北部湾盆地徐闻X3井抗高温承压堵漏技术

徐闻X3井是中石化在北部湾盆地部署的一口重点预探定向井，该井渐新统涠洲组下部地层裂缝孔隙较为发育、地层承压能力低、钻井液漏失严重且井下温度高达180 ℃，导致部分堵漏材料高温后失效，采用常规桥接堵漏和水泥浆堵漏效果不理想，需研发出抗高温承压堵漏技术。为此，通过实验室试验优选出抗高温架桥材料高强支撑剂GQJ、抗高温纤维材料SW，以SAN-2工程分布理论为指导，加入不同粒径的CaCO₃和云母作为片状填充材料，并配合高失水剂HH-1及无机盐CaO，形成了抗高温承压堵漏配方，室内模拟0.5～4 mm裂缝宽度承压能力高于12 MPa。现场采用分段逐级堵漏法注入配制好的堵漏浆进行承压堵漏作业，在地层复杂情况下将地层承压能力提升至4.5 MPa，徐闻X3井第三次开钻固井期间再未发生漏失。实践证明，所研发的抗高温承压堵漏技术能够满足该井的固井施工要求，取得了较好的应用效果。

Hole plugging technology with high-temperature resistance and wellbore strengthening capacity applied in the Xuwen X3 well

The Xuwen X3 well is one of the major exploratory wells located at the Beibuwan Basin by the Sinopec. The lower Weizhou Fm with developed pores and fractures has a poor pressure bearing capacity, resulting in severe lost circulations and lost circulation material failures with a high BHT even up to 180℃. The conventional bridge plugging and cement plugging methods do not produce desired results, so it is necessary to develop the hole plugging technology with high temperature resistance and wellbore strengthening capacity. First, the high temperature resistant bridging material GQJ and the fiber material SW are optimized in experimental tests, then different particle sizes of calcium carbonate and mica are added as packing flakes according to the particle size distribution theory SAN-2, and finally the high filtration loss agent HH-1 and calcium oxide are also supplemented, as a result, the formula of a plugging fluid with high temperature resistance is worked out. The evaluation experiments show that this formulated fluid can strengthen the wellbore to withstand pressures up to 12 MPa when plugging artificial fractures are 0.5 ~ 4 mm wide. This fluid is pumped for plugging downhole in stages, and the withstanding pressure of wellbore is increased to 4.5 MPa under conditions of complex formation. And there have been no such accidents as lost circulation in the Xuwen X3 well since the 3rd spud in and the cementing job afterwards. So this developed plugging program is proved to meet the need of successful cementing in this well with good results obtained.