The research and testing of the tracer method for surveying gas-lift wells

Abstract

During operation, gas-lift wells often have problems, such as the gas-lift valves designed to close are actually open or vice versa. In addition, sometimes, there is a leak of lifting gas into the tubing or out of the annulus. Therefore, surveying gas-lift wells to find out the causes of the above-mentioned problems is necessary for oil and gas exploitation using the gas-lift method. This article presents the results of research and testing of the tracer method for surveying
gas-lift wells. As a result, the method has been developed and tested in the field on well 7010, the BK7 platform, and the Bach Ho oil field of the Vietnam-Russia Joint Venture. Test results have determined that well 7010 has two gas injection points at a depth of 2973 and 2248 m, respectively, with gas-lift valve no. 5 (the last valve) and a leak point in the tubing located between gas-lift valve no. 3 and valve no. 4. Moreover, it was determined that more than 80% of the lifting gas was pumped through the tubing perforation and only nearly 20% of the lifting gas was pumped through the gas-lift valve no. 5. Therefore, the 7010 gas-lift well is inefficient. This result is also quite consistent with the results of PT (measurement of pressure and temperature in the well) and the results of measuring the liquid level in the annulus. The results of this research and experiment show that the tracer method can be applied in the practical survey of gas-lift extraction wells, becoming a regular service for the oil and gas industry.