Impacts of proppant distribution on development of tight oil reservoirs with threshold pressure gradient

Abstract

Field evidence indicates that proppant distribution and threshold pressure gradient have great impacts on well productivity. Aiming at the development of unconventional oil reservoirs in Triassic Chang-7 Unit, Ordos Basin of China, we presented an integrated workflow to investigate how (1) proppant placement in induced fracture and (2) non-linear flow in reservoir matrix would affect well productivity and fluid flow in the reservoir. Compared with our research before (Yue et al., 2020), here we extended this study into the development of multi-stage fractured horizontal wells (MFHWs) with large-scale complicated fracture geometry. The integrated workflow is based on the finite element method and consists of simulation models for proppant-laden fluid flow, fracture flow, and non-linear seepage flow, respectively. Simulation results indicate that the distribution of proppant inside the induced cracks significantly affects the productivity of the MFHW. When we assign an idealized proppant distribution instead of the real distribution, there will be an overestimation of 44.98% in daily oil rate and 30.63% in cumulative oil production after continuous development of 1000 days. Besides, threshold pressure gradient (TPG) also significantly affects the well performance in tight oil reservoirs. If we simply apply linear Darcy’s law to the reservoir matrix, the overall cumulative oil production can be overrated by 77% after 1000 days of development. In general, this research provides new insights into the development of tight oil reservoirs with TPG and meanwhile reveals the significance of proppant distribution and non-linear fluid flow in the production scenario design.