基于页岩气井返排特征的闷井时间优化方法

Optimization of Shut-in Time in Shale Gas Wells Based on the Characteristics of Fracturing Flowback

翁定为 江昀 易新斌 何春明 车明光 朱怡晖

WENG Dingwei JIANG Yun YI Xinbin HE Chunming CHE Mingguang ZHU Yihui

中国石油勘探开发研究院，北京 100083 中国石油油气和新能源分公司，北京 100028 中国石油西南油气田分公司页岩气研究院，四川成都 610051

PetroChina Research Institute of Petroleum Exploration & Development, Beijing, 100083, China PetroChina Oil & Gas and New Energy Company, Beijing, 100028, China Shale Gas Research Institute, PetroChina Southwest Oil & Gas Field Company, Chengdu, Sichuan, 610051, China

为确定页岩气井压后闷井时间，提高最终采收率，提出了基于页岩气井返排液特征的闷井时间优化方法。首先，以泸州地区深层页岩和威远地区中深层页岩为研究对象，开展自发渗吸试验确定实验室尺度闷井时间；然后，利用返排液矿化度和返排率数据反演得到矿场尺度裂缝宽度和特征长度；最后，结合自发渗吸无因次时间模型，计算得到矿场尺度闷井时间。结果表明，矿场尺度闷井时间与岩心尺度闷井时间并不一定呈正相关关系，其结果受渗吸速率、返排液矿化度和返排率等因素影响。研究结果为页岩气井压后闷井时间优化提供了一种新的方法。

To determine the shut-in time after fracturing and improve the ultimate gas recovery of shale gas wells, the optimization method of shut-in time in shale gas wells based on the characteristics of fracturing flowback fluid was proposed. The deep shale in Luzhou area and the medium and deep shale in Weiyuan area were studied. First, the shut-in time in the lab scale was obtained by spontaneous imbibition experiment. After that, fracture width and characteristic length in the field scale were inverted by using fracturing flowback fluid salinity and flowback efficiency data. Finally, the shut-in time in the field scale was calculated according to the dimensionless time model of spontaneous imbibition. The results indicated that the shut-in time was not always in a positive correlation with that in the lab scale. It was affected by factors including imbibition rate, fracturing flowback fluid salinity, flowback efficiency, etc. The result provides a new idea for optimizing shut-in time after fracturing of shale gas wells.

中国石油天然气股份有限公司科技专项“海陆过渡相页岩气勘探开发关键技术研究”（编号：2021DJ2004）资助

https://doi.org/10.11911/syztjs.2023080