Improved Measurement Quality and Reliability in a Formation-Evaluation LWD System
| Autor: | G. L. Moake, D. R. Heysse, C. E. Jackson, Al Jerabek, G. A. Merchant, W. E. Schultz |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | SPE Drilling & Completion. 12:196-202 |
| ISSN: | 1930-0204 1064-6671 |
| DOI: | 10.2118/28429-pa |
| Popis: | SummaryThis paper describes a new logging-while-drilling (LWD) tool-string, which is equivalent to a wireline triple-combo. It is composed of two tools, resistivity and nuclear, that can be combined or run separately. New features have been incorporated in the tool designs to minimize problems encountered with previous tools, and to reliably provide near-wireline-quality measurements. The resistivity tool provides symmetrical measurements of both phase and attenuation resistivity for two different transmitter spacings. This provides enough information to determine Rt, as well as to quantify invasion. The symmetrical design provides borehole compensation and ensures that the actual measure point of the tool is the same for all formations. The nuclear tool measures density, Pe, neutron porosity, standoff, and borehole diameter (caliper). The standoff measurement is used to improve the nuclear-data quality by weighting small-standoff data greater than large-standoff data. It is also used to correct the neutron porosity for standoff and borehole diameter. Logs comparing this toolstring to wireline tools are presented. |
| Databáze: | OpenAIRE |
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