新型广谱"油膜"暂堵型钻井完井液体系研究与应用

在钻井过程中为达到保护油层的目的,通常根据油层的平均孔喉半径,在上部钻井液中加入合适粒经的暂堵剂,再配合胶体填充粒子等,将上部钻井液改造为对油层具有保护作用的钻井完井液;但往往在实际钻井中,油层孔喉半径分布范围较宽,导致改造后的钻井完井液仅对某井段具有较好的屏蔽暂堵效果,而对另外的井段起不到较好的保护油层作用.本研究针对油层非均质性强、孔径分布范围较大、油层孔径难以准确预知等特点,根据室内岩样污染评价结果,提出了采用广谱"油膜"暂堵剂GPJ进行广谱"油膜"暂堵,通过室内评价和现场应用表明,该钻井完井液体系不仅实现了对油层的广谱暂堵,而且保护油层效果更佳,可获得更大的日产油量.

Study on System of Broad-spectrum Oil-film Temporary Plugging Drilling and Completion Fluid

To achieve the objective of protecting reservoir during drilling, the common means is to add proper graded temporary plugging materials, coupled with colloid filling particles in upper drilling fluid based on the average radius of pore throat in reservoir to convert upper drilling fluid to reservoir protection fluid. However, in practice due to wide distribution of average radius of pore throat, the converted fluids exert good shielding temporary plugging effects only on certain intervals, and can not exert the function of protecting reservoir. Aimed at the reservoir of severe heterogeneity, wide pore radius distribution, and unpredictability of pore radius, the study put forward to the use of broad-spectrum oil-film temporary plugging agent GPJ for temporary plugging purpose, based on the lab pollution evaluation results of core samples. The lab evaluation and field tests showed that the drilling and completion fluid system not only has broad-spectrum temporary plugging effect, but also bears the function of reservoir protection, thus greatly increasing daily oil production.