Theory Calculation And Application Of Axial Deformation Of Underground Work String

With the increase of oil demand and the development of drilling technology,the application of the downhole operation such as staged fracturing,zonal injection and high pressure well drilling is becoming more and more widely,in the process of these assignments,the tubing will happen axial deformation at the influence of weight,temperature and pressure,if the axial deformation is general that will cause many accidents,such as the packer setting position deviating from the objective layer,the packer seal,string broken and helical buckling of tubing in the downhole.For a long time,the depth of downhole string mainly through artificial ground survey,and coupled with the electromagnetic logging curve to depth correction string and the position of the packer setting.Interpret the factors affecting magnetic positioning curve,curve more difficult,large work volume on assignments,and take up the production time is long,the cost is higher,especially the test data and artificial measurement data is very difficult to explain,accuracy is not high.Magnetic positioning also failing to consider the elongation of the cable and setting.Therefore,accurate calculation the axial deformation of tubing string under the influence of different factors,for accurate positioning operation layer,evaluating the safety of underground work string,choice of reasonable production parameters,and reducing downhole operation accidents has important significance.In this paper,on the basis of predecessors' research,through a lot of literature research.First,comprehensive analysis of the factors influencing the axial deformation of the underground work string,including the basic effect such as gravity,buoyancy effect,temperature effect,the piston effect,expansion effect,friction effect and buckling effect;The effects of borehole trajectory;The influence of the packer.The effect of different pipe string structure and the influence of operating mode.using of micro yuan after superposition method And elastic-plastic mechanics,established the theoretical calculation model of homework string axial deformation under the influence of the single factor.Secondly,through the string infinitesimal body force analysis,combining with the string infinitesimal body static equilibrium equation and physical equation,differential equation of the deformation of tubing string is derived,based on the differential equations of dimensionless,and deduced homework string axial deformation theory calculation model in the three-dimensional curved Wells' eyes.Thirdly,In horizontal well staged fracturing and zonal injection two underground work as an example,detailed analysis of the influence of different operation condition on the axial deformation of tubing string,set up under different operating mode of axial deformation of tubing string under the influence of various factors comprehensive theoretical calculation model,and the application of the calculation results are analyzed in detail.Finally,with Chen ping 5-2 Wells,for example.calculating the tubing axial deformation,the calculation results with more international recognition of Landmark software were compared,contrast test results show that the calculation is more accurate and reliable,according to the result of calculation can be accurate to underground work positioning,checking homework string strength and determine slip compensation distance,etc.