强抑制性有机正电胶钻井液完井液体系研究

新开发的有机正电胶(代号为SDPC)与常规无机正电胶相比，具有更强的正电性，能被水润湿，具有油溶性，与其它钻井液处理剂的配伍性好，具有更强的页岩抑制性、稳定井壁和保护油气层能力。以SDPC为主剂，室内实验对有机正电胶加量和膨润土量的配比、高聚物包被剂、降粘剂、降滤失剂、防塌剂进行了优选，对优选出的强抑制性有机正电胶钻井液完井液体系进行了评价。优选出的强抑制性有机正电胶钻井液完井液高温高压滤失量和粘附系数均较小，老化后终切力较高，携岩能力较强，防塌能力突出，油层保护效果理想，完全满足水平井钻井液完井液对井眼净化、井壁稳定、润滑防卡以及油层保护等方面提出的特别要求，可用于定向井、水平井的钻井作业。

Study on organic positive gel drilling and completion fluid system

A new organic positive gel (remarked as SDPC) has been developed.Comparing witn conventional inorganic positive gel, SDPC has stronger electropositivity and inhibition to shale and good compatibility with other drilling fluid additives.It can be wetted by water with certain oil-dissolvabili-ty.Borehole stability and reservoir protection can be achieved by using it.A novel strong inhibition drilling fluid/completion fluid system was prepared using SDPC as the main additive based on optimizing selections of the proportion of SDPC dosage and bentonite, polymer coalers, viscosity reducers, filtrate reducers, and shale-control agents in laboratory.The system possesses good properties such as low filtration and sticking coefficient in HTHP, high ten -min gel strength after aging at high temperature, good cuttings carrying capacity, strong reservoir protecting ability.It can satisfy the special requirements of wellbore cleaning, stabilizing borehole, lubricating and reservoir protecting in directional and horizontal drilling.