页岩气地质导向技术在威远地区的应用

Application of Shale Gas Geosteering Technology in Weiyuan Area

摘要: 随着页岩气藏开发的深入，利用水平井开发页岩气已成为一项重要技术并被广泛采用，已钻水平井试油试采数据表明水平段在储层的位置十分重要，优势储层的产量是一般储层产量的几倍。威远地区页岩气区域探井分布少，地层发育状况探明程度低，构造落实程度差，微幅构造复杂；目的层岩性变化不明显，通过常规导向手段，判断钻头所在储层中的位置存在多解性，优势储层的随钻识别和钻探地层位置判断成为现场工作的主要难题。应用页岩气地质技术导向技术，对目的层做出精细划分，寻找出优势储层；应用地质导向技术建立导向精细模型，通过对精细模型的动态调整，轨迹实时修正，追踪优势储层，能够确保优势储层钻遇率和水平井实施的成功率，降低地质、工程风险。

Abstract: With the deepening of development of shale gas reservoirs, the horizontal well which is one of critical techniques has been used widely to develop shale gas reservoirs. The data of well test and production test from drilled horizontal wells showed that the position of horizontal section in the reservoir was very important, and the production of a good layer was several times that of common layer. There were few shale gas exploration wells in Weiyuan area, so little knowledge on stratigraphic development condition and structures was less, and microstructure was complex and the variation of lithology of the target layer was not obvious, position of the drill bit judged by the conventional means was ambiguous. Identification of favorable layers while drilling and determination of formation location were the main problems in the field work. The target zone is finely divided based on the geosteering in the shale gas reservoir, so as to find the favorable layers. A detailed model is established by geosteering. The model can be dynamically adjusted, the trajectory is corrected in real-time to track the favorable reservoir to ensure the drilling-encounter ratio of the favorable reservoirs and success rate of horizontal wells, and reduce the geological and engineering risks.