Design And Manufacture Of Pressure Sensors For Downhole Measurement In Petroleum

With the increase of the oil exploitation depth,the pressure resistance and working temperature of the pressure sensor are also increasing.When the oil production interface is more than 5km underground,the pressure on the oil production page will reach 40 MPa ～ 50 MPa and the temperature will reach 130℃ ～150℃.In order to ensure the safety and stability of oil exploitation in deep Wells,it is necessary to monitor the pressure of oil exploitation liquid level for a long time.At present,the main process of oil exploration method is a built-in pressure sensor in the mining equipment,connect with the production line,by measuring the pressure in the pipeline to control the operation of the whole equipment.As the core component of pressure monitoring,the operating temperature of domestic pressure sensors sold at present is mostly below 125℃,which cannot meet the increasingly complex harsh underground oil exploitation environment.Therefore,it is inevitable to develop a sensor for downhole measurement of petroleum with operating temperature up to 150℃ and measuring pressure range of 40 MPa ～ 50 MPa.The sensor can solve the problem of high temperature and high pressure measurement,improve the technical level of domestic pressure sensors,and solve the key technology of pressure monitoring of oil production and the manufacturing problem of special pressure sensors.The research and development is of great practical significance.Starting from the design of pressure sensor chip,this paper aims at the specific requirements of high temperature and high pressure resistance required by underground petroleum measurement.Combined with the existing technology platform and sensor development experience,redesign and optimize the pressure sensitive chip development plan and process flow.In this paper,the pressure measurement range of the chip is expanded through structural design and simulation,and key technologies such as chip passivation layer production,high temperature resistant electrode production and chip electrostatic bonding are explored to effectively improve the working temperature range of the pressure-sensitive chip.The research on corrosion resistant chip packaging technology is carried out in view of the complex and harsh environmental conditions of underground oil exploitation interface.A special auxiliary conditioning circuit is designed for signal conditioning and conversion,which realizes the conversion from environmental pressure signal to standard electrical signal.The sensor is tested and verified with standard pressure measuring equipment to obtain the final performance index of the product.In addition,a test system was built to simulate the operation of the actual underground oil production equipment,and the developed pressure sensor was connected into the system for testing.The test results show that the developed pressure sensor has good practicability while its performance index is qualified.The pressure sensor developed can meet the long-term and stable working requirements of underground oil production liquid level.By completing the design and manufacture of pressure sensors for downhole petroleum measurement,two key technologies,namely the long-term stability of pressure-sensitive chips and the harsh environmental adaptability of pressure-sensitive devices,have been successfully broken through.The measuring range and working temperature of the pressure sensor are in line with the downhole exploitation requirements of deep Wells,which can effectively fill the deficiency of domestic commercial pressure sensors in the field of downhole pressure measurement.The following work will be based on the experience accumulated in the development process of the pressure sensor for underground oil measurement,and the existing design,production and manufacturing process of the same type of sensor will be improved and perfected.The sensor will be further advanced from the sample stage in the laboratory to mature products that can be marketed and promoted.