Hydrophobicity of Reservoir Rocks in Sections of Oil and Gas Wells (Devonian and Carboniferous, Dnipro-Donets Depression)

The importance of using information about the hydrophobicity (hydrophilicity) of reservoir rocks when designing a system for developing oil and gas fields is highlighted. The degree of hydrophobicity of oil- and gas-saturated rocks significantly affects the filtration capabilities of the formations. However, it is quite difficult to determine this parameter in rocks in their natural occurrence. This is usually carried out in laboratories, where research conditions differ significantly from reservoir conditions. The article discusses ways to determine the hydrophobicity of reservoir rocks in their natural occurrence without the use of special laboratory techniques. Information for calculating the degree of hydrophobicity of rocks can be obtained from the results of well logging. Moreover, data from conventional typical methods of logging oil and gas wells are offered for use. The issues of grouping reservoir rocks according to the degree of hydrophobicity are also considered based on the use of the well-known power-law parameter in the Archie equation. It has been shown that the hydrophobicity of rocks varies significantly across well sections, even within individual oil and gas deposits.