Along-String Measuring Technique and Its Development Direction

At present, the drilling of oil and gas reservoirs in deep, ultra-deep, and complex strata or deep water suffers from some problems such as difficult operations, long periods, and frequent downhole troubles. Thus, it is necessary to monitor pressure and temperature in wells in real time for safe, efficient, and fast drilling. This paper introduces the composition of the along-string measuring system developed by NOV. It included a close look at the applications of the along-string measuring technique in the scenarios of wellbore cleaning monitoring, sticking position determination, drilling fluid leakage position determination, leakage test and formation integrity test, kick detection, and the analysis of string and bit working conditions, etc. Further, the technique was evaluated in terms of its suitability in the course of field development. It was found that the interpretation model and application scenarios of along-string measuring need to be improved, in-depth data mining and multi-parameter visual intelligent display should be strengthened, the sensor network distribution can be optimized, and a high-speed information transmission network capable of replacing cabled drill pipes need to be developed to improve the economic benefit, so as to realize more application scenarios. On this basis, development suggestions were provided, including continuously improving downhole engineering parameter measuring systems and promoting the commercial application of cabled drill pipes in China. With the maturity of these two technologies, the distributed measuring transmission technology should be realized gradually. The analysis shows that the distributed measuring transmission via the smart microsphere-based time-sharing transmission technology with a conventional string system and improved distributed string measurement tools is a low-cost along-string measuring approach worthy of further study.