As part of my independent consulting practice, I worked for several industrial companies – some of the most challenging development work was in building instrumentation for down hole exploration for petrochemical companies. These applications make space rated looks simple by comparison; to endure depths of miles under wide drilling conditions, tools were rated to 30,000 PSI, -40C to 250C, with significant shock and vibration. Design, simulation, part specification and testing were critical to delivering a product that would be reliable in such extremes.
Halliburton LOGIQ-MRIL
At 40’ long, and 4” in diameter fully assembled, this wireline tool was intended to deliver formation imaging to a distance of a few feet from the borehole radius.
The data acquisition was performed using a specially turned version of nuclear magnetic resonance imaging (NMRI). Batteries in the system would power a magnetic coil array, driven to several kW by a high performance amplifier to generate a shaped magnetic pulse. The amplifiers would then be shut down, and the same coils would be switched to a listening mode, where a low noise amplifier would scale of the signal produced by the resonance of the coils in response to the surrounding formations. This process had to happen at a precise frequency, timing window, and phase relationship, in order to work. My responsibility was for the design, schematic implementation, FPGA design, PCB design, simulation, firmware implementation of the algorithms, and verification for the data acquisition system. It utilized specialized hi reliability parts, and used 16 channels synchronously at 10MPSPS, 16-bit resolution, for a system performance on 160MSPS. Acquisition was performed with a signal chain with impedance matched front end, high performance ADC, FPGA, and an Analog DSP processor.
Petromar Conductivity tool
This tool used a set of six retractable arms with a pod containing 12 channels of surface conductivity sampling on each arm. These conductivity sampling pads would be used to detect an E-field generated by the tool to the arms, to image the walls of the borehole, for analysis of the geologic strata. After being lowered to the bottom of the area to sample, the tool would open the robotic arms to touch the borehole walls. The arms of the tool have springs to maintain contact pressure as the tool was pulled back up, sampling as it ascended. My responsibility was for the arm pod Analog DSP data acquisition / single wire communications firmware, PIC motor control firmware – for safe mode retraction in case of failure, and reporting of conditions – power consumption, overload, position, and actuation. I was also responsible for the firmware for and sensor interfaces for the host processor, algorithms for acquisition, communications and operating system task implementation, on a NXP M4F Kinetis processor.