Mack M, Granguly U, Suarez-Rivera R (2011) Hydraulic fracture crossing natural fracture at non-orthogonal angles: a criterion, its validation and applications. In: Paper SPE 139984-MS presented at SPE hydraulic fracturing technology conference. Society of Petroleum Engineers, The Woodlands, TexasGoogle Scholar
- Itasca Consulting Group Inc (2008) PFC2D user's guide. Minneapolis, MNGoogle Scholar
- Jeffrey RG, Zhang X, Thiercelin MJ (2009b) Hydraulic fracture offsetting in naturally fractured reservoirs: quantifying a long-recognized process. In: SPE hydraulic fracturing technology conference, The Woodlands, TexasGoogle Scholar
- Jeffrey RG, Bunger AP, Lecampion B, Zhang X, Chen Z, van As A, Alison DP, De Beer W, Dudley JW, Siebrits E, Thiercelin MJ, Mainguy M (2009a) Measuring hydraulic fracture growth in naturally fractured rock. In: SPE annual technical conference and exhibition, New Orleans, LouisianaGoogle Scholar
- Simpson MD, Patterson R, Wu K (2016) Study of stress shadow effects in eagle ford shale: Insight from field data analysis. In: Paper ARMA 16–190 presented at the 50th US rock mechanics/geomechanics symposium, American Rock Mechanics Association, Houston, TexasGoogle Scholar