No 6 (2023)
DRILLING OF WELLS AND FIELDS DEVELOPMENT
An interpretation of data after performing Step-rate-test in multi-layered, unconsolidated and weakly consolidated reservoirs
Abstract
The prerequisite for this study is the difficulty in interpreting data after stimulation of the bottomhole formation zone has been carried out. The objectives of this work are the applicability and interpretation of Step-rate-test (SRT) data to evaluate suitable injection regimes in multilayered, unconsolidated and weakly consolidated reservoirs and the demonstration of the correlation between injection rate and pressure in a graphical format. We investigated the stability of the reservoir structure to pressure gradients by increasing pressure and injecting fluid through the injection well stock. We concluded that this stability does not improve over time. This means that the practical significance of this method lies in its ability to alter the pressure gradient when injecting fluid to maintain a constant flow rate. The constancy of the pressure gradient has a major impact on the stimulation of the bottomhole formation zone and therefore it can be concluded that the reservoir properties in the bottomhole formation zone are dynamic in nature and can change over time. It should be noted that the study found that a change in pore pressure within the loose rock can also affect the phase (effective) permeability, which in turn can affect the required pressure gradients during injection.
Oil and Gas Studies. 2023;(6):11-24
11-24
Experimental and field studies of wave technology for bottomhole cleaning and clogging of permeable formations
Abstract
The article presents the results of field experiments and field tests of wave technology for bottomhole cleaning and clogging of permeable formations. Acceleration of well construction time and avoidance of plugging (especially in gas wells) is extremely important nowadays. It is widely acknowledged that rock fractures occur due to the alternating motion of the flushing fluid, and it has significant implications for accelerating drilling processes and maintaining wellbore stability. This can be achieved through the wave motion of the flushing fluid. The experiments were conducted on a specialized installation that simulates downhole conditions, enabling the modeling of downhole processes. We created and tested various designs of wave generators to flush holes of bits with different types and sizes. Experimental evidence suggests that wave technology can aid in bottomhole cleaning and the creation of a colmatation screen. The wave action helps to keep the bottomhole zone and well walls clean, and significantly reduces the penetration of drilling fluid filtrate into the rock. The use of wave technology for bottomhole cleaning and permeable formation ringing shows great potential for oil and gas well construction. The sealing of the borehole space is crucial in the construction of Underground Gas Storage facilities.
Oil and Gas Studies. 2023;(6):25-34
25-34
Integrated model "reservoir-well" based on D-CRMP
Abstract
The active use of integrated modeling in reservoir engineering of oil fields has led to research to overcome the problems of its practical application. Typically, a 3D hydrodynamic model is used as a component characterizing the fluid flow in the reservoir. The downsides of the model are high computational complexity and low reliability of the initial data. Therefore, the objectives of the study are to construct an integrated reservoir-well model that does not have these drawbacks and to verify its adequacy. The article presents an integrated model for fast decision-making in the development of oil fields, as well as for analysis of the characteristics of the inter-well space, which doesn't require prior information about the reservoir. The integrated model is based on a representation of the analytical capacitance-resistance model (CRM), which considers shutdown periods of production wells. Oil flow rates are calculated using the Koval method. The pressure distribution in wells is calculated using a correlation similar to that used in the tNavigator software. A comparison was made between the calculation results obtained using the integrated model based on D-CRMP and the calculations in the tNavigator.
Oil and Gas Studies. 2023;(6):35-46
35-46
Multiphase friction calculation peculiarities based on models implemented in the "d-Flow" software package
Abstract
In order to ensure efficient and safe operation of oil and gas fields, a tool is required to design production wells and surface infrastructure. It is important to take into account the physical processes that occur during production, as well as fluid properties and phase transitions. The "d-Flow" software package enables the creation of a comprehensive field model based on geological and field data to calculate hydraulic losses of pipelines and forecast hydrocarbon production. The fluid flow modelling is based on the calculation of multiphase friction with the wall of a well or a pipeline. The article discusses the implementation of four friction models: the Beggs-Brill model, the Gray model and its modification, and the Mukherjee-Brill model. The purpose of this work is to compare the predictions of friction models with the results obtained using commercial realizations of the same models. The results of the Schlumberger PIPESIM hydraulic simulator calculations were used as a benchmark for comparison with the "d-Flow" models. Numerical experiments were conducted to investigate two-phase flow under varying well geometry and flow regimes. The models used were compared, and the results showed that the predicted liquid holdup had an average relative error of 0.06%. In some cases, the error was as low as 0.02%. The predicted cumulative pressure drop in the well did not exceed 0.34% for all considered models. Based on the comparison results, we conclude that the "d-Flow" software package is suitable for calculating pressure drop in wells of different geometry and surface networks.
Oil and Gas Studies. 2023;(6):47-64
47-64
Geosteering, application of synthetic logging to horizontal wellbore sections
Abstract
This article provides an analysis of the process and optimization of horizontal wellbore tracking using geosteering control. Recently, the issue of high-quality and efficient drilling of wells through the reservoir and determining the position of the wellbore in the formations has been raised. In this regard, complex data analysis is used based on a 3D geological model and special software for well geosteering. In preparation for drilling a well, it is necessary to prepare voluminous, comprehensive information on previously drilled wells in a particular field and upload the results of seismic surveys. The article also describes an analysis of activities at various stages of drilling support, starting with geophysical reference and opening the target formation with the transport section. When drilling a horizontal section of a well, geosteering software is used while drilling wells, equipped with various tools, one of which is the 2D synthetic logging method. The method is based on the superposition of logging curves of a previously drilled reference vertical well and a directional well with a horizontal end currently being drilled. The two-dimensional synthetic logging method is the main and most optimal way to optimize the placement of wells with horizontal completion when drilling terrigenous reservoirs in Western Siberia.
Oil and Gas Studies. 2023;(6):65-77
65-77
Mechanisms of interaction of CO2 with reservoir oil
Abstract
The article aims to examine the mechanisms of miscible and immiscible interaction of CO2 with oil in detail. The study aims to investigate the effects of these mechanisms on the physical properties of oil, recovery efficiency, and oil reservoir parameters. This will enhance our understanding of the impact of these processes on oil production and carbon management. The article takes an analytical approach to examine the processes of CO2 dissolution in oil, changes in physical properties, and mechanisms of oil displacement in the pore space. The study utilises the results of laboratory experiments on the interaction of CO2 with oil. It reveals how the miscible interaction of CO2 with oil can alter the physical properties of oil, enhancing its flowability and recovery efficiency. An analysis of immiscible interactions enables us to comprehend the mechanisms of oil displacement and optimize the process. The work is relevant to oil production and carbon management, providing data for the development of more efficient production technologies and methods.
Oil and Gas Studies. 2023;(6):78-87
78-87
ORGANIZATION OF PRODUCTION AND ENSURING THE SAFETY AND ENVIRONMENTAL FRIENDLINESS OF PRODUCTION PROCESSES IN THE OIL AND GAS INDUSTRY
Criteria approach to the professional selection of an operator of an automated control system for an integrated oil and gas processing unit at the Kogalymneftegaz territorial production enterprise
Abstract
Research into the criteria for selecting professionals to operate automated control systems for integrated oil and gas processing units involves evaluating the qualitative and quantitative characteristics of employees and applicants in this field. The operator of automated control systems plays a crucial role in ensuring the efficiency of oil and gas production, industrial safety, and labour protection at the enterprise. The process of professional selection complex and can be affected by various negative factors that affect the working capacity of the studied group. These factors include objective and subjective fatigue processes, as well as the activity of the central nervous system. The latter is dependent not only on a person's psychotype but also on the intensity of these factors. Additionally, extreme climatic and geographical working conditions, shift work, and harmful parameters in the production process can also be mentioned. The Professional Selection Programme was developed for an operator of the automated control system of the integrated oil and gas processing unit of LUKOIL-Western Siberia LLC, Kogalymneftegaz territorial production enterprise. The analysis of the data enabled us to establish the main requirements for this Programme and devise an algorithm for its implementation.
Oil and Gas Studies. 2023;(6):88-97
88-97