针对深层页岩气藏的油基钻井液降黏剂研制及应用  

Viscosity-reducing agent of oil-based drilling fluid used in deeper shale gas reservoirs and its application

作　　者：梁文利[1] 代一钦[2] Liang Wenli;Dai Yiqin(Shale Gas Production Technology Services Company,Sinopec Jianghan Petroleum Engineering Company Limited,Qianjiang,Hubei 433121,China;No.2 Drilling Company,Sinopec Jianghan Petroleum Engineering Company Limited,Qianjiang,Hubei 433123,China)

机构地区：[1]中国石化江汉石油工程有限公司页岩气开采技术服务公司,430206 [2]中国石化江汉石油工程有限公司钻井二公司

出　　处：《天然气勘探与开发》2020年第1期71-76,共6页Natural Gas Exploration and Development

基　　金：中国石化重大科技攻关项目“深层页岩气开发工程关键技术研究”(编号:SK1704)。

摘　　要：油基钻井液重复利用后固相含量高,造成流动性变差,致使循环压耗高,最终严重影响钻速。常规掺稀降黏方法加入了大量的柴油、白油,很容易造成钻井液密度降低,且需要补充大量的降滤失剂材料和乳化剂调整泥浆性能,但目前市场上的原油降凝降黏剂与油基钻井液的配伍性不好,部分产品加入之后不降黏反而增黏;部分产品会导致油基钻井液破乳,电稳定性急剧降低,增加页岩的井壁失稳风险。因此,在室内采用强润湿反转剂、沥青分散剂、多点吸附表面活性剂复配而研制了1种油基降黏剂。应用结果表明:①油基降黏剂可以降低黏切,提高流动性,简化现场性能调整配方,且有利于提高排量;②该油基降黏剂能够降低油基钻井液黏度25%以上,提高了油基钻井液的流动性和老浆重复利用率。After oil-based drilling fluid is recycled, its solid content will increase, which may lead to a decrease of flowing capacity but an increase of circulating pressure loss, so as to seriously affect the rate of penetration(ROP). When adopting some conventional dilution-blending viscosity-reducing methods, a great amount of diesel and white oil is added, which may decrease drilling-fluid density easily. In addition, a lot of fluid loss additive and emulsifying agent are needed to adjust drilling-fluid property. At present, however, some available anti-freezing and viscosity-reducing agents are poorly compatible with the oil-based drilling fluid. After adding these agents, the viscosity increases instead of dropping. And some leads to the demulsification of oil-based drilling fluid and the sharp decrease of electrical stability, so as to increase much risk of borehole instability in the shale. So, a novel oil-based viscosity-reducing agent was developed by combining strong-wetting reversal agent, bitumen dispersing agent, and multi-point adsorption surfactant together in the laboratory. And its application results show that this agent can decrease the viscosity shearing, increase the flowability, simplify the on-site property adjustment formula, and improve the displacement. What’s more, the viscosity of oil-based drilling fluid can be reduced by over 30%, and its flowability and the recycling rate of old drilling fluid are improved.

关 键 词：高密度 油基钻井液 降黏剂 多胺基双子表面活性剂 涪陵页岩气 深层开发 

分 类 号：TE254.4[石油与天然气工程—油气井工程]