| Horizontal well drilling is a well-developed technology in recent years.It mainly includes horizontal well optimization design,horizontal wellbore trajectory control,drilling fluid and reservoir protection,well logging and other important technics.Horizontal well drilling is mainly based on improving oil and gas production or recovery.Compared with vertical wells,it can bring huge economic benefits.This thesis is based on the geological conditions of the middle and shallow gas reservoirs in the Zhongjiang-Gaomiaozi gas field and the research on the drilling technology of the horizontal wells developed in the second phase,combined with field experiments and implementation data.The data of horizontal wells in the gas field were analyzed by stratification and sub-section statistical methods,and the research on key drilling technology supporting technologies such as well structure and speed-increasing technology of multi-wells were carried out.The horizontal well drilling technology of Zhongjiang-Gaomiaozi gas field was improved,which effectively guided the drilling construction of the gas field.The main results or conclusions obtained in this paper are as follows(1)A standardization scheme for optimizing and adjusting the wellbore structure of Zhongjiang-Gaomiaozi horizontal well is proposed.The casing running programs and running depth are optimized for different completion characteristics.The complexity is reduced,and the risk of wellbore instability is controlled to a large extent,which is beneficial to reduce the probability of complex underground occurrence.(2)The technical key points of the "one-time drilling technique of inclined section/horizontal well"were put forward,and its technical scheme for Zhongjiang-Gaomiao horizontal well was also proposed.By optimizing the drill bit with faster drilling speed,longer life and higher stability,combined with the screw compound drilling technology,the inclined section/horizontal section footage is completed by one-time drilling.It has played a role in increasing the rate of mechanical drilling and significantly shortening the drilling time,and further promoted it in the Zhongjiang-Gaomiao block.(3)The finite element model of the drilling tool combination was established.The stress and deformation of the drilling tools in the horizontal wells of the Zhongjiang-Gaomiaozi horizontal well were numerically simulated and analyzed.According to the finite element quantitative results of the drilling tool combination,the drilling tool combination scheme that meets the geological complexity of the Zhongjiang-Gaomiao block and the well trajectory control requirements is designed and optimized.(4)A numerical study on gas drilling horizontal well drill string is also analyzed.This model can effectively simulate the axial force,stress,bending moment and deformation of each section of the drill string in the Zhongjiang-Gaomiaozi horizontal well.Through the analysis of finite element results,a gas drilling horizontal well drilling tool combination scheme is proposed to control the well trajectory.(5)The cementing technology optimization is proposed,including casing centering technology,feeding technology and cement slurry optimization,which help determine the location and method of the centralizer.The high-density cement slurry system with good comprehensive performance was designed by the feeding mode and weight and optimizing the cement additive through the change of hook load and friction during the casing insertion process.(6)The main drilling technology optimization schemes for the horizontal wells in the Zhongjiang-Gaomiaozi gas field were integrated,and a systematic set of recommended schemes for the horizontal well drilling technology was formed.The overall technological progress and benefits of the block were Promotion plays a guiding role. |
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