Research On Portable Detection Device To LDT Logging Tools

With increasing of the developing logging work in Shengli Oilfield,the SL-6000 LDT logging equipments are used more frequently.A portable equipment is designed in order to detect and repair the downhole logging equipment.It can be used for the tool detection,maintainance,and adjustment.The design ideas is determined through studying the work theory and the circuit diagram of downhole tools.The communication protocols,data formats,and sending sequences are also analysed.The panel includes: a communication circuit which is equivalent 3514 XA telemetry communication short sub,a surface circuit interfaced with communication short subs and computer communications interface circuits,and software design.The main function of data communications circuit is to receive the command from surface,converte it into a standard Manchester code,and then transmit it onto the command bus.It can also transmit the data from the tools into the signal form that can drive and send in the cable,and acquisition of three parameters 3981 and three-arm caliper data,providing cable head voltage.The functions of microprocessor program are mainly accomplishing the data acquisition of various auxiliary parameters,controlling of the relay and analog switch,and modem of mode 2 communication.The microcontroller receives the host computer commands through serial port,encodes them into Manchester code,and then sents them to communication circuit module.After amplifying,shaping,decoding,the signal from communication circuit module is sent to host computer through RS-232 serial port.The function of surface interface VHDL program is to complete the clock signal frequency division,lock and store the address,and read and write data.The surface design software is written in Visual Basic.A human-machine interactive interface is designed.Each command button can execute one or more commands after being selected.The application of the equipment shows that it can meet the needs of repairing dowhole tools.