长宁地区页岩气钻井平台不同开孔层位不良地质体勘查

The Exploration of Unfavorable Geological Body of Shale Gas Drilling Platform at Different Openings in Changning Area

四川省宜宾地区属页岩气资源勘探优质区块,但地处四川盆地西南缘,南临云贵高原,地表水文地质、地形复杂,页岩气钻井勘探过程中,在前期1 000m以浅常受一些不良地质现象(岩溶、裂隙、滑坡、破碎堆积体等)影响,造成卡钻、掉钻等孔内事故;钻遇岩溶通道时,会引起钻井液严重漏失,对工程施工造成损失,同时对生态环境造成影响,因此在前期钻井平台位置的选取至关重要。以长宁页岩气区块前期已进行的地表地质、物探勘查资料及已钻探成果为基础,分析总结该研究区在不同开孔地层存在的不良地质现象规律,为页岩气钻井平台的选取提供参考依据,避让较大地质异常,减少钻井风险,提高施工效率。

The Yibin area of Sichuan province is a high-quality block for shale gas exploration.In the southwest margin of the Sichuan basin and in the south of the Yunnan Guizhou Plateau,the surface hydrogeology and the terrain are complex.During the drilling process of shale gas drilling,there are some bad geological phenomena(karst,fracture,landslide,fractured accumulation,etc.)in the early 1000 meters of shale gas drilling,causing drilling stuck and other hole accidents.When drilling in the karst channel,the drilling fluid will be seriously lost,causing damage to the engineering construction and affecting the ecological environment.Therefore,it is very important to select the position of the drilling platform in the early stage.This paper,based on the surface geology and geophysical exploration data and drilling results that have been carried out in the early stage of the Changning shale gas block,analyzes and summarizes the bad geological phenomena existing in different opening strata of the study area,provides reference for selection of shale gas drilling platform,avoids large geological anomalies,reduces drilling risk and improves construction efficiency.