| With the development of the petroleum industry in the past ten years,most oil and gas fields have entered the middle and late stages of development,and the development of monolithic oil and gas reservoirs has gradually decreased.Complex oil and gas reservoirs such as thin interbeds,fault blocks,and low permeability have become the main directions of oil and gas field exploration and development.At present,directional logging technology can realize the prediction and judgment of formation interface,formation azimuth characteristics and anisotropic formation trend.Electromagnetic wave resistivity logging is the key technology of directional logging and has become the research target of many scholars.In response to the development requirements of a certain electromagnetic wave resistivity logging tool,this paper designs an electromagnetic wave signal generation,signal acquisition,detection and processing,communication control and other functions,as well as azimuth measurement,real-time clock(RTC),storage and reading and other auxiliary functions.system.The main functions of the system include: it can transmit five frequencies,support eight-channel reception,can independently complete weak signal processing,and have the functions of RS485,Qbus and other long-distance communication transmission.The development content includes the generation of multi-frequency emission signals,the collection of multi-channel signals,the design of phase-sensitive detection algorithms,the design of main control circuits,system power supply and interface design,etc.,as well as the system power consumption,heat dissipation,electromagnetic compatibility,miniaturization,etc.Evaluate and optimize,and finally realize system prototype production.The full text elaborates from the theoretical analysis and program design,hardware implementation,software implementation,and system testing.Design and manufacture hardware,software and systems in accordance with the design ideas of indicator analysis,device selection,schematic design,device layout,PCB drawing,board soldering,programming,and performance testing.Aiming at the synchronization problem of the transmission signal and the local oscillator,a DDS solution based on FPGA and DAC design is proposed.The transmission signal and the local oscillator are generated by the FPGA at the same time;for the problem of simultaneous acquisition and processing of multiple channels,a solution for the acquisition of the received signal by FPGA and multiple ADCs is proposed;aiming at the problem of weak signal detection,a digital phase-sensitive detection scheme based on FPGA and DSCs is proposed;the design scheme of dual-port RAM with XINTF interface is used to realize high-speed data exchange between FPGA and main control DSCs;RS485 and Qbus communication are used,Realize the long-distance and stable data transmission between the system and the host computer or other main control boards;the power supply voltage regulator chip adopts a distributed layout scheme to realize the power supply thermal balance design;the domestic J30 J military-grade plug is used to realize the interconnection between the input and output.After theoretical research,index analysis,overall scheme design,hardware design,software design,system implementation and performance testing,the prototype of the electromagnetic wave resistivity logging transceiver system is finally realized.The main parameters of the system include five transmitting frequencies of 4KHz,10 KHz,40KHz,100 KHz and 400KHz;eight receiving channels;six data parallel processing modules;±5V working voltage and less than 500 m A working current;10u V minimum detectable signal capacity;System size of 39mm*301mm*10mm. |
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