Alterations in the physical properties of reservoir rocks during the development of oil and gas deposits

Abstract

The article analyzes changes in the physical properties of reservoirs during the development of oil and gas fields. The impact of processes in the implementation of technologies such as hydraulic fracturing or pumping water into a contour zone is explained. The reason for the subsidence of the Earth's crust, man-made seismicity in the fields and the occurrence of tectonic disturbances, the forecast of which is a serious scientific and practical problem, is given. The relationship between the physical characteristics of samples of the same rock and differences in their mineral composition, granulometry, and structural features is considered. The factors influencing the reservoir properties are identified: changes in effective pressure, temperature fluctuations, flooding, and physico-chemical interaction with fluids. The necessity of laboratory modeling of reservoir conditions for verification of geomechanical models is substantiated, since standard geophysical studies provide only a static picture that does not reflect the kinetics of deformations. Special attention is paid to dynamic petrophysics, which studies the evolution of rock properties over time under the influence of cyclic loads and hysteresis effects. Three main approaches to studying changes in properties are presented: standard measurements, modeling of thermobaric conditions, and evaluation of deformation and strength characteristics. The negative effects of long-term exploitation of hydrocarbon deposits, including subsidence and induced seismicity, are grouped. Two scenarios of the development of deformation processes are considered: with the accumulation of stresses in strong pores and with plastic subsidence of weakly cemented collectors. The above theoretical patterns of changes in the filtration and capacitance properties of carbonate reservoirs were used as the basis for the development and implementation of a set of technologies to intensify the inflow at the Astrakhan gas condensate field. The application of hydrophobic emulsion solutions is considered, the results of field tests are described, which confirmed an increase in well productivity and environmental safety. The results obtained can serve as a basis for designing the development of deposits with similar mining and geological conditions.