预置管酸液射流钻进数值模拟与实验

Numerical simulation and experiment on acid jet drilling with preset pipes

为了解决深层缝洞型碳酸盐岩储层精确改造的难题,开展了预置管酸液射流钻进技术研究。建立了预置管酸液射流钻进碳酸盐岩数值模型,分析了酸液喷射钻进的流场结构,开展了酸液射流钻进物理模拟实验。研究结果表明:预置管酸液射流能在碳酸盐岩露头中实现稳定钻进,钻进中钻遇50~150 mm间隙时,管体满足稳定钻进强度条件,造孔孔径18~26 mm。结合模型介质流线分析,酸液溶蚀扩孔效果明显,排量及酸浓度在局部范围内与钻速成正比,酸盐反应速率是影响孔径主要因素,岩石力学性能与钻速及孔径相关性高,钻进轨迹沿喷射方向整体成直线。研究结果可为碳酸盐岩预置管酸液钻进径向水平井技术应用提供理论指导和技术支撑。

In order to solve the problem of precise stimulation of deep fractured-vuggy carbonate reservoirs,the research on acid jet drilling technology with preset pipes was carried out.A numerical model of acid jet drilling into carbonate rocks with preset pipes was established,the flow field structure of acid jet drilling was analyzed,and physical simulation experiments on acid jet drilling were carried out.The research results show that the acid jet from the preset pipe can realize stable drilling in the carbonate rock outcrop.When the drilling encounters a gap of 50-150 mm during drilling,the pipe body meets the strength conditions for stable drilling,leaving a hole diameter ranging from 18 mm to 26 mm.Combining with the analysis on the streamline in the model medium,it is found that,the hole expansion effect due to the acid solution is obvious,the displacement and the acid concentration are proportional to the drilling speed in local area,the acid reaction rate is the main factor affecting the hole diameter,the rock mechanical properties are highly correlated with the drilling speed and the hole diameter,and the drilling trajectory is in a straight line along the injection direction as a whole.The research results provide theoretical guidance and technical support for the application of the acid fluid drilling technology with preset pipes in radial horizontal wells in carbonate rock reservoirs.