Schlumberger Technology Corporation

Saudi Aramco

Saudi Arabian Oil Company

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Benjamin Nicot

Patrice Ligneul

Shouxiang Mark Ma

Henry N Bachman

Philip M Singer

Andrea Valori

Gabor Hursan

Farhan Ali

Jean-pierre Korb

Gabriel Freiman

Mamood Akbar

Ahmed Al-Muthana

A nuclear magnetic resonance relaxation dispersion method to determine the wettability and other parameters of a fluid in a porous medium such as in an earth formation is provided. The method includes the steps of measuring the spin-lattice relaxation time Tof the fluid in the porous medium at varying polarizing magnetic field strengths or nuclear Larmor frequencies; and determining whether the values of Tat varying Larmor frequencies follow a dispersion curve that is characteristic of the parameter of the fluid in the porous medium to be determined.

Method of determining formation parameter

Systems and methods for determining T2 cutoff are described. T2 cutoff can be derived from magnetic susceptibility measurements. By providing a depth curve of T2cutoff, improved permeability estimations from NMR can be generated. By combining a magnetic susceptibility tool and an NMR tool, a dynamic T2cutoff can then be provided, together with the standard NMR log, according to some embodiments. According to some embodiments the improved permeability estimations can be provided automatically and in real time at the wellsite.

T2-cutoff determination using magnetic susceptibility measurements

Methods are described for wettability characterization based on NMR measurements, which are sensitive to the surface wetting conditions of oil and water at the pore scale. The described methods make use of surface relaxation effects on the NMR relaxation (T). Workflows are described to obtain wettability profiles of a porous media such as a rock either in the native state or prepared to a certain state in the laboratory. An underlying forward model is also described for the mixed wet and fractionally saturated pore spectrum. Outputs of the described inversion include continuous saturation and wettability profiles as a function of the pore sizes in the porous media, as well as an averaged value for saturation and wettability over the entire pore spectrum.

Methods for determining wettability from NMR

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Rio de Janeiro, Brazil

Benjamin Nicot