深部裂缝性致密储层随钻堵漏材料补充时机研究

深部裂缝性致密储层地质条件复杂、天然裂缝发育,钻井液漏失风险大。加入随钻堵漏材料是预防裂缝性地层钻井液漏失、控制储层损害的重要手段。为系统研究考虑钻进过程中材料消耗的随钻堵漏材料补充时机,以塔里木盆地某深部裂缝性致密气藏为研究对象,实验评价了不同随钻堵漏材料消耗比例下的油基钻井液体系承压能力,并基于地层裂缝产状构建了随钻堵漏材料消耗率计算模型。结果表明:当材料消耗率超过15%后,随钻堵漏油基钻井液体系的封堵能力显著降低;地层裂缝宽度及倾角对随钻堵漏材料消耗率影响显著,裂缝倾角越接近90 °、裂缝宽度越大、裂缝线密度越大,材料消耗率增长越快;在确定随钻堵漏材料补充时机及补充量时,需要特别注意地层裂缝宽度及倾角变化。该计算模型在现场试验中取得了良好应用效果,对深部裂缝性致密储层高效钻井有指导意义。

Study on the Supplement Timing of Leakage Stoppage Materials while Drilling for Deep Fractured Tight Reservoirs

Deep fractured tight reservoirs have complex geological conditions and develops natural fractures, with high leakage risk of drilling fluid. In deep fractured tight reservoirs, adding leakage stoppage materials while drilling is an important means to prevent drilling fluid leakage and to control formation damage. In order to systematically study the timing to supplement the leakage stoppage materials consumed during the drilling process, a deep fractured tight gas reservoir in the Tarim Basin was taken as the research object. In the research, the pressure-bearing capacity of the oil-based drilling fluid system under different consumption ratios of the leakage stoppage materials while drilling was evaluated through experiments, and a calculation model for the consumption rate of the leakage stoppage materials while drilling was constructed based on the occurrence of formation fractures. The results show that when the material consumption rate exceeds 15%, the stoppage ability of the oil-based drilling fluid system while drilling is significantly reduced; the width and dip of the formation fractures have a significant impact on the consumption rate of leakage stoppage materials while drilling; the closer of the fractures to 90 °, the wider the fractures and the denser the fracture line, the faster the material consumption rate; after determining the supplement timing and supplement amount of the leakage stoppage materials while drilling, the changes in fracture width and dip should be paid special attention. This calculation model has achieved good application results in field tests, and has a guiding significance for efficient drilling in deep fractured tight reservoirs.