Study On Anti-deflection Vertical Drilling Technology For Deep Wells In Northwestern Margin Of Moliqing

There is 650 million tons of oil and gas in Yitong basin. The resource is abundant. But due to the Moliqing rift reservoir is with large dip angle of reservoir, large buried depth(2250-3000 m), high underground temperature and high pressure. It leads to the poor drilling quality, the sticking, impellers, well deviation etc outstanding engineering problems.In order to improve the drilling speed and well bore quality, it needs to conduct a complete set of drilling engineering technology research, to solve problems in drilling in the area, to achieve the goal of safety, high quality and fast drilling.According to the Moliqing formation layering, the paper counted and analyzed formation average angle, bottom hole horizontal displacement, the azimuth angle and the average penetration rate, to get the rule of the well deviation and deeply analyze the deviation reason.Based on the need of anti-deflection vertical drilling for the deep well. The vertical and horizontal bending method is adopted as a theoretical basis for solving BHA mechanics problems, to carry out the assembly stress analysis and calculation. The routine assembly mechanical characteristics analysis model and the guide assembly rotating drilling characteristics analysis model were established. It analyzed the interaction between bit and formation, obtained the relationship among the drilling direction, the drilling strata, borehole geometry, the bit and its mechanical characteristics. It put forward the index of trend drilling and drilling trend prediction method, obtained verification method of the assembly actual effect.On the basis of the BHA force analysis model and drilling trend prediction model, it respectively analyzed the use effect of Φ311.1 mm tower drill, pendulum drill, flexible pendulum assembly and Φ215.9 mm ordinary anti-deflection vertical drill assembly, guide drill assembly. Finally it optimized the design of the assembly and drilling parameters, to get a set of design method of anti-deflection vertical drilling. Through the research, in terms of engineering benefit, it provides technical guidance to prevent the occurrence of well deviation and improve the drilling quality. In terms of economic efficiency, it is beneficial to reduce the damage of drilling tools in the process of drilling, thus saving the cost of drilling.Therefore,the study not only has theoretical value, also has important application value and practical significance, to solve the current encountered several problems in the process of deep well drilling,.