柴达木盆地坪西地区基岩储层测井评价

Bedrock Reservoir Logging Evaluation of Pingxi Area in Qaidam Basin

柴达木盆地坪西地区基岩岩性复杂,储集空间多样,依据常规测井方法难以进行岩性识别、物性评价和有效储层划分。岩心、薄片分析资料表明,基岩以变质灰岩和钙质片岩为主,片岩物性略好于变质灰岩。在岩性识别基础上,结合常规测井资料,利用电成像、元素俘获(ECS)、阵列声波等特殊测井资料,形成了基岩孔隙度、孔隙结构、渗透性等评价方法,并以此建立了有效储层分类与含气性判识标准。多井应用结果表明,基岩气藏内部受裂缝分布、岩性变化及储层非均质影响,表现出非均一性,气藏无统一气水界面。

The bedrocks in the Pingxi Area of Qaidam Basin are complex in lithology and diverse in reservoir space.It is difficult to identify lithology,physical property evaluation and effective reservoir division according to conventional logging methods.According to the core and thin section analysis data,the bedrock is mainly composed of schist and metamorphic limestone,and the schist is slightly better than metamorphic limestone in physical property.Based on the lithology identification,combined with conventional logging data,special logging data such as electrical imaging,elemental capture(ECS),array acoustic wave,etc.are used to form methods for evaluating bedrock porosity,pore structure and permeability.In this way,the effective reservoir classification and gas bearing identification criteria are established.The results of application in multiple wells indicated that the bedrock gas reservoir is affected by crack distribution,lithological change and reservoir heterogeneity,showing heterogeneity,and the gas reservoir has no uniform gas-water interface.