Patent
Neutron well logging
Harry D. Smith,Ward E. Schultz +1 more
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TLDR
In this article, an improved method for determining the oil saturation of subsurface earth formations in the vicinity of a well borehole was proposed, in which high energy neutrons irradiate the subsural earth formations and gamma rays caused by inelastic scatter with the subsuranface earth formation constituent materials are measured.Abstract:
This invention relates to an improved method for determining the oil saturation of subsurface earth formations in the vicinity of a well borehole. High energy neutrons irradiate the subsurface earth formations and gamma rays caused by inelastic scatter with the subsurface earth formation constituent materials are measured. For a chosen borehole depth, gamma ray logs are taken in different situations: first, with the formation fluid water and oil mixture in an undisturbed state; second, after flushing the formation with alcohol to displace the formation water and oil mixture; and, finally, after flushing the alcohol from the formation with water to obtain a measurement with no oil in the formation. The gamma ray measurements obtained are then used to determine the oil saturation without requiring knowledge of the porosity of the earth formation, borehole conditions or formation type. When the original oil content of the formation is at a naturally flushed, or residual, oil saturation, the present invention may be used to determine the residual oil saturation.read more
Citations
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References
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Patent
Method of logging a sub-surface formation
TL;DR: In this paper, a log-in-log-inject-log technique was used to determine the oil saturation in an underground rock reservoir by using thermal neutron decay time logs in the native state, after fresh water injection and again after an alcohol injection followed by formation type water.
Patent
Neutron absorption and oxygen log for measuring oil content of formation
TL;DR: In this paper, a method for accurately determining changes in the fractional-volume oil and gas content of a reservoir from a cased well bore is described, which can be modified to measure changes in fluid content over long periods by running the combination of the thermal-neutron-decay-time log and the oxygen log when knowledge about current saturations is desired.