Improved pulsed neutron capture logging with slim carbon-oxygen tools: Methodology
- SPE, Richardson, TX (United States); and others
Recently, two new slim through-tubing carbon-oxygen tools were introduced and described in the literature. In addition to carbon-oxygen water-saturation capability, these new instruments can provide, during the same trip, pulsed neutron capture (PNC) measurements (formation sigma, porosity, borehole fluid salinity, etc.). The answers have improved accuracy and precision compared to prior logging instruments. This paper describes the Dual-Burst PNC measurement scheme for the RST Reservoir SaturationTool, as well as the algorithm methodology for determining corrected sigma, porosity, borehole fluid salinity, log quality and other associated outputs. Also documented are database measurements on which the algorithms are based, accuracy benchmarks in industry-standard calibration facilities, and precision (repeatability) comparisons. Therefore, a multidimensional dynamic parameterization technique, based on an extensive set of laboratory measurements, has been developed and refined. This technique keeps the order of parameters low, resulting in a well-behaved response both inside and outside the range spanned by the database. The supporting database for each tool includes over 1000 measured points augmented with approximately 400 modeled points spanning different lithologies, porosities, borehole sizes, casing sizes and weights, formation fluid salinities, and borehole fluid salinities typically encountered in the oilfield. Also reported are the sigma and porosity accuracy benchmark measurements made in the industry-standard calibration facilities (EUROPA facility, Aberdeen, Scotland and API test pits, University of Houston, Houston, Texas, USA). Precision (repeatability) is also compared to prior PNC logging instruments, demonstrating logging speeds typically several times faster for comparable precision.
- OSTI ID:
- 207303
- Report Number(s):
- CONF-951002-; TRN: 96:000704-0062
- Resource Relation:
- Conference: Annual meeting of the Society of Petroleum Engineers (SPE), Dallas, TX (United States), 22-25 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of Formation evaluation and reservoir geology. 1995 SPE annual technical conference and exhibition; PB: 1010 p.
- Country of Publication:
- United States
- Language:
- English
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