The application of diverting acid in oil and gas field
development
is becoming more and more widespread, with its characteristics of
clean and pollution-free, self-diverting, and good acidizing effect.
Currently, there is little research on the diverting characteristics
of diversion acids in reservoirs. Using nondestructive and high-precision
digital rock physics (DRP) technology, the diverting characteristics
of diverting acid can be studied in three dimensions. At the same
time, in the process of digital rock construction, deep learning (DL)
technology is used to accurately identify and segment fractures, pores,
and matrix in complex rocks, construct a three-dimensional pore-fracture
network model and rock mineral model that fit the actual situation,
and establish a fluid’s real flow channel. Finally, the acidification
characteristics of diverting acid and conventional hydrochloric acid
systems were studied using DRP technology, and it was found that for
rocks with strong heterogeneity, the conventional hydrochloric acid
system has a poor acidizing effect. On the one hand, it is difficult
to connect low-permeability channels and effectively increase the
oil drainage area. On the other hand, it will cause excessive dissolution
of reservoir rocks, destroy the rock skeleton, and block the flow
channels due to the destruction of some rock skeletons. Diverting
acid flows in rocks, constantly undergoing acid–rock reactions,
increases the viscosity of the acid solution, forcing the acid solution
to flow from high-permeability channels to low-permeability channels,
improving the connectivity of low-permeability channels, and effectively
improving the acidification effect to achieve uniform acidification
and increase rock permeability. The concentration of the diversion
agent is the main factor affecting the diversion effect. Considering
the acidification radius, construction cost, and pumping pressure
conditions, appropriately increasing the concentration of the diversion
agent can improve the effect of uniform acidification.