气举反循环连续取心工艺探索

Air lift reverse circulation continuous coring technology

气举反循环钻进技术是钻井工程中一种比较成熟的钻进手段,凭借钻进效率高、钻头寿命长、成井质量好等特点,目前已经得到了广泛应用及推广。气举反循环连续取心技术仍处在探索研究阶段,前人针对这一技术做了原理性的探究试验,但尚未进行连续的取心试验,而且现有的双壁钻具也存在无法满足由于上返岩心质量和直径大对其密封性和耐用性的要求。因此有必要进一步开展理论研究、参数计算、优化钻具设计、进行连续取心试验来探究这一工艺的发展前景。通过试验证明大通径双壁钻具具有可靠的耐用性,并能连续取得岩心。所取岩心及时,无污染,代表性强,能较真实地反映地层层位、深度、颗粒级配,不存在对岩心的反复冲刷及重复破碎情况。

Air lift reverse circulation drilling technology is a relatively mature drilling method in drilling engineering.With the characteristics of high drilling efficiency,long bit life,and good well quality,it has been widely used and promoted. However,air-lift reverse circulation continuous coring technology is still in the stage of exploratory research.The predecessors have done theoretical exploration tests on this technology,but continuous coring tests have not been carried out,and the existing double-wall drilling tools are also unable to meet the requirements for sealing and durability due to the quality and diameter of the returning cores. Therefore,it is necessary to further carry out theoretical research,parameter calculation,optimization of drilling tool design, and continuous coring test to explore the development prospects of this technology. The tests have been done,and the results show that the design of the large diameter double wall drilling tool is reliable and durable,and it can successfully obtain cores continuously. The cores were timely taken,free of pollution,highly representative,and can truly reflect the stratum level,depth,and particle gradation without repeated erosion and repeated fragmentation.