The Structural Design And Analysis Of Key Parts Of Formation Testing Tool

To assess the capacity of purpose zones on oil and gas Wells,oil workers often are required to conduct well testing.At present,there are some limitations in the existing formation testing technology,which raises the testing cycle and the cost of testing.Hence,a new formation testing technology has been proposed.A new type of formation testing tool can be used to test the zones in one trip.However,most oil company of China research on formation testing tool is still in the initial stage,and the relevant technology,been mastered by the well-known company of the developed countries.For China's some oil company,to develop a new type of formation testing tool is imminent.Meanwhile,it can also greatly reduce the domestic major oil service c ompany production cost.Electro-hydraulic pump that the key components of formation test tool was researched in this paper.It's main function is to pump filtered wellbore fluid into the packer until the packerreaches the state of expansion and to complete the zonal isolation and test,such as pressure build-up tests and injection pressure monitoring.Through the structure an alysis of the existing foreign,formation testing tools and digest the ingenious structure,then choose a simple operation,strong applicability,high reliability of the open-loop control method to achieve the purpose of control.To make the pump's capacity,switch between,rated output and control output,the positive displacement control,method is adopted,Then,the control signal act on the actuator and the Electro-hydraulic pump would has achieved the aim of reversing.The pumping system of Electro-hydraulic pump was analyzed and calculated,the pressure loss in the check valve assembly was calculated when the compresseid wellbore fluid flows through the valve body.Then,the external load and other main parameters of hydraulic system was calculated.On this basis,Three-dimensional modeling and the main assembly was completed by the software Pro/E.It also would provide a reliable basis for the virtual prototype in the future.Finally,screw connection contact stress that the drive shaft and the piston was analyzed by finite element method,and acquired the maximum stress at the tooth.By contrast,the maximum stress at the tooth is less than the material yield limit.So the structure to meet the requirements.Meanwhile,the body of check valve assembly was analyzed by the finite element method,and acquired the maximum stress at the body.Compare with the yield strength of the material body,the structure design of the check valve was reasonable.This study has a certain effect on the formation test tool,and provided the basis for the research and development of the formation test tool in china.