Emri Logging Tool Downhole Control And Communication Circuit Design

Well logging is called'the Eye of Petroleum Industry', geophysical well logging adopts a variety of measurement methods to obtain logging data by making use the different physical and chemical property of underground rock, especially the attributes of formation containing oil and gas. Electric logging Image is a new logging technique which is gradually developed in 1980s. And micro-resistivity imaging logging tool is an important logging tool. At present,Image well logging is developing rapidly. Internationally, only three Companies such as Schlumberger,Atlas and Halliburton take possession of mature tools. And the tool's price is extremely expensive. In recent years , these three companies only provide logging service instead of selling instruments by using monopoly technological strategy. Therefore, how to develop our own micro-resistivity imaging logging tool seems particularly important. transmission bandwidth.This paper studies that the control and communication circuit design of the micro-resistivity scanning logging instrument which possess the large data size and complex control the scheduling compared with conventional resistivity logging instruments. The micro-resistivity scanning logging instrument brings great difficulties in data transmission and control. Control and communication circuit is the controlling core of the whole instruments by down hole well logging,which receives and controls the commands and parameters, all imaging data are packaged by it and transmit upward through the EDIB bus. In order to achieve the aim of control instruments reliability and steady communication under the circumstances of high-temperature and strong quaking, we mainly consider how to choose the DSP chip and external communication interface design in the aspects of hardware circuit design. In addition,we chiefly consider control process and time sequence of DSP procedures in soft design, trying to divide some predictable processing events in different interval time.This dissertation puts emphasis on the software and hardware design of EMRI controlling and communication module. First, we introduce the working principle of tool, including the gross structure of instrument electronic circuit part; Secondly, we mainly elaborate the hardware design of EMRI control and communication circuits, including the selection of DSP chip and its design of hardware circuit, the design of supplementary data acquisition unit circuit, the communication interface design (EDIB bus interface, the McBSP interface, the asynchronous SCI interface,motor control interface); Then, we elaborate DSP software design of EMRI control and the communication module, including DSP software system design flow, the command subset and the corresponding processing flow and so on; Finally, we describe the debugging process as well as problems and solutions in the debugging process.