Articles

Oil production

Study of the effect of a bimetallic catalyst based on iron and cobalt on the aquathermolysis process under thermal steam treatment of high-viscosity oil

Baygildin E.R., Sitnov S.A., Vakhin A.V., Nurgaliev D.K.

DOI: 10.24412/2076-6785-2021-5-46-51

Abstract
In this work, we studied the effect of bimetallic catalysts formed in situ from mixtures of oil-soluble iron and cobalt precursors in the process of aquathermolysis of heavy oil from the Ashalchinsky field. Based on the results of determining the group composition (SARA analysis) and viscosity-temperature characteristics, an improvement in the composition and an increase in the mobility of oil under the action of steam and a bimetallic catalyst is shown. It was found that the catalyst intensifies the destructive processes of resinous compounds, provokes the enrichment of the destruction products of the latter in the saturated and aromatic fractions with high molecular weight n-alkanes and polycyclic hydrocarbons, respectively. It was revealed that the proposed catalyst of the optimal composition is a mixture of individual and mixed oxides and sulfides of iron and cobalt (ferrospinels). Catalyst can be used at the Ashalchinsky field of heavy oil in conditions close to reservoir conditions (200 °C, 10 bar), as a reagent providing an increase in the degree of oil recovery.

Materials and methods
Heavy oil of the Ashalchinsky field of the Republic of Tatarstan, SARAanalysis, viscometry, gas chromatography-mass spectrometry (GC-MS), catalyst active form, XRD.

Keywords
heavy oil, steam treatment, bimetallic catalyst, oil-soluble precursors, catalyst active form, in-situ upgrading, EOR

Revealing the direction of natural fracturing and cavernousness in order to optimize the field development parameters

Ponomarev M.D., Borkhovich S.Yu. , Mavliev A.R., Polozov M.B., Trubitsyna N.G.

DOI: 10.24412/2076-6785-2021-5-42-44

Abstract
This article evaluates the study of the direction of spread of natural fracturing and predominant direction of propagation of cavernousness of the carbonate reservoir of the Podol-Kashiro-Vereiskian object of the Elnikovskoye oil field. The studies are based on the analysis of information on the sampled core, tracer studies, the FMI method and the mutual influence of production/injection wells. The study identified the main directions of natural fractures and vugginess. These parameters must be taken for well coverage, in particular, adjusting the location of production/injection wells in order to prevent anticipatory water invasion, as well as when selecting candidates for geological and technical measures to increase the
final oil recovery factor.

Materials and methods
Based on the analysis of practical material on optimizing the conditions of the fields being developed in the territory of the Udmurt Republic.

Keywords
natural fractures, natural vugginess, development, oil field, carbonate reservoir rock, geological and technical actions, interference of wells

The experience of oil recovery using nonionic surfactants

Kozhin V.N., Gorodnov V.P., Kalinin E.S., Ryskin A.Y., Chernov E.N.

DOI: 10.24412/2076-6785-2021-4-46-52

Abstract
Nonionic surfactants provide benefits of possibility of large-scale production for oil industry demands. However, the laboratory and field tests
show their inferiority to anionic surfactants due to propensity for salting out when the reservoir temperature is higher than the cloud point of
the repressuring solution containing the nonionic surfactant. This paper describes the results of a field test of water solutions of alkylphenol
ethoxylates from different manufacturers, both with and without polyacrylamide, compared to the previous field tests of these reagents.
The innovative technologies for use of nonionic surfactants are based on their thermal salting out from the water solution and on the polyacrylamide
complex formation possessing high selectivity when moving in the reservoir, i.e. poor filtration into the watered and good filtration into the oilsaturated
areas.

Materials and methods
Materials: data on the field test of nonionic surfactants as a reagent
for improving reservoir oil recovery in Western Siberia and Urals-Volga
regions.
Methods: analysis of the results obtained when testing variety of technologies based on using aqueous nonionic surfactant solutions in
the oil fields of Western Siberia and Urals-Volga regions.

Keywords
nonionic surfactant, improving reservoir recovery, field tests

Seismogeological analysis as a tool of history matching: YNAO Case Study

Gorlanov A.A., Vorontsov D.Y., Schetinin A.S., Aksenov A.I., Ovchinnikova D.G.

DOI: 10.24412/2076-6785-2021-3-34-40

Abstract
The process of raising the gas-water contact (GWC) is inevitable during development of the reservoir. This leads to flodding of wells and reducing of daily gas production. Horizontal sidetracks and new horizontal drilling allows to maintain production at the required level. Mostly, the direction of the horizontal section of the well determines its efficiency. In difficult geological conditions, a detailed analysis of seismic data in the drilling area allows to reduce drilling risks and achieve planned starting rates. Accounting of seismic data in geological models is often limited by a low correlation coefficient between reservoir properties obtained from wells and seismic attributes. Simulation models use seismic data based on the assumptions made by the geological engineers.

Materials and methods
In this paper authors uses a iterative approach to geological modeling: implementations include in-depth analysis of seismic data and well performance dynamics. Modern software modules were used to automatically check the compliance of the geological implementation with the development history, as well as to assess the uncertainties. High correlation coefficients between well water cut and seismic attributes obtained. Authors developed a method for determining the presence of shale bodies and “confluence windows” of a massive gas reservoir with water-saturated volumes.

Keywords
geological modeling, simulation run, Pokurskaya suite, gas reservoir, cenomanian, horizontal wells, attribute analysis

The selection approach for the efficient development method gas-and-oil fields based on multialternative calculations

Potapov K.R., Polozov M.B., Trubicyna N.G., Borkhovich S.Yu.

DOI: 10.24412/2076-6785-2021-3-29-32

Abstract
The article describes the selection approach for the efficient development method of the vereiskian formation of the Chutyr field. To optimize the method, the filtration model of the vereiskian and bashkirian formations was prepared and historically matched. Based on multialternative calculations, the practical field development method was determined.

Materials and methods
Based on the analysis of practical material, the testing of the method of foam acid exposure in the conditions of developed fields in the territory of the Udmurt Republic.

Keywords
efficient system, development method, gas and oil field, filtration model, fluid flow model, multialternative calculations, modelling

Optimization of the search for zones of residual reserves with considering the non-newtonian properties of oil in the process of hydrodynamic modeling

Vylomov D.D., Shtin N.A.

DOI: 10.24412/2076-6785-2021-2-57-60

Abstract
The paper is devoted to the accounting of nonlinear filtration in hydrodynamic modeling of the oil displacement process. The authors analyzed and identified the main factors that are the reasons for the deviation from the linear filtration law. The work considered a method of mathematical modeling of non-newtonian oil properties. In the process of filtration modeling, an algorithm for converting the geological-physical characteristics (GPC) of oil fields into coefficients used by a hydrodynamic simulator to take into account nonlinear filtration was created and tested. Thus, a hydrodynamic model (HDM) of an oil field has been built, capable of taking into account the deviation from the linear Darcy's law and quantify the impact of non-newtonian oil properties on the development process.

Materials and methods
To calculate the limit dynamic shear stress (LDSS) of degassed (1) and gas-saturated oil (2), a technique was used based on studies of the properties of oils from the Volga-Ural province [1].

Keywords
hydrodynamic modeling, nonlinear filtering, deviation from linear Darcy's low, non-newtonian properties of oil, gradient of the dynamic structure destruction, gradient of the limit structure destruction, nine point development system of oil, residuals reserves, geological and physical characteristics

Integration of CRM capabilities and stochastic-analytical models in solving waterflooding problems

Pospelova T.A.

DOI: 10.24412/2076-6785-2021-2-48-52

Abstract
The article is devoted to the comparison of the capabilities of two analytical models describing the operation of oil fields, namely CRM and stochastic-analytical model (SAM). These tools for controlling and regulating the technological mode of withdrawal and injection neutralize the disadvantages expressed in the uncertainty of the adaptation of hydrodynamic models (HDM) and the distribution of reservoir properties (PRP) in the zones between wells, and also act as "assistants" in setting up the hydrodynamic model, conducting analysis and monitoring RPM systems. The inverse problem of underground hydromechanics is solved in the form of CAM (“autohydro-self-monitoring”), while CRM is represented by an equation based on material balance.

Materials and methods
Analytical solution of the problems of analysis and optimization of the waterflooding system, the ability to assess the filtration properties of the reservoir in the vicinity of wells and between pairs of wells of candidates for geological and technical measures.

Keywords
Hydrodynamic modeling, stochastic-analytical models, analytical models, reservoir pressure maintenance system

Justification of the wells production conditions of the Cenomanian gas reservoir of the Kharampurskoye field based on the results of geomechanical modeling

Pavlov V.A., Pavlyukov N.A., Subbotin M.D., Kovalenko A.P., Yantudin A.N., Abdullin V.S., Shekhonin R.S., Goloviznin A.Yu.

DOI 10.24412/2076-6785-2021-2-41-46

Abstract
The risk assessment of sand production in the wells was carried out based on the results of a core study and hydro-geomechanical modeling of the formation. The paper presents and implements an algorithm for calculating the project indicators for the development of the Kharampurskoye oil and gas condensate field using combined hydro-geomechanical modeling, which makes it possible to take into account changes in reservoir properties and elastic-strength properties in deformed and bottomhole formation zones. Based on the results of the calculations, the risk of sand production and the collapse of the bottomhole formation zone was predicted throughout the development of the field. Recommendations were given to minimize the risks of sand production.

Materials and methods
Based on the results of laboratory studies, an assessment of the change in the elastic-strength properties of core samples when saturated with various fluids (natural saturation and water) was carried out. Based on the results of core testing on thick-walled cylinders, an estimate of the permissible depression was obtained. 3D/4D coupled hydrogeomechanical modeling was performed to assess the geomechanical effects associated with the change in the elastic-strength properties of rocks from saturation, which allows taking into account the effect of rock destruction on permeability.

Keywords
laboratory core studies, elastic-strength properties, different saturation,
depression assessment, associated hydro-geomechanical modelingñ

Negative factors affecting the integrity of production strings and methods for preventing leakage

Nasyrov A.M., Epifanov Yu.G.

DOI: 10.24412/2076-6785-2021-2-33-36

Abstract
The main element of the well design, which determines the life of the wells, is the production strings (PS). Premature failure of the production strings requires significant expenses for its restoration, and the unprofitability of its restoration by repair methods leads to unjustified expenses for abandoning the well and drilling a duplicate well. The article briefly describes the impact of negative factors on the integrity of the PSs of the wells and outlines the possibilities to reduce their impact. Specific recommendations are offered.

Materials and methods
Actual data of well survey by geophysical, hydrodynamic methods, analytical methods of generalization of field data, engineering calculations of technological processes.

Keywords
production strings of a well, hermos-baric action, steam injection wells, corrosion effects, downhole protective composition, repair and insulation works, pressure testing

Application of the technology of foam acid treatment on carbonate reservoirs of the Bashkir object in the conditions of the Volga-Ural region

Polozov M.B., Mokhnacheva M.E., Borkhovich S.Yu.

DOI: 10.24412/2076-6785-2021-1-45-48


Abstract
The issues of stimulating the inflow from carbonate reservoirs, as well as increasing the oil recovery factor are among the most relevant. With classical multiple acid treatments, hydrochloric acid penetrates into the same high-permeability intervals of the bottomhole formation zone (BHZ), and the coverage of the formation by impact decreases. Thus, one of the most important tasks of oil production is to increase the efficiency of acidizing wells. The problem becomes most urgent due to the fact that at present most of the large fields in Russia are at a late stage of development, the work of the deposit is carried out at reduced reservoir pressures, and the reservoir itself is heterogeneous. The article deals with the use of foam-acid treatment of the formation to increase oil production at the fields of the Volga-Ural region.

Materials and methods
Based on the analysis of practical material, the testing of the method of foam acid exposure in the conditions of developed fields in the territory of the Udmurt Republic.

Keywords
acid treatment, foam acid, acid deviation, increased efficiency of repeated BHT, carbonate reservoir

The reasonability of a smooth start of injection wells

Izotov A.A., Sokolov S.V.

DOI: 10.24412/2076-6785-2021-1-40-44

Abstract
The efficiency of oil field development is largely determined by the current levels of oil production. In the field, the desire for intensification often leads to long-term development of injection wells and, as a result, to a decrease in reservoir pressure. Attempts to restore it due to forced injection of water into the reservoir lead to the development of man-made fracturing, which contributes to the breakthrough of water to the producing wells. To reduce the negative impact of the process of spontaneous formation of hydraulic fracturing cracks, it is proposed to smoothly start the injection wells by gradually increasing the bottom-hole pressure to the design value. The effect was justified using a hydrodynamic model.

Material and methods
Technological calculations of development options, reduction of the risk of formation of cracks in hydraulic fracturing with the use of a hydrodynamic model based on geological and field analysis and geomechanical dependencies.

Keywords
injection well, growth of fractures, auto fractures, reservoir pressure, rock fracking pressure, well flooding

Influence of the objective function normalization method on the reservoir model history matching result

Eremyan G.A., Rukavishnikov V.S.

DOI: 10.24411/2076-6785-2020-10112

Abstract
The article is devoted to the mismatch normalization as one of the aspects of the objective function formulation for automated history matching of hydrocarbon reservoir models. To carry out history matching, it is necessary to define the objective function that describes the discrepancy between simulation results and observed data. Objective function guides the optimization algorithm to move in the right direction across the model parameter space in the search for solutions. The aim of the work is to compare the influence of the normalization method on history matching results using the example of a synthetic model and a model of a real oil field. The novelty of this study is in the introduction of a behind-the-casing crossflow simulated in one of the production wells of the synthetic model. The crossflow acts as noise in the well observed data. The results of this research allowed to understand which method of the objective function normalization is more effective for history matching and why.

Materials and methods
The main methods in this study are numerical reservoir simulation, system analysis and computational experiment using a synthetic reservoir model and a sector model of a real oil field located in Siberia.

Keywords
reservoir simulation, oil field, numerical model, objective function, mismatch normalization, automated history matching, optimization algorithms, history matching quality

Quality criteria for automated history matching of hydrocarbon reservoir models

Eremyan G.A., Rukavishnikov V.S.

DOI: 10.24411/2076-6785-2020-10117

Abstract
The paper considers identifying of high-quality models obtained after automated history matching of hydrocarbon reservoir models. Numerical reservoir modeling consists of three main stages: creation of a static geologic model,
construction of a dynamic filtration model on its basis and an iterative process of history matching of the created reservoir model. Based on the selected history matched models, predictive simulations are made to estimate the
forecast uncertainties and associated risks. The purpose of this work is to study the quality criteria for the history matched models and the validity of their use on the example of a synthetic reservoir model. The results of this study
show disadvantages of using the value of the objective function as the only quality criteria. Also, ways are indicated for a more reasonable selection of desired quality models.

Materials and methods
The main methods in this study are numerical reservoir simulation, comparative analysis and computational experiment using a synthetic reservoir model.

Keywords
history matching quality, quality criteria, objective function, optimization algorithms, automated history matching, reservoir simulation, oil field, numerical model

Operating experience of rotating sucker rod strings of various designs for oil production from oil wells

Isaev A.A.

DOI: 10.24411/2076-6785-2020-10122

Abstract
The calculations revealed that a circular cross-section would be a very efficient solution for a rotating string. Hollow sucker rods have such a cross section, and the design of such rods maintain strength uniformity. Application of such
hollow rods makes it possible to increase the reliability and durability of the driving string by multiple times, as strength and rigidity characteristics of the string are increased, thereby increasing the operating time of the PCP unit
and extending the time between well repairs. The parting of rods, both hollow and solid in section, is very strongly influenced by dogleg severity. Hollow rods with uniformly strong structure have been implemented as a driving string in
6 wells of JSC Sheshmaoil. To reduce the influence of curvature on the service life of the rods, a centralizer with functions of bearing and bow spring centralizer has been developed, which undergoes bench tests at the moment.

Materials and methods
The conditions of strength and stiffness for rods of various designs were determined. Technical calculations were carried out to determine the polar moments of resistance and inertia. A special test bench has been manufactured for testing the centralizer, where it was possible to adjust the speed of the centralizer shaft.

Keywords
progressive cavity pumping unit, rod parting, hollow rods, dogleg severity

The bench for studying gas phase dispersion in gas-liquid mixture flow along the length of electric submersible pump

Goridko K.A.

DOI: 10.24411/2076-6785-2020-10106

Abstract
The paper presents a scheme of a new bench to study the characteristics of electric submersible pump on gas-liquid mixtures, taking into account the distribution of pressure and gas phase dispersion along the pump length, describes
the methods of experimental studies. The original design of the motor-weights for measuring the power on the electric submersible pump shaft is developed.

Materials and methods
Physical modelling of the electric submersible pump operation on gasliquid mixtures, scheme of the bench and study procedures.

Keywords
gas-liquid mixture, electric submersible pump, bench

Prospects in developing thermochemical procedure to treat bottom hole formation zone in wells for enhanced high-viscous oil recovery at the fields of “Samaraneftegas” JSC

Mikhailov A.V., Pchela K.V., Kozhin V.N., Gornov D.A., Manasyan A.E., Amirov A.A., Kozlov S.A., Pavlov V.A., Ugryumov O.V.

DOI: 10.24411/2076-6785-2020-10116

Abstract
Currently for challenging oil deposits, in particular for the deposits with high-viscous oil the well-known traditional methods of development are ineffective. Therefore, the search for new technologies to develop and operate such fields
for the purpose to increase oil recovery significantly and to stimulate its production is of fundamental importance. One of these methods with BH zone thermal treatment is the use of heat generated by thermo-chemical reactions
based upon the application of nitrogen-generating compounds (NGC) such as ammonium nitrate (NH4NO3) and sodium nitrite (NaNO2). The composition based upon these compounds is applied in the procedure of thermal gas chemical effect (TGCE). Hydrodynamic modeling was used to perform the preliminary efficiency assessment of this thermal gas chemical procedure for high-viscous oil fields in Samara Region.

Materials and methods
Reproduction of well operation history matching process in hydrodynamic model including the injection of thermo-chemical composition into formation bottom-hole zone, followed by thermo-chemical reaction, forecast on process efficiency of thermo-chemical effect.

Keywords
high-viscous oil, BH formation zone, BH zone treatment, thermal chemical composition, thermal gas chemical effect, hydrodynamic modeling

The study of the main technological properties of hydrochloric acid compositions of different types and their comparative assessment

Maria Yu. Shumakher, Viktor V. Konovalov, Vadim M. Khafizov

DOI: 10.24411/2076-6785-2020-10101

Abstract
The effectiveness of the bottom-hole treatment directly depends on the acid composition, which is selected on the assumption of both reservoir and composition characteristics. Nowadays modified acid compositions, including
emulsions, are actively used along with traditional acid compositions. Acid hydrocarbon-containing emulsions have a number of advantages, promoting the increase of the effectiveness of acid treatment. This paper presents the
results of a study of the main technological characteristics of hydrochloric acid compositions of different types and their comparative assessment.

Materials and methods
Different methods and laboratory equipment were used during the study of the properties of acid compositions. Viscosity of the compositions was determined using the Anton Paar rheometer, dispersed properties were detected using the digital microscope Altami and the software for digital data processing. The technological properties of the compositions were identified using the guidelines of the “Rosneft” PJSC. Ability of the compositions to dissolve asphalt-resin-paraffin deposits was investigated using the static basket method with the paraffin type asphalt-resin-paraffin deposits. Corrosiveness of the compositions was defined immersing the steel plates into them with the further evaluation of the weight loss of plates. Compatibility of the compositions with oil was evaluated mixing them with the sample of the high viscosity oil-water emulsion and filtering the mixture through a 100 mesh sieve. Reaction rate of the acid compositions with the carbonate rock was identified immersing the marble cubes into them with the further evaluation of the dissolution rate based on the weight loss of the marble.

Keywords
hydrochloric acid composition, oil-in-water emulsions, water-in-oil emulsions, technological properties, corrosiveness, solvent power, compatibility with oil, reaction rate with the marble

Grounds to apply complex process of bottomhole hydro-jetting effect at the fields with heavy oil

Roschin P.V., Nikitin A.V., Smirnov E.A, Kozhin V.N., Pchela K.V., Kireev I.I., Demin S.V., Manasyan A.E., Amirov A.A., Vorobyov S.V.

DOI: 10.24411/2076-6785-2020-10100

Abstract
The paper provides the information on the grounds and tests the process of acid composition hydro-jetting effect with pre-injection of solvent at heavy oil fields with the purpose to stimulate production. The paper also contains the results of complex hydro-jetting (CHJ) BH treatment process at 5 producing wells of “Samaraneftegas” JSC with heavy oil. As of the day of this publication the incremental oil production exceeded 2 000 tons as a result of these operations. The authors provide the infographics on increasing the number of wells with heavy oil at the objects of “Samaraneftegas” JSC in Samara Region. For objects that contain heavy oil at the objects of “Samaraneftegas” JSC it was found that pre-injection of a pre-selected hydrocarbon reagent/solvent will significantly increase the effect of BH acid treatment at the oil fields.

Materials and methods
Justification and selection of chemical reagents based on the conditions of use in carbonate reservoirs with heavy oils, the use of hydrojet nozzle on tubing, complex physicochemical treatment of the bottomhole formation zone, analysis of well performance data.

Keywords
complex hydro-jetting treatment, production stimulation, heavy oil, acid treatment, bottomhole zone, hard-to-recover reserves, well complication control

Analysis of efficiency of barrier flooding of Kiengopskoe field

Michail Â. Polozov, Sergey G. Zaynikaev, Sergey Y. Borchovich

DOI:10.24411/2076-6785-2020-10093

Abstract
The problems of developing oil rims are well known and relevant. Advance watering and an increase in the gas content of the production leads to a decrease in the relative phase permeability for oil, which leads to a decrease in oil recovery of the reservoir and a low recovery of reserves. Barrier flooding is one of the most effective methods of stimulation used in oil production from gas cap zones. One of the main problems in this type of waterflooding is the correctness of its organization. The complex system of two-phase filtration of oil and gas, as well as the ambiguity of the location of the gas-oil contact (GOC) in the reservoir should be taken into account when introducing barrier flooding as the main impact on the oil rim. The article analyzes the barrier waterflooding system introduced at the Vereisky site of the Kiengopskoye field. Based on the analysis of field data, a technological solution is presented to improve the efficiency of barrier flooding by preventing gas breakthrough from the gas cap, reducing the gas factor in the production well.

Materials and methods
Based on practical evidence.

Keywords
barrier flooding, GOR, oil rim, gas cap, gas breakthrough, injection well

Determination technological parameters of wellbore heat treatment for a deep pump with hollow rods

Aleksandr V. Lekomtsev, Pavel Y. Ilyushin, Vitalii S. Bakaneev, Grigorii Y. Korobov

DOI:10.24411/2076-6785-2020-10092

Abstract
One of the main complications, being during the exploitation of production wells, is the formation of asphaltene-resinparaffin deposits (ARPD). In conditions of low inter-cleaning periods of well work (less than 30 days) and high strength of structural-mechanical bonds in ARPD, formed in tubing above the pump, the most economically and technologically expedient way to combat complications are flushing-out of well. The calculation of the thermal state of a well equipped with a sucker rod pump during heat treatment through hollow rods with a bypass clutch are considered in the paper. Based on the results of the calculations, it was noted that the temperature of the injected agent (hot oil or water) affects the temperature of the inner wall of the tubing lower than the coolant flow rate.

Materials and methods
Assessment of the thermal state of the well during heat treatment through hollow rods and determination of the most optimal conditions for effective removal of asphaltenes, resins and paraffins.

Keywords
Ñomplications at oil producing, hollow rods, flushing-out of well, ìodeling of well flushing, struggle with ARPD