Saudi Arabian Oil Company

Schlumberger Technology Corporation

Baker Hughes Oilfield Operations LLC

Saudi Aramco

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Gabor Hursan

Shouxiang Mark Ma

Henry N Bachman

Philip M Singer

Babatope Kayode

Hasan Kesserwan

Andrea Valori

Benjamin Nicot

Farhan Ali

Ahmed Al-Muthana

A method of estimating a wettability characteristic of a rock and fluid system includes acquiring a sample of the rock material, performing a first nuclear magnetic resonance (NMR) measurement of the sample when the sample is in a full water saturation condition, and measuring a first T2 distribution, performing a second NMR measurement of the sample when the sample is in a second partial saturation condition, and measuring a second T2 distribution. The method also includes separating a hydrocarbon component of the second T2 distribution from a water component of the second T2 distribution, applying a fluid substitution model to the water component of the second T2 distribution to generate a computed T2 distribution, and calculating a wettability index (WI) based on a difference between the first T2 distribution and the computed T2 distribution.

Wettability estimation using magnetic resonance

Methods for simulation of hydrocarbon systems having a sharply varying viscosity gradient include receiving, by a computer system, Neutron Magnetic Resonance (NMR) logs for hydrocarbon wells in an oilfield. The computer system identifies viscosity regions of hydrocarbons present within the hydrocarbon wells based on the NMR logs. The computer system determines equation of state (EOS) parameters based on compositional analysis of pressure-volume-temperature (PVT) samples obtained from the hydrocarbon wells. The computer system generates a three-dimensional (3D) model of the oilfield, using as inputs, the viscosity regions, the EOS parameters, and a fluid composition gradient with respect to a depth within each viscosity region. The computer system determines a landing depth from the surface of the Earth for operation of peripheral water injectors based on simulating the 3D viscosity model.

Numerical simulation of hydrocarbon systems with viscosity gradient

Provided in some embodiments are systems and methods for determining characteristics of a hydrocarbon reservoir. Embodiments include conducting a nuclear magnetic resonance (NMR) logging operation of a targeted reservoir section of a wellbore extending into a hydrocarbon reservoir to generate a NMR log of the targeted reservoir section, conducting a resistivity logging of the targeted reservoir section to generate an uninvaded water saturation (S) log of the targeted reservoir section, determining for each of a plurality of depths in the section, a Tcutoff point based on values of the NMR and Slogs, identifying a subset of the Tcutoff points that exhibit a hyperbolic trend, determining a theoretical cutoff curve corresponding to the subset of the Tcutoff points, determining a free water level (FWL) of the reservoir based on the theoretical cutoff curve, and determining a rock type of the reservoir based on the theoretical cutoff curve.

Nuclear magnetic resonance and saturation well logs for determining free water level and reservoir type

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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Dhahran, Saudi Arabia

Gabor Hursan