延长南部低渗透储层天然裂缝定量识别技术

Quantitive identification of natural fractures in tight reservoir of southern Yanchang Oilfield

通常天然裂缝的定量识别是借助三维地震数据体建立三维裂缝模型,但在地表等条件恶劣的工区,三维地震数据质量往往较差,无法建立三维裂缝模型。文中以延长组南部地层为例,提出了一套在三维地震数据缺失情况下的天然裂缝定量识别技术。首先,利用成像测井对工区内的裂缝进行定量识别描述,确定常规测井系列对裂缝响应敏感的测井类型,建立微电极测井裂缝识别模型;然后,利用该模型对研究工区内的单井进行裂缝识别,再使用岩心描述资料对单井识别裂缝进行进一步标定,获得单井裂缝定量参数。结合野外地质勘测对研究区域内天然裂缝的产状及横纵向的分布特征描述,借助裂缝随机建模技术构建三维裂缝模型,为后续勘探开发提供技术指导和建议。

In general, with the assistance of 3 D seismic data, natural fracture can be identified and modeled by 3 D modeling.Unfortunately in some cases, 3D seismic data is not available due to survey conditions in the operation area. Based on a case study of southern Yanchang Formation, this paper introduces a technique of natural fracture identification by conventional logging interpretation in the absence of 3D seismic data. With comparison of image interpretation to the responses of conventional logging data, an interpretation model was built up to identify and evaluate nature fractures based on microresistivity log. According to core calibration, this technique was applied to each well in the study project. Integrated with geologic survey of outcrops, the results of analysis and evaluation of natural fractures can be used for discrete fracture network modeling to provide guidance and recommendations for exploration and development operations.