有限元法确定煤层气井钻井液密度窗口模型应用  

Determination of Drilling Fluid Density Window Model for CBM Well by FEM

作　　者：林海[1] 陈磊[1] 程远方 蒋振伟[1] 张振活[1] 凡帆[1] 董海东[1] 郝超[1] 刘婷婷[1] 

机构地区：[1]低渗透油气田勘探开发国家工程实验室,川庆钻探钻采工程技术研究院,陕西西安710018 [2]中国石油大学〈华东〉石油工程学院,山东青岛266580

出　　处：《探矿工程（岩土钻掘工程）》2014年第5期1-5,共5页Exploration Engineering:Rock & Soil Drilling and Tunneling

基　　金：国家科技重大专项"大型油气田及煤层气开发"(2011ZX05021)

摘　　要：随着国内市场对天然气需求量的迅速增长,如何成功开发宁武盆地储量丰富的煤层气资源已成为目前非常规气藏开发的一个重要课题。结合宁武盆地地应力状态、地层孔隙压力、地层强度参数、井斜角和方位角等参数,科学确定适合煤层气井钻进的钻井液密度窗口,成为宁武盆地煤层气项目能够高效、安全实现产业化发展的关键因素之一。通过ANSYS软件对宁武盆地9号煤层建立有限元模型,分别分析了不同地应力方向时不同井斜角钻井液密度对井眼扩大率的影响规律,针对不同方位和井斜得出了适用的钻井液密度窗口,对于下一步宁武盆地煤层气井产业化开发中有效控制煤层坍塌,降低复杂情况,提高钻井效率及提高煤层气开发综合效益提供了技术支撑。With the rapid growth of market demand for natural gas, how to successfully develop the rich CBM reservoir in Ningwu basin becomes an important subject in unconventional gas reservoir development.It is one of the key factors to sci-entifically determine a suitable drilling fluid density window by combining with the crustal stress state, the parameters of formation pore pressure and formation strength, as well as angle of deviation and azimuth angle in order to realize effective and safe coal-bed methane industrialization development in Ningwu basin.The finite element model of No.9 coal seam in Ningwu basin is established by ANSYS software, the influence rule of hole enlargement ratio is analyzed in the conditions of different crustal stress directions and different well inclination, by which the optimized range of mud density is obtained to control coal seam collapse and reduce complex prescription, and the support for research on improvement of drilling effi-ciency and comprehensive benefit of CBM in NingWu basin is found.

关 键 词：煤层气 地应力 有限元法 井壁稳定 钻井液密度窗口 宁武盆地 

分 类 号：TE371[石油与天然气工程—油气田开发工程]