Page 14 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

Introduction xiii

with porous media, and oil-gas-water distribution and application in petro-
leum engineering, in response to the special phenomena of gas wettability.

First, as the basic concept of “gas wettability,” it is defined as the ability of gas
to cover solid surfaces with greater preference than liquids that are immiscible
with gas in a “gas/liquid/solid” system. Based on this, rough microstructures
and low-surface energy materials can be modified and combined through sol-
gel method, to produce rock samples for indoor theoretical study.
Second, in terms of the gas wettability evaluation method, there are two kinds
of quantitative methods to evaluate gas wettability on a reservoir surface,
based on the particularity of gas wettability: sessile drop method and bubble
trap method. Each method has its own features and availability. The former
can reflect gas wettability strength based on the liquid phase’s wetting ability,
while the latter can directly evaluate gas wettability strength of solid interface
by bubble shapes. Both can effectively provide quantitative gas wettability
evaluation based on contact angle measurement and capillary rise test.

Third, in terms of reversal mechanism and gas wettability method, there are
two types of gas-wetting reversal materials, including fluorocarbon polymer
and fluorocarbon surfactant. By researching adsorption film properties on rock
surface of gas-wetting reversal material, gas-wetting reversal material’s action
mechanism is revealed. Thus, control method for gas wetting phase is estab-
lished and there is further discussion on suitable environment for adopting
the method.
Fourth, in terms gas-wetting rocks’ surface properties, surface chemical charac-
teristics, electrical properties, interfacial vibrancy, and interfacial forces, as well
as permeability law and distribution of oil, gas, and water affected by gas wet-
tability are described.

Finally, the book introduces four practical petroleum engineering techniques:
“the drilling fluid technology of protect reservoir by changing rock surface
properties in low permeability reservoir,”“the drilling fluid technology of car-
rying drilling cuttings thoroughly,”“trapezoidal protection technology for low
and ultra-low permeability infiltration reservoir,” and “oil removal technology
with drilling cuttings containing oil.”
This book’s main contents include research results (Project Name: Research on
basic theory of gas wettability of porous media reservoirs) achieved by Natural
Science Fund Project for Distinguished Young Scholars of China (a top-
ranking project for basic theoretical research in China), which Professor Jiang
Guancheng heads. At the same time, some of these have been incorporated
into research achievements of Key Scientific and Technological Projects, han-
dled by Professor Jiang Guancheng during China’s “Eleventh Five-Year Plan”
and “Twelfth Five-Year Plan.”
The Natural Science Foundation of China, Ministry of Science and Technology
of China, National Development and Reform Commission of China, China