特低渗裂缝性砾岩油藏储层特征及其对开发效果控制作用研究:以克拉玛依油田八区下乌尔禾油藏为例

在岩心储层研究及测井解释的基础上,动静结合确定了八区下乌尔禾组油藏的有效储层划分标准,在此基础上,运用综合评价方法将储层划分为4类,其中I类最好,IV类最差。对比四次加密试验井,储层评价效果好,储层厚度的预测误差率在5%以内,储层类型符合率为80%。统计岩心及成像测井资料显示,下乌尔禾组天然裂缝以构造高角度缝为主,人工裂缝以压裂羽状缝为主,各类裂缝多为闭合缝。结合开发动态资料分析认为:储层发育优势区控制了油井高产区,油层储层条件越好,初期产能越高;裂缝的存在导致注入水优先沿裂缝突进,使油井出现裂缝水窜、见水不见效等开发特征;综合分析发现油水井的驱替通道、储层及裂缝发育情况导致油井不同见效情况。在静动态研究基础上实施的四次加密试验井,90%以上的井可达到预期设计产能。

The reservoir characteristics and their controls on development in extra-low permeable fracture conglomerate reservoir：A case study from the P2w1 reservoir of Karamay Oilfield

On the basis of reservoir cores research and log interpretation,the research established criteria for reservoir classification of the Lower Urho of Region Eight both statically and dynamically.Using comprehensive evaluation method,reservoirs in the entire region were divided into four categories.The best was class I,the worst was class IV.Good results have been achieved when this method was used in the four encryption tests.Prediction error of reservoir thickness was within 5%,and matching rate of reservoir types was 80%.According to the regional tectonic evolution and various characteristics of the stress field,geological background of crack formation in Lower Urho of Region Eight was analyzed.With the statistical data of cores and logging imaging,natural fractures of the Lower Urho of Region Eight are dominated by high-angle joints.Artificial joints are dominated by fracturing pinnate joints and all kinds of cracks are mostly close cracks.Combined with the dynamic data of development,our study concludes that reservoir well-developed area controlled the distribution area of oil fields with high production.The better the oil reservoir conditions,the higher the initial production.The existence of cracks results in the prior onrush of the injected water along the crack causing fracture water breakthrough and the presence of water but no effect.Comprehensive analysis concludes that different oil-water displacement channels(reservoir matrix and fracture) and different development of reservoir and cracks lead to different effects on oil wells.On the basis of the mentioned static and dynamic study,the oilfield implemented four encryption test wells and more than 90% wells achieved the designed capacity.