Study on the pattern of hydraulic fracture propagation and fracture conductivity of conglomerate with different lithologiesin Ma'nan area

Abstract

The Ma’nan Fengcheng Formation in Xinjiang is rich in oil and gas resources, offering significant exploration potential. The reservoir’s lithology is diverse, comprising dolomitic, tuffaceous, and sandy conglomerates. However, the patterns of hydraulic fracture propagation and variations in fracture conductivity in these formations are not well understood. To address this, we conducted experiments using a true triaxial hydraulic fracturing physical modeling system and a fracture conductivity testing system. Our key findings are as follows: (1) In sandy conglomerate reservoirs, fractures tend to propagate along the direction of maximum horizontal stress. The presence of gravel causes these fractures to develop into a complex network of narrower microfractures. The breakdown pressure hierarchy is Dolomitic > Tuffaceous > Sandy conglomerate. Increased confining pressure raises the fracture pressure across all lithologies. (2) Fracture conductivity decreases with increasing confining pressure, particularly during the initial stages of pressure loading, and this loss is irreversible. The conductivity hierarchy is Sandy > Dolomitic > Tuffaceous conglomerate. Additionally, increasing the proppant concentration from 2 to 6 kg/m2 enhances fracture conductivity by approximately 1.5 times. These findings provide valuable insights and technical support for the efficient development of conglomerate reservoirs in China.

Cited as: Hu, S., Wei, C., Yan, Y., Wang, D., Ye, Y., Li, X., Zhang, J., Ba, Z. Study on the pattern of hydraulic fracture propagation and fracture conductivity of conglomerate with different lithology in Ma’nan area. Computational Energy Science, 2024, 1(2): 69-85. https://doi.org/10.46690/compes.2024.02.02

References:

Cai, J., Zhao, L., Zhang, F., et al. Advances in multiscale rock physics for unconventional reservoirs. Advances in Geo-Energy Research, 2022, 6(4): 271-275.
Chen, B., Barboza, B. R., Sun, Y., et al. A review of hydraulic fracturing simulation. Archives of Computational Methods in Engineering, 2022, 29(4): 1-58.
Chen, S. Study on sand production characteristics of conglomerate reservoir. Beijing, China University of Petroleum, 2022.Cooke Jr, C. E. Conductivity of fracture proppants in multiple layers. Journal of Petroleum Technology, 1973, 25(9): 1101-1107.
Fan, M., Mcclure, J., Institute, V. P., et al. Using an experiment/simulation-integrated approach to investigate fracture-conductivity evolution and non-darcy flow in a proppant-supported hydraulic fracture. SPE Journal, 2019, 24(04): 1912-1928.
Geertsma, J., De Klerk, F. A rapid method of predicting width and extent of hydraulically induced fractures. Journal of Petroleum Technology, 1969, 21(12): 1571-1581.
Gong, T., Xia, B., Liu, L., et al. Propagation of hydraulic fracture under the joint impact of bedding planes and natural fractures in shale reservoirs. Energy Science & Engineering, 2019, 7(6): 2690-2702.
He, M. The future of rock mechanics lies with China: Inaugural editorial for Rock Mechanics Bulletin. Rock Mechanics Bulletin, 2022, 1: 100010.
Jiang, Y., Li, B., Wang, C., et al. Advances in development of shear-flow testing apparatuses and methods for rock fractures: A review. Rock Mechanics Bulletin, 2022, 1(1): 100005.
Li, J., Tang, Y., Wu, T., et al. Overpressure origin and its effects on petroleum accumulation in the conglomerate oil province in Mahu Sag, Junggar Basin, NW China. Petroleum Exploration and Development, 2020, 47(4): 726-739.
Li, L., Meng, Q., Wang, S., et al. A numerical investigation of the hydraulic fracturing behaviour of conglomerate in Conglomerate formation. Acta Geotechnica, 2013, 8(6): 597-618.
Li, Q., Zhang, C., Yang, Y, et al. Preliminary experimental investigation on long-term fracture conductivity for evaluating the feasibility and efficiency of fracturing operation in offshore hydrate-bearing sediments. Ocean Engineering, 2023, 281: 114949.
Li, Z., Zhao Q., Teng, Y., et al. Experimental investigation of non-monotonic fracture conductivity evolution in energy georeservoirs. Journal of Petroleum Science and Engineering, 2022, 211: 110103.
Lian, Z., Zhang, J., Wang, X., et al. Simulation study of characteristics of hydraulic fracturing propagation. Rock and Soil Mechanics, 2009, 30(1): 169-174.
Liu, G. Challenges and countermeasures of log evaluation in unconventional petroleum exploration and development. Petroleum Exploration and Development, 2021, 48(5): 1033-1047.
Liu, K., He, H., Yin, D. Theoretical and experimental study on the long-term conductivity of heterogeneous artificial fractures in tight reservoirs. Energy Reports, 2023, 9: 3881-3895.
Liu, Y., Tang, D., Xu, H., et al. The impact of coal macrolithotype on hydraulic fracture initiation and propagation in coal seams. Journal of Natural Gas Science and Engineering, 2018, 56: 299-314.
McDaniel, B. W. Conductivity testing of proppants at high temperature and stress. SPE Western Regional Meeting. Paper SPE 15067 Presented at the SPE California Regional Meeting, Oakland, California, 2–4 April, 1986.
Meng, Q., Zhang, S., Guo, X., et al. A primary investigation on propagation mechanism for hydraulic fractures in conglomerate formation. Journal of Oil and Gas Technology, 2010, 32(4): 119-123.
Stegent, N. A. , Wagner, A. L., Mullen, J., et al. Engineering a successful fracture-stimulation treatment in the eagle ford shale. Paper SPE 136183 Presented at the Tight Gas Completions Conference, San Antonio, Texas, USA, 2-3 November, 2010.
Shi, X., Qin, Y., Gao, Q., et al. Experimental study on hydraulic fracture propagation in heterogeneous conglomerate rock. Geoenergy Science and Engineering, 2023, 225: 211673.
Sun, H. Study on the conductivity of conglomerate artificial fracture. Beijing, China University of Petroleum, 2022.
Wang, Z., Lin, B., Chen, G., et al. Experimental study on evaluation of conglomerate reservoir support-type fracture conductivity in Xinjiang oilfield. Energy, 2023, 278: 127877.
Wang, D., Ge, H., Wang, X., et al. A novel experimental approach for fracability evaluation in tight-gas reservoirs. Journal of Natural Gas Science and Engineering, 2015, 23: 239-249.
Wang, Q., Wang, D., Fu, W., et al. Effects of saturated fluids on petrophysical properties of hot dry rock at high temperatures: An experimental study. Geothermics. 2024a, 121: 103048.
Wang, Q., Wang, D., Yu, B.,et al. Evolution of elastic–plastic characteristics of rocks within middle-deep geothermal reservoirs under high temperature. Natural Resources Research. 2024b, 6: 1-24.
Wang, D., Qu, Z., Liu, C., et al. A numerical investigation into the propagation of acid-etched wormholes in geothermal wells. Unconventional Resources, 2024: 100083.
Wang, D., Zhou, F., Dong, Y., et al. Experimental Investigation of Thermal Effect on Fracability Index of Geothermal Reservoirs. Natural Resources Research, 2021, 30(1): 273-288.
Wang, J., Huang, Y., Zhou, F., et al. The influence of proppant breakage, embedding, and particle migration on fracture conductivity. Journal of Petroleum Science and Engineering, 2020, 193: 107385.
Wang, X., Hu, Y., Li, S., et al. Models for Conductivity and Productivity of Hydraulic Fractures in Tight Oil Reservoirs in Sedimentary Rocks. Xinjiang Petroleum Geology, 2023, 44(4): 442-449.
Xie, H., Lu, Y., Yin, X., et al. Flow conductivity of acid etching fracture of the conglomerates with various gravel content. Reservoir Evaluation and Development, 2011, 1(5): 40-42.
Yang, C., Liu, J. Petroleum rock mechanics: An area worthy of focus in geo-energy research. Advances in Geo-Energy Research, 2021, 5(4): 351-352.
Yu, J., Li, N., Hui, B., et al. Experimental simulation of fracture propagation and extension in hydraulic fracturing: A state-of-the-art review. Fuel, 2024, 363: 131021.
Zhi, D., Tang, Y., He, W., et al. Orderly coexistence and accumulation models of conventional and unconventional hydrocarbons in Lower Permian Fengcheng Formation, Mahu sag, Junggar Basin. Petroleum Exploration and Development, 2021, 48(1): 43-59.
Zhou, Z., Wang, G. D., Zheng, B., et al. Comparative experimental investigation on permeability and pressure bearing capacity of different types of temporary plugging bodies. Unconventional Resources, 2024, 4: 100062.
Zou, Y., Shi, S., Zhang, S., et al. Experimental modeling of sanding fracturing and conductivity of propped fractures in conglomerate: A case study of tight conglomerate of Mahu sag in Junggar Basin, NW China. Petroleum Exploration and Development, 2021, 48(6): 1383-1392.