鄂尔多斯盆地低压海相页岩气储层体积压裂及排液技术  

Volume fracturing and drainage technologies for low-pressure marine shale gas reservoirs in the Ordos Basin

作　　者：付锁堂[1,2] 王文雄 李宪文[1,2] 席胜利 胡喜峰[1] 张燕明[1,2] FU Suotang;WANG Wenxiong;LI Xianwen;XI Shengli;HU Xifeng;ZHANG Yanming(PetroChina Changqing Oilfield Company,Xi'an,Shaanxi 710018,China;National Laboratory for Exploration and Development of low Permeability Oil and Gas Fields,Xi'an,Shaanxi 710021,China)

机构地区：[1]中国石油长庆油田公司 [2]低渗透油气田勘探开发国家工程实验室

出　　处：《天然气工业》2021年第3期72-79,共8页Natural Gas Industry

基　　金：国家科技重大专项“鄂尔多斯盆地大型低渗透岩性地层油气藏开发示范工程”(编号:2016ZX05050)。

摘　　要：天然气资源量丰富的鄂尔多斯盆地中奥陶统乌拉力克组海相页岩气藏,是中国石油长庆油田公司油气增储上产的重要资源基础,但较之于国内外其他页岩气藏,前者地层压力系数低、储层物性及含气性较差、提产难度更大。为此,在前期直井试验的基础上,开展了水平井体积压裂研究与试验,总体按照长水平井分段多簇大规模压裂的技术思路,立足鄂尔多斯盆地页岩气储层压裂的地质特征,开展了裂缝扩展机理与形态特征研究与分析;在此基础上,优选建立全三维裂缝模型进行参数优化,试验井ZP1井压裂15段103簇,压后形成了较为复杂的裂缝网络,裂缝复杂指数介于0.4~0.6,微地震监测带长579 m、带宽266 m、缝高146 m。针对该盆地低压页岩气大液量压裂后面临的排液难题,开展了气体增能压裂试验,考虑储层物性、含气性和分段裂缝等特征,在试验水平井压裂时分段注入液氮805 m3,根据压力恢复数据测试地层压力系数由0.7~0.8提升到1.88;建立了井筒气液流动模型,优化了长周期控压排液参数;升级配套了地面关键设备,实现了精确计量与安全环保。研究和实践结果表明:①通过技术创新优化,试验井ZP1井实现了94天连续气液两相流,试采产量和压力稳定,井口测试日产页岩气6.42×104 m3;②试验井压后页岩气无阻流量达到26.4×104 m3/d,较同区块直井试气产量提高超过10倍,实现了中国北方海相页岩气勘探的重大突破。There are abundant natural gas resources in the marine shale gas reservoir of Middle Ordovician Wulalike Formation in the Ordos Basin,which is an important resource base for PetroChina Changqing Oilfield Company to increase the reserves and production of oil and gas.Compared with the other shale gas reservoirs at home and aboard,however,the marine shale gas reservoir of Middle Ordovician Wulalike Formation in the Ordos Basin has a lower formation pressure coefficient and poorer reservoir physical properties and gas-bearing property,so its production increase difficulty is higher.In this paper,horizontal-well volume fracturing was studied and tested based on the earlier vertical well tests.According to the technical idea of the staged multi-cluster massive fracturing of long horizontal section,the propagation mechanisms and morphological characteristics of fractures were studied and analyzed based on the fracturing geological characteristics of the shale gas reservoir in the Ordos Basin.On this basis,a full three-dimensional fracture model was optimally established for parameter optimization.The fracturing of the test well ZP1 was carried out with 15 stages and 103 clusters.After the fracturing,a more complex fracture network was formed with a fracture complexity index of 0.4-0.6.The microseismic monitoring zone is 579 m long and 266 m wide and the fracture is 146 m high.To address the drainage difficulty after large-volume fracturing of low-pressure shale gas in the Ordos Basin,this paper carries out a gas energized fracturing test.Considering the characteristics of reservoir physical properties,gas-bearing property and segmented fractures,805 m3 liquid nitrogen was injected in stages during the fracturing of the test horizontal well.The formation pressure coefficient measured from pressure buildup data is increased from 0.7-0.8 to 1.88.The wellbore gas-liquid flow model was established and the parameters of long-period control-pressure drainage under were optimized.The critical surface equipment was upgraded to

关 键 词：鄂尔多斯盆地 中奥陶统乌拉力克组 海相页岩气藏 低压页岩气 水平井 储集层 体积压裂 排液技术 产气量 

分 类 号：TE377[石油与天然气工程—油气田开发工程]