Numerical Simulation on Polymer Flooding Recovery of Conglomerate Reservoirs: Horizontal Fractures in Arched Wells After Multi-Stage Fraturing

doi:10.7657/XJPG20220113

Abstract

Abstract:

Conglomerate reservoirs are generally very heterogeneous, so it is easy to induce large channels during water flooding, resulting in low flooding efficiency, rapid water cut rise and unfavorable development effect. For shallow conglomerate reservoirs which are variable in lithofacies and poor in reservoir continuity, to improve the recovery of polymer flooding, horizontal fractures can be induced through multiple-stage fracturing in arched wells. Based on the geological model of the northwestern block of District Qidong-1 in Karamay oilfield, production history matching was performed for the high water-cut conglomerate reservoirs. Then we set up an injection-production well pattern composed of vertical wells and extended-reach arched wells with horizontal fractures induced by multi-stage fracturing stimulation in the area with enriched remaining oil, and conducted numerical simulation on how to enhance the recovery. The results show that the optimal polymer injecting intensity in the study area is about 0.05 PV/a; the sweep coefficient of an angular injection well pattern is higher than that of an edge injection well pattern; and the polymer flooding effect is the best when horizontal fractures are induced in the upper interval of an arched well. An arched well can make full use of horizontal fractures to improve fluid flow near the wellbore, and it can boost the effect of polymer in profile controlling. The two mechanisms complement each other and can effectively improve the advancement of flooding front, and enhance the recovery of shallow conglomerate reservoirs.

Key words: conglomerate reservoir, arched well, multi-stage fracturing, horizontal fracture, polymer flooding, recovery, numerical simulation

CLC Number:

TE357.46

WU Haoqiang, PENG Xiaolong, ZHU Suyang, FENG Ning, ZHANG Si, YE Zeyu. Numerical Simulation on Polymer Flooding Recovery of Conglomerate Reservoirs: Horizontal Fractures in Arched Wells After Multi-Stage Fraturing[J]. Xinjiang Petroleum Geology, 2022, 43(1): 85-91.

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