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Mechanistic Model Describes Wettability Change in Sandstones and Carbonates

Topics: Carbonates

Previously proposed models of wettability change have not been tied to the chemistry that controls wettability but instead were driven by simplistic criteria such as salinity level or concentration of an adsorbed species. In this paper, after testing proposed models in the literature on sandstones and carbonates, the authors propose a mechanistic surface-complexation-based model that describes observations quantitatively for ionically treated waterfloods. To the best of the authors’ knowledge, this is the first surface-complexation-based model that describes fully ionic compositional dependence observed in ionically treated waterfloods in both sandstones and carbonates.

Introduction

While some debate remains about the underlying mechanisms of ionically tuned waterflooding, the geochemical reactions that control the wetting of crude oil on the rock surface are likely to be central to a detailed description of the process. Models of wettability change often have been simplistic and not tied to the chemistry that controls wettability, instead driven by a simplistic criterion such as salinity level or concentration of an adsorbed species. Such models are inadequate for modeling the effect of compositional changes in brine, which is key to optimizing ionic design. One problem has been the lack of reservoir models that included geochemistry. The oilfield reactive-­transport simulators are simplistic; in these, either aqueous reactions are assumed to be ideal (i.e., with aqueous activity coefficients of unity) or they lack important geochemical features such as kinetics or surface-complexation reactions.

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 190236, “Modeling Wettability Change in Sandstones and Carbonates Using a Surface-Complexation-Based Method,” by Aboulghasem K.N. Korrani, SPE, and Gary R. Jerauld, SPE, BP, prepared for the 2018 SPE Improved Oil Recovery Conference, Tulsa, 14–18 April. The paper has not been peer reviewed.
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Mechanistic Model Describes Wettability Change in Sandstones and Carbonates

01 January 2019

Volume: 71 | Issue: 1

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