Gas Condensate Wells Research Articles

A MODEL FOR FORECASTING DEW POINT PRESSURE IN NIGER DELTA CONDENSATE RESERVOIRS USING CONSTANT VOLUME DEPLETION TESTS DATA

The dew point pressure plays a critical role in developing gas condensate reservoirs. It is a crucial factor used in fluid characterisation, performance estimation of gas reservoirs, and design of production systems. However, the composition of gas condensate fluid varies from one location to another, and thus, empirical correlations have been developed to determine the dew point pressure without conducting routine tests. As a result, correlations that are solely useful in the region where they were developed and analysed are developed. This work developed an empirical correlation using data from gas condensate wells in the Niger Delta using multiple linear regression. The model was developed using the Analytical Tools and techniques in Microsoft Excel. To develop the model, we utilised 63 data sets from the Constant Volume Depletion (CVD) experiment, which involved gas condensates from resources in the Niger Delta. The model comprises an empirical correlation that estimates the dew point pressure for gas condensate reservoirs. It uses compositional information of the fluid and reservoir temperature as input parameters. The correlation is derived through multiple regression analyses. Comparing the prediction accuracy of formulas based on the developed model and other conventional methods indicated that this model is more accurate than other statistical methods in predicting DPP within the Niger Delta region. This model can produce more accurate results than other estimation methods when working under limited field information and time constraints. The correlation developed in this process has a coefficient of determination of R2=0.869 and an Average Absolute Relative Error (AARE) of -2.0767%, along with a root mean square of 195279, indicating a high level of reliability in the proposed correlation.

Methods of combating watering in gas condensate wells, possibilities of using surfactants and rationale for its selection

Methods of combating watering in gas condensate wells, possibilities of using surfactants and rationale for its selection

Study of the efficiency of well repair at the Karachaganak field

The assessment of the effectiveness of the choice of formulations of clay-free inhibited salt solutions, recommended for washing when drilling side shafts and horizontal sections, based on the study of biopolymers, in the conditions of the Karachaganak deposit, is considered. The duration of the fountaining of production wells at the Karachaganak field depends both on the methods used to increase the oil yield of layers (primary and secondary) and on the dimensional characteristics of the fountain system for lifting well production. As a result of a gradual decrease in reservoir pressure and water inflow into the downhole zone of the well, its stability is significantly reduced, the filtration characteristics of the reservoir deteriorate, the formation of mineral deposits, sand and gas hydrate plugs increases, and the corrosion activity of production increases. And as a result, the production capacity of producing oil and gas condensate wells is significantly reduced. The character of the composition of the reservoirs of the deposits of the Karachaganak deposit, in the overwhelming majority, contain clayey cement. At the same time, the "swelling" of clay rocks is a significant reason for the decrease in productivity of production wells. Collectors with low permeability with practically irreversible "internal clogging" are especially sensitive to this effect. The use of technological fluids has been found to be the most effective – solutions containing a biopolymer as the main component, possessing pseudo-plasticity and contributing to high-quality cleaning of the bottom hole from mud, as well as the maximum removal of mud residues from the well system, which have a minimal polluting effect on reservoir reservoir systems, since biopolymer the substance entering the collector is enzymatically decomposed after a certain time. The use of the composition of the inhibitory biopolymer salt solution based on the KCl complex salt (potassium chloride-electrolyte) will allow to fully preserve the properties of the productive layer. For maximum isolation of the watered downhole zone of the formation, the authors propose to use a tamping solution on an adhesive basis with properties sufficient for reliable isolation. Injection of tamping solution under pressure into the layer will increase the strength of the cement stone by an average of 1.5 times.

A transient production prediction method for tight condensate gas wells with multiphase flow

Considering the phase behaviors in condensate gas reservoirs and the oil-gas two-phase linear flow and boundary-dominated flow in the reservoir, a method for predicting the relationship between oil saturation and pressure in the full-path of tight condensate gas well is proposed, and a model for predicting the transient production from tight condensate gas wells with multiphase flow is established. The research indicates that the relationship curve between condensate oil saturation and pressure is crucial for calculating the pseudo-pressure. In the early stage of production or in areas far from the wellbore with high reservoir pressure, the condensate oil saturation can be calculated using early-stage production dynamic data through material balance models. In the late stage of production or in areas close to the wellbore with low reservoir pressure, the condensate oil saturation can be calculated using the data of constant composition expansion test. In the middle stages of production or when reservoir pressure is at an intermediate level, the data obtained from the previous two stages can be interpolated to form a complete full-path relationship curve between oil saturation and pressure. Through simulation and field application, the new method is verified to be reliable and practical. It can be applied for prediction of middle-stage and late-stage production of tight condensate gas wells and assessment of single-well recoverable reserves.

Monitoring and elimination of intercasing pressure

Background: The appearance of intercasing pressure in many cases is associated with inadequate quality of primary cementing. Despite the fact that many studies are aimed at preventing problems of primary cementing, at improving the quality of well completion, it should be noted that the problem of intercasing pressure at existing gas and gas condensate wells is increasing.
 Aim: The purpose of this work is to study and eliminate wells with intercasing pressure at the Amangeldy gas condensate field.
 Materials and methods: This paper presents the procedure for preparing the well and carrying out the elimination of intercasing pressure, as well as the chemical components of cementing slurry.
 Results: The conducted studies and measures on wells No.121; No.105; No.103 and No.101 showed a positive result and the effectiveness of the composition of cementing slurry.
 Conclusion: The presented technology for the elimination of intercasing pressure and the composition of the cementing slurry can be widely used in many fields of Kazakhstan.

Повышение эффективности глушения скважин на истощенных газоконденсатных месторождениях с сверх аномально низкими пластовыми давлениями

The problem is studied by the example of gas condensate fields at the final stage of development, where production wells have abnormally low reservoir pressures and their killing for repair work is a serious challenge requiring a search for new solutions. The work is motivated by the need to create a method for controlling hydrodynamic processes in a pre-blocked bottom-hole zone of the formation, for carrying out repair work in wells, preventing destruction of the reservoir formation and ensuring the preservation of its fluid-capacitance properties. The possibilities of an integrated approach to killing wells under conditions of extremely low formation pressures are considered, which includes controlling hydrodynamic processes in the “well-reservoir” system, previously blocked in the near-wellbore zone by special process fluids. It has been specified that the use of blocking fluids (with filler) helps to level the injectivity profile and form an insulating screen in the bottomhole zone of the formation, creating the necessary conditions for killing wells in order to carry out repair work in them. To control hydrodynamic processes, a mathematical model of the blocking process in the near-wellbore formation zone is proposed. It has a three-stage scheme that ensures equalization of the injectivity profile under conditions of extremely low formation pressures. The possibilities of using gel-forming blocking fluids with filler to create a temporary screen that prevents the penetration of killing fluid into highly permeable formations from abnormally low formation pressures have been explored. Based on the results of the study, we can conclude that the control of hydrodynamic processes in the near-wellbore zone of the formation at abnormally low formation pressures creates the necessary condition for effective blocking of the productive horizon in gas and gas-condensate wells, and due to the sequential treatment of the formation with a special liquid to level the injectivity profile and gel-forming blocking composition, allows one to kill the well and prevents the working fluid from penetrating into the depths of the formation during work.

CALCULATION OF TECHNOLOGY ALGORITHM AND SUCCESSFUL APPLICATION OF THERMOCHEMICAL METHOD DURING WELL WORKOVER

This article is devoted to the analysis of the success of the thermochemical method of generating and transferring thermal energy for underground workover technologies of producing wells. In order to justify the design and consumption of reagents, an algorithm and calculator were compiled based on the well design and thermophysical properties of consumables and fluids: heat capacity of steel, water, ice, enthalpy of ice melting and chemical reaction, the length of the paraffin hydrate plug interval.Thermophysical calculations have shown that for a well with a diameter of 146 and a 73 mm tubing lift, 153 kg of fuel reagent is required for thermal destruction of a paraffin hydrate plug 100 meters long. Based on the geometry of the candidate well and the expected intervals of waxhydrate plug formation, reagent consumption is determined, and a design and work plan are drawn up. The algorithm makes it possible to calculate the flow rate and concentration of working solutions of reagents in order to reach the target temperature at the thermal exposure interval.Measurements of the deep thermometer made it possible to determine that the selected composition of reagents and the exothermic reaction with a delay in heat generation allow to achieve a loss of heat to dissipation at the level of 17 % by 2500 meters of the tubing elevator.The technology of thermal destruction of paraffin-hydrate plugs in gascondensate wells was implemented at the East-Tarkosalinskoye oil and gas condensate field and the Komsomolskoye field with achievement of the specified success criteria.Technologies for development and removal of water from the bottomhole of gas and gas-condensate wells ensure formation of a gas-liquid mixture and removal of water from the bottomhole at the wellhead. The technologies were used at the production facilities of the Vuktyl field (Komi Republic), Amangeldygaz (Kazakhstan Republic), and the East-Tarkosalinsky field (Yamalo-Nenets Autonomous Okrug). As a result of water development, gas wells are switched from pulsating to permanent operation. Heat (thermal) treatment of producing wells uses injection of heat and nitrogen-generating solutions with transfer of thermochemical energy of reagents through permafrost and low-temperature intervals with minimal heat losses. The efficiency of the heat transfer technology was confirmed by temperature measurement by downhole sensors at 139–147 °C at development facilities with reservoir temperatures of 41–43 °C (Ural-Volga region, Purovsky region).The technology of restoring the productivity of gas and gas condensate wells using aerated acids makes it possible to increase the success of subsequent development. The use of the technology of foam acid treatment with methanol makes it possible to successfully restore the productivity of gas and gas condensate wells prone to water removal. Aeration and heating of process solutions of reagents makes it possible to carry out comprehensive measures for treatment of the bottomhole zone of the well with acid and thermochemical impact.

Investigation of the temperature field in gas condensate reservoirs taking into account thermodynamic effects

Based on modeling of non-isothermal filtration of a multiphase fluid, taking into account thermohydrodynamic effects and heat of condensation, the formation of a temperature field in a homogeneous porous medium at different pressures at the onset of condensation is studied. A numerical model of one-dimensional two-phase filtration taking into account the phase transition is obtained. Testing of the numerical solution was carried out on the basis of a well-known analytical solution for non-isothermal two-phase filtration in a reservoir taking into account mass transfer. The change in gas flow rate during condensate precipitation and the change in temperature over time on the well wall are considered. It is shown that, depending on the pressure of the onset of condensation (the radius of the onset of condensation in the formation), a different rate of formation of the temperature field in the formation is observed after the well is put into operation: the temperature anomaly can be positive, negative or inverse. The results of numerical experiments can be used when planning field studies in gas condensate wells.

GENERALIZATION OF PROSPECTIVE TECHNOLOGIES FOR INCREASING HYDROCARBON EXTRACTION FROM NATURAL GAS FIELDS

The vast majority of hydrocarbon fields in Ukraine are at the final stage of development, characterized by complicated conditions for hydrocarbon production. The difficulty of extracting residual hydrocarbon reserves is associated with low reservoir pressures, high water cut, destruction of the bottomhole formation zone, and corrosion of underground and surface equipment. The depletion of the main fields in terms of production and reserves leads to a decrease in hydrocarbon production levels. The fields discovered in recent years are characterized by a complex structure, large depths of productive reservoirs, insignificant reserves and cannot significantly affect the maintenance of hydrocarbon production. Therefore, the main potential reserve for increasing production levels is the residual reserves of depleted fields. The raw material base of such reservoirsis characterized by a deterioration in the quality and structure of reserves over time and is accompanied by an increase in the share of hard-to-extract reserves. To increase the efficiency of development of proven hydrocarbon reserves, existing approaches have been improved and new approaches have been developed for the extraction of hydrocarbons from watered formations, the extraction of retrograde condensate that fell during the development of gas condensate fields for depletion, and the cleaning of bottomhole zones of gas and gas condensate wells and wells. Negative influence of complicating factors during their operation. However, increasing the efficiency of oil and gas field development is possible by investing in the implementation of developed technologies, which will increase their production capabilities in conditions of a significant shortage of hydrocarbon raw materials in Ukraine. Due to the high technological efficiency of secondary technologies for the development of hydrocarbon fields, which is also confirmed by industrial data, their implementation in the fields of Ukraine is recommended.

Treatment of paraffin deposition behavior in gas-condensate wells with chemical inhibitors

As deep gas-condensate reservoirs are explored, the problem of paraffin deposition is becoming more prominent. Therefore, this paper collects condensate samples from representative paraffin deposition gas-condensate wells and analyzes basic physical properties. The cold plate deposition device is employed to study paraffin deposition behavior under well conditions and to divide the critical regions for paraffin deposition in gas-condensate wells. The experimental apparatus, such as the crude oil dynamic paraffin deposition rate tester, is utilized to investigate the preventive effect of paraffin dispersants and paraffin crystal modifier. The results show that there is significant phase change behavior in gas-condensate wells and gas phase is dominant form, but there is also phase evolution. It can be identified from the experiments that paraffin deposition is mainly located in the 1000 ~ 1500 m region, and a paraffin deposition identification chart has been established. The maximum deposition rate could reach 15.50 mm/year, which matched the temperature and pressure conditions of 45 ℃ and 70 MPa. The preventive effect of paraffin crystal modifiers greatly exceeds that of paraffin dispersants, with paraffin prevention rates of 85–95% at the optimal concentrations of 0.25–0.50 wt.%. The dissolving paraffin rate can reach 0.0169 g/min. It decreases the paraffin appearance temperature approximately 40% and significantly changes the paraffin crystal morphology. Increased deposition surface area of the cold plate structural design describes the paraffin deposition. This diagram facilitates the reliable identification of paraffin deposition areas and the deposition rates in the wellbore during production. The optimum amounts of BZ and PI paraffin inhibitors are quantified. This study provides a comprehensive understanding of the paraffin deposition behavior, and scientific basis and guidance for the selection of paraffin inhibitors in gas-condensate wells.

STUDY OF ADDITIVES FOR SELF-HEALING OF CEMENT SHEATH

The article discusses a study of cement sheath integrity improvement in oil and gas wells. This problem has been studied for more than 40 years. Nevertheless, every year it inextricably linked with the solution of current problems that challenge drilling specialists. Therefore, the search for solutions to problems in this area has great potential and prospects for further improvement. There are three conceptual approaches to the self-healing of cement stone: self-healing systems based on capsules (granules), in a vessel (fiber) shell and without shells. There is also a definition proposed by the Union of Laboratories and Experts in Building Materials. According to this concept, self-healing can occur during autogenous (natural) process, in which the filling of cement cracks occurs due to its own fund of non-hydrated particles when contact with water. Self-healing can also be autonomous (artificial, due to the introduction of additives such as polymers, bacteria and other components capable of either expanding or producing a substance that fills the void space under certain environmental conditions). However, despite the absence of auxiliary materials, autogenous healing is limited by the size of the cracks formed. Experience also shows that autonomous recovery also has negative aspects, which are associated with the characteristics of a particular material and medium - an activator. Therefore, in each case, the approach to solving the problem should be specific and unique. becomes more and more relevant due to the constant deterioration of mining and geological conditions in the process of drilling new wells. The process of adaptation to new conditions is After a series of successful studies aimed at the effect of water-oil-swelling additives on the self-healing ability of cement stone, the focus of the study was shifted to the problem of integrity of gas and gas condensate wells. In this regard, the study provides a detailed step-by-step description of the various processes aimed at finding a solution to the problem. The process of selecting a modifying additive with an assessment of the swelling ability to obtain the effect of self-healing cement stone in difficult mining and geological conditions is considered. Tests of additives in various conditions and environments are carried out. Attempts are made to create an experimental stand that allows simulating well conditions and evaluating the effect of stone restoration when creating artificial cracks. This study makes a significant contribution to the search and understanding of the performance of various additives in the formation environment. The creation of a test equipment is the first step towards modeling formation conditions at the surface. Further modernization of the stand will allow for more accurate tests and significantly reduce the time for selecting reagents. Thus, the use of this technology will improve the quality of well casing, as well as the safety of work in environmental terms.

Methane pore accessibility, densification, and accommodation by organic matter in the Niobrara Formation at wet-gas thermal maturity conditions

Petroleum within unconventional source-rock reservoirs is hosted in organic matter and mineral pore space as well as in voids and microfractures. Recent work has shown that for source-rock reservoirs in the dry gas window, significant portions of methane (CH4), the main component of petroleum at elevated maturities, can be stored within fine (<5 nm) organic matter porosity. However, within reservoirs at lower thermal maturities (e.g., peak oil or wet-gas conditions), the distribution and behavior of CH4 and the higher alkanes that comprise gas condensates across pore sizes is unclear, especially for pores with diameters <50 nm. Understanding CH4 distribution within these settings provides insight for petroleum generation, movement, and recoverability, enabling increased accuracy of estimated ultimate recovery. Here wide Q-range total neutron scattering was used to evaluate perdeuterated methane (CD4) behavior at reservoir pressures (200–750 bar) and temperature (60 °C) in a sample at the late oil/wet gas thermal maturity stage from the Late Cretaceous Niobrara Formation, an active petroleum producing formation within the Denver-Julesburg Basin, U.S.Neutron scattering data show that mesopores within the Niobrara Formation sample exhibit mass fractal scattering, similar to previously measured U.S. marine shale samples. In the presence of CD4, scattering intensities between Q = 0.02–0.1 Å−1 (corresponding to nominal pore diameters from 25 to 5 nm, respectively) decrease with increased pressure up to 750 bar where at least 80% of all pores with ∼25 nm diameters are CD4 accessible. In contrast, between Q = 0.1–1 Å−1 (corresponding to nominal pore diameters from 5 to 0.5 nm, respectively), scattering intensity initially increased at the lowest CD4 pressure tested (200 bar) before decreasing with increasing pressure. These signal fluctuations with CD4 pressure are interpreted to arise from the creation of pores with diameters <5 nm, likely through deformation of solid bitumen by supercritical CD4, and/or the incorporation of CD4 within sample organic matter. This new porosity represents an increase of at least 8% in available pore volume within the sample, although the majority of these pores do not persist following removal of CD4. Additionally, there is strong evidence for densification of CD4 within the sample indicated by a shift in the CD4 intermolecular scattering peak to higher Q-values compared to bulk CD4. These results provide insight into fluid properties within source-rock reservoirs at late oil/wet gas thermal maturities, especially as they relate to organic porosity interconnectivity, and are discussed with perspective toward pressure management of gas condensate wells.

Study of the influence of non-carbon gases on the condensate recovery coefficient of gas condensate fields using a hydrodynamic model

There is enough research work on the effective use of non-hydrocarbon gases in order to increase the component recovery of hydrocarbon deposits. Over a long period, we have also carried out a number of research works on the effect of nitrogen and carbon dioxide on the final condensate recovery factor of fields, as well as on the productivity of gas condensate wells. However, it is known that the formation systems of gas condensate fields, along with other non-hydrocarbon gases, contain nitrogen and carbon dioxide. Sometimes their number has a rather large share in the total volume. But, the effect of the amount of nitrogen and carbon dioxide naturally present in reservoir systems on the final condensate recovery coefficient of gas condensate fields has not been studied enough. The influence of the amount of nitrogen and carbon dioxide in the composition of reservoir systems on the condensate recovery coefficient of gas condensate fields has been studied. To this end, a multicomponent hydrodynamic model of the Bulla-Sea field was used as a base case, the factors influencing the process were studied by comparing the final condensate recovery coefficient of the field with other systems containing nitrogen and carbon dioxide.

Nonseparation Method for Determining Volumetric Fractions of Gas, Condensate, and Water in the Extracted Products of Gas–Condensate Wells

Nonseparation Method for Determining Volumetric Fractions of Gas, Condensate, and Water in the Extracted Products of Gas–Condensate Wells

Gas condensate well productivity in fractured vuggy carbonate reservoirs: A numerical modeling study

The spatial distribution of fractures and cavities may generate important impact on the fluid flow behavior in fractured vuggy carbonate reservoirs. However, the recovery mechanism of gas condensate wells is not well understood due to the lack of effective reservoir simulation methods that coupled porous-medium and free flows occurring in fractured vuggy carbonate reservoirs. In this work, a novel compositional reservoir model is developed for modeling the production dynamics of gas-condensate well in complex fractured vuggy reservoirs. The compositional multiphase fluid flow through rock matrix and fractures is assumed to follow Darcy's law, while the free flow in cavities is modeled based on the assumptions of instantaneous thermodynamic equilibrium and phase segregation controlled by gravity. An advanced numerical calculation method combining finite volume method (FVM) and embedded discrete fracture-vug model (EDFVM) is developed to efficiently solve the multi-component multiphase flow problem. Case studies are conducted to investigate the gas-condensate flow behavior and well production performance under various configurations of fracture-cavity patterns. Two scenarios are considered by placing the production well at the top and bottom of the models, which aim to mimic different locations of directional well target. The results indicate that when cavities are present, condensate oil accumulates mainly beneath the cavities due to the effect of gravity segregation. Thus, more condensate oil may be produced with depletion at the bottom of the reservoir. However, condensate oil distributes surrounding the production well when cavities are absent, and the production performance of gas-condensate well is less affected by depletion location. Furthermore, the cumulative condensate oil and gas production are higher when cavities are present because of the continuous supplement of condensate gas by cavities. Our research findings have important implication for the design of directional well planning in the fractured vuggy gas condensate reservoirs.

Progress of Seepage Law and Development Technologies for Shale Condensate Gas Reservoirs

With the continuous development of conventional oil and gas resources, the strategic transformation of energy structure is imminent. Shale condensate gas reservoir has high development value because of its abundant reserves. However, due to the multi-scale flow of shale gas, adsorption and desorption, the strong stress sensitivity of matrix and fractures, the abnormal condensation phase transition mechanism, high-speed non-Darcy seepage in artificial fractures, and heterogeneity of reservoir and multiphase flows, the multi-scale nonlinear seepage mechanisms are extremely complicated in shale condensate gas reservoirs. A certain theoretical basis for the engineering development can be provided by mastering the percolation law of shale condensate gas reservoirs, such as improvement of productivity prediction and recovery efficiency. The productivity evaluation method of shale condensate gas wells based on empirical method is simple in calculation but poor in reliability. The characteristic curve analysis method has strong reliability but a great dependence on the selection of the seepage model. The artificial intelligence method can deal with complex data and has a high prediction accuracy. Establishing an efficient shale condensate gas reservoir development simulation technology and accurately predicting the production performance of production wells will help to rationally formulate a stable and high-yield mining scheme, so as to obtain better economic benefits.

Gas–Liquid Flow Behavior in Condensate Gas Wells under Different Development Stages

The phase state prediction methods of condensate gas are relatively mature, but the effect of phase changes on gas–liquid mixture flow behavior and the liquid-carrying capacity of gas has not been researched in detail. This study applied PIPESIM software to predict the fluid phase properties under different development stages of a condensate gas reservoir in Shengli Oilfield and determined the phase diagram and physical properties of the well stream on the basis of the optimized equation of state (EOS). Then the influence of phase change characteristics on wellbore flow behavior and critical liquid-carrying gas velocity was analyzed. The study showed that compared with the early development stage, fewer heavy components are produced and the produced gas–liquid ratio is increased in the late stage of the condensate gas reservoir. In addition, the pressure loss of fluid is decreased, the critical liquid-carrying gas velocity and flow rate are reduced, and the liquid-lifting difficulty is reduced for gas. The reason is that the liquid density decreases obviously due to the phase change, while the gas density is almost unchanged, and the oil–gas surface tension decreases obviously, resulting in a decrease in the critical liquid-carrying gas velocity. At the same time, the variation in the gas compressibility factor is very small, which leads to a decrease in the critical liquid-carrying gas flow rate.

Separationless method of determination of volume fractions of gas, condensate and water in products extracted from gas condensate wells

The problem of the lack of instruments for the operational measurement of the components of the production of gas condensate wells – multiphase flow meters – is considered. Actual problems solved with the use of multiphase flowmeters are described, and the main requirement for these devices is the measurement of the components of a gas condensate flow without separating it into gas and liquid phases using a separator. A method is proposed for determining the volumetric contents of the components of the products of gas condensate and oil and gas condensate wells using a non-separation technique for registering components. The probing of a gas-liquid flow by decimeter radio waves at the moment of flow passing through a microwave resonator is described, and a variant of the design of a non-separation analyzer of volume fractions of gas, condensate and water in the production products of gas condensate wells is proposed. The volume fractions of gas, water, and condensate were determined from the results of measurements of the frequency shift and the quality factor of the resonator. At the same time, an acceptable accuracy (less than 5 %) of determining the amount of condensate is provided only at high condensategas ratios (300–1000 cm3/ m3) and low water-gas ratios (30–100 cm3/m3). With an increase in the proportion of water or a decrease in the proportion of condensate, the error in determining the gas-condensate factor becomes unacceptably high (more than 10 %). It is proposed to reduce this error by introducing a bypass line into the flow meter containing a filter for separating the liquid phase and a reference resonator. The reference resonator registers the frequency shift due to the gas phase. The filter is probed with an eight-millimeter radio beam, which reacts to the content of only the water component. The data obtained from the resonator and filter significantly expand the range of recorded condensate-gas and water-gas factors. Possibilities of using the proposed technique: determination of volume fractions in the production products of gas condensate wells; application in multiphase flow meters for gas condensate fields; quality control of separators that separate liquid before further gas supply (when equipment is installed both before the separator and after it). Large bore resonators could be used to control gas-liquid flow through pipelines of large diameters, such as collector pipelines.

A NEW METHOD FOR PREDICTION OF THE CONDENSATE BANKING SIZE AROUND A GAS CONDENSATE WELL

The main problem in the production operation from gas condensate reservoirs is well deliverability loss due to condensate formation and banking around the well as pressure falls below the dew point pressure. It is a common practice to calculate gas condensate well production performance based on the three flow regions. The size of Region 1 (a near wellbore region with high condensate saturation) plays an essential role in the productivity loss of gas condensate wells. In this study, a radial reservoir model is constructed using a compositional model to perform a number of analyses on a single well model. Real data from a large gas condensate reservoir located in the Middle East is applied to the reservoir model. Then, the impacts of affecting parameters are studied using the validated reservoir model. The results of this study show that key parameters, which have a significant effect on the size of condensate banking around gas condensate wells, are rock permeability, rock porosity, reservoir thickness, cumulative gas production, and pressure-dependent fluid parameters such as interfacial tension, viscosity, and density. Finally, using dimensionless analysis, a new relation is proposed to predict the radius of condensate banking (Region 1). This procedure is applicable in similar cases.

Autoclave modeling of corrosion processes occurring in a gas pipeline during transportation of an unprepared multiphase medium containing CO2

The problem of selecting a method for ensuring the reliability of the unprepared fluid transport facilities of an unprepared fluid in the presence of carbon dioxide is considered. Carbon dioxide corrosion is one of the dangerous types of damage to field and main pipelines. It has been shown that dynamic autoclave tests should be carried out during staged laboratory tests in order to determine the intensity of carbon dioxide corrosion and to select the optimal method of protection. A hypothesis about the imperfection of the existing generally accepted approaches to dynamic corrosion testing has been put forward and confirmed. A test procedure based on the use of an autoclave with an overhead stirrer, developed using elements of mathematical modeling, is proposed. The flows created in the autoclave provide corrosive wear of the sample surface similar to the internal surfaces elements wear of the pipelines piping of gas condensate wells. The autoclave makes it possible to simulate the effect of the organic phase on the flow rate and the nature of corrosion damage to the metal surface, as well as the effect of the stirrer rotation speed and, accordingly, the shear stress of the cross section on the corrosion rate in the presence/absence of a corrosion inhibitor. The given results of staged tests make it possible to judge the high efficiency of the developed test procedure.