Mechanical Research On Tubing Erosion Damage In High-yields Well

Oil and gas well tubing string is the necessary equipment in oil and gas drilling operations,along with the deep oil and gas exploration and development,deep well,ultra deep well,high Angle well,directional well,big displacement well,horizontal well ratio increases has become an inevitable trend,oil and gas well tubing string work environment has deteriorated sharply,especially in high temperature and high pressure,high yield Wells,such as "three highs" oil and gas Wells,oil and gas well tubing string almost inevitably appear all sorts of damage,caused a great loss to human,material and financial resources.It is found that the failure of oil and gas well tubing is one of the main reasons.The erosion will directly cause the wall thickness of the oil and gas well pipe and other equipment to be thinner,the strength is weakened,the service life is reduced,and the risk of toxic and harmful gas leakage,such as H2S,is a hidden danger to safe production.When erosion wear of tubing string to a lesser degree,will cause a string of surface strengthening layer peeling,induction of sulfide oxygen on casing steel electrochemical corrosion damage,also reduces string of collapse strength and internal pressure strength,mining pose a serious threat for the safety of normal oil,When the erosion wear is bad,the load limit of the pipe column will be reduced,which will affect the deformation,collapse,rupture and leakage of the pipe column,which will lead to safety problems such as oil and gas well control.If the maintenance and replacement are not timely,it will eventually lead to the rupture of the oil and gas well string,which will lead to the blockage,leakage,card and other underground accidents,which may even lead to the death or blowout of the whole well.This paper collected about string erosion at home and abroad,as well as the carrier string failure and so on literature material,and then collect the block high-yield gas well tubing string failure cases and data,finally analyses high-yield gas well tubing string erosion failure of the law,this article research work and research results are as follows:1.After reading a large number of domestic and foreign literature and on the basis of predecessors' research,based on the particle movement in the fluid and particle collisions with the wall of the tubing string analysis,get the erosion wear model of a single particle.2.The vortex characteristics of the flow field are analyzed.In the whole process of natural gas flowing through the tubing string,the region where natural gas pressure and velocity change are prone to swirl.The flow direction of natural gas flows through these inclined and curved regions,resulting in uneven velocity on the same cross section and prone to vortex.3.According to the theory of gas dynamics,large calculation fluid dynamics software Fluent is adopted to establish the gas flow in the spiral buckling and sinusoidal buckling of tubing CFD model,and select can give full consideration to the complex flow field in the natural gas in the tubing string of RNG k-? model.4.Using the computational fluid dynamics software to simulate the flow of natural gas through the buckling section of the tubing,the results of the velocity(transverse,axial)and density distribution of natural gas in the oil pipe column are obtained;Then,the variation law of flow parameters and the variation law of the flow parameters in high-yield gas well tubing were analyzed.5.Impact of sand erosion rate and wall shear stress of tubing inwall proves the analysis of the helical buckling and sinusoidal bending string erosion rule and possible failure area,through high-yield gas well tubing string erosion mechanism of the numerical simulation research,analyses the various influencing factors of affecting string erosion,erosion damage prevention and control measures are put forward,in order to prevent erosion wear of high-yield gas well tubing string to provide the basis.