Randy A. Normann

Field comparison of conventional and new technology temperature logging systems

Abstract Field tests were conducted in the summer of 1995 on four state-of-the-art temperature logging systems: an analog, electric-line, system; two pressure and temperature recording memory tools (in-hole computer systems); and a Distributed optical fibre Temperature Sensing (DTS) system. The tools produced accurate, detailed, temperature versus depth and temperature gradient versus depth logs at depths to 2 km and temperatures to 200°C. Absolute temperature differences up to 0.4°C were noted between tools. The computer and electric-line tools have significantly better precision and resolution than the DTS, but the DTS has the advantage of being able to measure temperature instantaneously throughout the hole, and would be well suited for monitoring dynamic systems and gas-filled wells. The multiple independent logs demonstrate that most of the “noise” seen in gradient logs is due to convection cells, which may have dimensions several times the borehole diameter, and that these convection cells are currently the limiting factor in resolving wellbore temperatures in most settings.

Fiber optic Fabry-Perot interferometric sensor interrogated by the amplified spontaneous emission of an erbium-doped fiber amplifier for geothermal applications

As a clean, reliable, and comparatively inexpensive alternative to fossil fuels, geothermal electricity generation could provide energy for fifty years or more if properly managed. Real-time and remote measurement of some key parameters of the geothermal well as well as their temporal and spatial variations can provide critical information to improve plant efficiency and optimize plant operation to accommodate a resource that is declining with time. A hermetically sealed single mode fiber extrinsic Fabry-Perot interferometric (EFPI) sensor was developed for in-situ monitoring the temperature of geothermal wells. The amplified spontaneous emission of an erbium doped fiber amplifier was investigated as the broadband source to interrogate the fiber EFPI temperature sensor. Real-time compensation of the source spectrum distortion was investigated to improve the measurement accuracy and extend the sensor lifetime.

Shared multiplier design of a digital filter on a high-temperature FPGA module

This paper outlines the design of a space-efficient digital filter for use in high-temperature FPGA applications. It presents an implementation of a Butterworth filter design using VHDL: shared multiplier. It outlines the main signals and states used in the design. The shared multiplier design uses a single multiplier for each multiplication in the equation. The design is the smallest of the three. The results obtained by implementing the design on a FPGA are also presented. The shared multiplier approach is efficient in terms of demand of space on the FPGA

Design of a High-Temperature, Space Efficient Digital Filter on an FPGA

This paper outlines the design of a space-efficient digital filter for use in high-temperature FPGA applications. It presents three different methods of implementing a Butterworth filter design using VHDL: bit serial, shared multiplier and single step. It outlines the main signals and states used in these designs. The bit-serial approach uses bit-serial arithmetic for the filter equation instead of combinational adders and multipliers. This filter design is the slowest in processing the data, and is not very efficient in terms of flip-flops or overall space usage. The shared multiplier design uses a single multiplier for each multiplication in the equation. The design is the smallest of the three. The single step design calculates the filter equation in one step using multiple adders and multipliers. This design uses the least number of flip-flops. The results obtained by implementing these designs on a FPGA are also presented. The shared multiplier and the single step approach are both efficient depending on the resource in demand on the FPGA. The bit serial approach is not useful for space efficient designs

Characterization of Under-Building Contamination at Rocky Flats Implementing Environmental-Measurement While Drilling Process with Horizontal Directional Drilling

Characterization is required on thirty-one buildings at Rocky Flats Environmental Technology Site (RFETS or the Site) with known or suspected under building contamination. The Site has teamed with Sandia National Laboratory (SNL) to deploy Environmental MeasureWhile-Drilling (EMWD) in conjunction with horizontal directional drilling (HDD) to characterize under building contamination and to evaluate the performance and applicability for future characterization efforts. The Environmental Measurement-While-Drilling-Gamma Ray Spectrometer (EMWD-GRS) system represents an innovative blend of new and existing technology that provides the capability of producing real-time environmental and drill bit data during drilling operations. The project investigated two locations, Building 886 and Building 123. Building 886 is currently undergoing DD however, the slab is present with under building process waste lines and utilities. This report presents the results of the EMWD Gamma Ray Spectrometer logging of boreholes at these two sites. No gamma emitting contamination was detected at either location.

Precision pressure/temperature logging tool

Past memory logging tools have provided excellent pressure/temperature data when used in a geothermal environment, and they are easier to maintain and deploy than tools requiring an electric wireline connection to the surface. However, they are deficient since the tool operator is unaware of downhole conditions that could require changes in the logging program. Tools that make ``decisions`` based on preprogrammed scenarios can partially overcome this difficulty, and a suite of such memory tools has been developed at Sandia National Laboratories. The first tool, which forms the basis for future instruments, measures pressure and temperature. Design considerations include a minimization of cost while insuring quality data, size compatibility with diamond-cored holes, operation in holes to 425 C (800 F), transportability by ordinary passenger air service, and ease of operation. This report documents the development and construction of the pressure/temperature tool. It includes: (1) description of the major components; (2) calibration; (3) typical logging scenario; (4) tool data examples; and (5) conclusions. The mechanical and electrical drawings, along with the tool`s software, will be furnished upon request.

Final report of the environmental measurement-while-drilling-gamma ray spectrometer system technology demonstration at the Savannah River Site F-Area Retention Basin

The environmental measurement-while-drilling-gamma ray spectrometer (EMWD-GRS) system represents an innovative blend of new and existing technology that provides real-time environmental and drill bit data during drilling operations. The EMWD-GRS technology was demonstrated at Savannah River Site F-Area Retention Basin. The EMWD-GRS technology demonstration consisted of continuously monitoring for gamma-radiation-producing contamination while drilling two horizontal boreholes below the backfilled retention basin. These boreholes passed near previously sampled vertical borehole locations where concentrations of contaminant levels of cesium had been measured. Contaminant levels continuously recorded by the EMWD-GRs system during drilling are compared to contaminant levels previously determined through quantitative laboratory analysis of soil samples.