摘要
准噶尔盆地玛湖凹陷风城组发育厚层状白云质岩致密储集层,属典型的下生上储型油藏,岩性致密坚硬,对入井流体敏感,储集层改造难度极大。地层水矿化度极高且含有硼、钛、锆等离子,使得压裂液破胶不彻底甚至返胶,返排困难;油藏具有"三高一深"特征(压力系数大于1.5、温度大于100℃、岩石闭合应力大于90 MPa、埋藏深度大于4 000 m);地应力分布复杂和天然裂缝发育导致压裂改造时滤失大、裂缝形态多变、缝宽窄、易砂堵。针对上述难点,研究了新型耐高温酸性疏水缔合物压裂液,解决了压后返胶问题;通过建立岩石力学参数动静态转换解析式、研究支撑剂粒径选择方法、建立预测地层破裂压力的经验公式等,系统优化了压裂设计方法。目前已开展现场试验23井次,施工成功率由之前的50%提高到100%,施工入井支撑剂平均用量由低于35 m3提升至42.5 m3.
The Fengcheng formation in Mahu sag in Junggar basin develops a thick-bedded tight dolomite reservoir,which is a typical oil reservoir with lower generation and upper accumulation.The tight and rigid lithology is sensitive to the fluid in a wellbore and resulted in difficulty for reservoir stimulation.The reservoir is characterized by very high salinity and containing B,Ti and Zr heavy metal ions in the formation water,which lead to the incompletion of gel breaking and the difficulty of fluid returning.Also,the reservoir has the features of ＂three highs and one deep＂,namely,high pressure coefficient （＞1.5）,high temperature（＞100℃）,high closure stress （＞90 MPa） and large buried depth （＞4000 m）.The complexity of the stress distribution and the development of natural fractures have caused fracturing filtration,varied fracture shapes,narrow fracture width and easily sand plugging.Aiming at these difficulties,this paper presents a new kind of fracturing fluid with high-temperature resistant and acidic hydrophobic association to solve the post-fracturing gel-returning problem.In addition,by establishing the formula of rock mechanics parameters of static and dynamic conversion and studying screening approach of proppant grain size,this paper establishes the empirical equation for prediction of the formation fracture pressure,thus systematically optimizing the fracturing design program.At present,23 field tests have been implemented,and the success rate of the projects has increased from 50％ to 100％,then the average proppant volume has increased from less than 35 m3 to 42.5 m3.
出处
《新疆石油地质》
CAS
CSCD
北大核心
2014年第1期101-104,共4页
Xinjiang Petroleum Geology
关键词
玛湖凹陷
致密油藏
白云质岩
高闭合应力
压裂改造
Mahu sag
tight reservoir
dolomite
high closure stress
fracturing stimulation
