砾岩油藏弓形井多级水平缝压裂聚驱采收率数值模拟  

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

作　　者：吴昊镪 彭小龙[1] 朱苏阳[1] 冯宁 张斯 叶泽禹 WU Haoqiang;PENG Xiaolong;ZHU Suyang;FENG Ning;ZHANG Si;YE Zeyu(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Research Institute of Geology,Xibu Drilling Engineering Company Limited,PetroChina,Xi’an,Shaanxi 710000,China)

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500 [2]中国石油西部钻探工程有限公司地质研究院,西安710000

出　　处：《新疆石油地质》2022年第1期85-91,共7页Xinjiang Petroleum Geology

摘　　要：砾岩油藏非均质性较强,注水开发极易形成水流优势通道,注入水波及效率较低,含水率上升快,开发效果较差。为此,针对相变快、储集层连续性较差的浅层砾岩油藏,提出了采用弓形井多级水平缝压裂改造的方式,以提高聚合物驱的采收率。基于克拉玛依油田七东1区西北区块的地质模型,对高含水砾岩油藏进行生产动态历史拟合,在此数值模型的基础之上,选择剩余油较富集区块,建立多级水平缝压裂大位移弓形井和直井注采井网,进行提高采收率的数值模拟研究。结果表明,试验区的最优注聚强度约0.05 PV/a,角注井组的波及系数大于边注井组,弓形井压裂裂缝位于油层上部的注聚驱油效果最佳。弓形井不仅较好地利用了目的区块压裂裂缝多为水平缝的特点,改善了近井筒地带流体的渗流方式,还进一步发挥了聚合物的调剖作用,2种方式相辅相成,可以有效改善驱替前缘推进不均匀的情况,提高了浅层砾岩油藏的采收率。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.

关 键 词：砾岩油藏 弓形井 多级压裂 水平缝 聚合物驱 采收率 数值模拟 

分 类 号：TE357.46[石油与天然气工程—油气田开发工程]