Design of a cross-dipole array acoustic logging tool

When entering an anisotropic formation, a shear wave splits into a fast wave and a slow wave. Based on the principle of four-component cross-dipole acoustic wave measurement, the anisotropy of HTI （Horizontal Transverse Isotropy） formation can be determined. The method of calculating the fast and slow wave data when a shear wave propagates along the borehole axis in anisotropic formation was analyzed, and the implementation of a cross-dipole acoustic logging tool was demonstrated. The tool was composed of transmitter electronics, transmitter mandrel, acoustic isolator, receiver mandrel and main control electronics. Sonde, transmitter circuit, signal receiving and processing circuit, data acquisition system, system control circuit and telemetry interface circuit were presented and analyzed. The test model was used in production wells and standard wells in various areas and the four-component cross-dipole waves were acquired and processed. The waves had good signal-to-noise ratio and clear characteristics, and the fast and slow waveforms, processed slowness curves, anisotropy and fast shear wave azimuth well matched with each other.

An ARM-based debugging system for multipole array acoustic logging tools

This paper presents a debugging system for multi-pole array acoustic logging （MPAL） tools. The debugging system proposed in this study can debug the MPAL tool system, sub-system and local electronics. In the test equipment, we have used principal and subordinate structures, and interconnected the host computer and the front-end machine via Ethernet. The front-end machine is based on the ARM7 （advanced reduced instruction set computing （RISC） machine） technique, the processor of which runs an embedded operating system, namely, uClinux OS. We have analyzed the system telecommunication, human-machine interface circuit, transmitter mandrel interface circuit, receiver mandrel interface circuit, and board-level test interface circuit. The software used in the system consists of the embedded front-computer software and the host application software. We have explained in detail the flow chart of the boot loader in the embedded front-computer software. The host application software is composed of four application subroutines, which match with the functional modules of the system hardware. A net communication program based on the server^client mode is implemented by means of socket programming and multi-thread programming. Test results indicate that the data transmission rate of the system is higher than 1 MB/s, which completely meets the current requirements of the data transmission rate between the tool system and the wireline telemetry device. Application of the debugging system, which includes multiple level test methods, shows that the proposed system can fully meet the test requirements of MPAL at various levels.