西峰油田庄58区块长8储层特低渗透成因

Genesis of extra-low permeability for Chang 8 reservoir of Block Zhuang 58
in Xifeng Oilfield

张 创 高 辉 孙 卫 任国富

西北大学大陆动力学国家重点实验室，陕西 西安 710069 长庆油田分公司油气工艺技术研究院，陕西 西安 710021

State Key Llaboratory of Continental Dynamics, Northwest University, Xi’an 710069, China PetroleumTechnology Research Institute, Changqing Oilfield Company, CNPC, Xi’an 710021, China

综合应用测井资料和铸体薄片、扫描电镜、X衍射、粒度、压汞等分析化验资料，对西峰油田庄58区块长8储层的特低渗透成因和主控因素进行了分析。结果表明，特低渗透成因主要受沉积作用和成岩作用的共同影响，主要表现为：沉积微相对储层物性的影响较大，水下分流河道和河口坝明显好于水下分流间湾，而且成分成熟度低和粒度偏细也是造成特低渗的主要因素之一；成岩压实作用和胶结作用使得储层孔隙减小、渗透性变差，而溶蚀作用和少量成岩微裂缝的产生又为储层中油气的附存和渗流、运移提供了有利条件；水下分流河道与河口坝砂体是研究区的主要储层分布相带。

Based on the syntheticaluse ofwelllogging data and testing data such as cast slice,scanning electron microscope,X-ray diffraction, grain size and mercury penetration, this paper studied the genesis and main controlling factors of extra-low permeability for Chang 8 reservoir of Block Zhuang 58 in Xifeng Oilfield. The study results show that the genesis of extra-low permeability is mainly affected by
sedimentation and diagenesis. The sedimental microfacies had a great influence on the reservoir physical property. The porosity and permeability of subsea distributary channel and mouth bar were better than that of subsea distuibutary bay. The low compositional maturity and fine grain size are one ofmain factors thatresults in the extra-low permeability.The compaction and cementation have made the porosity and permeability decreasing. And the denudation and microfractures have provided the advantages to hydrocarbon storage
and migration.Thesubsea distributary channeland mouth bar sandbody are the main faciesbelts ofreservoirdistribution.