Xingzichuan Oil Production Plant, Yanchang Oilfield Co., Ltd.
College of Geology and Environment, Xi’an University of Science and Technology
Research Institute of Shaanxi Yanchang Petroleum( Group) Co., Ltd.

为明确鄂尔多斯盆地中部安塞地区延长组长6致密砂岩储层特征和控制因素,综合运用岩芯描述、显微镜鉴定、扫描电镜和压汞试验等手段,对长6储层的岩石学、物性和孔隙结构等进行了研究,其对指导致密砂岩油气的高效勘探开发具有重要意义。结果表明:安塞地区长6储层主要为长石砂岩和岩屑长石砂岩,孔隙类型以残余粒间孔和长石溶孔为主,孔隙结构以Ⅱ类(中高排驱压力-微细喉)为主;储层的平均孔隙度为9.97%,平均渗透率为1.37×10-3μm2;储层物性的主控因素为沉积环境和成岩作用,不同微相下的沉积结构不同造成储层的物性差异;强烈成岩作用造成孔隙的孔喉结构差,其中压实压溶作用造成16.7%的孔隙度损失率;受东北方向物源方向影响,不同胶结物差异分布导致储层非均质性较强,后期溶蚀作用改善储层物性,主要是长石溶蚀,以及区域东北部浊沸石发生溶蚀。在成岩演化基础上进行成岩序列分析,将安塞地区长6致密砂岩储层的成岩阶段划分为中成岩A期。

In order to clarify the characteristics and controlling factors of Chang 6 tight sandstone reser- voir in Ansai area of the central part of the Ordos Basin, a comprehensive study was conducted using methods such as core description, microscopic identification, scanning electron microscopy, and mercury injection experiments to investigate the petrology, physical properties, and pore structure of Chang 6 reservoir. The results show that Chang 6 reservoir in Ansai area is mainly composed of feldspathic sand- stone and lithic feldspathic sandstone, with residual intergranular pores and feldspar dissolution pores as the main pore types, and type Ⅱ( medium-high displacement pressure-micropores) as the main pore structure. The average porosity of the reservoir is 9. 97% , and the average permeability is 1. 37 × 10 μm2. The main controlling factors of reservoir properties are sedimentary environment and diagenesis, and the different sedimentary structures under different microfacies result in differences in reservoir properties. Intense diagenesis leads to differences in pore-throat structure, with compaction and pressure dissolution causing a 16. 7% loss in porosity. Influenced by the northeast provenance direction, the dis- tribution of different cementation materials results in strong reservoir heterogeneity, and later dissolution improves reservoir properties, mainly through feldspar dissolution, as well as regional zeolite dissolution in the northeast. Based on the diagenetic evolution, the diagenetic stages of Chang 6 tight sandstone res- ervoir in Ansai area are divided into the middle diagenesis A stage.

国家自然科学基金项目(41641018)第一作者:张波波,男,陕西绥德人,高级工程师,E-mail:404178706@qq.com

张波波,杨塞锋,贺洁,等.安塞地区延长组长6致密砂岩储层特征[J].西安科技大学学报,2024,44(2):301-310.

ZHANG Bobo, YANG Sefeng, HE Jie, et al. Characteristics of tight sandstone reservoir in Chang 6 of Yanchang Formation in Ansaiarea[ J] . Journal of Xi’an University of Science and Technology, 2024, 44( 2) : 301-310.