防流体倒灌的新型泡沫锤研制及其应用

空气锤在油气田研磨性地层提速和高陡地层防斜应用中逐步成熟,但还存在出液地层钻井作业受井底压力的影响而出现输出功率低甚至不工作,以及停止循环时地层液体倒灌气缸而污染空气锤的问题。为此,研制出了同时适应于气体(干气)和雾化泡沫(湿气)钻井介质、具备防止井下流体倒灌的新型泡沫锤。该泡沫锤与空气锤相比,优化了气室结构以保证气体和雾化泡沫钻井介质的输出功率;新增的防倒灌装置在接单根时,依靠泡沫锤阀体与液体当量密度差推动阀体向上运行,可封闭地层流体进入泡沫锤的通道。在松辽盆地徐深气田外围的肇深17井下白垩统泉头组、登娄库组开展了现场试验,泡沫锤在气体介质条件下相比常规钻井机械钻速提高6.5倍,相比气体牙轮钻井提高1倍;在泡沫介质条件下相比常规钻井机械钻速提高2倍且钻进过程未发生井底流体倒灌现象。试验结果表明,所研制的泡沫锤在气体介质条件下相比空气锤输出功率未降低且具备了适应雾化泡沫钻井介质和防井下流体倒灌的能力。

Research,development and application of a novel foam hammer capable of preventing downhole fluid backflow

Air hammers are gradually used for speed improvement in abrasive formation and anti deflection in high steep strata in oil and gas fields. However, when used in water formation, an air hammer is easy to output less energy or fails to work due to the downhole pressure, even the formation fluid flows back into gas cylinder and pollute the air hammer when stopping circulating. In view of this, a novel foam hammer was developed, which is suitable for air (dry), mist or foam (wet) drilling medium and capable of preventing downhole fluid backflow. Compared with an air hammer, this foam hammer has an optimized gas chamber structure to enhance the power output in air, mist or foam drilling medium. Moreover, the foam hammer is equipped with an anti backflow device which uses the equivalent density difference between valve block and formation fluid when making a connection to make the valve move upward to seal the channel through which the formation fluid flows into foam hammer. In the field test conducted at the Quantou and Denglouku Fms of Well Zhaoshen 17 outside the Xushen Gas Field in the Songliao Basin, the penetration rate with a foam hammer and gas drilling medium was 6.5 times higher than that of traditional drilling machine, and was twice as high as that of tri cone bit drilling in gas medium; the penetration rate with foam medium was twice higher than that of traditional drilling machine and downhole fluid did not flow back. The test results showed that compared with an air hammer, this developed foam hammer is featured by higher energy output, and is applicable with mist and foam drilling media and capable of preventing downhole fluid backflow.