Numerical Simulation On Erosion And Wear Of Fracturing Manifold And Analysis Of The Mechanical Behavior

As the most important construction component in oil exploration and transportation operations,the fracturing manifold was mainly responsible for the arduous task of transporting high-viscosity acidified fracturing fluid to the underground oil layer.With long-term high-pressure use,the complex acidic fluid inside the fracturing manifold and the solid particles carried would cause a certain degree of erosion and wear on the inner wall,and then accumulate corrosion defects.Eventually,the fracturing manifold would fail and burst due to irreversible damage,causing serious safety accidents.In order to monitor the corrosion damage of the oil and gas well fracturing manifold in real time,and to ensure the safe service of the manifold while maximizing its service life,this paper focused on the research on the erosion and wear mechanism of fracturing manifold,and carried out a detailed analysis and evaluation of the safe operation status of the fracturing manifold containing corrosion defects under high-pressure vibration loads on the basis of fluid-solid coupling theory.Creating a finite element model of the high-pressure gas wellsite fracturing manifold based on the theory of CFD,using Fluent to simulate and study the erosion and wear mechanism of the inner wall of the manifold,and discussing the influence of liquid velocity,particle size and particle mass flow rate on erosion and wear.The results demonstrated that the erosion wear of the fracturing manifold was mainly concentrated on the outer arch wall of the elbow,and the maximum erosion rate can reach 1.33×10^-4 kg/m²·s.The liquid velocity had the most significant effect on the erosion and wear of the inner wall of the pipeline.Secondly,the maximum erosion rate gradually increases with the increase of particle size.Although the increase of the mass flow rate would also accelerate the erosion and wear,the effect was not conspicuous compared with the flow velocity.Using ANSYS to carry out the fluid-solid coupling statics simulation and fatigue life analysis of the complete fracturing manifold.Then further building the erosion damage model of the fracturing manifold,focusing on the fluid-solid coupling stress and strain simulation calculation of the damage model,and obtaining the stress and strain distribution of the pipeline under different corrosion defect states.The results indicated that the fracturing manifold revealed obvious stress concentration at the corrosion defect.Elbow was more prone to structural failure due to corrosion defects than straight pipe under the same corrosion depth condition.Comparing the three corrosion defect size factors among depth,length and width,the depth of the defect had the most significant effect on the stress and strain of the fracturing manifold,and the threshold of corrosion defect depth was 50%of the original wall thickness.Using modal and harmonic response analysis methods to simulate the fluid-solid coupling vibration of the fracturing manifold,and study the vibration response of the fracturing manifold structure under external excitation.Discussing the vibration characteristics of the fracturing manifold under different constrained conditions,formulating and optimizing the best structural confinement control plan suitable for the fracturing manifold.The results demonstrated that the fluid-solid coupling effect would reduce the modal frequency of the fracturing manifold and increase the vibration amplitude of the manifold.When the external excitation frequency was close to the modal frequency of the fracturing manifold,the manifold was prone to resonance,which endangerd structure safety.In the actual installation process of the fracturing manifold,adding appropriate constraints could make the fracturing manifold operate more safely and smoothly.