Research And Application Of Solid Expandable Profile Liner In Directional Well Section

As an effective means to solve the complex situation,solid expandable profile liner technique(EPL)has a unique advantage in solving the problems of serve loss circulation,sloughing and shrinkage formation.However,due to the influence of borehole conditions,the success rate of the technique applicationin the directional well should be further improved.Based on works we had developed four kinds of EPL independently before,this paper analyzes the feasibility of EPL in the directional well by using the methods of theoretical analysis,simulation and laboratory test in order to meet the actual needs of oil companies.Formed the methods of end restoration,weld defects detecting and evaluationcan improve the performance and stability of welds.Developed screw casing roller and reamer while drilling in directional wells can improve the efficiency and reliabilityIn order to identify the utilization feasibility of EPL,finite element simulation analysis and laboratory test are used to analyze the influence of borehole conditions on the hydraulic expansion process of EPL and obtain the variation of the external diameter and the stress with the borehole condition and the expansion pressure.According to the analysis results,the expansion test of pipe string in curved wellbore is simulated in the laboratory which provide the reference data for fieldapplication.Aiming at the problem of the poor consistency of the ends of EPL,a restoration device with three valve wedge structure is developed to improve the stability of weld,which can reduce the amount of the offset between the ends of the 4mm-5mm to less than 1mm.Inview of the lack of weld inspection methods and evaluation standards,X-Ray digital imaging system combined with image processing software is used to detect welding defects.The technology can accurately detect the type,size and location of defects and the detection accuracy can reach 0.01 mm.Combining ABAQUS software with laboratory experiment,the critical sizes of three kinds of typical weld defects,gas pore,incomplete penetration and crack,which could cause weld leakage at 30 MPa pressurewere,are analyzed to provide a basis for the weldperformance test.For low strength,poor efficiency and bad expansion effect of small size tube expander,screw casing roller is designed with the integrated structure,low friction and high wear resistance,which can deal with complicated downhole conditions.In order to solve the problem of reaming after drilling,directional drilling bit is designed to ream while drilling in directional well,which can effectively save the time to deal with the complicated situation.Research products successfully pack sloughing formation with coal and mudstone in two wells of Daniudi Gas Field.It is the first successful application of domestic EPL indirectional well section of PG22 well,the packer length of 109 m,the maximum inclination from 73.69 degree.The packer length of DPT-112 wells reached to 132.7m.This paper has made a significant progress in clear understanding expanding state,improving the performance of stability,complete tools,which provides a new technical means to increase the safety of downhole works.