异常高压深井裂缝性厚层砂岩储层“酸化+酸压”技术

塔里木油田库车前陆冲断带气藏地层压力高、天然裂缝发育,钻井过程中漏失严重。岩心造缝及岩心流动实验结果表明,常规基质酸化不能有效解除污染,需要能够使天然裂缝张开的"酸压"工艺才能有效解除深部钻井液污染;同时,针对长井段合理布酸需要,推导了黏性暂堵酸化机理,指出增大暂堵酸液黏度有利于合理布酸;结合二者,提出了针对高压天然裂缝性砂岩储层的暂堵酸化+砂岩酸压改造工艺。KS2井现场应用表明,该工艺对改造该类储层适应性强,增产效果显著,对同类储层的增产改造具有一定的指导意义。

Acid fracturing technology for thick fractured sandstone reservoir of deep wells with abnormal high pressure

The pay formation of Kuqa foreland thrust belt in Tarim Oilfield is features in high formation pressure and natural fracture developed here. Lots of drilling fluid often leaked off into the formation during drilling. The experiment of core fracture initiation and core flow shows that the conventional matrix acidizing could not effectively remove the damage, so the acid fracturing technology which could open the natural fractures is required to be applied. Meanwhile, in view of the requirement of reasonable acidification of long hole sections, the temporary acidizing mechanism is derived. It is pointed out that increasing the viscosity of temporary acidizing fluid is useful to reasonable acidification. Then a new technology combining acidizing with sandstone acid fracturing for fractured sandstone reservoir of high pressure is proposed. Through the application to KS2 well, the technology is proved to have high adaptability and remarkable stimulation effect. It could be valuable reference to stimulation and alteration of similar reservoirs.