琼东南盆地高温高压井强承压堵漏技术

Mud Loss Control Technology in Qiongdongnan Basin under High Temperature and High Pressure Bearing Conditions

XX23-1-1井是位于琼东南盆地的一口重点预探井,该井在钻进至井深4186.22 m时发生井漏。根据XX23-1-1井地层井漏情况及漏层高温高压工况特点,提出了一种新型高温高压强承压堵漏技术。该高温高压堵漏配方由颗粒、片状和纤维材料复合而成,基于“颗粒架桥+楔入承压+井壁泥饼加固”堵漏机理,在挤注压差下形成结构稳定、密实的封堵层,封堵漏失通道,提高堵漏层的强度和堵漏成功率。对高温高压堵漏材料粒径分布特点、抗高温老化能力、堵漏承压效果进行了评价。实验结果表明:该堵漏剂粒径分布范围广,可解决诱导性裂缝漏失问题;高温高压堵漏剂在180℃老化16h后,材料质量损失率低,具有优异的高温耐久性;对5~3 mm缝板进行封堵,承压能力达到20 MPa以上。高温高压强承压堵漏技术在XX23-1-1井进行了现场应用,最终承压至3 MPa,稳压30 min,压降为0,井底承压当量密度为1.90g/cm^(3),达到了预期效果。

The well XX23-1-1 is a key exploratory well drilled in the Qiongdongnan basin(a basin located in the southeast of Hainan Province).Mud losses were encountered when drilling to 4,186.22 m.A new HTHP pressure bearing lost circulation control technique was presented to deal with the mud losses based on the rate of mud losses and the high temperature high pressure encountered in the mud loss zone.The lost circulation control slurry was formulated with particles,flakes and fibers.Based on the mud loss control mechanisms of“particles to bridge+wedge in to provide pressure bearing capacity+strengthen the borehole wall with mud cakes”,a tight plugging zone with stable structure was formed under squeeze pressure.The channels through which the mud was lost were plugged with the slurry and the loss zone was strengthened.With this technique,the mud losses were successfully stopped.Laboratory evaluation was performed on the particle size distribution,the ability of high temperature resistance and success rate of the slurry.The experimental results show that this slurry has a wide particle size distribution and is able to effectively control mud losses through induced fractures.The HTHP lost circulation materials used in the slurry has low weight losses after aging at 180℃for 16 hours,showing an excellent high temperature durability.Plugging of a 5-3 mm seamed plate with the slurry can stand a pressure of more than 20 MPa.This HTHP pressure bearing mud loss control technique was used in controlling mud losses encountered in the well XX23-1-1,the final pressure bearing capacity of the plugged zone reached 3 MPa and was stabilized at this level for 30 min,with no pressure drop,and the ECD on the bottom of the hole was 1.90 g/cm^(3),meeting the expected requirements.