Study On Mechanical Behavior Simulation And Performance Experiment Of Packer For Testing And Completion

As a key tool in the test and completion downhole operations of oil and gas field,packers are widely used in oil testing and completion integration operations.It is often occurs when the packer is abnormally seated and abnormally invalid in recent years.In order to find out the cause of the packer failure more accurately and understand the mechanical properties of the packer during the setting process and the subsequent working load,the mechanical behavior simulation and performance experiments of the packer system are carried out.In this paper,the 5.5-inch RTTS packer which is commonly used for oil testing and completion is taken as an example,the combination of numerical simulation and experiments is used to study the safety and reliability of the packer overall system.The full-scale RTTS packer simulation analysis model is established by the software of SolidWorks and Workbench.And the packer system is numerically simulated under the normal setting load and critical load respectively to study the stress distribution laws of the key components of the packer under different working conditions.Combining the simulation results and the characteristics of the packer performance envelope,the inverse calculation method and the intersection verification method are used to summarize theoretical calculation process of the packer performance envelope.With the help of downhole tool test bench to simulate the field load,the strain gauge data was collected by the resistance strain gauge,and the mechanical relationship between the packer rubber,the slip and the interaction between the hydraulic anchor and the casing was studied.The results show that the overall force of the RTTS packer is unbalanced during the operation.Compared with other parts,the lower part of the packer is more stressed,the stress of the contact parts of the key parts is significantly higher than that of the non-contact parts.The slips and the inner and outer center tubes are the vulnerable parts of the packer.The deformation of the rubber element is large under the action of the critical load.The experiment found that the axial force of the packer cylinder is uneven,the circumferential force is uniform,and the contact stress of the upper rubber cylinder is larger than that of the lower rubber element,the difference between the two is about 6%.The contact stress of the upper part of the slip is slightly smaller than the lower contact stress,approximately 3.5% difference.The contact stress at the upper of the hydraulic anchor is greater than the lower,and the difference is about 3%.The test results are compared with the simulation results.Although overall simulation values are larger,but the trends are basically the same,which verifies the reliability of the simulation model.