超深井钻井液完井液HCO_3^-和CO_3^(2-)污染规律和处理方法  

HCO_3^- & CO_3^(2-) contamination in ultra-deep wells and its treating method

作　　者：黄宏军[1] 

机构地区：[1]中原油田分公司工程监督中心

出　　处：《钻井液与完井液》2003年第4期31-33,共3页Drilling Fluid & Completion Fluid

摘　　要：在中原油田十几口超深井目的层钻进中,钻井液完井液均受到过不同程度的HCO3-和CO32-化学污染。通过室内研究和现场应用,总结出HCO3-和CO32-的污染规律、性能特征及针对性处理措施。要正确鉴别钻井液的老化与受化学污染的不同。对HCO3-和CO32-污染的准确判别和及时处理,可减少处理剂用量,缩短处理时间,确保井下安全。HCO3-和CO32-污染的最大特点是,钻井液气泡多,颜色暗黑,粘度高,用稀释剂处理无效或效果差,切力呈上升趋势,性能极不稳定,触变性强。判定为HCO3-和CO32-污染后,必须进行滤液分析,并根据滤液的pH值、泥饼质量和滤失量等数据,拟定处理方案,通过小型试验确定Ca(OH)2加量,在1～2个循环周内加入;控制pH值为11.0～11.5是处理该污染的关键;同时,在满足携屑能力的前提下尽量降低粘度和切力,保证钻井液有良好的流变性。Drilling/completion fluids were contaminated to different degree by HCO3- and CO32- while drilling through objective intervals in a group of ultra-deep wells in Zhongyuan oilfield. The most visible characteristics of HCO3- and CO32- contamination are that lot of gas foams exist in drilling/completion fluid, and the color of the fluid is dark;fluid viscosity is higher and the thinner is helpless or its effect is not good; shear force of the fluid presents a escalating trend; fluid thixotropy is strong and its properties are very unstable. The additives dosage and treating time can be decreased owing to the accurate discriminating and timely treating for the contamination. The states and characteristics of the contamination have been investigated and a treating method has been developed based on laboratory study and field applications. The aging of drilling/completion fluid and its contamination must be accurate diagnosed, and filtrate fluid analysis must be done immediately as soon as HCO3- and CO32- contamination is determined, treating plan is then made according to pH value of filtrate fluid, to mudcake quality and to filtrate loss volume, and confirming dosage based on test and add Ca(OH)2 into drilling/completion fluid within one or two circulations. In addition, the keys of treating the contamination are controlling the pH value within 11. 0-11. 5 and to ensure the fluid has good rheological property. Its viscosity and shear force should be reduced to the least as long as it satisfies the requirement of carrying cuttings.

关 键 词：超深井 钻井液 完井液 HCO3^- CO3^2- 污染规律 处理方法 污染 

分 类 号：TE254[石油与天然气工程—油气井工程] TE257.6