The Experimental Study of High speed Shear Valve Pulser Telemetry System in MWD

China Oilfield Services Limited(COSL)'s indigenous “XUANJI” system, is China's first rotary steerable drilling and logging while drilling system, allows real-time analysis of formation data to greatly reduce the cost of oil and gas field development. Since it was put into use, the “XUANJI” system has been operating all over China's four seas as well as Xinjiang, Shanxi and other land oil and gas fields, and has completed high-difficulty drilling for many times. It has successfully achieved 1,000 Wells and a total drilling penetration of 1 million meters, and the key operating indicators have reached the world-class level. The speed of data transmission is crucial in the process of “XUANJI” system operation, so it is necessary to develop a high speed mud pulse data transmission system while drilling. In this paper, the principle of the high-data-rate measurement while drilling(MWD) telemetry system based on the swing valve is introduced, and the influencing factors in the mud pulse telemetry are analyzed. The key technologies in the development of the high-data-rate MWD transmission system, such as the drive system design, the control scheme, the modulation and the method of noise reduction are given, and the development idea of the high-data-rate MWD telemetry system is clarified. The actual drilling test shows that this system can achieve 12bps transfer rate at 3000 meters depth. It indicates that the technical indicators are reasonable, technical route is correct and the implementation is available. The successful research and development of the high-data-rate MWD telemetry system will fundamentally solve the data rate bottleneck of the Drilog® & Welleader® system. The design and technical analysis have a certain guiding role for the research and development of such drilling tools.