页岩气压裂返排液甲烷溶解度分布特征及影响因素  

Distribution characteristics and influencing factors of methane solubility in shale gas fracturing backflow fluid

作　　者：马杰 马行陟[2,3] 覃龙 叶秀茹 成元灵 蒲笛 李秀丽[2,3] 郝加庆[2,3] Ma Jie;Ma Xingzhi;Qin Long;Ye Xiuru;Cheng Yuanling;Pu Di;Li Xiuli;Hao Jiaqing(Sichuan Changning Natural Gas Development Co.,Ltd.,Chengdu 610056,China;Research Institute of Petroleum Exploration and Development,Beijing 100083,China;Key Laboratory of Basin Structure and Oil and Gas Accumulation,China National Petroleum Corporation,Beijing 100083,China;Sichuan Baoshihua Xinsheng Oil and Gas Operation Service Co.,Ltd.,Chengdu 610056,China)

机构地区：[1]四川长宁天然气开发有限责任公司,四川成都610056 [2]中国石油勘探开发研究院,北京100083 [3]中国石油天然气集团公司盆地构造与油气成藏重点实验室,北京100083 [4]四川宝石花鑫盛油气运营服务有限公司,四川成都610056

出　　处：《能源与环保》2024年第8期145-149,共5页CHINA ENERGY AND ENVIRONMENTAL PROTECTION

基　　金：国家自然科学重点基金(42030804);中国石油天然气股份公司科学研究与技术开发项目(2021DJ0101)。

摘　　要：页岩气作为重要的天然气资源,其成功的商业开采主要依赖于水力压裂等技术。页岩气水力压裂过程中会产生大量的返排液,压裂返排液甲烷溶解度大小和影响因素的研究对于降本增效、减少温室气体效应和页岩气绿色开发具有重要意义。根据压裂返排液特点,在传统甲烷溶解度测定方法进行了改进,改进的容积法可以在不破坏溶解平衡的状态下连续测定不同压力、温度下的甲烷溶解度,实验结果的稳定性相对较高。基于改进容积法对四川盆地长宁地区页岩气压裂返排液甲烷溶解度进行了测定,甲烷溶解度主要在1.32~1.60 m^(3)/m^(3),估算通过压裂返排液每井可回收13200~32000 m^(3)的甲烷。温度、压力和矿化度等因素对页岩气压裂返排液甲烷溶解度影响较大,研究表明,低温条件下,甲烷溶解度随温度的升高逐渐减小,高温时甲烷溶解度随温度增加而增大。返排液甲烷溶解度具有随压力的增加而增大的变化特征,并表现出低压阶段溶解度快速增加、高压阶段缓慢增加的“两段式”规律。甲烷溶解度随返排液矿化度的增大,甲烷溶解度小幅度的减小。Shale gas as a significant natural gas resource,relies heavily on technologies such as hydraulic fracturing for its successful commercial extraction.During the hydraulic fracturing process of shale gas,a large amount of backflow fluid is generated.The study of the solubility of methane in the fracturing backflow fluid and its influencing factors is of great significance for reducing costs and increasing efficiency,reducing greenhouse gas effects,and promoting green development of shale gas.This research refined the traditional method for measuring methane solubility according to the characteristics of fracturing backflow fluid.The improved volumetric method can continuously measure methane solubility at different pressures and temperatures without disrupting the dissolution equilibrium,and the stability of the experimental results is relatively high.Based on the improved volumetric method,the methane solubility of shale gas fracturing flowback fluid in Changning area of Sichuan Basin was determined.The methane solubility mainly ranged from 1.32 to 1.60 m^(3)/m^(3),and it was estimated that 13200 to 32000 m^(3)per well of methane can be recovered through fracturing flowback fluid.Factors such as temperature,pressure,and mineralization have a significant impact on the methane solubility of shale gas fracturing flowback fluid.Research showed that under low temperature conditions,the solubility of methane gradually decreases with increasing temperature,while at high temperatures,the solubility of methane increases with increasing temperature.The solubility of methane in the backflow fluid exhibits a characteristic of increasing with pressure,and shows a"two-stage"pattern of rapid increase in solubility in the low-pressure stage and slow increase in the high-pressure stage.The solubility of methane decreases slightly with the increase of mineralization degree in the flowback fluid.

关 键 词：页岩气 压裂返排液 甲烷 溶解度 四川盆地 

分 类 号：X741[环境科学与工程—环境工程]