Induction Logging Instrument Monitoring And Control Circuit Design

The resistivity measurement of subsurface formations is the primary method for interpreting and evaluating the oil and gas deposits underground, which can be explored by induction well-logging instruments effectively. The measure and control circuit is the core component of the whole downhole tool, which is responsible for generating continuous stimulus signals for transmitter, receiving and processing response signals coming from the formation, controlling the operation of each functional module and building communication with surface terminal system.With the rapid development of petroleum industry and the expansion of oil demand, higher requirements have been proposed to well-logging tools'functionality and performance. Meanwhile, limitations in circuitry designed by traditional mode have been exposed more and more obviously, including several specific aspects, such as low integration in components and devices, low digitalization in systems, bad real-time performance, complex hardwired structure, excessive cost and power consumption.To solve these specific problems mentioned above, the research work in this paper is to design real-time measurement and control circuitry and system based on DSP and FPGA structure, according to the rapid development of integrated circuit technology and electronic design automation technology. Optimization and integration for software development and design can achieve the goal of improving the stability and reliability, diminishing the circuit board's occupancy space and volume, reducing the total power consumption of system essentially.At first, the related research background is reviewed at the beginning of this paper, including the current research status and state-of-the-art both in domestic and overseas fields, as well as the significance and practical value of the subject study are discussed. Secondly, the principle of induction logging technique and the entire architecture of downhole tool are analyzed in details, which can provide definite theory foundation for subsequent circuit design. Thirdly, the hardware platform for measurement and control system is established, including transmitter controlled block, multi-channel combined receiver module and communication cable driver circuit. And the relevant FPGA logic design and DSP software development are applied to perform signal acquisition and processing, system real time control. At last, the preplanned function is verified through experiment analysis and characteristic test, which is proved that the design satisfies the demand on technical target and specifications. It's demonstrated that the research work mentioned in this paper can provide reliable reference foundation for practical industrial development of induction well-logging tool.