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In situ characterization of mixed-wettability in a reservoir rock at subsurface conditions.

ABSTRACT: We used X-ray micro-tomography to image the in situ wettability, the distribution of contact angles, at the pore scale in calcite cores from a producing hydrocarbon reservoir at subsurface conditions. The contact angle was measured at hundreds of thousands of points for three samples after twenty pore volumes of brine flooding.We found a wide range of contact angles with values both above and below 90°. The hypothesized cause of wettability alteration by an adsorbed organic layer on surfaces contacted by crude oil after primary drainage was observed with Scanning Electron Microscopy (SEM) and identified using Energy Dispersive X-ray (EDX) analysis. However, not all oil-filled pores were altered towards oil-wet conditions, which suggests that water in surface roughness, or in adjacent micro-porosity, can protect the surface from a strong wettability alteration. The lowest oil recovery was observed for the most oil-wet sample, where the oil remained connected in thin sheet-like layers in the narrower regions of the pore space. The highest recovery was seen for the sample with an average contact angle close to 90°, with an intermediate recovery in a more water-wet system, where the oil was trapped in ganglia in the larger regions of the pore space.

SUBMITTER: Alhammadi AM

PROVIDER: S-EPMC5589931 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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In situ characterization of mixed-wettability in a reservoir rock at subsurface conditions.

Alhammadi Amer M AM AlRatrout Ahmed A Singh Kamaljit K Bijeljic Branko B Blunt Martin J MJ

Scientific reports 20170907 1

We used X-ray micro-tomography to image the in situ wettability, the distribution of contact angles, at the pore scale in calcite cores from a producing hydrocarbon reservoir at subsurface conditions. The contact angle was measured at hundreds of thousands of points for three samples after twenty pore volumes of brine flooding.We found a wide range of contact angles with values both above and below 90°. The hypothesized cause of wettability alteration by an adsorbed organic layer on surfaces con ...[more]

PMID: 28883407

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Dataset Information

In situ characterization of mixed-wettability in a reservoir rock at subsurface conditions.

Publications

In situ characterization of mixed-wettability in a reservoir rock at subsurface conditions.

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