大牛地气田保护储层钻井液技术

大牛地气田为低孔低渗砂岩气藏,自产能力低,如不采取全面系统的油气层保护技术,完井后气层基本无自然产能,压裂改造后,单井产气量也普遍较低.通过对储层特征和钻井过程中造成地层伤害的主要因素进行研究,探索出了一套针对大牛地气田的钻井液保护技术,主要包括:屏暂暂堵技术、钾铵基钻井液、两性离子钻井液、聚醚多元醇钻井液、改性天然高分子钻井液等.保护气层钻井液技术的应用,提高了机械钻速和井身质量,减少了钻井液对气层的浸泡时间,解决了井壁失稳、气层伤害问题,提高了气产量.其中,屏蔽暂堵技术对于裂缝性气层具有较好的保护能力;钾铵基钻井液对基质渗透率损害非常小,适合于裂缝不发育的开发井施工,在裂缝发育的区块应结合屏蔽暂堵技术对气层进行全面的保护;聚醚多元醇和改性天然高分子钻井液可以进一步推广应用.

Reservoir protective drilling fluid technology for Daniudi gas field

Daniudi gas iield is a low porosity - low permeability sanded gas reservoir, with low self-productivity. If reservoir protection technology is not taken in full-scale and systemetically, the gas- bearing formation will produce nothing useful by itself. Even stimulated by fracturing job, the individual well gas production is generally low. On basis of investigation on reservoir characteristics and drilling factors damaging the formation, a drilling fluid technology for reservoir protection in Daniudi gas field was proposed. The technology includes shielding and temporary plugging technique, potassium based drilling fluid, zwit terionic drilling fluid, polymer/polycohol drilling fluid and modified natural high molecule polymer drilling fluid. By using this set of technology, the penetration rate was increased, the hole quality is improved, soaking time by drilling fluid was shortened, and wellbore failure, also damage to gas formation was prevented.