中扬子地区当阳复向斜奥陶系五峰组-志留系龙马溪组页岩储层特征

Shale reservoir characteristics of Ordovician Wufeng-Silurian Longmaxi formations in Dangyang synclinorium, Middle Yangtze region

范家维 陈孔全 沈均均 朱薇 唐协华 李君军 王鹏万 张放

FAN Jiawei CHEN Kongquan SHEN Junjun ZHU Wei TANG Xiehua LI Junjun WANG Pengwan ZHANG Fang

长江大学 非常规油气湖北省协同创新中心, 武汉 430100 中国石油 长庆实业集团有限公司, 西安 710016 中国石油 浙江油田分公司, 杭州 310023 中国石油 杭州地质研究院, 杭州 310023

Collaborative Innovation Center of Unconventional Oil and Gas, Yangtze University, Wuhan, Hubei 430100, China PetroChina Changqing Industrial Group Company, Xi'an, Shaanxi 710016, China PetroChina Zhejiang Oilfield Company, Hangzhou, Zhejiang 310023, China PetroChina Hangzhou Institute of Petroleum Geology, Hangzhou, Zhejiang 310023, China

以当阳复向斜内典型井钻井资料为基础，通过双束扫描电镜、矿物含量分析、有机地球化学分析和低温低压氮气吸附测定等方法，对富有机质页岩岩石学特征、有机地球化学特征、储集空间类型及特征和含气性特征等进行系统研究。研究结果表明：①五峰组-龙一1亚段页岩储层在纵向上差异较大，优质页岩储层发育在龙一11小层-龙一12小层，其有机质丰度高(2.45%~6.98%)、有机质类型好(Ⅱ1-Ⅱ2型)、热演化程度较高、脆性矿物含量高(34%~85.5%)、黏土矿物含量低(9%~40.3%)、总含气量高(1.76~4.30 m3/t)，有机孔非常发育；进入龙一13小层后，受到加里东运动构造活动加剧的影响，陆源输入量增大，储层品质开始变差。②在横向上，当阳复向斜内由东南向西北方向，五峰组-龙马溪组富有机质页岩越来越发育，储层品质越来越好。③研究区龙一11小层-龙一12小层页岩储层具有"最甜"和"最脆"的特征，但考虑到水平段钻进过程中需要对井轨迹进行实时监控与调整，应选择龙一11小层内GR峰的上下半幅点之间作为水平井的最佳水平箱体。

The petrological and organic geochemical characteristics, reservoir porosity types and features, and gas-bearing characteristics of organic-rich shale were systematically studied using FIB-SEM, mineral contentanalysis, organic geochemical analysis and low-temperature and low-pressure nitrogen adsorption porosity determination, and drilling data of typical wells in the Dangyang synclinorium. (1) Vertically, shale reservoirs from the Wufeng Formation(O3w) are quite different from the first section of the first member of Longmaxi Formation (S1l11). High-quality shale reservoirs are developed from S1l11(1) to S1l11(2) sublayers, with a high abundance of organic matter (2.45%-6.98%), type Ⅱ1-Ⅱ2 organic matter, rather high thermal evolution degree, high brittle mineral content (34.0%-85.5%), low clay mineral content (9.0%-40.3%), and high total gas content (1.76-4.30 m3/t). Organic pores are well developed. In the S1l11(3) sublayer, affected by the intensified Caledonian tectonic activity, terrigenous material input increased, and reservoir quality began to deteriorate. (2) Horizontally, organic-rich shale of the Wufeng-Longmaxi formations in the Dangyang synclinorium become thicker from southeast to northwest, and the reservoir quality becomes better. (3) Shale reservoirs in the S1l11(1)-S1l11(2) sublayers in the study area are the "sweetest" and the "most brittle".However, considering the convenience of real-time monitoring and adjustment of well trajectory during horizontal drilling, the upper and lower half of GR peak in the S1l11(1) sublayer should be selected as the best horizontal target of horizontal wells.

国家科技重大专项"四川盆地及周缘页岩气富集规律与重点目标评价" 2017ZX05035001;湖北省高等学校优秀中青年科技创新团队计划项目 T201905

https://doi.org/10.11781/sysydz202001069