While Drilling Resistivity Logging Tool Master System Research

With the deepening and development of oil exploration and well logging, Logging-While-Drilling (LWD) tools have been replacing the traditional wireline tools gradually for its many advantages. LWD is now widely used for drilling and formation evaluation horizontal wells and high angle wells. LWD resistivity tool is an important part of LWD. The research background of this paper is the research and development of a LWD resistivity tool. The research project is mainly focused on the master control subsystem.LWD tools design is faced with the challenges of the high-temperature, high pressure and high vibration environment. At the same time, the instrument require a highly system control reliability, communication reliability, data storage reliability. Taking into account the above factors, The key technologies such as system design, hardware design and software system design, logging data storage, communication protocol design, are well researched in this thesis, and poor working conditions and reliability requirements are well concerned, the appropriate solution is proposed.In this thesis, in order to ensure the stability of the system reliability and improve design efficiency, a process-oriented electronic system design methodology is used in the hardware and software design. The master control board system scheme is proposed. Hardware of master control board based on high-performance DSP controller is designed. The factor affecting the signal integrity is analysised, and applied to the master control board PCB design. The hardware is debugged in a modle to system way.In this thesis, considering requirements in accordance with the reliability and bit error rate, LWD resistivity tool system software and communication protocols is researched and designed. A embedded real-time software system is proposed, which is consisted of front and back structure and modular drivers. The front software, background software and drivers of the master main board are designed basing on that system.Long-distance high-speed, high reliability embedded systems inner and inter communication protocal are researched in this thesis. Two kind of bus are proposed: IBUS and SPBUS. IBUS, which based on RS485standard, is tool internal bus.The function of IBUS is board to board communication and high-speed logging data download. The IBUS communication protocol is designed based on the simplify of OSI model. Technical approaches such as address match, the sum check, timeout retransmission, automatic error recovery, and collision detection are used in reliability design. SPBUS, which based on manchester encoding, is tool external bus. SPBUS have a strong anti-jamming capability and reliability.In addition, large-capacity data storage under harsh environments is studied. In this paper, an integrated memory group structure and management software are designed. In this paper, many technical approaches are used to improve the reliability of data storage. In this article, instrument parameter table is storaged in the tool in a address index, dynamic file allocation way.Finally, by system testing and high temperature testing system, especially constantly improve of the the high temperature performance design, the system intended targets and functional requirements have been achieved.This research has laid a solid foundation for the development of LWD resistivity logging tool. This thesis provid design reference and technical implementations for instrument communication and storage reliability design which work under harsh conditions.