煤系致密粉砂岩N_(2)泡沫压裂特性试验  

Experimental on N_(2)foam fracturing characteristics of tight siltstone in coal measures

作　　者：肖贺成 梁卫国[1,2] 李文达 王在勇 柴望阳 XIAO Hecheng;LIANG Weiguo;LI Wenda;WANG Zaiyong;CHAI Wangyang(Key Laboratory of In-Situ Property-Improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan 030024,China;College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学原位改性采矿教育部重点试验室,山西太原030024 [2]太原理工大学矿业工程学院,山西太原030024

出　　处：《煤炭学报》2025年第3期1683-1694,共12页Journal of China Coal Society

基　　金：国家区域创新发展联合基金资助项目(U22A20167);山西省基础研究计划资助项目(20210302124664)。

摘　　要：低用水量、低储层伤害、高返排效率的泡沫压裂是低压、低渗、强水敏煤系储层开发的潜在技术之一,但相关研究与应用主要聚焦于泡沫稳定性与流变性能优化,其压裂增渗特征研究不足。鉴于此,开展了不同泡沫干度(泡沫中气体体积分数)的N_(2)泡沫、清水与N_(2)气体压裂煤系致密粉砂岩的裂缝起裂扩展规律对比研究,并评价了裂缝面形态和导流能力特征。结果表明:①泡沫为气液混合物,其压缩性介于清水和N_(2)气体之间,且泡沫干度越高,压缩性越强,压裂增压时间越长;②泡沫呈现高黏、低滤失特性,其岩石破裂压力高于清水和N_(2)气体,且岩石破裂压力与泡沫干度正相关,泡沫干度越高,岩石破裂压力越高;③压裂液排量影响岩石破裂压力,40、20mL/min排量下,90%干度泡沫的破裂压力分别高于清水15.66、6.08MPa;④泡沫压裂的水力输入能量和声发射能量高于清水,且随着泡沫干度升高,其破裂时的最大和累积声发射能量均越大;⑤纯N_(2)气体压裂致密粉砂岩的水力输入能量最高,但主要用于气体压缩,其破裂时的声发射能量最低,压后重注压力高,造缝能力弱。泡沫干度提高,无因次裂缝面积和粗糙度均增加,进而泡沫压裂裂缝导流能力高于清水和N_(2)气体。强水敏储层泡沫流体可替代常规水基高黏压裂液,形成粗糙度和面积更大的高导流裂缝,可为强水敏煤系储层高效压裂增渗开采提供理论指导。Foam fracturing with low water consumption,low reservoir damage and high flowback efficiency is one of the potential technologies for the development of low-pressure,low-permeability and strong water-sensitive coal measures reservoirs.However,the related research and application mainly focus on foam stability and rheological property design,and the research on fracturing and permeability enhancement characteristics is rare.In view of this,this experiment car-ried out a comparative study on the law of crack initiation and propagation of N_(2)foam with different foam quality(volume percentage of gas in the foam),clean water and N_(2)gas fracturing tight siltstone in coal measures,and evaluated the charac-teristics of fracture surface morphology and conductivity.The test results show that:①The foam is a gas-liquid mixture,and its compressibility is between water and N_(2)gas.The higher the foam quality,the stronger the compressibility and the longer the fracturing pressurization time.②The foam has the characteristics of high viscosity and low filtration,rock breakdown pressure is higher than that of water and N_(2)gas,and the rock breakdown pressure is positively correlated with the foam quality,the higher the foam quality is,the higher the rock breakdown pressure is.③The flow rate of fracturing fluid directly affects the rock breakdown pressure,with the flow rates of 40 and 20 mL/min,the breakdown pressures of 90%foam quality are 15.66 and 6.08 MPa higher than those of clear water,respectively.④The hydraulic input energy and acoustic emission energy of foam fracturing are higher than those of clear water,and with the increase of foam quality,the maximum and cumulative acoustic emission energy at the time of rupture are greater.⑤The hydraulic input energy of pure N_(2)gas fracturing tight siltstone is the highest,but it is mainly used for gas compression.The acoustic emission en-ergy is the lowest when it breaks,and the reinjection pressure is high after fracturing,then the fracturing capacity to in-duce f

关 键 词：煤系储层 N_(2)泡沫压裂 泡沫干度 裂缝形态 导流能力 

分 类 号：TE377[石油与天然气工程—油气田开发工程]