Reservoir Pressure Maintenance Research Articles

The study of the effect of flooding process in Neft Dashlary field on parameters of aggressive medium

The paper reviews the damage effect of aggressive medium occurring as a result of sea water injection for the maintenance of reservoir pressure and production in Neft Dashlary field, which is in a long-term development, as well as the treatment of bottomhole zone with various agents, biological contamination and hydrogen sulphide (H2S) arising due to the bacterial activity on the works towards the consolidation of well bottomhole zone. Depending on the contact degree of cement stone with aggressive medium its corrosion probability is defined. Corrosion activity increases fast when well product contains small amount of H2S gas. According to the gas law, the gas solubility in fluids including in water is in direct proportion to the pressure. Small amount of H2S gas in produced water has a great effect on corrosion activity. On the basis of the studies of rock-operation data, it was specified that the degree of the consolidation of well bottomhole zone carried out in the well of IX horizons and Low Kirmaki suite is inversely proportional to the amount of H2S. Thus, in the zones with great amount of H2S, the efficiency degree is low, and in the zones with small amount – high. These zones and the efficiency degree are reflected in the current maps of development of IX horizon and Low Kirmaki suite of the field.

Evaluation of the gas recycling duration on the hydrocarbon recovery from gas condensate fields

Optimization of formation pressure maintenance technologies in the development of gas condensate fields with a high initial content of condensate in the reservoir gas using numerical modelling. A study on the efficiency of dry gas injection for pressure maintenance in gas condensate fields was performed with the help of numerical 3D models. Key technological indicators of the reservoir development were calculated for the dry gas injection period of 12, 24, 36, 48, and 60 months. The results are presented as plots for the parameters in a study. Based on the results of the studies, it was found that the introduction of dry gas injection technology ensures that reservoir pressure is maintained at the highest level compared to the development of gas condensate reservoirs on primary depletion. Due to this, further condensate drop-out in the reservoir is slowed down, and the production of partly already condensed hydrocarbons is ensured by their evaporation into the dry gas injected from the surface. The simulation results indicate that increase in the injection duration period leads to an increase of the cumulative condensate production and hence the final hydrocarbon recovery factor. The heterogeneity of oil and gas deposits, both in terms of area and thickness, significantly affects the efficiency of the developed hydrocarbon enhancement technologies. In order to minimize the negative impact of heterogeneity, it is necessary to conduct additional studies on the conditions of specific reservoirs or fields. The reservoir pressure maintenance technology implementation according to various technological schemes, as well as using various types of injection agents, will significantly intensify the development of depleted gas condensate fields with a high condensate yield. Statistical analysis of the simulation results identified the optimum value of the dry gas injection period into the gas condensate reservoir, which is 34.3 months for the conditions of a given reservoir in the study.

Investigation of the influences of asphaltene deposition on oilfield development using reservoir simulation

This paper investigates the deposition of asphaltenes in the porous medium of the studied field in Russia and predicts production profiles based on uncertainty evaluation. This problem can be solved by dynamic modeling, during which production profiles are estimated in two scenarios: with and without the activation of the asphaltene option. Calculations are carried out for two development scenarios: field operation under natural depletion and water injection into the aquifer as a reservoir pressure maintenance system. A full-scale compositional reservoir simulation model of the Russian oilfield was created. Within a dynamic simulation, the asphaltene option was activated and the asphaltene behavior in oil and porous medium was tuned according to our own special laboratory experiments. The model was also matched to production historical data, and a pattern model was prepared using the full-scale simulation model. Technological and the asphaltene option parameters were used in sensitivity and an uncertainty evaluation. Furthermore, probable production profiles within a forecast period were estimated. The sensitivity analysis of the pattern model to input parameters of the asphaltene option allowed determining the following heavy-hitters on the objective function: the molar weight of dissolved asphaltenes as a function of pressure, the asphaltene dissociation rate, the asphaltene adsorption coefficient and the critical velocity of oil movement in the reservoir. Under the natural depletion scenario, our simulations show a significant decrease in reservoir pressure and the formation of drawdown cones leading to asphaltene deposition in the bottom-hole area of production wells, decreasing their productivity. Water injection generally allows us to significantly reduce the volume of asphaltene phase transitions and has a positive effect on cumulative oil production. Injecting water into aquifer can keep the formation pressure long above the pressure for asphaltene precipitation, preventing the asphaltene deposition resulted from interaction of oil and water, so this way has higher oil production.

Methodical approach to substantiation of the strategy for the development of residual oil reserves at the final stage of development, taking into account facies analysis

The article considers and solves the problem of finding the optimal strategy for the development of terrigenous deposits of the Bobrikovsko-Radaev horizon of one of the deposits of the Ural-Volga region. Based on the analysis of the behavior of the curves obtained during geophysical surveys in more than three thousand wells, four main types of facies zones were identified, characterized by different porosity and permeability properties and formed development systems. As part of the analysis of the reservoir pressure maintenance system, a direct influence of reservoir properties on the efficiency of waterflooding was established, which made it possible to develop an optimization strategy and the formation of new injection sites. Using the method of multiple regression analysis, two statistical models have been obtained – the reservoir properties model and the facies model, which make it possible to quickly assess the recovery factor and select the optimal development system for fields with a lesser degree of knowledge. Keywords: oil field development; geological structure; facies model; hydraulic fracturing; horizontal wells; hydrodynamic model; multiple regression analysis.

Optimization of reservoir pressure maintenance system based on monitoring of actual field data

Optimization of reservoir pressure maintenance system based on monitoring of actual field data

Estimation of well drainage radius and reservoir pressure maintenance system efficiency in a tight reservoir by the data obtained by minifrac in the offset horizontal wells with multifrac

The low efficiency of classical methods of well testing during the development of hydrocarbon fields with tight and ultra-tight reservoirs forces engineers to use indirect approaches, one of which is the analysis of pressure drop curves during minifrac and main hydraulic fracturing operations to estimate reservoir pressure by the Nolte method. The paper focuses on obtaining a qualitative assessment of reserve recovery for an area of a field with hard-to-recover reserves with the wells arranged linearly and the distance between them of 500 m by estimating the drainage area and the impact of the pressure maintenance system in a reservoir with permeability of 1 mD or less based on restored inter-well reservoir pressure from the Nolte after-closure analysis of falloff data by quantitative and qualitative pore pressure estimations for each of the frac ports in a horizontal well with multifrac.

Some Features of Quaternary Ammonium Compounds as a Corrosion Inhibitor in Environments With Sulfate-Reducing Bacteria

The development of oil fields with the maintenance of reservoir pressure by pumping water without antibacterial preparation leads to widespread infection by microorganisms of oil-field waters that circulate in the res-ervoir system – surface equipment. In this aspect, it was interesting to conduct research on the identification and identification of microorgan-isms of metal destructors of field installations, as well as oil itself on specific microbiological media intended for various groups of microor-ganisms causing biocorrosion of pipelines. In this regard, the biocenosis of samples of water, oil, scrapers from oilfield pipelines, selected in dif-ferent seasons: winter, spring, summer, autumn, was studied. In order to solve the problem of eliminating corrosive processes caused by certain groups of microorganisms, the influence of a number of effective bacte-ricides on the viability of bacteria has been tested, recommendations for their use have been developed. Keywords: Aggressive envi-ronment;Biocenosis; Biocorrosion; Reagent; Recommendations.

Method for determining the parameters of a substitution scheme for an electromechanical module with an increased electromagnetic momentwith increased electromagnetic torque

THE PURPOSE. Consider the problems of determining the energy parameters of electrical equipment elements of electrical complexes for oil production with submersible electric centrifugal pumps. Develop a methodology for determining the parameters of the equivalent circuit of an electric motor for oil production when connecting compensating devices to the terminals of the electric motor of a submersible pump. Develop a methodology for calculating the energy performance of electrical equipment elements of an electrical complex with electric centrifugal pumps. Carry out simulation modeling of an electric motor for oil production with a directly connected compensating device.METHODS. When solving the tasks set, optimization methods were used in terms of efficiency, power factor correction methods, methods for calculating the electromagnetic field by finite elements, methods of mathematical and computer modeling in the ELCUT software package.RESULTS. Improving energy efficiency and reducing costs in the operation of submersible pumping units for oil production is an urgent problem and dictates a reasonable solution. The price of extracted oil depends on the following indicators, such as climatic conditions, equipment used, depth of oil deposits, remoteness of the field from central roads, and so on. The most significant energy-intensive processes in oil production include: electromechanized oil extraction, oil transportation, reservoir pressure maintenance system. A technique for finding the parameters of the equivalent circuit of an electric motor for oil production and a study of the effect of reactive power compensation on an electric motor in an oil well when compensating devices are connected to the terminals of the electric motor of a submersible pump are proposed. A method for calculating the energy performance of electrical equipment elements of an electrical complex with electric centrifugal pumps is proposed. The calculation of a compensating device in an oil well for an electric centrifugal pump with a frequency-controlled electric drive must be implemented taking into account the highest value of the output network frequency. Simulation modeling of an electric motor for oil production with a directly connected compensating device was carried out to establish the effect of a reactive power compensating device inside an oil well on the rotating electromagnetic moment of an electric motor for oil production. The indicators of the electromagnetic torque and the electromagnetic field of an electric motor for oil production without a connected compensating device and with a directly connected compensating device are presented, the supply wires of which in the first version are laid along a single route and in the second version are laid at an angle of 120 ° relative to each other in the corresponding grooves of the stator winding of the electric engine for oil production.CONCLUSION. When conducting a study of the effect of a directly connected compensating device on the electromagnetic torque of an electric motor for oil production, it was determined that additional windings of a directly connected reactive power compensating device, laid at an angle of 120 ° relative to each other in the corresponding grooves of the stator winding of the electric motor, increase the efficiency and electromagnetic torque of an electric motor for oil production by 11% and 15%, respectively.

Treatment of formation water at oil fields using granular filters with varying particle sizes

Purpose. Increasing oil recovery from reservoirs, reducing water content, and decreasing costs by pumping formation water effectively cleaned of suspended solids allows you to get a picture of the uniform distribution of water over the reservoir and, in general, the quality maintenance of reservoir pressure in productive reservoirs. Methodology. The study on water treatment issues for maintaining reservoir pressure at existing oil fields has a variety of approaches. Therefore, the methods of analysis, review, comparison, modeling, experiment were used in the work. The analysis method made it possible to divide the problems of approaches to the formation water preparation for its injection into the reservoir into many elements, which made it possible to learn their properties, connections and relationships. This method contributes to a more detailed structuring of the problem of water treatment. The analogy method uses the study of the technology of preparation of reservoir water with suspended solids. Based on the data, an effective technology was studied for treating formation water from suspended solids and injecting it into a productive formation. Findings. The experiments carried out reflect the high-quality water preparation using the developed new industrial sand-gravel filter made of granular materials with variable particle sizes in the vertical direction, taking into account the rational parameters of the column height of the filter working area. The regularities were studied and the process of formation water preparation without suspended solid particles was improved on the basis of the theoretical and experimental studies carried out on a special laboratory unit. The dependence of the reservoir permeability in the bottomhole zone of injection wells on the size of solid suspended particles in the injected water was determined, and rational filter parameters were established for preparing injected water without suspended solid particles into the reservoir using granular materials with a variable fraction and water supply from the bottom up. Originality. An effective technology for deep purification of formation water from suspended clay particles is proposed by using filters made of granular materials with a variable particle size. The technical result of the invention is to increase the efficiency of purification of industrial waste and industrial formation waters with suspended solids. Practical value. A new method for deep formation water treatment is proposed, which ensures the capture of suspended solids. The results of experiments on establishing the regularity of the process of formation water filtration with suspended clay particles through a porous medium with variable pore sizes and granular particles are presented. A recommendation has been developed for choosing rational parameters and operating modes of a new filter for formation water treatment.

Control of MIMO linear plants with a guarantee for the controlled signals to stay in a given set

In this paper, we propose a new method for synthesizing the control of multi-input multi output linear plants with a guarantee of finding controlled signals in given sets under conditions of unknown bounded disturbances. The problem is solved in two stages. At the first stage, the coordinate transformation method is used to reduce the original constrained problem to the problem of studying the input-to-state stability of a new extended system without constraints. At the second stage, the control law for the extended system is obtained by solving a series of linear matrix inequalities. To illustrate the effectiveness of the proposed method, simulation in the MATLAB/Simulink is given. The simulation results show the presence of controlled signals in the given sets and the boundness of all signals in the control system. The proposed method is recommended for use in control problems where it is required to maintain controlled signals in given sets, for example, control of an electric power network, control of the reservoir pressure maintenance process, etc.

RESERVOIR PRESSURE MAINTENANCE (RPM) ON OIL DEPOSITS

The article provides a brief analysis of the issue of improving oil recovery as a result of lower formation pressure in offshore oil wells. In the introductory part, the issues of lowering the formation pressure during the operation of oil and gas fields were considered. It is known that during the initial operation of wells, the wellhead pressure is high, so the wellhead is sufficient to transport pressure. However, after a period of operation, a sharp drop in formation pressure is observed, and when the wellhead pressure is less than the pressure in the in-house pipelines, it is not possible to transport the oil or gas obtained through these pipelines. In such conditions, in order to improve the development of oil storage, products from offshore oil and gas fields are transported to the shore through special tanks. The issue of increasing the wellhead pressure of such wells has been widely studied, as the occurrence of such transport leads to the consumption of additional funds. The decrease in formation pressure is observed differently in different wells. This situation mainly varies depending on the operating conditions and service life of the wells. In this case, in order to increase the service life of oil and gas fields, work is underway to artificially increase the formation pressure. Thus, in order to eliminate the problem of reducing the formation pressure, gas or liquid is injected into the well from the outside, which helps to increase the pressure. In wells where the pressure in the pipe mouth space is reduced, the process of applying additional pressure from the outside is carried out continuously during the next operation. Then the pumps used to inject liquid and gas into the reservoir were inspected. Their equipment and various parts are shown through graphs. It was noted that pumps and pumping equipment differ in their characteristics depending on the volume and conditions of liquids and gases injected from the outside as a result of the reduction of formation pressure. In addition, the collection system and transportation process of such wells have been reviewed and explained in detail using graphs and tables. Finally, the generalized results from the considered topic were noted. Keywords: fountain armature, reservoir pressure maintenance, injection pressure, pumping equip-ment, pump station, manifold block.

Assessment of the economic effect in the development of a methodology for calculating the coordinates of the location ofobjects of the reservoir pressure maintenance system

Assessment of the economic effect in the development of a methodology for calculating the coordinates of the location ofobjects of the reservoir pressure maintenance system

Simulation and Modelling of Water Injection for Reservoir Pressure Maintenance

Water injection has shown to be one of the most successful, efficient, and cost-effective reservoir management strategies. By re-injecting treated and filtered water into reservoirs, this approach can help maintain reservoir pressure, increase hydrocarbon output, and reduce the environmental effect. The goal of this project is to create a water injection model utilizing Eclipse reservoir simulation software to better understand water injection methods for reservoir pressure maintenance. A basic reservoir model is utilized in this investigation. For simulation designs, the reservoir length, breadth, and thickness may be changed to different levels. The water-oil contact was discovered at 7000 feet, and the reservoir pressure was recorded at 3000 pounds per square inch at a depth of 6900 feet. The aquifer chosen was of the Fetkovich type and was linked to the reservoir in the j+ direction. The porosity was estimated to be varied, ranging from 9% to 16%. The residual oil saturation was set to 25% and the irreducible water saturation was set at 20%. The vertical permeability was set at 50 md as a constant. Pressure Volume Temperature (PVT) data was used to estimate the gas and water characteristics.

Improvement of oil and gas production infrastructure as an effective tool for maintaining basic oil and gas production

The modern world is a complex mechanism in which each process, direction, sphere of activity, despite visual differences, ultimately creates a single complex element aimed at ensuring human life. One of the key processes occurring on the planet is the extraction of hydrocarbons. The article proposes to consider a solution that will contribute to ensuring the efficiency of oil and gas production processes, will extend the life cycle of mature oil and gas production assets of the Russian Federation (hereinafter referred to as the RF) and extend their economic profitability. Economic and technological efficiency from infrastructure reengineering measures is individual for each region, and directly depends on the volume of oil, water production and the state of the ground infrastructure. The described areas of infrastructure reengineering, in aggregate, represent an effective tool for optimizing operating and capital costs, increasing the reliability of technological equipment, removing infrastructure restrictions, which will contribute to the achievement of the set task - maintaining oil production at mature assets. Keywords: facilities for oil treatment; gas compression; reservoir pressure maintenance; power supply; engineering networks; operating costs; reengineering.

Methodological approaches to increasing the flooding system efficiency at the later stage of reservoir development

Based on the analysis of the efficiency of CVI.1 and CVI.2 oil reservoirs development, which partially coincide in structural terms, and the terrigenous strata of the Lower Carboniferous of one of Volga-Ural oil and gas province oil fields, an algorithm for assessing the efficiency of waterflooding was proposed, which takes into account the geological structure of the facility, the results of core and geophysical well surveys, as well as the historical performance of wells. The presented algorithm makes it possible to identify ineffective injection directions for making decisions on waterflooding system optimizing. The effect is the identified potential to cut costs by reducing inefficient injection, as well as identifying areas for the introduction of enhanced oil recovery techniques. Keywords: field development; reservoir pressure maintenance system; waterflooding efficiency; cost reduction.

Risk decreasing of water waste through spontaneous fracturing in injectors by integrated well-testing and production logging

Background. When creating an effective reservoir pressure maintenance system, unstable spontaneous hydraulic fractures can be created in injection wells. This can both negatively and positively affect hydrocarbon production. First, fracture improves reservoir connectivity, which increases injection efficiency. On the other hand, unstable fractures can cause behind-the-casing flows and unproductive injection into off-target layers or fingering. 
 
 Goal. The paper is devoted to the analysis of well testing (PTA) and production logging (PLT) improvement for the diagnosis of unstable fractures in injection wells. 
 
 Materials and methods. The analysis is based on the results of modeling the pressure in the reservoir system, describing the penetration reservoirs by an unrestricted conductivity unstable fracture. It is taken into account that the fracture can cross both the perforated formation and the thickness not penetrated by the perforation, and can grow with increasing overbalance. 
 
 The modeling results made it possible both to assess the potential informative capabilities of well testing and to substantiate recommendations for the practical use of the obtained results. 
 
 Conclusions. The proposed approaches to the technology of well testing and production logging and the interpretation of their results make it possible to estimate the additional thicknesses of the reservoirs connected by the spontaneous hydraulic fracturing to injection, the proportion of nonproductive injection in the total volume of the well. The research technology used by the authors is based on continuous measurements of pressure and flow rate during cyclic change of pressure and assessment of the effective transmissibility of the formation system at different heights of unstable fractures. 
 
 The role of the PLT is to determine the effective production thickness of the reservoirs. When assessing the injectivity profile when penetrating the injector with the spontaneous hydraulic fracturing, the key role belongs to non-stationary temperature logging. In this case, it is necessary to take into account the specific features of temperature relaxation in the wellbore after the injection cycle, related to hydraulic fracturing, primarily the increase in the relaxation rate with increasing fracture length.

Метод оценки энергетических параметров и потенциала энергосбережения насосных агрегатов, работающих вне допустимого рабочего диапазона, в системах поддержания давления в нефтяных пластах

Oil reservoir pressure maintenance pumps are often pushed to operate significantly outside of their original design parameters. This can cause operating problems which impact their reliability and efficiency. The author offers the evaluation methodology for energy parameters and energy saving potential of oil reservoir pressure maintenance pumps in order to develop major pump parameters like efficiency, pressure, and specific electric power. The methodology was tested on 42 pump units. The values of variations of basic parameters indicate the energy saving potential of pump units.

Failure prediction of reservoir pressure maintenance system at the Prirazlomnoye Arctic Offshore field

Failures of reservoir pressure maintenance system at offshore facilities cause production losses and a significant increase in OPEX. Predicting failures of a water injection pump or its parts can highly improve the overall performance by promptly adjusting operating parameters to prevent failure occurrence or by scheduling maintenance to reduce unplanned repairs and to minimize downtime. This is particularly relevant for Arctic offshore projects, characterized by considerable logistical challenges and substantial environmental safety risks. The paper presents a data-analytic approach for failure prediction for the water injection pump operated at the ice-resistant GBS Prirazlomnaya. The study used pump failure history and field sensor data to predict the technical condition and identify a failed component in advance. An ARIMA model implemented in the R software environment was developed for the analysis. The results demonstrate that the approach works appropriately based on the generalized risk assessment and feedback from subject matter experts.

Research and application experience of water Huff and Puff technology on low-permeability oil field

Background. This paper presents a study of the applicability and the first results of pilot works of the technology of periodic water injection into production wells with subsequent oil production (Huff and Puff ), which was not previously used in Russia. The oil field of the company “Gazprom Neft” with a terrigenous reservoir of low permeability is considered. Aim. It is planned to use the technology at marginal waterless wells with hydraulic fracturing, which are on the verge of profitability, to increase oil production. Materials and methods. The physical principles of capillary impregnation in a hydrophilic reservoir were presented, which, under given conditions, should lead to an increase in oil production in waterless wells during cyclic water injection and shutdown with subsequent production. Since this technology was not previously used in Russia, a review and analysis of the unsuccessful application in the United States and the successful experience in China in fields with similar properties and wells was carried out. For the design of pilot works, calculations were made on a synthetic hydrodynamic model with double porosity and permeability, according to which a significant increase in oil production in a marginal well was obtained relative to standard operation. Pilot work was carried out on four oil wells of the company’s field, which were previously planned to be transferred to the reservoir pressure maintenance stock. Only two of them managed to meet the required injection and shutdown periods. Results. Pilot work didn’t show significant increase in oil production after the application of the technology. At the same time, there was no decrease in representative wells, which should have occurred due to a decrease in the phase permeability of oil, which indicates the work of the effect of capillary imbibition during water injection. Conclusions. Based on the analysis of the ambiguous results of pilot works, a conclusion is made about the ineffectiveness of the huff and puff technology in the specified modes, the necessity of their optimization and further research.

Optimization model of material balance for reservoir energy survey analysis and control

Introduction. When monitoring the development of hydrocarbon fields, the energy state of the reservoirs is monitored. An inaccurate understanding of the current distribution of reservoir pressure leads to the wrong strategy for the development of residual oil reserves. Isobar maps are constructed to assess reservoir pressure for productive formation. The simplest and most common method of map generation (by interpolating the values of the measurements) has a high sensitivity to the coverage of the well stock by well tests and does not take into account the dynamics and compensation of fluid withdrawals. To eliminate these shortcomings, it is proposed to use the method of multi-tank material balance. Objectives. The purpose of the work is to show the possibility of using the multi-tank material balance method (MMB) to reduce the risks related to low current reservoir pressure at the stage of well workover planning under conditions of limitations on the number and duration of well tests and taking into account the history of production / injection, as well as to predict the dynamics of reservoir pressure in the drainage area. Methods. In the MMB model, for each well, its own block (tank) is specified, for which the mathematical balance equation is drawn up, taking into account the crossflow between the blocks. The transmissibility values are obtained iteratively by numerically solving the problem of minimizing the loss function of the discrepancy between the calculated reservoir and bottom hole pressures and their actual values. Results. The paper provides examples of good convergence of the calculated pressures by the MMB method to the actual build-up test results at the wells of the Ural-Volga fields. The possibility of predictive calculations to optimize the reservoir pressure maintenance system is shown. The practical advantages of the method are: relative simplicity of model, automated adjustment of interblock transmissibility. Discussion. The field of application of the MMB method is determined by the tasks in which it is necessary to determine the reservoir pressure in conditions of a lack of fresh measurements. The MMB methodology is applicable to assess reservoir pressure in order to remove risks before well workovers, as well as to predict the optimization of the reservoir pressure maintenance system.