长宁区块页岩气水平井无土相油基钻井液技术

Clay-Free Oil Based Drilling Fluid Technology for Shale Gas Horizontal Wells in the Changning Block

凡帆 王京光 蔺文洁

FAN Fan WANG Jingguang LIN Wenjie

低渗透油气田勘探开发国家工程实验室, 陕西西安 710021; 中国石油川庆钻探工程有限公司钻采工程技术研究院, 陕西西安 710021

National Engineering Laboratory of Low-permeability Oil & Gas Exploration and Development, Xi’an, Shaanxi, 710021, China; Drilling & Production Engineering Technology Research Institute of CNPC Chuanqing Drilling Engineering Co. Ltd., Xi’an, Shaanxi, 710021, China

针对四川长宁区块页岩气水平井应用的有土相油基钻井液存在的流变性差、易诱发井漏等技术难题，开展了无土相油基钻井液技术研究。为提高油基钻井液的电稳定性和悬浮性，研制了复合型乳化剂G326和油溶性聚合物增黏剂G336，并确定了无土相油基钻井液配方。室内试验结果表明，与有土相油基钻井液相比，无土相油基钻井液具有更强的电稳定性和更低的终切力，有利于预防高密度条件下油基钻井液的稠化和复杂地层漏失问题。无土相油基钻井液在长宁区块某平台4口页岩气水平井进行了现场应用，这4口井井壁稳定，无缩径无掉块，起下钻畅通，井眼始终处于良好净化状态，平均机械钻速提高37.8%。研究结果表明，无土相油基钻井液解决了传统高密度油基钻井液因结构强度大而易诱发井漏的问题，满足了长宁区块页岩气水平井安全快速钻井的需要。

Due to fact that the conventional clay oil based drilling fluid used in shale gas horizontal wells in the Changning Block, Sichuan Basin, is poor in rheology and easy to induce lost circulation, the clay-free oil based drilling fluid has been studied. To enhance the electric stability and suspension performance of the proposed oil based drilling fluid, the composite emulsifier G326 and oil-soluble polymer viscosifier G336 were developed, and determined the formula for the clay-free oil based drilling fluid. Indoor test results showed that the clay-free oil based drilling fluid had a higher electric stability and lower final gel strength than conventional clay oil based drilling fluids, which is faverable for eliminating the thickening problem of oil based drilling fluids and lost circulation in complicated formations in the case of high density. When the clay-free oil based drilling fluid was deployed in four shale gas horizontal wells in the Changning Block, drilling operations were performed smoothly with stable borehole wall, no tight hole and sloughing, smooth tripping and clean wellbore, average ROP enhanced by 37.8%. Research results showed that the clay-free oil based drilling fluid could prevent the lost circulation that caused by conventional oil based drilling fluid with high density due to its high structural strength, which can meet the need of drilling shale gas horizontal wells fast and safely in Changning Block.

中国石油天然气集团公司科技项目“西部大庆建设长庆钻完井整体提速及压裂一体化技术研究与现场试验”（编号：2013T-0105-001）部分研究内容。

https://doi.org/10.11911/syztjs.201605006