Design And Realization Of Displacement Measurement System For Downhole Sliding Valve

Through installing sensors and ICV,the intelligent well system can monitor the dynamics of the oil and gas reservoirs in real time and realize the real-time dynamic control of the stratum fluids.Intelligent wells can effectively improve the efficiency and the final recovery rate of oil and gas reservoirs,therefore,has been widely attention.The ICV is the key of the intelligent well system,and the real-time automatic detection of the valve displacement is the prerequisite for real-time automatic control of the valve.In this paper,a set of sliding casing displacement mearsurement system for ICV is studied.The main contents are as follows:First,several non-contact displacement measurement principles are compared,with LVDT displacement measurement sensor as a technical reference,the structure design of the sleeve valve is put forward,the relationship between valve displacement and sensor output signal is deduced,which proves that the design of the three-wire inductive displacement sensor has a stable linear relationship between the valve displacement with output signal.Second,a three-wire displacement measurement sensor is developed.The consistency of the theoretical formula and the actual working condition is verified by the test method,and the parameters of the sensor are optimized according to the experimental results,the sensor and the valve are assembled to verify the rationality of the structural design.Third,in view of the special requirements of the underground high temperature environment,the signal processing device is designed for the development of the ICV displacement measurement sensor,and the circuit principle and the main software design are given.Fourth,the temperature characteristics of the valve displacement measurement sensor are analyzed,the relationship between the displacement,the temperature and the output signal is established,the conclusion that the signal will change non-linearly with the temperature is obtained.Further verification was made through the temperature characteristics and simulation.The temperature characteristic of the signal processing part of the displacement measurement system of the sliding sleeve is tested,the experiments also show that with the temperature changes,the processed signal shows a non-linear change.Fifth,in the case of temperature change,it leads to the problem that the measurementresult of the signal can not be directlly obtained,a simplified approach to linear approximation is proposed.Based on the test data,a linear fitting equation is given every 5?,and the processing method of the intermediate temperature point is proposed.The verification of these approximation methods using the measured data shows that the maximum valve displacement measurement error of the valve displacement measurement system is not more than 10% in the temperature range of 20-125?.These research work provide a practical reference for the development of the ICV.