川西拗陷中侏罗统沙溪庙组储层特征及综合评价

Reservoir Characteristics and Comprehensive Evaluation of the Middle Jurassic Shaximiao Formation in Middle of Western Sichuan Depression

张玲 陈恭洋 叶素娟 杨映涛 程乐利

ZHANGLing CHENGongyang YESujuan YANGYingtao CHENGLeli

中国石化西南油气分公司勘探开发研究院, 四川 成都 610041 长江大学录井技术与工程研究院, 湖北 荆州 434023

Exploration and Production Research Institute, Southwest Oil&Gas Company, SINOPEC, Chengdu, Sichuan 610041, China Institute of Mud Logging Technology and Engineering, Yangtze University, Jingzhou, Hubei 434023, China

川西拗陷中段中侏罗统沙溪庙组为多物源背景下发育的三角洲—滨浅湖沉积体系，不同物源背景对储层影响较大且勘探效果差异明显。以岩屑、岩芯等实物资料为基础，结合薄片观察及储层测试分析资料，对研究区沙溪庙组龙门山中段（近物源）及龙门山北段和米仓山（远物源）两大物源沉积体系的储层特征进行了对比性研究。结果表明，近源体系储层砂岩整体成分成熟度低、粒度较粗，有利储层为成分成熟度高、碳酸盐胶结物含量低、裂缝发育的细粒砂岩，保孔效应的强弱决定了优质储层的发育；远源体系优质储层的特征主要为成分成熟度相对较低、碳酸盐胶结物含量低、长石富集的中粒砂岩，溶蚀作用的增孔效应强度决定了优质储层的发育。以此为基础，分别建立了两大物源体系的储层综合分类评价标准，评价结果显示，远源体系的储层发育更优，其有利储层分布面积远大于近源体系。

The Shaximiao Formation of Middle Jurassic in the West Sichuan Depression is a delta-shore-shallow lake sedimentary system developed under the background of multiple provenance. Different provenance background has great influence on reservoir and the exploration effect is obviously different the reservoir characteristics of the near-source and distal-source depositional systems have been analyzed and compared on the basis of core and drilling cutting analysis, thin section observation and reservoir test analysis. The results imply that the near-source reservoir is dominated by low-maturity, coarse grained sandstone. Its favorable reservoirs consist of fine-grained sandstone characterized by matured lithology, low calcite cement, and well-developed fractures. The preservation of porosity is the major controlling factor of reservoir quality. On the contrary, the favorable reservoirs of distal-source depositional system are composed of low-maturity, medium-grained sandstone with low calcite cement and high feldspar contents. Pressure dissolution has significantly contributed to the development of secondary porosity, which further improve the quality of reservoirs. On such basis, classification standards are established to evaluate the reservoirs quality of the two depositional systems. The results show that the reservoir development of distal-source depositional system is significantly better than the near-source system, since its favorable reservoir has greater lateral extent.

10.11885/j.issn.16745086.2019.08.28.03