Multi-channel Data Acquisition System For 3D Induction Logging Tool

Three-dimension induction logging is a whole new stratum structure detection systems, which is mainly used for detecting the anisotropic reservoirs. It can directly measure both horizontal and vertical resistivity. It is effective methods for people to recognize the stratum characteristics and have an oil or gas reservoirs evaluation.This paper puts forward a new kind design scheme of three-dimension induction logging tool multi-channel data acquisition system. The design with digital signal processing (DSP) and field programmable gates array (FPGA) as the core framework, realized overall control and data processing function of the whole system. The Three-dimension induction logging tool multi-channel data acquisition system is mainly composed of the preamplifier module, filter module, modulus conversion module, acquisition control and data conversion module, data processing module, CAN bus interface module and power supply module.In order to verify the feasibility of the design, this paper firstly has a simulation analysis and calculation before design on the key modules such as the preamplifier module, filter module and differential module. In software design, this paper firstly introduces the digital signal processing algorithm principle of the finite impulse response (FIR) filter and digital phase-sensitive detection (DPSD), and then separately designed and implemented the suitable finite impulse response (FIR) filter and digital phase- sensitive detection (DPSD) algorithm which can be in practical use.Experimental results show the system can not only ensure the high-speed synchronous sample of wide band signal, raising sample efficiency and data reliability but also well extract the multi-frequency weak signal about 4μV from the strong environmental noise.