bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Design Reduces Risks of a Siberian Development with Subsurface and Financial Uncertainties
Authors: Tipping David E. , Deimbacher Franz X. , Kovyazin Dmitry , Medvedev Alexey , Valencia Randy
Published: October 2008

We applied Experimental Design methodologies to evaluate development options in a Siberian field with major uncertainties in the geological, reservoir and financial parameters. Our approach, used for the first time in Russia, demonstrates an inverted 7-spot injection pattern is expected to yield 11% more oil than a line drive – identified by conventional evaluation methods. Of more significance, for decision making, the analysis predicts that the expected net present value (NPV) of this pattern is 46% more than the pattern proposed previously.

The primary reservoirs consist of stacked fluvial, delta distributary channel and mouth bar sands. Although exploration tests confirmed oil rates exceeding 120 tonne/day, the location and orientation of the individual sand bodies could not be mapped from existing seismic. Recognising this was a risk to project success, we developed an Experimental Design technique for quantifying the uncertainties in oil rate predictions. The major stages were:

Identification of the 20 geological and reservoir parameters that influence the simulation production forecasts. Examples include the dimensions of the sand bodies, residual oil saturation, facies distributions, amongst others. Determination which parameters have a major impact on oil rate predictions. In principle, this requires simulating all combinations of possible values for the 20 parameters. In practice, this is not realistic; hundreds of thousands of dynamic models would be needed. With the Plackett-Burman Experimental Design, we only needed 48 reservoir descriptions – each consistent with the available field data – to identify the 11 significant subsurface parameters. Creation of a second order polynomial equation that expressed the net present value (NPV) as a function of the 15 most significant reservoir and financial parameters. This equation, intended to reproduce the response of the dynamic simulator and the financial model, gave a probabilistic distribution of NPVs for each development pattern. For the 6 patterns under consideration, we created the equation with a Composite Face Centred Experimental Design technique. This required a total of 378 simulation cases. Results from these cases were obtained in 3 days with the use of parallel processing technology that allowed submitting multiple models simultaneously.

Our experience shows that Experimental Design techniques integrated with advanced computer technology can cut evaluation times from months to weeks. More importantly, they give unbiased probabilities of production profiles and NPV so that downside risks can be quantified.
Formation Testing and PVT Sampling in Low-Permeability, High-Pressure Gas Condensate Reservoirs by Example of Achimovskaya Formation of Urengoyskoe Field
Authors: Achourov Vladislav , Kaledin German I. , Kroell Erwin , Rymarenko Konstantin , Jennevin Christian
Published: October 2008

Formation and fluids evaluation of heterogeneous and over pressured retrograde gas condensate low-permeability but high-reserves potential reservoirs requires use of advanced formation evaluation techniques. The Achimovskaya formation of Urengoiskoe field is one of Russia's giant low-permeability gas condensate fields. The main objectives of the pilot phase of the exploration projects in the Achimovskaya formation are reducing reservoir and fluid uncertainties, confirmation of technical and commercial feasibilities, construction of a pilot gas processing plant (UKPG), and startup of a pilot gas and condensate production. The initial formation evaluation in the first two "Achimgaz" vertical wells included an extended formation logging suite followed by formation testing and downhole PVT sampling achieved using a wireline formation tester (WFT) that had a dual packer to test a large area of open hole. Formation testing and sampling objectives were: reservoir evaluation, formation pressure profiling, direct measurements of mobility (effective permeability), downhole PVT sampling for hydrocarbons confirmation, and full laboratory studies of formation fluids before the production phase of the field. Rig time constraints were one of the main issues for the extended formation evaluation program, defining logging and testing scope.

In addition to traditional downhole sampling methods like low-shock PVT sampling (which allowed taking gas samples above the dewpoint), new approaches for logging and testing techniques were applied for the first time in Russia during this job. These were the combination of inflatable straddled dual packer wireline formation tester with nuclear magnetic resonance (NMR) logging in a single logging string and the use of two downhole pumps, also in a single string. The quality of sampling was controlled by application of downhole fluid analysis techniques. Comprehensive pre-job planning, close cooperation with drilling and operating companies’ representatives, and real-time decision-making during data acquisition led to the successful completion of the operation.

This paper describes this first successful application of a dual-packer wireline formation tester to obtain PVT samples of retrograde gas in the Achimovskaya formation. As a result of the job, the presence of hydrocarbons was proved, formation pressure and mobility profiles were obtained along the tested sublayers of Achimovskaya formations, and high-quality PVT fluid samples were acquired. This provided valuable information for future testing, appraisal drilling, and field development planning. Furthermore, comparison between core permeability, formation testing fluid mobilities, and NMR permeabilities acquired in one of the exploration wells is also shown in the paper.
Facilitating Data Quality Improvement in the Oil and Gas Sector
Authors: Radhay Rene
Published: October 2008

Seamless workflows among and within functional groups, and the resulting quality of inputs used for decision making, are common areas of concern in the oil and gas industry today. Sales of information management applications and methodologies are based on this definition of quality, which refers to the usefulness and direct availability when needed of known or high-quality information. The reality, however, is that increasing pressure to reduce costs, the volume and dynamic nature of E&P workflows, and the difficulty in measuring return on investment in addressing data quality have led to the existence of "siloed" workflows, databases of substandard quality, and resulting decision-making inefficiencies. These inefficiencies are frequently accepted as the nature of the job, both because of the difficulty in measuring their impact, and the challenge of effectively measuring the return on vestment that would result from improvements. One solution to this situation is to apply technologies and methodologies that have been proven in other industries. This can help determine key performance indicators - from operation to executive levels - to enhance workflow and data quality, and can also facilitate fast cleanup and the trending of improvements and their impact on the bottom line and user perception. Modular technology also facilitates phased rollouts to minimize investment before value can be determined. Business Process Management and Six Sigma methodologies, proven in other industries, can help control cross-functional processes and the systematic reduction of defects to acceptable levels, opening the door to the establishment of industry-relevant quality benchmarks that can ultimately impact investor confidence in the oil and gas sector and within individual organizations.

Introduction

Personal as well corporate experience with oil and gas data has revealed that data quality is a huge problem at many oil and gas companies. Based on this realization, this project's goal was to combine proven and well known technologies and methodologies to create an information management framework that would facilitate measurable improvements in oil and gas data quality. A recent survey showed that 49 percent of oil and gas companies would perform information management differently if starting over from scratch - justifying the need for a fresh approach. It can been seen that technology and methodology well proven in other industries can greatly assist in the oil and gas domain in improving and controlling data quality.
Successful Cementing Case Study in Tuscaloosa HPHT Well
Authors: Ravi Kris , Vargo Richard , Lasley Barbara
Published: October 2008

The wells in the Tuscaloosa trend in South Louisiana are high-pressure high-temperature (HPHT) wells reaching as deep as ±23,000 ft, with a bottomhole static temperature (BHST) as high as ±400°F. In the past these wells were completed using conventional cementing techniques. In some cases, soon after the wells were put on production, the intermediate casing annulus would show an increase in pressure. Historically, this pressure is manageable and can be easily reduced through current procedures and practices. However, a project was undertaken to understand the underlying cause and then subsequently deploy a solution to prevent pressure on the annulus side.

The first task was to make sure that the annulus pressure was not caused by other problems such as wellbore stability, hole cleaning, and cement slurry placement. Then the next possible cause was damage to the cement sheath during subsequent well operations and production. A detailed study was done to investigate this possibility. Mechanical and thermal properties of the formation were derived from the log data and drilling data. Additionally, this data was evaluated to identify the depths and formations associated with significant gas shows at surface.

Possible failure mechanisms in the previous conventional cement sheath were identified. The cement system was modified to prevent such failure and the new cement system was designed and tested. The modified cement system was deployed in the field in April 2006, and the well was put on production a few months later, and since then has been on line and producing without annular pressure problems.

The techniques and solutions discussed in this paper can be applied to wells around the globe that have related problems. These solutions may help prevent annular pressure and improve the safety and economics of operating these wells.
Oil Recovery by Miscible SWAG Injection
Authors: Jamshidnezhad M.
Published: October 2008

Previous studies showed that injection of water and gas as water alternating gas (WAG) process or simultaneous water and gas (SWAG) process can improve the sweep efficiency. Therefore, oil recovery from depleted reservoirs can be enhanced by combined injection of water and gas. However, SWAG process compare to WAG process is less known. Investigation of factors that affect on miscible SWAG injection is the aim of this study. For this purpose, a three-dimensional finite-difference reservoir simulator is used. Methane (as gas) at minimum miscibility pressure (MMP) is injected into an under-saturated reservoir which contained typical North Sea oil. Water and gas are injected at fixed rates by two separate horizontal wells. For more sweep efficiency and increase the distance gas and water travel before segregation, gas is injected at the bottom of reservoirs. For water, different locations of injection are tested and the effect of water injection location is studied. We also investigate the effect of water to gas injection rate ratios, well models, and reservoir heterogeneity on sweep efficiency and oil recovery.
An Interpretation Method of Downhole Temperature and Pressure Data for Flow Profiles in Gas Wells
Authors: Achinivu Ochi I. , Li Zhuoyi , Zhu D. , Hill A. D.
Published: October 2008

Accurate and reliable downhole data acquisition has been made possible by advanced permanent monitoring systems such as downhole pressure and temperature gauges and fiber optic sensors. These downhole measurement instruments are increasingly incorporated as part of the intelligent completion in complex (highly slanted, horizontal, and multilateral) wells where they provide bottomhole temperature, pressure and sometimes volumetric flow rate along the wellbore. To fully realize the value of these intelligent completions, there is a need for a systematic data analysis process to improve our understanding of reservoir and production conditions using the acquired data and to make decisions for well performance optimization.

We have successfully developed a model to predict well flowing pressure and temperature (i.e. the forward model), and applied an inversion method to detect water and gas entry into wellbore using synthetic data generated by the forward model (i.e. the inversion model). It is concluded that temperature profiles could provide sufficient information to identify fluid entries, especially in gas wells. However, both the mathematical complexity and advanced well structure lead to challenges in model validation and application. In this paper, hypothetical examples based on previously published field example were used to explain how the interpretation model works. Some parameters used in the model are discussed. Practical guidelines on how to initialize the inversion process and achieve a quick conversion are presented. Judgments should be used based on the understanding of temperature and pressure behavior when initializing the forward model and this can increase efficiency of model application. The study results and guidelines developed in this study will help us to design permanent monitoring systems and set realistic expectation for predictive capability of intelligent well systems.
Field Development Optimization of Siberian Giant Oil Field under Uncertainties
Authors: Volz Richard , Burn Karam , Litvak Michael , Thakur Subhash , Skvortsov Sergey
Published: October 2008

The field development of a clastic reservoir in Siberia has been optimized. Uncertainties in geological description have been incorporated into the optimization process. A reservoir modeling study was undertaken to ascertain the impact of subsurface uncertainties on field production predictions and to evaluate a large range of field development options. Many exploratory wells have been drilled in this field covering a large areal extent. Pressure data from pressure buildup and well interference tests are available from these wells. BP's powerful Top Down Reservoir Modeling technology (TDRM™) has been used for assisted history matching. Multiple geological descriptions matching historical pressure data have been generated. The calibrated multiple reservoir models representing uncertainties in reservoir geology have been evaluated over a large range of field development options and for the definition of uncertainties in future production performance. BP's Top Down Depletion Planning technology (TDDP™) has been used for the optimization of well patterns, well spacing, well types (vertical versus high angle wells), lengths of high angle wells, order of well pad development, etc. The net present value (NPV) of the project has been maximized whilst meeting field development constraints. Thousands of potential field development options meeting field development constraints have been automatically evaluated. Multiple reservoir models have been run for every evaluated field development option to determine uncertainties in future production performance. As a result, an optimized field development option has been proposed with significant incremental net present value and oil recovery in the comparison with the current technical development scheme.
Feasibility Study of Combining Drilling with Casing and Expandable Casing
Authors: Shen Hendry , Aadnoy Bernt
Published: October 2008

Rig cost, service company rates and materials costs have gone up significantly in accordance to the oil price. Industry is therefore continuously searching for new technologies to make the drilling of wells safer, more efficient and economical. This paper will explore the possibilities of combining two existing technologies to meet these challenges.

Drilling with casing (DwC) uses standard casing as the drillstring and leaves it in place to case the well. It has a potential of saving of rig time by eliminating drillstring tripping and also minimizing downhole problems. With expandable technology, expanded casing can provide a larger diameter of the production casing. This can increase the well productivity.

Because both technologies have similar operational procedures, they could be combined into one operation. The new concept is to use expandable casing as a drillstring which will be expanded when the target depth is reached.

The conclusion of this analysis is that the drilling with expandable casing concept is possible. However, there are some technological challenges, especially on tools and on the strength of post expansion materials.

The examples analyzed, indicate that we can save 39% of the operation time by running this combined technology. Expenses can be reduced through lowered rig costs and the operational risk can be mitigated. A better understanding of the technology and operational procedures will help to further reduce the risks and make the technology even more acceptable. If this new method succeeds, there will be a high potential for cost savings, higher production rates and better well control.
Data Architecture of Real-Time Drilling and Completions Information at Saudi Aramco
Authors: Khudiri M. M. , Shehry M. A. , Curtis J. D.
Published: October 2008

This paper describes the current data architecture that Saudi Aramco has recently implemented for real-time drilling and completions (D&C) information. This new architecture enables us to make wider use of our monitoring and collaboration centers through a common approach. It also allows us to leverage the evolving WITSML standard more effectively in our drilling operations.

Saudi Aramco uses many different service organizations to deliver its global drilling and completions agenda. In the past, this has resulted in a lack of stability and standardization in real-time information flow. We have been unable to share data and expertise readily between different operating centers. Applying a common approach to information access on a global basis has enabled us to streamline our operations and make wider use of emerging analysis, monitoring and collaboration technologies.

Real-time technologies have been utilized to capture, monitor and analyze drilling data from rig sites so that critical decisions can be made real-time in order to help reduce and eliminate borehole problems, thus reducing non-productive time. That includes high-tech rigs, business continuity solutions for real-time information, collaboration tools and real-time data visualization systems.

Our aim has been to implement a standard D&C information architecture. Our adoption of WITSML was the vehicle which allowed this to happen. However, we still believe that over the next years it is likely that there will be much more of a challenge to support open connectivity between different vendors and services supporting the increasing drilling and completions functions.
Horizontal Wells - Their Application and Status in Russia
Authors: Gallivan J. D. , Gunningham T. W. , Holtslag R. J. , Kuramshin R. M. , Pepelyaev R. V.
Published: October 2008

Horizontal wells have a long history in Russia in many different producing basins. This paper relies on published sources to give the reader both general and detailed information about the applications, well types and performance which could be gleaned from published articles in Russian journals and books. A period of 60 years is covered, from 1947 to 2007, during which about 3000 horizontal wells have been drilled in Russia. The current rate of drilling is about 300 wells per annum. The paper looks at horizontal wells in four regions of Russia: Volga-Urals, Timan-Pechora, western Siberia and the Far East.

In the early days spectacular improvements in production were reported, in the range 10 to 20, compared with production from vertical wells. Lower improvement factors have been reported more recently in Tatarstan, in the range 1.3-1.6 in limestone formations and 1.5-3.5 in sandstone formations but in one case in western Siberia a factor 10+ improvement was seen. In heavy oil fields the rate improvement factors reported are 5-10. Underbalanced drilling has been tried successfully using oil-nitrogen mixture as drilling fluid. The improvement over horizontal wells drilled with conventional overbalance is 4 times.

It is proposed that an industry-wide data base be sponsored by the Ministry of Natural Resources so that operators could pool their data, establish a set of best practices and cooperate to optimize the performance of wells with horizontal well bores.

Techniques such as:

logging on coiled tubing, well testing with packers and downhole shutin, completions with downhole monitoring and control (smart well completions),

are used in Russia only by a small number of operators. Their benefit is in enabling the operator to check that the well is flowing over its full horizontal length and that the mechanical skin is close to zero. If not then drilling and completion practices need to be improved.
Improved Oil Recovery by Cyclic Injection and Production
Authors: Shchipanov A. A. , Surguchev L. M. , Jakobsen S. R.
Published: October 2008

Cyclic waterflooding is an IOR-method that improves oil production in heterogeneous reservoirs with high-permeability contrast. The concept of the method is based on pulsed injection and alternating of waterflood patterns. The main effect induced by the cycling of wells is oil production increase accompanied by water production decrease. The production increase is achieved by improved sweep efficiency in low permeable zones of a reservoir non swept by traditional waterflooding process. The cyclic water injection process was successfully applied in a number of sandstone and carbonate oil fields in Russia, USA and China. The important advantages of the method are virtually zero additional cost and simple implementation procedure. The uncertainty with the method is related to understanding the IOR mechanism, ability to accurately model the process and design a field application.

The paper presents the results of the study of cyclic water injection and oil production at a North Sea heterogeneous sandstone reservoir. The study consists of the field history analysis, pre-screening cyclic efficiency estimation and numerical reservoir simulation to design the field application of the IOR-method.

The field history analysis shows the presence of cycles in injection and production and their influence on water-cut change. Pre-screening analytical tool was used to perform a wide-range sensitivity analysis with respect to rock-fluid parameters, heterogeneity, cycle length and pressure conditions in order to understand the mechanism and to estimate the IOR potential. Finally the sector model reservoir simulation was used to optimize the cyclic process by alternating the waterflood patterns and to design the field application. The simulations show decrease of water production and improvement of oil production by up to 3% with short time and by 5% with long time cycles.
Water Shutoff Gels Improved Oil Recovery in Naturally Fractured Raman Heavy Oilfield
Authors: Demir M. , Topgüder N. N. , Yilmaz M. , Karakeçe Y. , Ince Y. , Karabakal U. , Gould J. H.
Published: October 2008

Raman field is a naturally fractured limestone reservoir located in southeastern Turkey. The field is a heavy oilfield with 18° API gravity oil and has strong aquifer pressure support. There are about 140 producers and daily oil production is about 6,000 bbl/d. However, average water cut has exceeded 90% in recent years because of the fractures communicating between the aquifer and the oil zone, which required some remedial treatment such as polymer gels to reduce the WOR. As it is well known, gel treatments have become a more convenient method as they can penetrate deep into the reservoir without a complete shutoff.

As a pilot application, deep penetrating gels were used in seven wells. Wells with different behavior were selected as candidates on purpose, in order to see the effect of gel treatments on reducing WOR. The main purpose of the treatments was to increase oil recovery, with water shutoff was considered as a secondary benefit.

Treatments were performed in September 2007. Very favorable results have been seen in the eight months following the treatments. Although gross production rates were generally reduced to get the most benefit from the gel treatments, still, pretreatment oil rates from 0-14 bbl/d were increased to 6-91 bbl/d along with average water cut decrease from 97% to 80%, and even up to 40% in one well. These successful results will also provide the necessary clues for improving the design and field application of gel treatments which are to be extended on a field wide basis in the near future.
Performance Evaluation Of Non-Conventional Wells In Hassi-Messaoud Field, Algeria
Authors: Youcef Boughaba , Kamel Belkhiar
Published: October 2008

Recent developments in drilling field technology allow drilling advanced wells in Algeria oil field. In the past fourteen years several horizontal and multilateral wells have been drilled in Hassi-Messaoud field. In the other hand, the interest in re-entry of existing wells keeps growing. The first goal of such wells is to improve the primary production through increasing the reservoir exposure and accelerating the recovery.

The most important aspects to consider regarding the application of non-conventional wells are the potential cost benefits and potential risks in utilizing the technology. Difficulties exist in predicting the performance of these wells arrangements. Many of the performance prediction difficulties are being addressed through different projects.

Also, these wells can provide means to produce more oil at an economic cost. Applications to actual field cases are provided to illustrate the potential of horizontal and multilateral wells and of their synergy with EOR methods.

This study presents the simulation and the assessment of non-conventional wells in Hassi-Messaoud field, and discusses the factors affecting the productivity of such wells, it confirms the production regime of the reservoir with recovery of 60% by water injection, and illustrates the effectiveness of multi-lateral wells in anisotropic formations, also drilling and production performances for re-entries, short radii and long radii are evaluated. The success in oil rate using long radii can each 93.8% better than re-entries with 80.4% where Long radii wells exhibit a much better behavior than re-entries

In addition, Borehole stability represents a real issue in HMD where the instability may slow down the drilling progress, reduce well rate, and in the worst case it may cause the loss of the whole well, therefore planning non conventional wells should take into account this aspect in addition to reservoir heterogeneity.
Prediction of Oil-and-Gas Bearing Capacity of Low-Permeability Reservoirs within Lower Cretaceous Clinoform Sedimentary Formations in Kondinsky-Priobsky Oil-and-Gas Area
Authors: Kruchkova T. V. , Igoshkin V. P. , Kuklin A. V. , Davitashvili G. I.
Published: October 2008

The article addresses a large area (a territory 100 km long and 80 km wide) encompassing several oil fields, including South Priobskoye, Chaprovskoye, Kondinskoye, Malokondinskoye, North Kondinskoye and West Kondinskoye. The breakdown of this huge and actually a single oil-and-gas bearing zone consisting of a series of sand lenses and containing 1.5 bln tons of recoverable reserves is rather tentative. The authors of this paper have been working in this area and participated in exploration, investigation and development of numerous fields within the Priobsky-Kondinsky zone. Due to complex geology of clinoform formations, low flow properties of the rocks, wide spacing of exploratory wells and seismic surveys, a number of fields situated in the southern part of the Frolovsky depression were brought into production 15 to 20 years later than expected. A significant engineering breakthrough in oil production occurred due to implementation of massive reservoir fracturing treatments and integrated approach to 3D seismic interpretation. These are the technologies that allowed successful development of low-permeability clinoform productive reservoirs within AS9-AS12 formations in all the fields discovered in this area. As of today, a great amount of 3D seismic surveys were shot in many license areas totaling over 3000 sq km. Production drilling and oil production in actually all the fields within the Priobsky-Kondinsky area involve massive frac jobs. Integrated interpretation of 3D seismic led to surprising results indicating the most complex geology of the Neocomian clinoform reservoirs including both tectonic processes associated with sediment slides, and formation of fans within turbide flows. Thorough insight into spatial position and forecasting of flow and storage properties of each sand body allows efficient drilling and development of low-permeability oil saturated reservoirs in the Priobsky-Kondinsky area.
The Use of Ejectors Pulsating at a Late Stage of Developing the Gas Fields
Authors: Slobodkina Francheska , Kadet Valery , Evtjukhin Andrey
Published: October 2008

The eject devices have been known for a long time and are broadly used in various fields of technology for increasing the waste of low-pressure gas be way of mixing it with the steady flow of the high-pressure gas.

The ejectors as jet pumps are successfully used in the chemical, oil and gas industry, in the aero cosmic industry as well as in the technology of electrical stations. The simple design and high reliability of fluid ejectors allows them to meet various demands. Their production cost is minimal; they don't have rotating details and are therefore quite durable. They work without leakage; they don't need the technical testing and therefore have a high production safety. When the active gas has enough pressure the exploitation cost is not high.

In the oil and gas industry when a field is being developed the lowering of the debit of the boreholes is quite a negative phenomenon, especially at the final stage of the exploitation. This happens because of the fall of the layers pressure and the increasing of the water debit, which can bring about the self-stopping of the скважины To avoid these negative things one should switch on the low-pressure скважины into the common gas storing network with the help of an ejector, in which the pressure of the low-pressure gas is increasing at the expense of the energy of a small waste of gas of the high pressure wells.

This allowed to get a considerable additional amount of gas for the already stopped скважины at the Urengoi field. If you switch the ejector devices at earlier stages of the development of the fields the effect of its use can be much more considerable.
Van-Yogan Field: Evaluation of the Optimal Development Strategy for a Thin Viscous Oil Rim with a Large Gas Cap
Authors: Shaykhutdinov Ildar , Galimordanov Vadim , Bardin Valeriy
Published: October 2008

This paper is devoted to the issues related to the strategy of development of an oil-and-gas accumulation of Cenomanian age. Vanyogan field is taken as an example (West Siberia).

Results of the conducted well tests and pilot work to develop a thin and highly-viscous oil rim in PK1-2 reservoirs at Vanyogan field demonstrate that it is impossible to develop this oil accumulation without its separation from the gas cap. Gas breaks through immediately from the gas cap to the producing wells.

One of the possible ways to develop this oil rim is barrier waterflooding.

The system of development via the barrier waterflooding (water injection into the gas-oil contact) may enable conditions preventing gas coning movement towards producing wells. However, to create the water barrier will require significant overcompensation (200-250 %).

Controlled gas production from the gas cap is a possible way to produce oil reserves at immovable GOC (gas-oil contact) and lower voidage replacement ratio. Decrease in initial oil-and-gas reserves ratio by a quarter, may provide lower level of compensation (about 150%) required for barrier forming.

Based on the projected system of development (barrier waterflooding) it is possible to use thermal methods by injecting hot water into a reservoir.

Analysis of simulation results manifests a significant loss of heat during the process of barrier forming due to dominating filtration of the working agent into a gas saturated part of the reservoir that is an evidence of low efficiency of the thermal stimulation.

Results of the steam injection lab studies (fresh water) demonstrate significant swelling of clay in the rock, multiple reduction of permeability and thus impossibility of using these methods in practice.

The optimal way to retain rheological properties of oil is to inject water heated up to the reservoir temperature.

The pilot program is underway to test the barrier waterflooding at the field and assess the efficiency of the thermal method on the representative areas of the accumulation.

Implementation of the program will enable to evaluate technological efficiency of the barrier waterflooding in combination with the thermal stimulation and prepare the object for the commercial development.
Hydrochloric Acid Fracturing Combined with Water Shut-Off
Authors: Magadova L. A. , Silin M. A. , Gubanov V. B. , Marinenko V. N. , Magadov V. R , Gubkin I. M. , Demianenko N. A.
Published: October 2008

Institute of oilfield chemistry under Russian State University of oil and gas named after I.M. Gubkin in cooperation with BelNIPIneft, RUE «Production Association «Belorusneft» have developed the technology of formation hydrochloric acid hydraulic fracturing combined with water shut-off in producing wells, exposing carbonate reservoirs.

It is known that during interaction of hydrochloric acid solutions and oil, containing big quantity of tars and asphaltenes sludging and formation of emulsions colmataging porous space of reservoir take place.

In our work we have used the ability of generating such compounds when hydrochloric acid contacts hydrocarbon gel, composed using gelling complex "Khimeco-H" based on ferric salts of organic orthophosphoric ethers and stock (commercial) oil.

Hydrocarbon gels based on ferric salts of organic orthophosphoric ethers are obtained by dissoluting in hydrocarbon fluids gelling agent (mixture of alkylphosphoric ethers, mainly diakylphosphoric ethers) and activator based on ferrous compounds. As a result of interaction between gelling agent and activator we ontain ferric salts of organic orthophosphoric ethers which in their turn create associated complexes of molecular weight in hydrocarbons.
Principle of Iteration Composition of Sector Models for Full Field Reservoir Simulation
Authors: Kostuchenko S. V. , Bordzilovsky A. S.
Published: October 2008

The full field simulation of large reservoirs with number of cells more than 107 using majority of modem hydrodynamic simulators is hampered or even impossible. However, often such problem is topical.

For full field simulation of large reservoirs the authors offer decomposition of large models into a population of simple sector models. In each sector model conditionally independent simulation problems are formulated and solved. The consistency of an initial model is provided with matching of pressure fields and fluid flows on the boundaries of adjacent sector models for each time step of simulation. Authors offer to perform such conjugation by executing on special iterative algorithm realized in the form of the software.

The principle of iterative conjugation of sector models can be realized practically for anyone modern hydrodynamic simulator. This provides the new unique possibilities for simulation of large reservoirs, simulation on initial geological grids (without upscaling), paralleling and acceleration of simulation, usage different simulators for each sector model.
Study of Processes of Water Injection in a Reservoir on fall of Curves Pressure
Authors: Karnauhov Mihail L. , Piankova Elena M. , Gaponova Larisa M.
Published: October 2008

Field control and regulate of water flooding during field development essentially determine effectivity of oil production. The process of moving water front into reservoir may be recognized by analyzing fall off pressure curves (CFP) in the wells stopped after durable injecting or by registrating reaction of production wells on changing the regim of injecting during waterflooding, or due fixsate the time appearing injected water in the production wells.

Recodring CFP after shut in an injector well and analyzing the results may be used for determine parameters of formation as nearby of injector well, so in far zones directed from this well.

In the last years there are appeared many publications deal with process of water flooding where pointed out that there may be hydraulic fracturing of formation in nearby of injector. There are different opinions on this process: one consider that fractures are created like hydraulic fracturing made for intensification of production wells with creating only one fracture, having two wins; another consider that after during long time pumping with high pressure there may be created many fractures and than appeared high pearmeability zone near wellbore. But obvious, that both variants deal with improve rate of pumping in injector wells.

It well known and third opinion, that during pumping water in the injector well there may be created some fractures with complex configurations, which propogated from injector to production well. It like to electric discharge between two points with different charge. It's usually one argumented for one or another sheme of hydraulic fracturing with analyzing date of CFD. The CFD had interpretated made like interpretation CPD (S-type form pressure build-up curves). But any concrete configuration of CFD may be considered by different authors as one, second or third process.

The main task of this paper is studding process of injecting water in the wells for different variants intensifications wells, studding process of moving the front of water in the formation and determine the time when water reaches the production well, studding process of moving fluids (water with oil) in water flooding zone.

The analysis based on solutions of diffusion equation for a radial flow of filtration in the finite difference shape. There were simulated situations with pumping water in the well and than closed well for registration CFP and fixing transient process.

The configurations of curves (CFP), received with simulation, like the selected model of filtration. The analysis of real CFP, received in oilfield conditions, demonstrated that most of practical curves like on theoretical curves for reservoir with high permeabylity near wellbore zone (fractured zone). After durable pumping that zone may increasing it's space (more than 100 meters). We developed method of calculate characteristics of zones, surrounded of injector well. Some different oilfield examples considered in this paper.
Gas Utilizing Methods –A New Technology of Oil Recovery Factor Improvement
Authors: Karpov V. B. , Kokorev V. I.
Published: October 2008

Today, there is a clear tendency towards structure and quality deterioration of reserves. One of the reasons lies in low initial oil saturation (about 0.45-0.55 for the regions of Western Siberia). Average residual oil saturation is equal to some 0.3 (in this case displacement efficiency – 0.4). With displacement efficiency being that low, final oil recovery factor will be just over 25% even if the reservoir sweep factor can be increased to about 70%.

In the mid-XX century the method of oil field development using gas injection which theoretically allows 100% displacement was developed.

The paper discusses two technologies for implementation of gas methods used in oil field development. – alternating gas-water injection (AGWI) and water-gas stimulation (WGS) in which combined injection of displacement agents (gas and water) is used. It describes the principle of operation and features of special equipment developed on the basis of a multi-purpose booster compressor unit operating under the principle of a single-stage "compressor with hydraulic seal".

The paper presents procedures for realization of AGWI & WGS, as well as practical developments allowing to prevent typical problems which occur in the process of field equipment operation when pumping high pressure gas.

Actual results of WGS introduction in one of the JSC "RITEK" fields are presented and technological benefits of the process are assessed using 3D geologic-hydrodynamical simulation data.
Creation of technical/technological complex for bottom-hole monofuel solution based gas vapor stimulation for production of viscous and highly viscous oils
Authors: Kokorev V.I. , Maksutov R.A. , Orlov G.I. , Osipov A.V.
Published: October 2008

Progressing development of viscous and highly viscous oil (VHO) deposits is becoming an issue of the day with the recovery of light oils.

Key feature of geological and physical properties of viscous and highly viscous oil is high flow reservoir resistance, which makes it difficult to employ traditional oil recovery method - hydrodynamical oil replacement.

Traditional development methods for VHO reservoirs are thermal methods, primary, steam injection.

The use of the above methods makes it possible to solve the most complicated development problem of these deposits, i.e. most of low-permeable reservoirs development using heating, thermal expansion of reservoir fluids and capillary inhibition.

At present the main source of thermal energy in the reservoir is known to be surface steam generation units. Transfer of thermal energy from the surface is associated with partial heat losses in land communications, mainly, in the well. This fact is one of the principal reasons which empede the use of steam injection into formations occurring in the depths of over 700m. Meanwhile, the analysis of VHO reserves located in the RF territory shows that major VHO reserves (86.1%) occur in the depths ranging 1000–1500 m (Fig.1)
Permanent Magnet Synchronous Motor (PMSM) – New Type of Drives for Submersible Oil Pumps
Authors: Pavlenko V.
Published: October 2008

Although the design and manufacturing technology of submersible rotary pump units (SRPU) are constantly improving, for the last few years no fundamental technological solutions for the drives of these units have been offered. Efficiency of submersible asynchronous electric motors which conditions both energy consumption and service life has virtually never been changed within many years. Today, it has become obvious that opportunities of further efficiency increase for standard electric motors of PED type (submersible) are virtually exhausted. During operation of SRPU in specific modes the resource of PED and the unit as a whole significantly decreases.
Peculiarities of Water Flooding the Naturally Fractured Reservoir
Authors: Volgin E. , Katz R. , Andriasov A.
Published: October 2008

Fractured oil reservoirs are divided into four groups. Type I reservoirs have little matrix porosity and permeability. Fractures provide both storage capacity and fluid-flow pathways. Type II reservoirs have low matrix porosity and permeability. Matrix provides some storage capacity and fractures provide the fluid-flow pathways. Type III (microporous) reservoirs have high matrix porosity and low matrix permeability. Matrix provides the storage capacity and fractures provide the fluid-flow pathways. Type IV (macroporous) reservoirs have high matrix porosity and permeability. Matrix provides both storage capacity and fluid-flow pathways, while fractures merely enhance permeability.

The Lower Silurian reservoir of the East Rogozin oilfield represents with naturally fractured, presumably oil wet, carbonate collector. The East Rogozin reservoir belong to Type III.

In order to study filtration in this reservoir, six numerical experiments were conducted on elements of development. There was studied pressure behavior in matrix and fracture network, examined a question about forecasting new well productivity, opprtunities on developing areas with sparse fracture system. Special attension is paid to the problem of waterflooding.
Construction Method of Horizontal Steam-Injection and Producing Oil Wells on the Test Sections OPU-4 and OPU-5 Yarega Heavy Oil Deposit
Authors: Denis Loparev
Published: October 2008

Report content:

Yarega deposit geological characteristic Special features of mine and surfacial heavy oil production Principal features of SAGD technology Performance specification for Yarega project development Drilling rig requirements Engineering calculations and technical decisions Drilling results Conclusions

Yarega deposit geological characteristic

Yarega deposit is situated in the south part of Timano-Pechora province in Ukhta region Komi Republik.

Oil-titanium deposit lies 200 m beneath the surface in upper and middle Devonian sandstones. This sandstone contains anomalous heavy oil.

Deposit involves 3 structures: Yaregskaya, Lyaelskaya, Vezgavozgskaya.

From 1939 Yarega deposit is in commercial development, heat-mining technology has been using since 1972.

Shallow depth occurrence (≈200m) and high density and viscosity of reservoir fluid is a special feature of Yarega deposit.

Reservoirs are low permeable with different grains, well clean-gap-graded, low clay, fine grained sandstones. Also fine grained sandstones with siltstone and clay.

Yarega oil is heavy, high viscosity, sulphide, with dry gas. Average density in bed conditions is 933 kg/m3, viscosity – 15300 mP x s (reservoir pressure 0,8 MPa, t=8 °C).
Enhancement of Underbalanced Drilling-in Technology Efficiency
Authors: Agzamov F. A. , Dijashev R. N. , Krysin N. J.
Published: October 2008

Drilling-in producing formations at negative pressure in borehole-formation system is one of the most perspective technologies, increasing efficiency of drilling. However effectiveness of operations frequently happens below expected. The purpose of work is to establish the reasons of this condition and development of recommendations on their removal. Technological process analysis of opening-up carbonaceous reservoirs with depression on the basis of actual materials on 66 wells has shown, that one of the reasons of producing possibilities reduction of wells is improper object selection for application of the given technology.

Other factors which can lead to efficiency reduction of drilling technology with depression are shown. One of them is formation mudding by fine-dispersed cuttings, which completely did not separate from a solution in mobile separator. Calculations and following field observations shown that cuttings particles remain in aerated oil weighted and do not remove from drilling mud while opening productive stratum process. Difficult particles precipitation from oil assisted highly viscous emulsion constitution from gas and water, dispersed in oils, and strengthen water-gas-oil emulsion by formation «armours» from fine-dyspersate cuttings at surfaces of water or gas particles.

Offers on configuration of drilling equipment and technology of open-up producer for formation mudding prevention are formulated and experimental works on wells are executed.