Research On Well Structure Design Of High Pressure Gas Well

The geological conditions of the Longmen gas field in the Sichuan Basin are complex.It can be known from the analysis of the existing geological data that the gas field is located in the lower part of the fault and the nearby fractures are developed.The gas reservoir is a lithologic-structural composite trap gas reservoir.During the drilling process,through the analysis of the well Tiandong 5 well,it can be seen that there are well leakage and blowout phenomena.The root cause of this situation is the complexity of formation pressure conditions.The traditional casing sequence series has too few layers,and the target casing and borehole clearance are too small to meet the needs of the complex geology of high pressure gas wells.At the same time,the traditional pressure profile curves cannot accurately reflect the complex conditions of the strata..Therefore,a new well structure design method needs to be established to meet the design requirements.On the basis of considering the geological conditions,this article first determines the location of the necessary sealing points,adopts a design method that will be sealed from both sides to design the well structure of the high-pressure gas well,and it will be based on commonly used self-Bottom-up and top-down approach design.At the same time,considering the presence of corrosive gases such as H2 S in wells,corrosion-resistant casing pipes were selected to ensure the safety of the casing and meet the special requirements of high-pressure gas wells;the material suitable for high-pressure gas well environments was selected and used for the selection of thread fasteners.Metal-to-metal seals are specially designed to ensure tightness while meeting strength requirements.Based on the design method established in this paper,an example was calculated for the Tiandong 57 well in the Longmen gas field in Sichuan Basin.