bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Black Oil Correlations for PVT Properties Estimation
Authors: Odegov A. , Khabibullin R. , Khasanov M. , Brusilovsky A. , Krasnov V.
Published: October 2015

Over the last 30 years, considerable research into the assessment of PVT-properties of hydrocarbon formation has been carried out. Based on laboratorial and field research of oil and gas samples, two basic approaches of PVT-properties assessment were developed. They are correlation approaches, based on statistical analysis of the result of research and compositional simulation approach based on the equation of state (EOS) solution. These approaches have both advantages and disadvantages. It is clear that both of them are essentially dependent on the quality of the initial data obtained from the analysis of reservoir and surface samples of hydrocarbons. Therefore, it would be wrong to contrast two approaches in terms of priority. Compositional simulation is indispensable for the assessing of reservoir system behavior near the critical point for volatile oil and gas condensate systems, which have no correlation models, or give results with poor accuracy. The basis of compositional simulation is the composition of the formation system, which consists of individual components to C6 inclusively, and fractions of C7+ pseudocomponents. Correlation models are successfully used in assessing of the behavior of black oil. Basic parameters of PVT model correlation are Rsb - gas-oil ratio at bubble point, γo - oil specific density, γg - gas specific density, Pb - bubble point pressure, Tres - reservoir temperature. It should be noted these parameters can be obtained in different experiments of degassing, namely, single or differential, as well as within the framework of standard or commercial separation. Moreover, each PVT correlation usually tuned to its own regional data bank. As a result, different correlations may use different statistics on overlapping intervals. Recently, several articles have been published, which analyzed the correlation approaches of PVT properties assessment [1-3]. However, the study provides an analysis of correlations without recommendations for their use. The main conclusion of these studies is a statement of fact that the choice of correlations should be conducted with respect to basic oil properties. Usually, it recommends to use new coefficients for the standard correlation model.
Special Treatment of Thermo-Hydrodynamic Well Studies in Massive Fractured Reservoirs of Crystalline Basements
Authors: Shtyrlin V. Ph. , Fomkin A. V. , Plynin V. V.
Published: October 2015

In recent years, geologists have discovered new oil-bearing lithospheric layer – fractured oil-bearing igneous and metamorphic basement rocks, so interest in foundation as oilfield facilities increased significantly. Analysis showed that oil in 32.5% of reservoirs is confined to granitoid rocks, in 29.0% of reservoirs oil is concentrated in metamorphic rocks, in 14.0% - in carbonates, and in 12.5% - in volcanic formations. Not more than 7.0% of reservoirs are in weathering mantle of penetrative rocks.

Known methods of reservoir structure studying can be divided into external and internal. External methods are based on acquisitions from the land or sea surface, where seismic survey (seismic waves) is a tool of study. Internal methods are based on acquisitions in reservoir itself, where the well is object of study. Innovative well survey technology SOTGDIS (special treatment of thermo-hydrodynamic well studies) enables to identify texture of internal structure for borehole environment in massive reservoirs. This technology is based on data acquired during standard thermo-hydrodynamic well studies and does not require changes in oil production technology and well survey.

Developed technology enables to describe flow geometry in reservoir near-wellbore zone, which significantly improves quality of hydrodynamic simulation and provides additional information for flow analysis. As a result, there is a possibility to build adequate hydrodynamic model and locate remaining recoverable reserves in complex reservoirs such as crystalline basement.

Based on data stored in thermodynamic and hydrodynamic well studies, SOTGDIS developed by the authors enables to determine a variety of new parameters describing internal structure of massive fractured reservoir: –Geometrical size of super-fractures (effective length, width and openness);–Super-fracture angle;–Geometrical size and location of active well zone.

In other words, it is possible to describe flow properties geometry in bottom-hole zone for fractured reservoir conditions.
Fold Belts: Shall We Expect a Shift in Petroleum Exploration Priorities?
Authors: Sobornov K. O. , Afanasenkov A. P. , Danilov V. N. , Zhemchugova V. A. , Volozh Yu. A.
Published: October 2015

Oil and gas exploration in Russia passed through 3 cycles of rapid reserve base build-up. The first one is related to the exploration in the foothills of the Caucasus. The second successful exploration campaign occurred in the Volga-Urals. The last one took place in the West Siberia. All of them were driven by new ideas coupled with technological advances. The vast Soviet legacy provided sufficient reserves to boost oil and gas production for many years to come. As a result exploration activities in Russia were drastically reduced. Oil and gas companies were mainly focused on capitalization of business through increasing of oil and gas recovery on existing fields. It seems that this period comes to an end. Production from the aging giants is getting more expensive. The existing producing fields have predominantly hard-to-recover reserves with a high water cut.

The identification of new exploration plays to offset the declining production on old fields eventually becomes an important issue. Petroleum exploration in the mature areas, such as the West Siberia and Volga Urals, deliver predominantly small fields. This necessitates the identification of new exploration opportunities capable to provide large volumes of oil and gas to support future production. Examination of G&G data characterizing petroleum potential of Russia indicates that reserve replacement may have three possible directions. These include: (1) exploration in the Arctic shelves; (2) realization of potential of shale deposits; (3) exploration in the underexplored fold belts. It is likely that the third option may provide very substantial resource potential. In addition, while the Arctic exploration and shale development projects are affected by the sanctions, equipment and technologies needed for operations in the fold belts are available for Russian companies.
Paleogeographic Reconstruction and Structural Morphology of Domanik Formation in the Repubilc of Tatarctan
Authors: Liang X. , Philippov V. , Galushin G.
Published: October 2015

High OM shale formations are common in almost all sedimentary basins from the Cambrian to the Neogene period in Russia. Typical unconventional resource of oil and gas in Volga-Urals basin of Russian platform belongs to the deposits of Domanik complex, which is developed in undercompensated hollows and depressions from Middle Frasnian Semiluksky (Upper Devonian) to Later Tournaisian (Lower Carboniferous) formation, of which one of the most promising objects are in the Republic of Tatarstan (RT). It is not only theoretical but also practical in the studying structure of these sediments, their genesis and typing sections because these oil-gas bearing characteristics are not only existed in the sedimentation of Volga-Ural Basin, but also in other oil and gas provinces of the world.

On the basis of geological and geophysical studies, we use primary exploratory and drilling materials, including core analysis (lithological descriptions, definitions of reservoir properties, geological survey wells, etc.), analysis the paleontological conditions and characteristics of Domanik formation in Late Devonian on the territory of the Republic of Tatarstan (RT).

Domanik formation on the territory RT has a wide spatial distribution with dark siliceous-clayey-bituminous limestones and typical complex fauna in Semiluksky time. Higher in the cross section, Domanik facies are reduced as narrowing axial parts of the Kama-Kinel deflections (Ust-Cheremushansky, Nizhnekamsk, and others) from Upper Frasnian to Larer Tournaisian time with weakly bituminous and unbituminous carbonate rocks closer to the inner sides. As a result of differentiation in the vibrational motions distribution, from Semiluksky to Zavolzhsky time it is devided several zones with different conditions of sedimentation, of which the typical "Domanik" type is developed in relatively deep shelf.

The most greatly developed rock in the cross-section is chemogenic (granular) limestones, which are most widespread in Cm-3 and Mn-1 stratums with 2 genetic groups of collectors - pure crack (KP < 4 %) and porous-cavernous fractured (KP > 4 %).

The study result shows that tectonic fracture is the most important factor in reservoir formation, therefore favorable zones are mainly determined by the local lithology and tectonic conditions.
Modeling Gas Dissolution in BlackOil Models
Authors: Zubov V. R. , Indrupskiy I. M. , Bogachev K. Yu.
Published: October 2015

Light oil fields development often demonstrates some evidence of oil-gas phase transition hysteresis. Phase transition rate depends on the process considered: changing state from dissolved in oil to free gas or reverse gas dissolution (re-solution) in oil [1]. The difference in phase transition dynamics leads to such phenomena as continuous free gas production in reservoirs with pressure above initial bubble point. Reservoir simulators are used for forecasting reservoir dynamics and decision support. For most of the common practical problems, BlackOil model is the choice. The main object of the present study was to analyze reservoir simulators option for controlling gas re-solution and to modify the mathematical model of the option in order to account for the process dynamics known from experimental data.

The existing and new versions of the gas re-solution reservoir simulator option were considered on the example of a waterflood pattern. The process studied was gas liberation during primary oil production followed by waterflooding with increasing reservoir pressure. Fluid properties were taken by data from Sherkalinskaya formation Tala zone of Krasnoleninskoye field, for which the effects of slow gas re-solution were observed. Results of the simulations with different gas re-solution options were compared by basic field development indicators. Also the contact experiment in a pVT bomb was simulated in order to demonstrate physical effects observed for different versions of the mathematical model of gas re-solution.

The suggested extension of the option accounts for two major aspects of gas re-solution known from experimental data. The first one is the dependence of gas re-solution rate on the value of over pressure above the initial bubble point. The second one is the fact that re-solution is a relaxation process which has exponential time dynamics. The developed mathematical model included these two aspects and was implemented in a reservoir simulator. The results of the test runs show considerable influence of a gas re-solution option used on the dynamics of reservoir pressure, gas-oil ratio and oil production.

The presented approach to gas re-solution control in reservoir simulators is based on data of experimental studies of non-equilibrium phase transitions of hydrocarbons. A flexible tool has been developed for history matching of flow models for the reservoirs with pressure increase after primary oil depressurization below bubble point. Matched model can be used to produce physically consistent forecasts of efficiency of various technologies for gas re-solution and further field development.
Creating of Multivariant Geological and Statistical Model as a Solution for Assessing the Quality of Reserves
Authors: Sitnikov A. N. , Belozerov B. V. , Glozhik R. Yu. , Muzychenko A. A. , Vasilyev M. O.
Published: October 2015

The paper suggests an algorithm for the building of multivariant Geological and Statistical Model (GSM) based on the analysis and comprehensive assessment of multidimensional dependencies among geologic, technological and economic parameters for the qualitative ranking of target reserves by the degree of quality, which is determined by the feasibility of their extraction. The key methods that were used to study the impact produced by the geological, technological and economic parameters were the methods of assessing the investment potential profitability and development history analysis, multidimensional statistical analysis and simulation etc. The existing UN Framework Classification experience was used. The term "reserves quality" means the economic feasibility of recovery under specified geological characteristics and using available technologies, and under current economic conditions and existing tax rate, was introduced by the authors.
Concept Baseline for the Development of a Major Complex Field in Eastern Siberia using Flow Simulation
Authors: Levanov A. N. , Belyansky V. Y. , Volkov I. A. , Anuriev D. A. , Grinchenko V. A. , Neftegazodobycha Taas-Yuryakh , Musabirov T. R.
Published: October 2015

A case study of Srednebotuobinskoye Field, the oil deposits of which are confined to gas-oil-water and oil-water zones, describes the evolution of design decisions for development after the first year of asset operation. The first production data showed the need for separate solutions for under-gas-cap and water-oil zones, and the formation of a new field development concept, and their justification was the purpose of the work the results of which are shown in this paper.

The difference with the previously performed work lies in the fact that development decisions were made based on the results of multiple runs on a variety of complex flow simulation models - fine-cellular and full-scale.

The outcome of the study was the creation of a new development concept which provides different design solutions for under-gas-cap and water-oil zones.

The value of the work lies in the fact that the decisions involve different oil displacement processes in different parts of deposits, which affects the oil recovery rate and as a consequence the whole field development and infrastructure complex.
The Main Tendencies of Water-Induced Hydraulic Fracture Propagation
Authors: Trimonova M. , Dubinya N.
Published: October 2015

A mathematical model of water-induced hydraulic fracture propagation is introduced in the paper. The main point of the proposed model being compared to the existing ones is the correct asymptotic behavior: the classical models of hydraulic fracture propagation being implemented for solving the problem of water-induced hydraulic fracture lead to infinite fracture growth. We use a special method of taking the leak off into account to get around this issue. It includes the analysis of poroelastic effects in the vicinity of the fracture. Applying this method to solve the problem of water-induced hydraulic fracture propagation a following result can be obtained: the fracture continues to grow as long as the leaks are less than the amount of fluid injected. Nevertheless, there is a moment when the leaks become equal to injection and thus the fracture growth stops. So the fracture length becomes a bounded function of time and the upper limit of it may be calculated and used in reservoir development as a final length of water-induced hydraulic fracture.
Development of Algorithms to Control the RPM System under Full Implementation of the Swag Injection Technology at Roman Trebs' Oilfield
Authors: Nadezhdin O. V. , Lutfurakhmanov A. G. , Vinogradov P. V. , Efimov D. V. , Sergeev E. I.
Published: October 2015

To maintain reservoir pressure and to increase efficiency of oil production at Roman Trebs' oilfield it is planned an injection of water-gas mixture into reservoir. Reservoir pressure maintenance (RPM) system is a branched double-tube network – gas and water pipelines are laid in parallel in all sections. Water pipeline provides water delivery from pad pumping station (PPS), and gas pipeline delivers gas from compressor station (CS) to multywell pads of injection wells. Further water and gas are mixed on well pads in individual mixing devices, and water-gas mixture is pumped into injection wells. Control of water and gas volumes injected in each well is achieved by means of control valves mounted on gas and water supply lines of each mixer.

Pipeline of RPM system with injectors represents a complex dynamic facility and managing such complex dynamic object is a problem with a nontrivial solution. This problem is complicated by the fact that it is planned injection not of a single-phase liquid but two-phase water-gas mixture. Moreover, problem of controlling injection of water-gas mixture includes maintaining a certain ratio of water and gas in each well. This article shows problems of complex object management (multidimensionality, multistability, influence of injected agent's properties) and ways of solving these problems.

While developing control algorithms, RPM system was studied as a nonlinear non-steady multidimensional control object with vector input and output. Characteristics of transient modes were defined. There were studied the algorithms of structural-parametric identification of dynamics of multidimensional control object. Various options of regulator structure were investigated: PID-control, modal PID controllers, controllers with a higher degree of astatism, controllers with identifiers.

Based on analysis of simulation results there were found the recommended paths of well starting and decommissioning. Similarly, recommendations were made on settings changes. In addition to lower level of water and gas control it was proposed to apply an additional upper level control of wellhead pressure, which allows operation of well, even when settings are taken not from work area.

As a result, it was shown how developed control model allows continuous operation of entire RPM system with a desired injection level.
Solid Expandable Tubular Systems: Advantages and Prospects of Application in Russia
Authors: Glebov S. , Kulikov S. , Sidorenko K.
Published: October 2015

Over a number of years production casing leaks have been one of the major issues of oil well operation in Russia. Experts believe that this issue is one of the main reasons of oil well shifting from the active well stock into temporarily shut-in wells.

The share of shut-in wells in Russia has reached 15% of the total oil well stock without any significant changes in recent years.

It is evident that conventional solutions providing for smaller size production casing running and cementing to surface are not cost efficient.

Operators are surely interested in alternative solutions being less material, tool and time consuming.

In this context, solid expandable systems deserve close attention as their application will enable to reduce both work costs and nonproductive time.

Operator's benefits from using solid expandable systems for production casing leak repairs include:

Reduction of production decline rates at brown fields; Extension of field producing life; Reduction of shut-in well servicing costs.

Solid expandable tubular systems significantly differ from each other in the design of expandable tubing (patches), the expansion method, and, correspondingly, the complex of equipment applied.

This article describes one of the most common solid expandable tubular systems, presents an analysis of its application geography, and provides a case study of this system application in Russia.
New Approach for Gas Lift Optimization Calculations
Authors: Khabibullin R. , Burtzev Ya.
Published: October 2015

This work is devoted to development of gas lift optimization calculus methods applicable under high uncertainties with initial data. The initial data that can be missed or have high degree of uncertainty is the gas injection rates, gas oil ratio, bottom-hole flowing pressure, and productivity index. Optimization refers to the assessment of the well's current operation mode from the point of view of gas lift efficiency enhancement, the possibility of gas injection reduce or oil production increase. An approach - the construction of a mathematical model of gas lift wells based on the multiphase flow correlations and gas lift equipment modeling. The proposed model allows to analyze well behavior, identify the correct solution from several possible describing the observable parameters. It allows evaluating wells optimization potential using current gas lift installation and can be used to design new one.
Flow assurance in gas-gathering networks of two gas-condensate formations of Urengoyskoe Gas-Condensate Field
Authors: Bikbulatov S. M. , Buleiko V. V. , Mukminov I. R. , Bikbulatov R. V. , Vinokurov V. N.
Published: October 2015

The last 18 years CJSC "Rospan International" is producing gas and condensate from the two formations of The Urengoyskoye Gas-Condensate Field located in the Yamalo-Nenets Autonomous District. By 2016, the company expects a significant increase in production capacity, with an annual production of hydrocarbons more than 18 billions of cubic meters. About 250 wells are planned to drill at both formations. Gas transport is carried out based on the collector-beam pattern onto the GTU (gas treatment unit), which at this stage operates on the subcooling separation scheme. In the long term it is expected to complete modernization of the GTU.

Multiphase flow transported through collectors is seen as a dynamic phenomenon and is subject for dynamic modeling. Non-stationary processes can often be observed in the gas-gathering networks. Moreover, a stable (close to steady state) stage often is not achieved, and thus the use of stationary calculation methods may not correctly model the real situation.

In order to provide current and future control of production processes that occur during the operation of gas-gathering networks, and to provide the necessary engineering support, models of gas-gathering networks in the OLGA software have established.

In this article authors present an analysis of calculations and offer recommendations based on results of dynamic modeling of transport processes in the production system using OLGA software. Analysis of stability of flow in gas-gathering system has been performed for an abnormality in the piping due to the formation of hydraulic slugs. Problem areas were examined, and recommendations for elimination of the negative phenomena thus regimes of transport products have been excluded in which the violation of a stable flow regime in the pipeline will be observed. The reasons of wells self-killing were investigated.
Environmental Monitoring of Arctic Waters with Unmanned Bivalve Biosensor Technology: One Year of Background Data Acquisition in the Barents Sea
Authors: Massabuau Jean-Charles , Gudimov Alexander , Blanc Philippe
Published: October 2015

Adequate and efficient environmental monitoring is a key element of the environmental risk reduction process in the Oil & Gas industry, all the more where sensitive areas in harsh environmental conditions are at stake. This is the case in remote and extreme cold places such as the Arctic, where robust systems are required to withstand adverse climatic conditions and minimize intervention of man. Sharing clear and easily understandable information (as biological indicators) in total transparency with stakeholders, including local population, is an essential issue for both environmental and societal purposes. Working with public research organizations under the responsibility of governments is another key issue.

Within this scope, an innovative online biomonitoring technology, High Frequency Non Invasive Valvometry, based on the use of bivalves equipped with light electrodes has been successfully tested during one year in a bay located in the North-East of Murmansk (Barents Sea). This has been done through a joined project between CNRS, the French National Center for Scientific Research, MMBI, the Murmansk Marine Biological Institute in Russia, and TOTAL Exploration & Production. Groups of bivalves (Icelandic scallops and Blue mussels) were placed at 15-18m under sea level, with minute electromagnets glued to each of their valves to record opening and closing activity. A remote intelligent device composed of a waterproof case next to the animals and a card out of water (the whole thing is a low power, 1W, fully-rugged Linux-running microcomputer) was installed. The master unit where data are automatically handled is in Arcachon, France. The connection uses GPRS & internet. The data are publically monitored on MolluSCAN Eye website (google molluscan eye).

Daily acquisition of data during one year has demonstrated the ability of the technology to automatically rebuild easily understandable biological rhythms, growth rates and spawning activities of the bivalves. This includes activity during the harsh Arctic winter period. This technology opens the gate to "intelligent" monitoring of aquatic environments enabling sensitive and continuous assessment of harmfulness of industrial impacts, in particular for the Oil & Gas industry.
System Approach to Planning the Development of Multilayer Offshore Fields
Authors: Lubnin A. A. , Afanasiev I. S. , Yudin E. V. , Fedorchenko G. D. , Sansiev G. B. , Shchekin A. I.
Published: October 2015

This paper discusses a system approach to planning the development of multilayer offshore fields consisting of producing horizons with various types of reservoirs. The method is based on simultaneous analysis of seismic data, well logging and well testing results, field geophysical reservoir tests, well exploitation findings, and PVT analysis and detailed hydrodynamic field modeling. The model is developed consecutively and based on a "simple-to-complex" principle – from background data verification, application of the material balance method for estimating geological reserves and reservoir energy state, fault conductivity analysis, application of analytic and semianalytic methods for reservoir porosity and permeability calculations to development of a consistent hydrodynamic model as a basic tool for calculating various options of field development and selecting the optimal exploitation method with account for technical infrastructure limitations. As a result of works completed at an area of one of the biggest fields of the Socialist Republic of Vietnam, optimal positions for planned wells have been determined, a geological and technical action program has been developed, and a flooding pattern has been validated and arranged.
Digital and Automated Offset Well Analysis with Focus on the NCS
Authors: Mosesyan Mikhail A. , Surguchev Leonid M. , Mathisen Petter
Published: October 2015

The Norwegian Continental Shelf (NCS) consists of more than 6000 wells, where a great portion of the data is publicly available. In addition each and every operator holds its private data. When planning a new well, obtaining high quality reference data from comparable projects in the nearby area often becomes an issue of vital importance and part of the modern Well Delivery Process (WDP), named the offset analysis. Our work has been focusing on improving and on streamlining this part of the WDP.

Up until recently, offset well reference data analyses for wells drilled on NCS could only be performed by "manual" search in the Diskos or internal databases. With this work we attempted to bring to the fore how to increase efficiency by having all relevant data directly available to the end user. Combining different data formats, public and private, was the major challenge allowing quick and automated analyses. By developing a digital tool, the aim was to achieve significant savings in engineering man-hours not jeopardizing, but increasing an overall quality of the well delivery process. Additionally, the target was to measure how much time an engineer could save by skipping the manual part of the data gathering but rather using data that is logged and recorded during a standardized process.

Increased efficiency, cost reduction, proper contingency planning, and accurate consideration of uncertainties and project specific risks, not least the safety aspect, are among the key indicators of successful offset well analysis. The data has to be thoroughly calibrated and further analyzed to benefit the knowledge of the area, adjacent wells, equipment, casing desing and previous experiences. Previous data and experiences should first increase an overall understanding of upcoming project and secondly, fill the gaps in offset analysis. Having a system where all previous wells are quickly accessible and data as well as experiences saved and grouped by standardized formats, users' defined criteria will automatically allocate the most comparable and appropriate wells, thus not overseeing the most relevant data. Time is thus saved by eliminating manual search and the data quality is increased by incorporating quality check procedures.

Right decision making, given time constraints, cannot afford overseeing important information, thus data need to be quickly available, trustable and easily accessible for the user. By implementing automated quality check functionality, the data integrity is taken care of. By simultaneously gathering the data from several sources in one place, the user has improved access to all the information needed to make the right decision, the first time, and in a timely manner. With relevant and properly selected data, we can at last afford adequate analysis including stochastic modeling, thus finally approaching proper decision making with focus on uncertainty and randomness.
Real Options as a Tool for Arctic Offshore Fields Valuation and Project Management According IFRS 6
Authors: Pelmeneva A. A. , Talipova A. S.
Published: October 2015

Current processes of globalization and integration of the companies into the world economy necessitated the unification of financial reporting to the third parties and external users, its transparency and uniformity of financial calculations and calculation procedures.

International Financial Reporting Standards (IFRS) today play the role of a certain standard or an example of how international companies have to generate financial reports. This imposes certain obligations on the reporting procedure. Thus, on the one hand companies operate under strict rules of how and that they can be reported. On the other hand, oil and gas companies implement large risky projects, which feasibility evaluation is often difficult in the conditions of high risk and lack of the information. This situation is typical for offshore fields, particularly in the Arctic offshore, where the degree of exploration is extremely low.

The present article is concerned with the real options valuation of offshore fields in the Arctic. The main point of the article is an example of the subsequent correlation of the price value of the real options and possible costs for exploration and evaluation of the field resource potential in accordance with the principles of IFRS 6 – «Exploration for and Evaluation of Mineral Resources», an accounting standard that is core to the understanding of accounting in the mining and oil and gas industries. IFRS 6 includes modified impairment testing of exploration and evaluation assets and replaced several others international standards as IFRS 8, IFRS 16 and IFRS 36.

This approach allows us to demonstrate the applicabilityof ROV (Real Options Valuation) method and its application to offshore projects with a high degree of uncertainty, carried out at an early stage and, in particular, for the Arctic offshore projects. For illustrative purposes two possible deposits were taken on the shelf of the Barents Sea and the Kara Sea. For these two illustrative examples of the fields in the above sea waters in accordance with the climatic conditions, taking into account the current tax and investment regimes three types of option were designed: to stop the project, to delay the project and to expand the project.

The main purpose of this work is to show the applicability of various models of real options for offshore development projects through the examples in the Arctic seas at the stage of prospecting and exploration. There is also the objective to show how the techniques of project management can be agreed under the rules of reporting standards reporting for companies operating according to IFRS 6 standard.
Pilot Tests of New EOR Technologies for Heavy Oil Reservoirs
Authors: Altunina L. K. , Kuvshinov V. A. , Kuvshinov I. V. , Chertenkov M. V. , Ursegov S. O.
Published: October 2015

Thermal-steam stimulation (TSS) is considered as the most effective among all up-to-date methods for heavy oil production. However problem consists in lower coverage by steam injection and decreased TSS efficiency at later stage of the development. Paper presents the results of solving this problem by combining thermal-steam and physicochemical stimulations and using "cold" technologies involving thermotropic gel-forming and oil-displacing systems: gels increase reservoir coverage, whereas oil-displacing systems increase oil displacement.

In 2008-2013 172 wells were treated on the Permian-Carboniferous reservoir of high-viscosity oil in Usinsk oilfield using IPC SB RAS technologies. As a result the increase in oil production rate ranged of 3-24 ton/d per one well and incremental oil production amounted to 980 tons per one well treatment. It is promising to use integrated technologies alternating injection of steam, gel-forming and oil-displacing systems. They are commercially produced in Russia and China.

In 2014 to improve TSS efficiency pilot tests of new technologies were successfully carried out: using gelled system based on surfactants with controlled viscosity to increase simultaneously reservoir coverage and oil-displacement factor; using polymer gel-forming system – for selective water shutoff in production wells.

TSS is effective, but expensive method. It is promising to use "cold" technologies. To enhance oil recovery from high-viscosity reservoirs at 20-40 °С we propose to use gels and sols based on low temperature inorganic gel-forming system and oil-displacing alkaline and acid systems based on surfactants, inorganic buffer solution and polyol with controlled viscosity, from tens to hundreds mPa·s, and low freezing point, -20÷-60 °С. In 2014 pilot tests of new "cold" technologies were carried out in Usinsk oilfield. Alkaline system was injected into 5 and acid system into 10 low productivity production wells. After injections oil production rate increased by 5-15 ton/d, fluid flow rate increased by 15-25 m3/d. The technologies were recommended for commercial application.
Assessment of the Reservoir Monitoring System and Value of Real-Time Temperature and Pressure Profiles at a HASD Demonstration Project
Authors: Ficocelli Peter , Crecana Virgil , Legcevic Darko , Iordanescu Bogdan , Vincelette Andre , Hyland Connor
Published: October 2015

The Company is developing a heavy oil field in Romania with both in-situ combustion and steam stimulation methods. This paper describes the use of permanent fiber optics based array temperature sensing (ATS) technology in two (2) wells that utilize a horizontal alternating steam drive (HASD) process. The monitoring systems were installed in existing very shallow wells to capture temperature and pressure profiles for both the steam and production cycles of the HASD process and also provide some information about the combustion in-situ effects. During the cyclic steam stimulation (CSS) phase the reservoir's maximum temperature could reach up to 230°C. The steam is generated using mobile boilers which have been proven effective in minimizing steam loses. The ATS optical sensors are written in the core of the fiber and encapsulated within a 6.35 mm capillary using a six sigma qualified process. The ATS instrument string was deployed in the wells with a simplified capillary pump–in installation method and using proven and common well-services equipment. This slimline capillary deployment technique involves minimum wellbore intrusion to reduce deployment and retrieval risks. The wellhead located surface data acquisition and control system captures and stores the subsurface real-time temperature and pressure profiles and provides VPN access and updates to the Supervisory Control and Data Acquisition (SCADA) servers. Modbus over TCP/IP connectivity is used to gain real-time data from the PLC and for archiving the data at centralized location. The temperature and pressure data captured during the installation will be shown to validate the accuracy of the monitoring system and the thermal and pressure profiles of an HASD cycle. This data will be reviewed and analyzed with the emphasis on controlling the processes that have the greatest impact on optimizing production.
Results of Thermo-Hydrodynamic Modeling of Multiple Cyclic Steam Stimulations of Wells in the Permian-Carboniferous Reservoir of the Usinsk Field
Authors: Taraskin Evgenii , Ursegov Stanislav , Gerasimov Igor , Ruzin Leonid
Published: October 2015

The Permian-Carboniferous reservoir of the Usinsk field is one of the largest objects in the world with unconventional reserves of heavy oil. Despite the long history of the development of the reservoir (over 35 years), the cumulative oil recovery is less than 10.0 %. Difficulties in the development of the reservoir reserves due to non-Newtonian properties of the saturating oil with a viscosity of 700 mPa*s and a unique geological structure of a massive reservoir, which is represented by a 300 m carbonate strata of the Middle and Upper Carboniferous and Lower Permian age located at a depth of – 950 to −1500 m and underlained around the perimeter by the active aquifer. The prospects for increasing the oil production of the reservoir are associated with the introduction in the development with the help of innovative thermal technologies its poorly drilled edge area, in which almost one-third of all reservoir reserves is accomulated.

This article is devoted to a discussion of the results of thermo-hydrodynamic modeling performed on the sector models and aimed at selecting the most effective option of the further development of the edge area of the reservoir, for which it is advisable to consider the use of multiple cyclic treatments of wells with radial horizontal bores by dry superheated steam in combination with the central hot water flooding into injecting wells.
Evaluating Heterogeneity of Heavy Oil Viscosity According to NMR Core Analysis
Authors: Musin K. M. , Abdullin T. R. , Khisamov R. S.
Published: October 2015

The paper presents the results of laboratory nuclear magnetic resonance (NMR) studies of oil-saturated core samples of the Sheshminskian horizon of heavy oil fields in the Republic of Tatarstan. The analysis of the results showed that T2 spectra of oil recovered via centrifugation from the pre-heated core and oil remaining in the core are substantially different from each other. Magnetic relaxation rate of residual oil is much faster, and thus its viscosity is significantly higher than that of the recovered oil. The difference can be up to ten times. The spectrum of relaxation times T2 in the original oil-saturated core integrates information about all the fluid contained in the rock.

The results and findings underscore the ability of NMR logging tools to characterize the entire oil fluid in the rock in situ.
Stimulation of Unconventional Reservoirs using Graded Proppant Injection
Authors: Keshavarz A. , Badalyan A. , Johnson R. , Bedrikovetsky P.
Published: October 2015

A method is proposed for enhancing conductivity of micro-fractures and cleats around the hydraulically induced fractures in coal bed methane reservoirs. In this technique, placing ultra-fine proppant particles in natural fractures and cleats around hydraulically induced fractures at leak-off conditions keeps coal cleats open during water-gas production and, consequently, increases the efficiency of hydraulic fracturing treatment.

Experimental and mathematical studies for stimulation of natural cleat system around the main hydraulic fracture are conducted. In the experimental part, core flooding tests are performed to inject suspended particles inside natural fractures of a coal sample. By placing different particle sizes and calculating concentration of placed particles, an experimental coefficient for optimum proppant placement is evaluated. This coefficient corresponds to the maximum permeability achieved after proppant placement. In the mathematical modelling study, a laboratory-based mathematical model for graded proppant placement in naturally fractured rocks around a hydraulically induced fracture is proposed. Derivations of the model include exponential form of the pressure-permeability dependence and accounts for permeability variation in the non-stimulated zone. The explicit formulae are derived for well productivity index by including the experimentally found coefficient for optimum proppant placement.

Particle placement tests result in almost three times increase in coal permeability. The laboratory-based mathematical modelling as performed for the field conditions shows that the proposed method yields around 6-times increase in well productivity index.
Implementation of Low-Residue Polysaccharide Fracturing Fluid System Aids Flowback Recovery at Chicontepec Basin: Field Experiences on Sandstone Tight-Oil Wells
Authors: Castro-Vera Erick , Chuc Edgar A. , Gutierrez Leonardo , Sanchez Alan
Published: October 2015

Low-energy and compartmentalized reservoirs make flowback more difficult than in conventional reservoirs following massive fracturing treatments. Conventional guar-based fracturing fluid systems can cause additional skin damage to the fracture because of fluid residues. Low-residue polysaccharide-based fracturing fluid systems, compared to conventional systems, provide a smaller residue percentage according to laboratory tests, and this result agrees with flowback data from wells discussed in this paper. Costs in primary treatments associated with operational events, such as flowback time, can be considerable for well completion operations. Guar-based fracturing fluid systems were used at the beginning of this basin study. After analyzing flowback and early production data, it was decided to change to a low-residue polysaccharide-based fracturing fluid system and to maintain other variables constant, such as injection rate, proppant concentrations, and treatment schedules, to compare fluid performances, cost benefits, and post-stimulation production rates.

This paper summarizes results for 70+ fracture stages in 30 wells, with an average of 150,000 gal of clean volume per stage and 250,000 lbm of proppant. Guar-based fluid fracturing systems comprise 25% of this study with an average flowback time of 231 hours with 30% (at most) fluid recovery. On the contrary, 75% of the treatments used a low-residue polysaccharide-based system, which required an average of 110 hours of flowback time, while only 10% of the volume was recovered to deliver to production facilities because of the lack of water percentage.

Metal-crosslinked low-residue polysaccharide-based fluids are more sensitive to shear stress than borate-crosslinked conventional systems, and they can become unstable at high injection rates and reduced pipe diameters (3 1/2-in. tubing). Increasing tubing friction requires more hydraulic power to apply the same amount of net pressure at the fracture. According to the diameter restriction, this study includes pumping through pipes with diameters larger than 5 1/2-in., therefore making sensitivity to shear stress a nonissue.

Low residue polysaccharide-based fracturing systems represent an early production alternative for massive fracturing treatments because of their low residue percentage. These fracturing systems can be used in both conventional and unconventional plays, and represent a low associated cost for the well completion.
More with Less: Channel Fracturing Delivers Improved and Sustainable Production with Less Resources in Low-temperature Reservoirs of Tsarichanskoe Field
Authors: Sukovatiy Vladimir , Titov Ivan , Konopelko Alexey , Ovsyannikov Dmitry , Yudin Alexey , Borisenko Alexey , Gromovenko Alexander , Pshenov Konstantin
Published: October 2015

Tsarichanskoe is one of the largest oil fields in the Volga-Ural region of Russia with proven reserves oven 25 million tons of oil equivalent. An ambitious goal to produce up to 2 million tons over the next 5 years was set to achieve. The target formation to produce from is a Devonian reservoir also known as DKT. It is represented by alternation of sandstone, mudstone and siltstone and has challenging properties to deal with such as low permeability and low temperature (60–70C). Economic production from these reservoirs requires an effective stimulation. Conventional hydraulic fracturing in vertical and horizontal wells has been intensively utilized in the field with varying success since the beginning of its development. In some cases, wells completed with conventional fracturing underperform expectations and demonstrate rapid production decline. In other, complex geological conditions restrict treatment size with fracture conductivity being compromised. Therefore, the need exists for a novel stimulation technique capable to perform in the given environment and unlock the reservoir to its full potential.

Channel fracturing technique has been successfully deployed in Russia with more than 170 treatments pumped in different fields. The channel fracturing technique creates highly conductive open pathways within the proppant pack by combining specific pumping protocols with fluid and fiber technologies. It is aimed at maximizing fracture conductivity and establishes unrestricted flow of fluids from the reservoir to the wellbore through the network for channels formed by heterogeneous proppant placement. To ensure stability of the channels network, the use of appropriate degradable fiber materials is imperative. The fiber additive has to be chosen based upon specific reservoir temperature. Several treatments were pumped with unique low-temperature fiber among the first trials worldwide. Successful application of low-temperature fiber enabled channel fracturing technology for Tsarichanskoe. Field campaign was supported by extensive laboratory analysis of the fiber to prove its mechanical properties and required functionality for channel fracturing in low temperature reservoirs.

Initial production analysis indicates that application of channel fracturing in conjunction with the unique degradable fiber resulted in a sustainable oil rate increase up to 30% in comparison with conventional fracturing. The step change in production was achieved with noticeable reduction in proppant and water consumption by 40% and 15% respectively. Successful deployment of the channel fracturing in Tsarichanskoe field offers new opportunities for effective stimulation of low temperature formations in Russia.