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Discussion of shale rock wettability and the methods to determine it
Author(s) -
Sheng James J.
Publication year - 2018
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.2263
Subject(s) - wetting , oil shale , capillary pressure , capillary action , geology , petroleum engineering , permeability (electromagnetism) , geotechnical engineering , petroleum reservoir , relative permeability , imbibition , mineralogy , composite material , materials science , chemistry , porosity , porous medium , paleontology , biochemistry , germination , botany , membrane , biology
Because of ultra‐low permeability of shale rocks, capillary pressure is very high. Wettability not only determines the value of capillary pressure, but, more importantly, it also determines whether the capillary pressure is a driving force or a resistance to fluid flow. This paper is to address the wettability characteristics of shale rocks. First, the common methods to determine wettability are reviewed and discussed for their feasibility for shale rocks. It is found that the real reservoir wettability must be determined in a system with oil and water being present; it cannot be determined by comparing the water and oil‐wetting angles measured on dry rock surfaces. It is also interesting to note that more shale rocks are water wet, although the oil‐wetting angles are smaller than water‐wetting angles on dry rock surfaces. The factors that affect shale wettability are also reviewed.