Method for determining density of an earth formation
AssigneesSchlumberger Technology Corporation, Japan National Oil Corporation
InventorsMichael L. Evans, Jacques M. Holenka
Life of this patent
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Abstract
Apparatus for determining the density of underground formations surrounding a borehole, such as a wireline logging tool or a logging-while-drilling tool, includes a neutron source for irradiating the formations from within the borehole and at least one detector which detects neutrons and gamma rays in the borehole resulting from the irradiation of the formations with neutrons. Multiple detectors can also be used to separately detect neutrons and gamma rays. Detected neutron and gamma ray signals are each analyzed and combined to determine the density of an earth formation.
Claims22
A method of determining the density of an underground earth formation surrounding a borehole comprising:
- a) irradiating the formation from a neutron source within the borehole;
- b) detecting neutrons and gamma rays resulting from the irradiation;
- and
- c) analyzing the detected neutrons and the detected gamma rays to determine the density of the formation surrounding said borehole.
A method of determining the density of an underground formation surrounding a borehole comprising:
- a) irradiating the formation from a neutron source within the borehole;
- b) creating a source of gamma rays in the formation from said irradiated neutrons;
- c) detecting neutrons and gamma rays in the borehole resulting from the irradiation;
- and
- d) analyzing the detected neutrons and the detected gamma rays to determine the density of the formation surrounding said borehole.
Dependencies are inferred from the claim text.