Measuring rock wettability

Patent metadata

Field	Value
Publication number	US-10416063-B2
Application number	US-201715801509-A
Country	US
Kind code	B2
Filing date	Nov 2, 2017
Priority date	Nov 2, 2017
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A method for characterizing wettability of a porous medium is described. A core sample of the porous medium is secured in a core holder, which includes a first end and a second end. A model of the core sample and a pore volume of the core sample are obtained. A wetting phase is displaced from the core sample by supplying a non-wetting phase at one end of the core holder. The non-wetting phase is displaced from the core sample by supplying the wetting phase at one end of the core holder. A saturation profile of the core sample is determined based on cross-sectional images of the core sample. A wettability index value is calculated at least based on a comparison of the saturation profile and the model of the core sample.

First claim

What is claimed is:

1. A method for characterizing wettability of a porous medium, the method comprising:
securing a core sample of the porous medium in a core holder, the core holder comprising a first end and a second end, the first end and the second end configured to allow fluid to enter or exit the core holder;
obtaining a model of the core sample and a pore volume of the core sample;
displacing a wetting phase from the core sample by supplying a non-wetting phase at one of the first end of the core holder or the second end of the core holder while supplying the wetting phase to a first different one of the first end of the core holder or the second end of the core holder;
displacing the non-wetting phase from the core sample by supplying the wetting phase at one of the first end of the core holder or the second end of the core holder while supplying the non-wetting phase to a second different one of the first end of the core holder or the second end of the core holder;
determining a saturation profile of the core sample based on cross-sectional images of the core sample; and
calculating a wettability index value at least based on a comparison of the saturation profile and the model of the core sample.

2. The method of claim 1 , wherein the core holder has a vertical axis and a vertical orientation, wherein the first end and the second end are parallel to the vertical axis of the core holder, and at least one of the first end or the second end is conical and configured to maintain contact between the wetting phase or the non-wetting phase and the core sample.

3. The method of claim 1 , wherein obtaining the model and the pore volume comprises scanning the core sample in a dry state.

4. The method of claim 3 , wherein displacing the wetting phase from the core sample comprises injecting the non-wetting phase at a rate of substantially 4 cubic centimeters per hour (cm 3 /hr) for at least 10 pore volumes, and displacing the non-wetting phase from the core sample comprises injecting the wetting phase at a rate of substantially 4 cm 3 /hr for at least 10 pore volumes.

5. The method of claim 3 , further comprising preparing the core sample for core flooding, the preparing the core sample for core flooding comprising:
saturating the core sample with the wetting phase;
displacing the wetting phase from the core sample with the non-wetting phase until steady state is reached; and
aging the core sample.

6. The method of claim 5 , wherein the porous medium comprises a reservoir rock, and the core sample is aged for at least 4 weeks.

7. The method of claim 6 , wherein determining the saturation profile of the core sample based on cross-sectional images of the core sample is repeated:
after saturating the core sample with the wetting phase;
while displacing the wetting phase from the core sample; and
while displacing the non-wetting phase from the core sample.

8. The method of claim 7 , wherein the non-wetting phase comprises a hydrocarbon fluid, and the wetting phase comprises a brine solution.

9. The method of claim 8 , wherein determining the saturation profile of the core sample comprises scanning the core sample using magnetic resonance imaging (MRI), and the brine solution is a deuterium oxide-based brine solution.

10. The method of claim 9 , wherein scanning the core sample using MRI comprises scanning the core sample to obtain a plurality of images and producing an average across the plurality of images to increase a signal-to-noise ratio (SNR).

11. The method of claim 8 , wherein determining the saturation profile of the core sample comprises scanning the core sample using X-ray computed tomography (CT).

12. The method of claim 11 , wherein the wetting phase comprises an attenuating agent configured to decrease detection of the wetting phase by X-ray CT scanning.

Assignees

• Saudi Arabian Oil Co

Inventors

• Gao Jun
• Al-Harbi Ahmad Mubarak
• Kwak Hyung Tae

Classifications

• G01N13/00 Primary

  Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects (scanning-probe techniques or apparatus G01Q) · CPC title

• G01R33/48

  NMR imaging systems · CPC title

• G01N23/046

  using tomography, e.g. computed tomography [CT] · CPC title

• G01N2015/0846

  by use of radiation, e.g. transmitted or reflected light · CPC title

• G01R33/5608

  Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels (image data processing or generation, in general G06T) · CPC title