Kazakhstan journal for oil & gas industry

The article considers the results of part of the research, groundworkss, as well as the experience gained in the implementation of the project to study the core of the Triassic and Tatar horizons of the Karachaganak field. This project included both direct work with core material, conducting a series of laboratory studies on it in order to determine the conditions of sedimentation, understanding their extent, determining the age of rocks, their qualitative and quantitative characteristics, and facies modeling to obtain facies maps, correlation schemes and profiles. One of the most interesting and important stages of the project implementation was biostratigraphic analysis and the construction of a correlation scheme on its basis in order to conduct a qualitative correlation of the section, which is the basis for identifying the conditions of sedimentation and understanding their strike in space.

Intensive development of discovered oil and gas fields since the early 90s.of the last century, mainly associated with structural traps in Jurassic-Cretaceous complex, to date has led to a reduction in proven hydrocarbon reserves in the South Torgai sedimentary basin. The prospective potential for an increase in the resource base of the studied region can be focused within the deposits of pre-Mesozoic complex.

Historically it was believed that the South Torgai sedimentary basin has a two-deck structure: a sedimentary cover of the Mesozoic-Cenozoic age and an underlying crystalline-folded basement of the Paleozoic-Proterozoic complex. The oil and gas potential of the Paleozoic complex in the region has been proven by obtaining direct signs of oil and gas in the core, oil and gas shows, up to industrial oil flows on a limited number of areas within the weathering crust zones.

Analytical studies of recent years indicate a significant heterogeneity of the Paleozoic-Proterozoic complex, where promising structures of the Upper Paleozoic quasi-platform complex, represented by carbonate rocks, may be present. This article is focused on the analysis of a new and previously unexplored potential oil and gas complex of deeper-lying Paleozoic sediments that are of interest for setting up geological exploration.

Due to the confidentiality policy, the names of wells, fields, coordinates and other detailed information are hidden. The article was formed to demonstrate the concept of the prospects of the heterogeneous Paleozoic-Proterozoic complex.

The dynamic loads and internal stresses applied onto a well during its operation period, gradually leads to deterioration of the cement sheath that usually exists behind the casings. Such mechanical and chemical exposure causes the cement to develop severe cracks that enables cross feeds behind casings and uncontrollable flow between formations leading to oil-gas mixture and migration of hydrocarbons into freshwater aquifers causing immediate harm to local water sources [1], affecting the zonation capability of the cement itself behind the casings.

This issue has been in the industry of oil and gas for ages, leading us to investigate the possibility of maintaining the integrity of the cement stone behind the casings through the principle of ‘’self-healing’’ materials, through this principle a self-healing cement was formulated adding secret agents into the ordinary cement powder which will be able to cure cracks in the cement stone under special conditions without human intervention. This can be an effective measure for loss of well integrity prophylaxis and eliminates well shutdowns for well workover operations.

This article analyzes the volatility of retrograde condensate when a gas condensate field is exposed to “dry” natural gases containing carbon dioxide (CO₂), which is associated with some of its advantages over other non-hydrocarbon gases.

The indicators of the process of impact on the bottomhole zone of a producing gas condensate well by "dry" gas enriched with carbon dioxide are studied, taking into account the influence of the physicochemical and thermodynamic properties of the gas condensate system, as well as the thermobaric conditions of the process itself.

"Dry" hydrocarbon gas containing carbon dioxide more actively evaporates retrograde condensate compared to other non-hydrocarbon gases. However, to increase the efficiency of this process, one should take into account the number of injected gas contacts and the temperature of the bottomhole zone.

The article presents the results of approbation of the methods of determining the coefficient of difference of physical properties of oil and displacing agent (µ₀), proposed by Lysenko V.D. on the example of the Kalamkas field. Determination of this parameter is necessary for designing and improving the development based on direct oilfield data. The coefficient of difference between the physical properties of oil and the displacing agent (µ₀) was determined by several methods, which showed high convergence, thereby confirming the theoretical validity in practice. The presented methods were successfully applied for the first time on the example of the Kalamkas field.