Analysis and Understanding of Interwell Communication in Multiple Fracture Monitoring Technology: A Case Study of the Qingcheng Shale Oil Hydraulic Fracturing Field Lab

Abstract With the continuous expansion of the Qingcheng shale oil development scale and the sustained expansion of the production construction area, fracturing communication issues have emerged in some blocks, seriously affecting the normal production of adjacent wells. In order to clarify the spatial distribution characteristics of fractures, reduce the probability of fracturing communication events, and improve the compatibility between the fracture network and the well network, the Qingcheng shale oil Hydraulic Fracturing Field Lab in the Ordos Basin was taken as the research object to systematically carry out inter-well fracturing communication assessment. The research integrated 10 types of fracture testing in 16 wells, including dual-well downhole microseismic, fiber optic, tracer, downhole TV, and downhole pressure gauge, as well as 2 post-fracturing coring wells. The evaluation work on fracture morphology, proppant placement degree, and multi-cluster fracture expansion balance was systematically carried out. The main insights obtained include: ①The re-calibrated fracture length after core sample results range from 247 to 711 meters, with the western limb being 230 meters and the eastern limb being 212 meters, which is approximately 85% of the initial interpretation results; ②The existing fracturing technology parameters are not suitable for a 250-meter well spacing, which easily leads to inter-well fracture communication, and it is necessary to increase the well spacing. ③A total of 41 Frac Hit events were monitored during the fracturing process of the test wells, mostly occurring during the pre-pad fluid injection stage (10-31 min), with a cumulative fluid injection volume of 80-150m³. However, most fracture communication events will disappear in the early stage of production. ④The uniform expansion of fractures is mainly controlled by the continuity of sweet spots. The better the continuity of sweet spots, the higher the balance of multi-cluster fracture expansion. The Qingcheng shale oil reservoir has strong heterogeneity and poor sweet spot continuity, so optimization should mainly adopt 3～5 clusters/section. ⑤Temporary plugging can appropriately improve the fluid intake of some disadvantaged clusters, and the fracture tip temporary plugging technology is more effective in multi-section and fewer clusters than in large Stage with multiple clusters. The research results can provide guidance for the optimization of shale oil well networks, the formulation of development technology policies, and the optimization design of volume fracturing in the Ordos Basin.