PathFinder’s Density Neutron Standoff Caliper service provides the best available bulk density, neutron porosity and caliper measurements while drilling.
Density Neutron Standoff Caliper
PathFinder offers a variety of sizes from 8 1/2” tools to 4 3/4” tools compatible with all of the PathFinder LWD services for Slim Quad Combo capabilities.
While nuclear LWD tools have been available for several years, early designs had no direct means to account for standoff induced errors. Since these errors are potentially large, the DNSC™ tool was the first LWD tool designed to measure standoff directly and use that measurement to improve the accuracy of nuclear measurements. The DNSC™ uses a unique system consisting of three ultrasonic standoff sensors (one in-line with the nuclear source) to make both a caliper measurement and calculate a standoff measurement. Downhole data processing yields highly accurate measurements over a wide range of hole conditions.
In addition, the DNSC™ service includes a “3-axis” caliper log while drilling, enabling adjustments in mud properties and any other drilling parameters to reduce hole enlargement/degradation and have a positive impacting on drilling mechanics.
The DNSC™ accentuates measurements made when the nuclear sensors are closest to the formation, reducing the effect of those measurements made when standoff is great. Compared to other tools using azimuthal selection of quadrants (which may have difficulty identifying the right measurement point) the DNSC™ tool is proven to offer accurate porosity information under a variety of hole conditions.
Technical Specifications (PDF)
Slim Density Neutron Standoff Caliper
PathFinder’s Slim Density Neutron Standoff Caliper tool provides real-time bulk density, neutron porosity, density/neutron porosity, photoelectric index, standoff and caliper measurements in bore holes from 5 7/8” to 7 7/8”.
Built to operate in HPHT environments, the SDNSCTM has a modular design for placement anywhere in the PathFinder BHA, and utilizes the LWD industries first low energy, high yield, Californium252 neutron source. Two ultrasonic transducers provide accurate and redundant standoff and while rotating caliper measurements.
The SDNSC™ tool has a high capacity memory which includes very large data volume storage. The battery capacity provides over 300+ hours of power ensuring that system is powered over extended bit runs.
Can be configured to operate in environments with temperatures up to 350°F (175°C) and pressures up to 25,000 psi.
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