川南泸州地区页岩气甜点地质工程一体化关键要素耦合关系及攻关方向

Coupling Key Factors of Shale Gas Sweet Spot and Research Direction of Geology-Engineering Integration in Southern Sichuan

页岩气甜点地质工程一体化关键要素分析与评价是页岩气高效勘探开发的必要工作.从甜点优选、钻完井工程、压裂工艺等多方面对川南泸州地区开展研究,结合地质工程一体化研究思路,系统分析了工程要素与地质要素的耦合关系.结果表明:泸州地区地质条件复杂,水平最大主应力方向为NWW-SEE向,由西向东裂缝发育程度减少;天然裂缝方向与最大主应力方向和井轨迹有效匹配提高压裂改造体积,井轨迹方位与地应力夹角大于60°、与裂缝主方向夹角大于20°时,水平井压裂效果越好;通过加密分簇、提高排量、暂堵转向、提高加砂强度等技术优化,可保证深层页岩改造体积及缝网有效性.综上,利用工程与地质双因素耦合分析,开展深层井轨迹与甜点预测关系、深层裂缝体积改造与地应力关系、深层钻-完井工程与岩石力学关系技术攻关,能够有效推动地质工程一体化的动态运行,提高单井最大可采量和区块最大动用量.

The geology-engineering integration of shale gas is necessary for analyzing and evaluating the key elements in efficient exploration and development of shale gas.This paper presents a study from the perspectives of sweet spot optimization,drilling,well completion engineering,and fracturing technology in Luzhou area,southern Sichuan.Combined with the geology-engineering integration,the coupling relationship is systematically analyzed between engineering and geological factors.The results show that the geological conditions of the Luzhou area are complex,and the direction of horizontal maximum principal stress is NWW-SEE.The development of fractures decreases from west to east.The effective matching well trajectory can improve the fracturing volume between the natural fracture direction and the maximum principal stress direction.When the angle between the good trajectory azimuth and the stress is greater than 60°,and the angle between the good trajectory azimuth and the main fracture direction is greater than 20°,the horizontal well fracturing effect is better.Through technical optimization such as encryption clustering,an increase of displacement,temporary plugging and steering,and an increase of sand strength,the volume of deep shale transformation and the effectiveness of the fracture network can be ensured.In summary,with the coupling analysis of engineering and geological factors,the technical research on the relationship between deep good trajectory and sweet spot prediction,the relationship between deep fracture volume transformation and in-situ stress,and the relationship between deep drilling and completion engineering and rock mechanics can effectively promote the dynamic operation of geological engineering integration,which can improve the maximum recoverable amount of single well and the maximum production of the block.