Development and evaluation of an electropositive wellbore stabilizer with flexible adaptability for drilling strongly hydratable shales

作     者：Wei-An Huang Zheng-Song Qiu Ming-Lei Cui Xin Zhao Jun-Yi Liu Wei-Ji Wang 

作者机构：School of Petroleum EngineeringChina University of Petroleum School of Mechanical and Chemical EngineeringThe University of Western Australia Shandong Shengli Vocational College 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2015年第12卷第3期

页      面：458-469页

核心收录：

学科分类：0820[工学-石油与天然气工程] 082001[工学-油气井工程] 08[工学] 

基　　金：financially supported by the National Science Foundation of China (No.51374233) Shandong Province Science Foundation (No.ZR2013EEM032) the Fundamental Research Funds for the Central Universities (No.13CX02044A) the Project of China Scholarship Council (201306455021) 

主　　题：Shale Wellbore stabilizer Colloidalstability Plugging Hydrophobic modification 

摘      要：In order to overcome serious instability prob- lems in hydratable shale formations, a novel electropositive wellbore stabilizer （EPWS） was prepared by a new approach. It has good colloidal stability, particle size dis- tribution, compatibility, sealing property, and flexible adaptability. A variety of methods including measurements of particle size, Zeta potential, colloidal stability, contact angle, shale stability index, shale dispersion, shale swelling, and plugging experiments were adopted to characterize the EPWS and evaluate its anti-sloughing capacity and flexible adaptability. Results show that the EPWS has advantages over the conventional wellbore stabilizer （ZX-3） in particle size distribution, colloidal stability, inhibition, compatibil- ity, and flexible adaptability. The EPWS with an average particle size of 507 nm and an average Zeta potential of 54 mV could be stable for 147 days and be compatible with salt tolerant or positive charged additives, and it also exhibited preferable anti-sloughing performance to hydrat- able shales at 77, 100, and 120 ~C, and better compatibility with sodium bentonite than ZX-3 and KC1. The EPWS can plug micro-fractures and pores by forming a tight external mud cake and an internal sealing belt to retard pressure transmission and prevent filtrate invasion, enhancing hydrophobicity of shale surfaces by adsorption to inhibithydration. The EPWS with flexible adaptability to tem- perature for inhibition and sealing capacity is available for long open-hole sections during drilling.