Analysis of the changes in filtration and capacity properties of the oil and gas condensate field reservoirs using X-ray computed tomography methods

Objective. To study the nature of changes in structural, capacity and filtration properties of the Chayanda oil and gas condensate field reservoir resulting from mechanical and hydrodynamic testing and to improve the quality of laboratory assessment of the reservoir properties of rocks by applying the digital approach. Materials and methods. A high-resolution X-ray micro-CT scanner ProCon X-Ray CT-MINI was used for computed tomography. Digital analysis of images was carried out in GeoDict software. Results. The results of digital analysis of changes in the pore space of hydrocarbon reservoir by computer tomography methods after the tests with fluid filtration under baric conditions are presented, including comparison of macroscopic changes in the pore space and determination of the nature of changes in reservoir porosity and pore geometry at the macro level. Porosity values were determined using digital methods and compared with laboratory data. Numerical modeling of filtration processes on the created 3D models of the rock was performed. The fact of nonuniform distribution of filtration flows was established: filtration in the rock occurs mainly through isolated alternating channels. It was determined that the change in the rock pore space occurred mainly due to deformation and expansion of the walls of the main filtration channels. Conclusions. Nonuniformity of changes in filtration-capacitance properties of rock specimens caused by mechanical and hydrodynamic tests can lead to incorrect estimation of porosity and permeability when applying traditional laboratory methods. The results of nondestructive digital studies can be advised as a supplement to laboratory studies of core material properties. Joint application of digital and traditional laboratory methods allows obtaining the most complete range of data on reservoir properties to solve problems arising during development.