川南地区下寒武统筇竹寺组页岩储层特征

Shale reservoir characteristics of the Lower Cambrian Qiongzhusi Formation in the southern Sichuan Basin

王同 熊亮 徐猛 董晓霞 周瑞琦 付晓宁

Wang Tong Xiong Liang Xu Meng Dong Xiaoxia Zhou Ruiqi Fu Xiaoning

成都理工大学能源学院, 成都 610059 2. 中国石化西南油气分公司, 成都 610016 3. 中联煤层气有限责任公司太原分公司, 太原 030000 4. 四川省煤田地质工程勘察设计研究院, 成都 610072

College of Energy Resources, Chengdu University of Technology, Sichuan, Chengdu 610059, China 2. SINOPEC Southwest Oil & Gas Company, Sichuan, Chengdu 610016, China 3. Taiyuan Branch, China United Coalbed Methane Corporation Limited, Taiyuan, Shanxi 030000, China 4. Engineering Investigation and Design Institute, Sichuan Provincial Coalfield Bureau, Chengdu, Sichuan 610072, China

根据川南地区绵阳-长宁拉张槽3口井的源储实验资料研究表明,川南地区筇竹寺组具有有机质丰度高、富有机质页岩厚度大、演化程度高、高脆性等特征,经历多期构造运动改造,B1井区保存条件较好。微观储集空间分为有机孔、无机孔(黏土矿物晶间孔、脆性矿物粒间孔、粒内溶蚀孔及黄铁矿晶间孔)和微裂缝(构造微缝、成岩收缩缝和溶蚀缝)3大类,并可进一步细分为9种类型,孔隙形态表现为细颈墨水瓶广体孔含少量狭缝形孔和平板、楔形缝2种结构,孔径分布复杂,以中孔为主,少量微孔及大孔。优质页岩孔容、BET比表面积较大,为页岩游离气及吸附气提供良好的储集吸附空间。其孔隙类型与分布特征的差异主要受有机碳含量、成熟度、成岩作用、孔隙流体压力的控制。

Experimental source-reservoir data from three wells in the Mianyang-Changning intracratonic sag in the southern Sichuan Basin showed that the Qiongzhusi Formation in the study area features high TOC, thick black shale, high maturity, and high brittleness. Although the southern Sichuan Basin has experienced multiple episodes of tectonic movement, the B1 well block still has favorable preservation conditions. Micro-reservoir space includes organic pores, inorganic pores (intercrystal pores in clay minerals, intergranular pores and intragranular dissolution pores in brittle minerals, and intergranular pores in pyrites), and micro-cracks (micro-structural seams, diagenetic shrinkage joints and dissolution seams), and can be further subdivided into 9 types. Most of the pores have narrow necks, and some are slit type holes. Fractures are tablet or wedge shaped. Mesopores were abundant, and there also exist micropores and macropores. High quality shales have high entrance and BET specific surface area, which is favorable for the preservation of free and adsorbed gas. TOC, maturity, diagenesis and pore fluid pressure determined the difference of pore type and distribution.

国家重大科技专项(2011ZX-05002-004)和中国石化油田事业部非常规重大导向项目"四川盆地及周缘页岩气整体评价与目标优选"(13KT-14)资助。

https://doi.org/10.11781/sysydz201602197