基于电成像资料的裂缝有效性评价和储集层品质分类——以鸭儿峡油田白垩系为例

Fracture effectiveness evaluation and reservoir quality classification based on electrical imaging data:a case study of Cretaceous in Yaerxia Oilfield

酒泉盆地鸭儿峡油田柳北地区K1g0段为扇三角洲前缘亚相的砂砾岩裂缝性油藏,有效裂缝是主要的储集空间和渗流通道,也是产能的主控因素。为了研究K1g0段裂缝的有效性和储集层的品质分类方法,综合利用电成像和试油试采资料,分析了裂缝宽度、密度和倾角这3项关键参数对裂缝有效性的影响;通过关键参数和裂缝发育厚度构建了裂缝发育度和裂缝开启度用以定量表征裂缝的有效性,并建立了这2项表征参数和米采油量指数的定量评价图版。结果表明:裂缝发育度和裂缝开启度指数能较好地评价研究区裂缝的有效性;裂缝有效性指数和储层产油量的评价图版可实现定量、快速的裂缝性砂砾岩储层品质分类。这为研究区裂缝性储层的老井复查和新井产量预测提供了参考依据。

K1g0 member of Yaerxia Oilfield is a fractured glutenite reservoir with fan delta front subfacies in Liubei area,Jiuquan Basin. Effective fracture is not only the main reservoir space and seepage channel,but also the main controlling factor of productivity. In order to study the validity of fracture in K1g0 member and the classification method of reservoir quality,the effects of three key parameters including fracture width,density and dip angle, on fracture validity were analyzed by using electrical imaging and production test data. Through key parameters and fracture development thickness,the fracture development degree and fracture opening degree were constructed to quantitatively characterize the effectiveness of fractures,and the quantitative evaluation charts of the above two characterization parameters and index of oil production per meter were established. The results show that the fracture development and fracture opening index can better evaluate the effectiveness of fractures in the study area, and the evaluation chart of fracture effectiveness index and reservoir oil production can carry out quantitative and rapid classification of fractured glutenite reservoir quality. The study results can provide a basis for the review of old wells and production prediction of new wells in fractured reservoirs in the study area.