气体钻井井斜机理与控制初探

气体钻井由于能有效地保护低压油气层，解决恶性井漏、压差卡钻，提高机械钻速而得到了广泛应用。然而气体钻井井斜机理方面的研究文献报道甚少，井斜机理还不十分清楚。为此，基于气体钻井井底岩石受力状况，从温度、地层各向异性、井径扩大、下部钻具组合等方面对气体钻井不可控因素和可控因素2方面对气体钻井井斜影响进行分析，认为新的岩石破碎机理和地层各向异性是影响气体钻井井斜的主要原因；气体钻井井径的扩大对钻头侧向力产生较大影响，是引起气体钻井井斜的又一因素；并对气体钻井井斜控制做了初步讨论，这将对气体钻井井斜控制及下部钻具组合设计具有一定指导意义。

Research on mechanism and control of borehole deviation in gas drilling

Gas drilling has been widely used, because it can effectively protect low-pressure hydrocarbon reservoirs, solve the problems of severe well leakage and differential pressure sticking, and increase the penetration rate. Few literature reports related to the research on the mechanism of borehole deviation are made, so the mechanism is not quite clear year. Based on the stress status of the downhole rock during gas drilling, the controllable and uncontrollable factors influencing borehole deviation are analyzed, such as the temperature, the formation anisotropy, the borehole diameter enlargement, and the bottom hole assembly. The new rock-breaking mechanism and the formation anisotropy are considered to be the main factors influencing gas drilling. The borehole diameter enlargement of gas drilling exerts great effect on the bit lateral forces, therefore, it is another cause of borehole deviation. The control of borehole deviation is preliminarily discussed, which can be a good reference to the control and the design of bottom hole assembly. 