保护储层的油基钻井液研究

发布时间：2019-06-26 18:33

【摘要】：通常认为油基钻井液比水基钻井液具有抗高温、抗盐/钙侵、有利于井壁稳定、润滑性好和对油气层损害程度小等多种优点。目前已成为高温深井、大斜度定向井、水平井和强水敏地层等各种复杂地层钻进的重要手段。但油基钻井液同样存在一些缺点。例如,油基钻井液悬浮稳定性差,地层损害机理认识不足,储层保护性能评价手段欠缺等问题,这些问题尚有待解决。本文以塔里木油田大北区块储层为研究对象,以研究保护储层的油基钻井液技术为目标,在明确低孔特低渗裂缝性储层地质特征和损害机理的基础上,开展现用油基钻井液综合性能评价,通过优选性能优良的处理剂,并结合储层保护性能研究,形成保护储层的油基钻井液体系。大北区块储层为低孔特低渗储层,裂缝、微裂缝发育,黏土矿物含量较高。室内研究表明,大北区块储层水敏、盐敏及碱敏程度强；盐酸酸敏程度中等偏强,基块岩样应力敏感程度弱,裂缝岩样应力敏感程度强。实验研究表明现用油基钻井液体系稳定性、储层保护性能表现较差,对储层造成一定程度的伤害,渗透率损害率均值可达30%,尚有改善空间。通过对处理剂种类的筛选及加量的优选,最终确定选用有机土AJ、主乳化剂EMUL-2、辅助乳化剂TLMFR、降滤失剂Duratone+Geltone和润湿剂TLMRSJ等处理剂,结合优选出的各处理剂配伍性能评价,在大量实验基础上最终确定油基钻井液体系配方为：柴油+3%有机土AJ+3%主乳化剂EMUL-2+1%辅助乳化剂TLMFR+(浓度20%)CaCl2盐水(油水比80：20)+2.5%CaO+2%降滤失剂Duratone+2%降滤失剂Geltone+1.5%润湿剂TLMRSJ+重晶石(ρ=1.80g/cm3)。针对大北区块储层特征及现用油基钻井液综合性能特点,结合保护油气层技术手段,确定了保护大北区块裂缝性储层的油基钻井液体系基本配方：自配油基钻井液(ρ=1.80g/cm3)+0.2%纤维状暂堵剂HF+2%复配活性CaCO3+0.5%酸溶性微锰矿(KGD)+0.5%可变形粒子(FEP)+其它。结合动态损害评价实验,设计的保护储层油基钻井液体系可以满足同时保护孔喉和裂缝的要求,暂堵后渗透率返排恢复率可达90%以上,达到了保护储层的目的。
[Abstract]:It is generally considered that the oil-based drilling fluid has the advantages of resisting high temperature, resisting salt/ calcium, and being beneficial to the stability of the well wall, good lubricating property and small damage to the oil and gas layer. At present, it has become an important means of drilling in various complex formations such as high-temperature deep well, high-grade directional well, horizontal well and strong water-sensitive stratum. Oil-based drilling fluids also have some disadvantages. For example, the problems of poor suspension stability of oil-based drilling fluid, insufficient understanding of formation damage mechanism, lack of evaluation methods of reservoir protection performance, etc., are still to be solved. Based on the study of the geological characteristics and the damage mechanism of the low-porosity and low-permeability fractured reservoir, the comprehensive performance evaluation of the oil-based drilling fluid is carried out on the basis of defining the geological characteristics and the damage mechanism of the low-porosity and low-permeability fractured reservoir. The oil-based drilling fluid that protects the reservoir is formed by a treatment agent that is preferably excellent in performance, and in combination with the reservoir protection performance. The reservoir of the northern block is the low-porosity, low-permeability reservoir, the fracture, the micro-crack development, the clay mineral contains The results show that the water-sensitive, salt-sensitive and alkali-sensitive degree of the reservoir in the large north block are strong, the degree of acid sensitivity of the hydrochloric acid is moderate, the stress sensitivity of the base block is weak, and the crack rock-like stress is sensitive. The results of the experiment show that the stability of the oil-based drilling fluid system, the poor performance of the reservoir protection performance, the degree of damage to the reservoir, the average value of the permeability damage rate can reach 30%, The preparation method comprises the following steps of: selecting an organic soil AJ, a main emulsifier EMUL-2, an auxiliary emulsifier TLMFR, a filtrate reducer Duratone + Geltone and a wetting agent TLMSRJ, and the like, Wood-based drilling fluid system formula: diesel + 3% organic soil AJ + 3% main emulsifier EMUL-2 + 1% auxiliary emulsifier TLMFR + (concentration 20%) CaCl2salt water (oil-water ratio 80:20) + 2.5% CaO + 2% filtrate reducer Duratone + 2% filtrate reducer Geltone + 1.5% wetting agent TLMSRJ + barite (1 = 1.80 g / cm3). In view of the reservoir characteristics of the large north block and the characteristics of the comprehensive performance of the oil-based drilling fluid, the oil-based drilling of the fractured reservoir in the large north area is determined in combination with the technical means of protecting the oil and gas layer. Basic formula of liquid system: self-aligned oil-based drilling fluid (1 = 1.80 g/ cm3) + 0.2% fibrous temporary plugging agent HF + 2% compound active CaCO3 + 0.5% acid-soluble micromanganese ore (KGD) + 0.5% deformable particles ( In combination with the dynamic damage evaluation experiment, the designed oil-based drilling fluid system can meet the requirements of simultaneously protecting the pore throat and the crack, the recovery rate of the permeability after the temporary plugging can reach more than 90%,
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE254

【参考文献】