Study On The Mechanical Behavior And The Matching Tool Of The CT Pipe String In The Hydraulic Blasting Section Fracturing

The development of low permeability oil and gas field dominated by shale gas has become the main field of oil field development in the present and future.With the maturity and popularization of coiled tubing technology,coiled tubing hydraulic sand blasting subsection fracturing technique has become an effective measure to solve the problem of vertical multilayer fracturing and horizontal well volume fracturing in China.But the tubing stiffness is low,prone to buckling behavior in operation,and can cause the column into the predetermined depth or after not working properly.In order to improve the reliability of coiled tubing,it is important to study the hydraulic sand fracturing CT string mechanical behavior and supporting tools.Based on the mechanics of column on the basis of previous results,according to the uniform tube when the characteristics of friction and axial force balance,mathematical model by friction in-stead of axial force and for calculating the true depth of the column from top inverse column was established.Using MATLAB for example programming calculation,analysis of the pipe column state and depth,the results show that shorten the deformation caused by the deviation of first decreases and then increases with the coiled tubing string with the depth increasing.But the rate of deviation is too small,so the shortening amount caused by the tube column buckling deformation compared with the whole root canal columns can ignore the law regardless of.The mathematical model of wear,a tool string thickness and depth is established by the coiled tubing string into the process of the application of the principle of wear behavior of friction and wear.The relationship between the allowable friction loss and the internal pressure is analyzed by using the Mapud calculation example.The result shows that the wear capacity of the coiled tubing is decreased gradually with the increase of the fracturing pressure.According to the coiled tubing Hydrajet fracturing technology principle and pipe string design principles,the coiled tubing hydraulic sandblasting tool on the overall scheme is designed,and the various tools of detailed design analysis and simulation study are done.The optimal size of nozzle structure,optimal positioning slip angle,Y211 sealing packer slip best anterior horns,teeth angle,tooth profile angle,tooth hight,tooth spacing,slip work height,cone angle,glue tube of optimum structure parameters are identified.Through the front of a series of research work,the theory of the coiled tubing fracturing pipe column hydraulic sandblasting positioning accuracy and wear behavior,fracturing string tool string optimization design are improved.It has certain guiding significance for coiled tubing hydraulic sand fracturing string of sectional design.