Research On Perforation Section Detection And Blocking Removal Technology In Cold Production Heavy Oil Wells

With the decrease of conventional oil and gas resources year by year,the exploitation of heavy oil has become an important way to alleviate the shortage of oil and gas resources in my country.Cold sand production is one of the main methods of heavy oil production.Long-term production leads to deposits and blockages in the casing perforation section,which greatly reduces the recovery rate of heavy oil.Therefore,detecting the position of the perforation section of the casing downhole and removing the plugging treatment is of great significance for avoiding secondary perforation and improving the recovery of heavy oil.In this paper,magnetic permeability detection technology is used to detect the perforation section of the casing,and a detection sensor with a differential E-type structure is designed.The magnetic core material of the sensor,the design of the excitation coil and the detection coil,and the optimization of the sensor are deeply studied.Using experimental methods,optimized parameters such as excitation voltage,excitation voltage frequency,excitation coil turns,detection coil turns,and excitation coil winding cross-sectional area are determined.The research results show that when the excitation coil has 200 turns,the detection coil has 300 turns.The detection sensitivity of the sensor is the highest when the number of turns,the excitation voltage is 4.5V,and the excitation frequency is 400 Hz.The signal acquisition system of the perforation section was designed,and the ground data processing and display software was developed.In addition,the mechanism and realization method of block removal based on microwave method are also studied,and the working frequency and power are determined.An indoor test platform was built to conduct a large number of tests on the perforation section detection system and the effect of removing the plugging based on the microwave method.The test results show that the detection signal amplitude of the casing perforation section is significantly smaller than that of the non-perforated casing.The presence of the perforation section causes the permeability of the material to decrease,and the decrease of the permeability is proportional to the amplitude of the detection signal;when the microwave frequency is 2.45 GHz,the microwave power is 600-800 W,and the microwave radiation time is about 10 min,the microwave is on the perforation section.The plugging removal effect is the best.At the same time,the water content of the heavy oil also has a certain influence on the plugging removal effect of the perforation section.A simulation test was carried out on the detection and removal of the perforation section of the downhole casing,and the optimal parameters under the test environment of this article were determined to provide a reference for practical applications.