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At present, fiberglass sucker rod has been gradually utilized in low permeability reservoirs because of their high strength and strong corrosion resistance. However, the bonding joint of fiberglass sucker rod in high water-content well is particularly prone to break and fall off, which influences the service life and construction safety of recovery operation. Current researches mainly focused on the bonding strength at room temperature, and less consideration was given to the residual strength and failure pattern under immersion. This paper proposed a novel diffusion-structure finite element model (FEM) based on transient dynamic method to simulate the process of water into the joint, and the life-death element method was adopted to study the progressive damage of bonding joints verified by indoor experiment in order to predict residual failure strength and obtain failure mode in submerged environment. As immersion duration extended, the results illustrated that a) the cohesive failure gradually became main failure; b) the maximum von Mises stress, shear stress, and end deformation of bonded joint increased and the maximum interfacial stress barely unchanged within the range of 5%; c) the numerically predicted strength decreased from 21.8 to 11.5 MPa, which was in good agreement with the experimental results within a deviation of 8%. [ABSTRACT FROM AUTHOR]

The nonlinear constitutive model of the proppant column was established through laboratory experiments on the stability of the proppant column. Based on reservoir geomechanics and the finite element method, a fracture-proppant column interaction model was established for high-conductivity channel fracturing. The effects of in situ stress, reservoir rock elastic parameters, and spatial distribution characteristics of the proppant column on the closure deformation of the high-conductivity fracture channel and the stability of the proppant column were studied. The higher the in situ stress, the higher the contact stress on the rock plate; the lower the height and the larger the diameter of the proppant column, the more prone to deformation and breakage, while the more the effective support decreases with the increase of the in situ stress. Under the condition of constant in situ stress, with the increase of the reservoir elastic modulus, the relative axial displacement of the two slabs decreases gradually, the effective propping ratio of fractures increases, and the reservoir elastic modulus has little effect on the stability of the proppant column. The effective propping ratio decreases with the increase of the proppant column diameter, increases with the increase of the proppant column height, and increases with the increase of the ratio of the reservoir elastic modulus to in situ stress. When the proppant column diameter (proppant column spacing) is less than 3 m, the effective propped fracture ratio increases significantly. Through the above research, the optimal proppant cluster diameter was finally optimized. [ABSTRACT FROM AUTHOR]

Ball and seat multistage fracturing technology has significantly contributed to the development of oil and gas reservoirs. In this study, a combined finite element analysis (FEA) and experimental method was employed to investigate the deformation characteristics of an aluminum alloy fracturing ball. The distributions of stress, strain, and deformation under different fracturing pressures were investigated. The FEA results showed that the maximum stress, strain, and plastic deformation were generated in the contact region between the fracturing ball and ball seat. Furthermore, experiments were performed to study the pressure-bearing capacity of fracturing ball. The sealing region between the ball and ball seat underwent severe plastic deformation, which indicated that failure is likely to occur. The numerical simulation and experiment results were in agreement. In summary, the fracturing ball demonstrated high-quality sealing performance at pressures exceeding 60 MPa. The risk of failure that might be caused by large deformation was eliminated, and production cost and operation time were reduced. [ABSTRACT FROM AUTHOR]

In order to understand the effect of secondary perforation on screen pipe strength, the finite element models of bullet hole were established with the help of software ANSYS when the positions of secondary and original perforation were different, and then the effect of secondary perforation on the residual intensity of screen pipe was analyzed. The results show that the best position for secondary perforation is regions near the midline. With the favorable position, large oil and gas flow area can be ensured which will result in higher oil recovery efficiency. And the goals of secondary perforation can be met by enhancing residual intensity of screen pipe. At the same time, the intersection of secondary and original perforation bullet hole should be avoided, if it can't be avoided, the cross hole central angle should be more than 90 degree, because that the residual strength will grow with the increase of central angle. [ABSTRACT FROM AUTHOR]

Aiming at solving the problems of small footage, easy skid and immovability of milling during the process of milling multistage fracturing ball seats by milling tools, and considering simultaneously the difficulties of establishing a full-sized simulation model of the milling tool due to the irregular structure and wide variety, a novel method for analyzing the working performance of milling tools based on reverse engineering was proposed to improve the working efficiency on the premise of construction safety. In this paper, a 3D scanning model of the MX97 milling tool was obtained through a 3D laser scanner, and a full-sized simulation model was established based on reverse engineering for finite element analysis. Besides, an experimental system for milling tools was developed to verify the simulation result. Also, the systematic analysis of the influence rule of working parameters on working performance based on the full-sized simulation model was performed, and a selection database of working parameters in the form of charts was established. The analysis results show that the error between simulation and experiment is only 9.9%, which verified the accuracy of the analysis method based on reverse engineering. The surface morphology of the workpiece after simulation and experiment are both circular cuts, and the bottom surface of the milling tool should be designed as an eccentric structure to avoid the zero point of cutting speed that affects the working efficiency. WOB and rotating speed of milling tools affect and interact with each other, which jointly determine the working performance of milling tools. It is necessary to comprehensively use the data from the selection database to accurately determine the working parameters to improve the working performance of the milling tool. • A 3D scanning model of the MX97 milling tool was obtained through a 3D laser scanner. • A full-sized simulation model was established for finite element analysis. • An experimental system for milling tools was developed to verify the simulation result. • A selection database of working parameters was established to improveworking performance. [ABSTRACT FROM AUTHOR]