焦页54-3HF井低油水比油基钻井液技术"

Oil-Based Mud with Low Oil/Water Ratio for Well Jiaoye 54-3HF

针对焦页54-3HF井三开对油基钻井液封堵性和携岩能力要求高、回收油基钻井液利用率低的技术难点,以聚合物类表面活性剂为主乳化剂,优化了乳化剂、有机土的加量,构建了具有良好稳定性和流变性的油水比65∶35的油基钻井液,并对其性能进行了评价。结果表明,油水比65∶35油基钻井液的稳定性、携岩能力和封堵性能达到了钻井要求,并确定了低油水比油基钻井液与回收油基钻井液的最佳体积配比为1∶2。焦页54-3HF井三开井段在钻进过程中采用了低油水比油基钻井液与回收油基钻井液按体积比1∶2混合的钻井液,钻井液的油水比控制在67∶33~76∶24,破乳电压600~1 000V,动塑比0.30~0.40,三开井段井壁稳定、井眼清洁、摩阻低、起下钻顺利。这表明,低油水比油基钻井液技术可完全满足页岩气水平井钻井需求,具有良好的应用前景。

During drilling the third interval of the Well Jiaoye 54-3HF,oil-based mud（OBM）was required for its higher plugging and cuttings-carrying capacity.To recover the OBM with high utilization rate,polymer surfactants were used as main emulsifiers to produce a new OBM with desirable stability and rheological property by optimizing the volumes of emulsifier and organic clay,with oil/water ratio of65/35.The performance evaluation showed that the new OBM has desirable cuttings-carrying and plugging capacities,which can meet the needs of drilling operations.It was determined that the optimal volumetric ratios should be 1∶2,i.e.the new low oil/water OBM to the recycled OBM.Drilling fluids characterized by low oil/water ratio and recycled OBM were used in the Well Jiaoye-54-3HF,which featured avolumetric ratio of 1∶2,oil/water ratios of 67/33-76/24,emulsion-breaking voltage of 600-1 000 V,and yield point and plastic viscosity ratio of 0.30-0.40.The third interval of the well has a stable sidewall,clean borehole,low friction resistivity and smooth in tripping operations.Thus results indicate that OBM with a low oil/water ratio can meet the demand of drilling horizontal wells for development of shale gas,having good prospects of applications.