页岩钻井储层伤害研究进展

由于非常规储层的特殊性(即低孔、低渗、易膨胀和易破碎等),该类储层在开发过程中极易受到不可逆的伤害。为了认识钻井过程中非常规储层伤害机理,以页岩储层为例,系统地调研了页岩钻井储层伤害的国内外研究现状,分析了目前研究中存在的问题,并对下一步储层保护工作开展提出了建议。研究发现,目前页岩钻井储层伤害研究主要体现在钻井技术和钻井液两方面,但针对非常规储层中井壁稳定性问题的研究相对较少,且对钻井液引起的储层伤害机理认识不够深入。结合页岩钻井储层伤害研究现状,应全面开展非常规储层井壁稳定性、钻井对储层伤害机理和非常规储层钻井液优选的研究。

Research development on formation damage induced by shale drilling

Along with the world energy demand rising, unconventional energy such as shale gas, tight gas, and CBM, etc. have emerged as the supplement of conventional energy. However, due to specialties of unconventional reservoir, i.e., low porosity, low permeability, easy expansion and fragility, this kind of reservoir can be readily damaged irreversibly during the reservoir development. In order to understand the mechanism of formation damage induced by drilling in unconventional reservoirs, research on the formation damage by shale drilling domestically and internationally was systematically reviewed. In addition, existing problems in the study of formation damage were analyzed and suggestions for next formation protection were given. Based on the analysis, it was found that the study of formation damage by shale drilling is mainly reflected in two aspects, i.e. formation damage induced by drilling technology and drilling fluid. However, there are fewer studies of borehole stability in unconventional reservoirs and lack of deep understanding of the formation damage mechanism induced by drilling fluids. Based on the development of formation damage by shale drilling, the studies of borehole stability in unconventional reservoirs, mechanism of formation damage induced by drilling fluids and the optimization of drilling fluids will be conducted systematically.