The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 01, 2000
Filed:
Dec. 31, 1997
Charles Flaum, Ridgefield, CT (US);
Schlumberger Technology Corporation, Ridgefield, CT (US);
Abstract
A technique is disclosed for determining the gas-filled porosity and oil-filled porosity in a region of investigation of earth formations surrounding a borehole including the following steps: (a) providing a logging device that is moveable through the borehole; (b) generating, from the logging device, a static magnetic field in the region of investigation of the formations, the static field having a magnetic field gradient that is not constant in the region of investigation; (c) determining the gradient distribution of the static magnetic field in the region of investigation, and determining a first function of the gradient distribution and the diffusion coefficient of oil, and a second function of the gradient distribution and the diffusion coefficient of gas; (d) generating a first sequence of magnetic field pulses in the region of investigation of the formations using a first wait time, and detecting a first sequence of nuclear magnetic resonance spin echoes from the formations; (e) generating a second sequence of magnetic field pulses in the region of investigation of the formations using a second wait time, and detecting a second sequence of nuclear magnetic resonance spin echoes from the formations; (f) producing, from differences of respective echoes of the second and first sequences of spin echoes, an echo difference signal; and (g) determining the gas-filled porosity and oil-filled porosity in the region of investigation of earth formations from: the echo difference signal, a response function which depends on the first function, and a response function which depends on the second function.