• 油气地质 •

### 四川盆地川西坳陷新场须家河组二段致密砂岩储层裂缝发育特征及主控因素

1. 中国石化 石油勘探开发研究院, 北京 100083
• 收稿日期:2020-09-16 出版日期:2021-08-28 发布日期:2021-08-27
• 作者简介:李王鹏(1986-), 男, 博士、副研究员, 构造地质、断裂解析和石油地质。E-mail: liwp.syky@sinopec.com
• 基金资助:
国家自然科学基金项目(41902149);国家自然科学基金项目(41702238);中国石化科技部项目(P18089-1)

### Characteristics of and main factors controlling the tight sandstone reservoir fractures in the 2nd member of Xujiahe Formation in Xinchang area, Western Sichuan Depression, Sichuan Basin

Wangpeng Li(), Zhongqun Liu, Zongquan Hu, Wujun Jin, Pengwei Li, Junlong Liu, Shilin Xu, Anlai Ma

1. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China
• Received:2020-09-16 Online:2021-08-28 Published:2021-08-27

Abstract:

The sandstone reservoirs in the 2nd member of Xujiahe Formation (hereafter referred to as Xu 2 Member) in Xinchang area, Western Sichuan Depression, are characterized by deep burial depth and tightness, to which the natural fractures are critical. An integration of outcrop survey, core description, conventional and imaging logging interpretation is applied to analyze the development characteristics of natural fractures in the gas reservoirs therein. It is believed that these fractures can be categorized as network fractures, vertical fractures, high dip angle fractures, horizontal fractures, oblique fractures, and low dip angle fractures, with the last two in the dominant position. Mainly developed in the middle and upper submembers of Xu 2 Member in central and eastern Xinchang tectonic belt, these fractures generally trend NE-SW, NW-SE and EW, basically consistent with that of the present maximum principal stress within, with the EW-striking structural fractures in the late period the most developed. On the other hand, the cross-plotting analysis of fracture and productivity parameters, serves to clarify the contribution of different types of fractures to productivity, and the results show that the effective fractures in the Xu 2 Member gas pool are structural ones with a dip angle of over 30° (namely, vertical, high dip angle and oblique fractures). The development of effective fractures in the study area is controlled by many factors, including faulting, tectonic deformation, grain size, rock composition, and stratum thickness, etc., and the distance from the late SN-striking reverse fault is the most critical factor controlling the development of natural structural fractures, followed by structural deformation and structural pattern in combination. In conclusion, the area with well-developed folds and within 200 m away from the hanging wall of the late SN-striking reverse fault can be regarded as a key zone for future fracture prediction, evaluation and natural gas development in Xinchang area.