bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship Between the Hydraulic Fracture and Observed Microseismicity in the Bossier Sands, Texas
Authors: Guest A. , Settari A.
Published: February 2011

In the past years, an increased effort was directed to improving our understanding of hydrofracturing by microseismic monitoring and analysis. We are developing a numerical method that would predict microseismicity occurring during hydrofracturing and the influence of fracturing on the permeability of the reservoir. The core of our technique is a representative pre-fractured volume of the reservoir that deforms locally and allows for the coalescence of deformation as the stress reequilibrates. Such an approach allows not only for implementation of the geological and seismic information on the scale of the representative volume but also to follow the deformation at the scale of the complete hydrofracture. We apply this technique to the hydrofracturing of the Bossier sandstone. The main goal is to predict observed microseismicity and permeability changes of the reservoir based on the modeled strains. The results show that the distribution of microseismicity is dependent on the regional stress state and the heterogeneity of the stimulated domain. If the permeability is calculated from the strains developing in the reservoir during the treatment, permeability will increase mostly in the areas of active fracturing. The next step is to fully couple the poroelasticity and the geomechanical response and to fit the model to the engineering parameters during the treatment.
Evolving Recovery Technologies Directed Towards Commercial Development of the Grosmont Carbonate Reservoirs
Authors: Yuan J-Y. , Jiang Q. , Russel-Houston J. , Thornton B. , Putnam P.
Published: February 2011

Starting in the 1970s, Union Oil Company of Canada (Unocal), in partnership with Canadian Superior and the Alberta Government, conducted a series of exploratory field tests in the bitumen-saturated carbonate rocks of the Grosmont Formation. These tests applied thermal recovery technologies, including steam drive and cyclic steam stimulation (CSS), that were in their early stages of development. Significant amounts of production and observational data were obtained. Although some results were encouraging, activities in Grosmont were eventually stalled in the mid 1980s as economic attention was shifted to Cold Lake and Athabasca Cretaceous siliclastic reservoirs. Since then, in situ bitumen recovery, 3D seismic, horizontal well and surface processing technologies have matured significantly. In light of the enormous resources (406 billion barrels) hosted within the Grosmont Formation, it is pertinent to ask whether those new technologies are applicable for carbonate reservoir development.

To answer this question, we studied data from the Unocal pilots conducted in the Grosmont C and augmented it with recent laboratory tests on newly acquired Grosmont C cores. The previous pilot CSS results were encouraging, with the cycle steam-to oil ratio as low as 3.65 and a peak rate of 440 bbls/d from a single vertical well. With subsequent cycles the ratio of the produced fluid to the injected fluid increased, signifying the injected energy was retained and more effective in later cycles. The operation strategy of the Unocal pilots and its implementation were not optimal and we believe that this could be improved with modern techniques.

Based on our new understanding of the Grosmont Formation and specifically the Grosmont C, a numerical model was created and verified with production data. Model results indicate that the application of SAGD will be a commercially viable recovery process for Grosmont carbonate reservoirs and that low pressure injection (below 3500kPa) would be desirable. The laboratory tests not only support these conclusions but also suggest that performance of the applicable thermal processes can be enhanced with the addition of solvent. A SAGD/solvent pilot test is planned to start up in late 2010. This pilot will be critical to the development of exploitation strategies applicable to Grosmont carbonate bitumen resources.
Characterization of Production Commingled From Deep Basin Plays, Wild River Region of Western Alberta
Authors: Dixon R. K. , Flint D. W.
Published: February 2011

Previous study of unconventional tight gas plays in the Deep Basin area of the Western Canadian Sedimentary Basin identified a rapidly increasing volume of production and EUR developed in wells where production is commingled from multiple reservoirs in stacked plays. Historically, most Deep Basin wells were drilled for a primary target play – a single play strategy – and completed producing from a single play. However from 2007 to 2008, over 40% of the EUR connected in all Deep Basin plays was from multiplay producers. Extensive commingling to maximize the recovery per well and reductions in segregation and testing costs should improve well economics and increase total recovery. However, commingling multiple plays often obscures information important for resource characterization by play, such as: EUR per zone, individual zone productivity, producing success by play and well spacing by play.

Commingling is especially common in the Wild River region of the Deep Basin area, where up to eight potential plays may be stacked for completion. This paper will discuss the characteristics and distribution of commingled wells in the Wild River region. What is the impact of these multi-play wells in terms of activity, EUR connected and supply compared to single play wells? Where are the commingled play wells located? Which plays are targeted in terms of zones penetrated? Which plays are completed most frequently in these commingled wells? Is recovery per well improving with experience? Does recovery improve as more plays are completed? What is the overall success rate in this area? What is the density per section of Deep Basin producing wells? How do strategies and results vary by operator?

Based on the results observed in the Wild River region, the implications for resource estimates and development in other areas of the Deep Basin will be discussed.
The Tradeoff Between Surfactant Costs and Water Heating to Enhance Friction Reducer Performance
Authors: DeMong K. , Sherman D. , Affleck B.
Published: February 2011

In slick water fracture stimulations the standard treatment utilizes water with very few chemicals. In the Horn River Basin during the winter months the water from surface sources can be very cold. Besides the obvious problem of freezing, the low temperature of the frac source water causes serious problems with the effectiveness of friction reducers by increasing the inversion time (the time to maximum friction reduction). In low temperature, high rate conditions the maximum friction reduction may not be reached as the fluid may have travelled a considerable distance through surface equipment, and even down the casing, without the friction reducer being fully effective. This condition can increase pumping pressure, horsepower charges and surface equipment failures. It can also affect the ability to get to design rates for the frac resulting in undesirable conditions such as extending the time to get to rate, being unable to start sand scours or pressuring out early on in the frac treatment.

To solve the problem there have been two key solutions employed: either the water can be heated to a temperature where friction reducer inversion time is reduced and therefore is more effective, or more friction reducer is added to the cold frac source water until the friction pressure is manageable. On a multiple frac campaign in the Horn River these two methods were tested against a novel chemical that increased the effectiveness of the friction reducer in cold water. The presentation will include the field test data and a cost analysis of implementing this on a job by job basis. In addition, the foaming and flow back characteristics of this chemical were tested at near in situ conditions to determine the potential for unplanned consequences.

In addition, the technique is being considered for use in a system where the primary fluid is warm (~ 25°C) brackish produced water but the auxiliary fluid supply may be fresh cold water. The objective is to show the cost and benefit of the chemical solution compared to heating or increasing friction reducer loading. Field testing was required to determine if the chemical solution could be applied more cost-effectively then inline heating of the cold frac water supply at full frac rate. Field testing was also conducted to determine if cold frac source water could be efficiently friction reduced with no external heating using only friction reducer, or a combination of a friction reducer and a novel chemical to reduce inversion time.
Prospects of Use of the Ecological Equipment for Clearing of Water Objects of Oil
Authors: Vorobiev D. S.
Published: February 2011

The theme of protection of water objects always was and will be вы со ко пр ио ри те тн ой. At federal level it is expressed in one of last documents - Water strategy of the Russian Federation to 2020 [1]. With a view of water improvement of quality in water objects, restoration of water ecosystems and recreational potential of water objects the decision of the basic “problem” problems is required: –Reduction of anthropogenous influence on water objects and their water modular territories;–Prevention of degradation of the small rivers;–Protection and prevention of pollution of underground water objects.

For restoration and protection, and also as prime actions anthropogenous influence dispersed (ди фф уз но го) a drain is necessary to reduce arrangements of the small rivers, to restore self-clearing ability of the rivers, to realize a complex of actions for ecological rehabilitation of the small rivers in cities and rural settlements. One of strategic targets is allocated: «protection and restoration of water objects to a condition providing ecologically favorable living conditions of the population, assume the decision of some problems on decrease in anthropogenous loading on water objects, protection of underground waters from pollution, rehabilitation of water objects and liquidation of the saved up ecological harm [1].

Strategy provides realization of the actions directed on restoration of water objects and liquidation of the saved up ecological damage.
The Integrated Approach to the Prediction of Water Shut-Off Jobs Effectiveness
Authors: Strizhnev .  A. , Ilyasov .  M. , Lomakina .  Y. , Kornilov .  V.
Published: February 2011

This paper presents an integrated approach to the optimization of properties and volumes of chemicals by the example of water shut-off work-overs in vertical and deviated producing wells completed in sandstone reservoirs. It includes laboratory testing of water shut-off chemicals and mathematical modeling of its injection into the layered reservoirs. Testing the chemicals is necessary to optimize the selection of materials that suit best to the current reservoir conditions, numerical experiments on the presented model allows evaluating the technological and economical effect from the treatment.
Mathematic Models for Interpretation of Temperature Changes in ESP Wells
Authors: Valiullin . A. , Ramazanov . Sh. , Fedotov . Ya.
Published: February 2011

Temperature transient analysis of oil and gas fields in Russia has long history. The paper is dedicated to application of temperature transient analysis for monitoring ESP wells. Currently several technologies of monitoring ESP wells are used on practice: ✓analysis of residual temperature distributions in wellbore after pumping equipment is pulled-out✓measurement along the wellbore in the formation intervals during moving of cable equipment, lowered by pump✓logging through tubing above the pump✓measurements with permanently installed sensors below ESP.

The analytical and numerical models of temperature transient analysis in the wellbore taking into account convective heat transfer, heat generation in the pump and electric motor, counter flow in annular space and thermo-hydrodynamic effects in reservoir are described. In particular the possibility of gas-liquid contact and oil-water contact determination in annular space based on temperature logging through tubing is shown. Obtained results are of the interest as for production monitoring as well as for the control and management of pump-lifting equipment operations.

This paper presents the case studies of temperature logging conducted in ESP wells of oilfields of Russia.
Sidetrack and Well Deepening Operations in the Jurassic Formation of Vyngapur Oil Field
Authors: Pavel Kolba , Mikhail Klimov
Published: February 2011

One of the methods of extraction of remaining reserves used in JSC “Gazpromneft-Noyabrskneftegaz” is sidetrack operations which also enable to involve fishing well stock of oil fields. Efficiency of these arrangements depends mainly on cooperation of specialists in geology, field development and drilling. At present, interaction pattern between subdivisions of the Company and contractor drilling organizations is developed which allows to perform full cycle of implementation of sidetracks starting with selection of wells and finishing geological support of drilling operations. Permanent field development monitoring of perspective oil deposits, application of the developed well selection technique and analysis of geological features using state- of-the-art program packages of seismic interpretation, geological and simulation modeling packages encouraged successful drilling jobs in the selected wells, getting agreement of actual flow rates and forecast and, as a result, increase of incremental oil production of the Company.
Findings of Experimental and Field Research into Oil Displacement by Means of Finely Dispersed Water-Gas Mixtured (FDWGM)
Authors: Savitski N.V.
Published: February 2011

Application of gas as oil displacement agent is constrained not only due to the paucity of gas resources, but due to high cost of site buildup, adverse effect of gas breakthrough on producing well behavior, and as consequence, relatively poor efficiency of the process.
A New Approach in Modeling Hydraulic Fractures and Auto Fractures at Injectors in Full-field Models
Authors: Bogachev K. Yu. , Shelkov V. G.
Published: February 2011

Realistic simulations of full-field models including hydraulic fractures made at producing and injecting wells, and fractures created automatically, when the bottom hole pressure at injectors exceeds the overburden pressure remains problematic in the most commercial hydrodynamic simulators. The existing software can either provide a very detailed fracture dynamics description for one or few wells with high grid resolution and precise fracture geometries, or provide full-field modeling with many wells and skin-factors used to account for hydraulic fractures. With model grids getting finer resolution it becomes more common to have the fractures half length to exceed the grid block sizes.

In the existing hydrodynamic simulators it is the realistic description of large fractures that remains the most problematic issue. In the absence of adequate modeling solutions the reservoir engineers are forced to come up with a set of unphysical approximations causing significant distortions of model properties and deterioration of its forecasting power. The new technology proposed in this paper is based on building networks of new (“virtual”) well perforations in the model grid blocks intersected by the fracture. With the help of this new approach, reservoir engineers can realistically model fracture dynamics in full-field models with hundreds and even thousands of fractured wells.
Study of Viscous Oil Emulsions at Various Rations of Treating Oils with Extreme Temperatures of Solidification
Authors: GRISHAGIN A. V. , KALININA O. S. , MELOSHENKO N. P. , SHERSTNIKOVA Yu. E.
Published: February 2011

Of late there is a sharp increase in the area of oil field development that contains the reserves due to several reasons referred to as hard-to-recover ones.

In this connection there is expediency in conducting severe studies, both from the standpoint of geological conditions of their formation and from the standpoint of the reservoir and its fluids.

One of the major objectives while performing viscous and wax field development program that are characterized by abnormally high temperature of solidification is the performance of studies related to rheological properties of water/oil emulsions during the process of their dehydration and their further transportation in a mixture with other types of recovered products.

The recently published materials on rheology of water/oil emulsions are mainly based on system modeling that uses distilled water and what is more important, within the frames of negative oil solidification temperature range [1]. On the other hand, the requirements towards the quality of preliminary dehydration are usually governed inside a wide interval (up to 10-20 of %) of residual water contents and cannot serve as a benchmark to select the degree of well product dehydration in specific cases.
The Thermogas Treatment of the Bazhen's Series Deposits
Authors: Grayfer V. I. , Nikolaev N. M. , Kokorev V. I. , Bokserman A. A. , Chubanov O. V. , Uschakova A. C.
Published: February 2011

The work aim is to create an innovative complex of thermogas treatment which allows to involve in industrial development nonconventional hydrocarbonic resources of the Bazhen′s series.

Nonconventional oil resources of Russia are known to be ultraheavy oils and bituminous sands, combustible shales and source beds of the Bazhen′s series (BS). There are ultraheavy oils on the Yaregsky field. Effective exploitation has been created by thermal methods and is being developed successfully. These methods can be adapted for exploitation of the natural bitumen fields which is in the greatest concentration in Tatarstan. where about 450 oil deposits are discovered and oil reserves are estimated in 7 billion tons.

Another kind of nonconventional hydrocarbonic resources - combustible (petroliferous) shales - is presented in Russia by 80th oil fields which are basically in the European part of the country, in Republic Komi, in the Volga region. Ways of development and refining of combustible shales are well known. These are open ways at small depths of occurrence and interbedding combustion - at underground development.
Design of Equipment and Technologies using the Down-hole Steam and Gas Generator Based on Monofuel Solution
Authors: Graifer V. , Nikolayev N. , Kokorev V. , Orlov G. , Bugayev K.
Published: February 2011

The objective of the paper is designing of equipment and technologies to stimulate viscous and high viscosity oil deposits by steam and gas using monofuel. The activities were conducted as part of the governmental programme. The specific feature of the technology lies in the use of a steam and gas generator being installed in the bottomhole of the well.

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

One of the ways to enhance the efficiency of thermal VHO development methods is generation of a thermal agent directly in the bottomhole (1). To implement such technology the OJSC “RITEK” specialists as part of the governmental programme have performed works on designing a down-hole steam and gas generator as well as surface and down-hole equipment system to ensure its operation.
Optimization of Produced Water Dumping Using Conceptual Model of Field Infrastructure
Authors: Lomovskikh S. , Smyslov V. , Sukhov E. , Shashel V. , Kozhin V. , Nekipelov Y.
Published: February 2011

The systematic and structured approach towards field development that is actively developing now has resulted in occurrence of a series of conceptual tasks resolved within the framework of one field or the whole region [1]. The papers dedicated to conceptual and integrated designing are considering these tasks at a level of one field [2, 3] and do not cover the problems arising within the framework of joint development of group of oil fields. The given paper presents the approach towards the solution of optimization tasks of various complexities within the framework of oil-producing region. One of these tasks is presented by a problem how to dispose the increasing volume of produced water from the whole group of oil fields located at Samara region and connected to some extent by common corridors for surface lines [4]. The given task has a set of features characteristic just for this region, such as incompatibility of formation waters and restrictions for water injection at water disposal sites.

In order to resolve the above-stated tasks the authors of the given paper present the regional conceptual model of surface facilities for southern group of OAO ”Samaraneftegas” fields that include 57 fields and 27 field objects. Every field object of the model is described using a simplified pattern to work in various modes. The model allows analyzing and optimizing at the basis of dynamic programming the joint operation of field and linear objects to maintain the planned levels of fluid production and fluid injection remote horizon planning. The open object-guided programmed code describing conceptual model, easily allows complicating of its structure, increasing the detailing and accuracy of decision taken, as is required.

Using the regional conceptual model of surface facilities shows the solution of an urgent task to optimize the disposal of formation water produced at the southern group of OAO ”Samaraneftegas” fields.
Integration of Production, Geological and Geophysical Data While Building Geological Models of Oilfields
Authors: Kolesnikov . S. , Shipenkov . A. , Ignatov . S. , Kostuchenko . V. , Cherkas . O , Tsibizova . N. , Babuhina . A. , Mezhnova . Y. , Roschin . V.
Published: February 2011

The paper presents examples of integration of production, geological and geophysical data at different stages of geological modeling: input data systematization, well-logs normalization, interpretation of lithology, calibration to dynamic data. The goal of such integration is to reduce labor efforts on construction of geological models and subsequent history matching of hydrodynamic models comparing to traditional approach to modeling.
Integrated Approach of Field Development System
Authors: Shoshin A. A. , Valiev A. K. , Chuprakov I. V.
Published: February 2011

The paper describes the developed method called “modified reservoir quality map ”. The paper includes the theoretical base of the method, the methodology for quality map construction and mathematical operations over the map. Definitions for well and well network qualities are presented. The work includes a description of the working principle of our developed software for mapping the quality of the reservoir. Finally, the results of applying the method for three fields with examples of wells (that are in “good” and “bad” zones) are presented.
Evaluation of Remaining Recoverable Reserves in Water-Flooded Areas
Authors: Kats R. M. , Volgin E. R.
Published: February 2011

The localization of oil reserves in water-flooded areas is considered. Despite a high watercut of 90% or more well production, individual regions of the reservoir can retain recoverable oil. These reserves may have rather high (up to initial) oil saturations. Developing these reserves even partly will deliver a valuable incremental field production. Oil field development experience shows that recovery factor can be comparatively low, even at the late development stage. The issue of additional recovery is illustrated by the Bavly oil field experiment which ran for 30 years. This experiment included high watercut wells that were shut-in for a long time and subsequently brought back into production, and some of the wells yielded tens of thousands of tons of crude. Moreover it was established that remaining reserves can be located in certain areas.

So, the problem of finding the location of such areas needs to be solved without resort to large-scale experiments like this. If we could do this, the scope of late stage infill drilling could be reduced thus preventing wells being drilled in swept zones.

Currently the issue of finding high oil saturation zones is generally solved through reservoir modeling. The issue of the accuracy of modeling oil saturation distribution is of primary importance for a reservoir engineer.

There are a variety of numerical methods for modeling oil and gas field development processes widely in use, but are not sufficiently reasonable for this goal. In the general case, heterogeneous media cannot be described by averaged equations with scientifically based pseudorelative permeabilities.

The inconsistency of using pseudo relative permeabilities for simulation of the heterogeneous reservoir development is illustrated by numerical experiment.

The pseudo relative permeabilities technique enables forecasting the field production and injection rates and cumulatives only. The reliability of the prediction of the oil saturation distribution turned to be unsatisfactory. This means that currently used pseudo relative permeabilities techniques do not allow reliable detection of bypassed oil. At the moment, the only efficient method of locating unrecovered oil reserves is integration of advanced reservoir study methods combined with geological modeling and reservoir simulation.
Possibilities to Use Basidiomycetes to Rise the Efficiency of Oil-Contaminated Soil Remediation
Authors: Kokanina A. V. , Vinokurov V. A. , Gubkin I. M. , Leont'yeva M. I. , Barkov A. V. , Krasnopolskaya L. M. , Gauze G. F.
Published: February 2011

Features of basidiomycetes to improve remediation of oil-contaminated soil

Ability of definite strains of basidiomycetes to use oil components as the source of carbon in their lifesustaining activity is shown in the result of screening. Efficiency of these strains to remediate oil polluted soil was studied in laboratory conditions. It is shown that the fungi strains selected in the screening actively form colonies on oil-polluted substrates. Growth of air mycelium is possible not only on an oil- saturated substrate, but on a surface of an oil film as well. Besides, ability of the fungi to grow on a soil using petroleum hydrocarbons as the only source of carbon is shown. Mycelium is observed to grow both on the surface and in the bulk of the substrate. Ability to utilize hydrocarbons is shown in a model experiment for the following strains: basidiomycete belonging to the genus Trametes utilizes up to 39% with respect to control level of oil content in the soil and basidiomycete genus Fomitopsis utilizes up to 22%, respectively. Ability of basidiomycetes strains to maintain high oil oxidizing activity in the presence of natural soil microflora confirms their potential to be used in techniques of recultivation of oil-polluted soil both as a self-consistent method of bioremediation and in combination of other techniques of oil- polluted soil cleaning.
Geological Features of the Deep Horizons (Lower Part of the Jurassic Section and Pre-Jurassic Basement) of Tomsk Region: Examples of Mayskoye and Festivalnoye Fields
Authors: Pinous O. , Ivanov D. , Gostev M. , Naymushin D. , Popov A.
Published: February 2011

This paper describes a comprehensive analysis of the 3D seismic data, well logs, and cores from productive intervals of the Mayskoye and Festivalnoye fields. The analysis covered the sandstone layers of the lower part of Tyumen Formation and the fractured reservoirs of pre-Jurassic basement. The goal of this study was to build geological models that will serve as a basis for field development planning of the low-permeability, low-porosity reservoirs of the described intervals.

First, we completed a structural and tectonic analysis, i.e. identified the main mechanisms of structural and tectonic evolution. At the Festivalnoye field, the main anticline structure is a pop-up fold that was formed by displacements along a major regional-scale wrench fault. This conclusion guided the structural interpretation, and in particular, resulted in more reliable fault recognition and tracing. The fault tracing widely involved the Ant Tracking function. The revealed direction of a regional stress (interpreted from FMI and sonic scanner data) has enabled a planning of the optimal trajectories for horizontal wells that is of special importance when hydraulic fracturing is involved.

Second, we interpreted depositional environments and facies distribution of the Jurassic sandstone layers. In the Mayskoye productive interval we have identified two major parts of the section corresponding to different depositional systems: The lower section (zones J15—J16) was deposited in a braided river depositional system that fills the pre-Jursassic erosional relief. This environment was identified using the results of sedimentological core descriptions. The upper section (zones J12—J14) was deposited in a meandering river depositional system, with depositional cycles (sequences) topped with coals. This part of the section demonstrates higher heterogeneity compared to the lower unit deposited in braided rivers.

The results of facies analysis provided grounds for the selection of optimal algorithms for geological modeling and adequate honoring of the reservoir heterogeneity. The conclusion about facies and the evolution of fluvial sedimentation for the lower part of the Tyumen Formation is presented first time for the southeastern region of Western Siberia.
Recoveries of Heavy Oil and Bitumen Techniques With the Radio Frequency Electromagnetic Irradiation
Authors: Kovaleva Liana , Davletbaev Alfred , Minnigalimov Rais
Published: February 2011

Production improvement of heavy-oil/bitumen recovery by using Radio-Frequency (RF) Electromagnetic (EM) fields present great practical interest. Most of the material of the oil industry - oil-saturated reservoir, formation fluid, oil, bitumen and then- components (resins, asphaltenes, paraffin, oil-water emulsion, high-viscosity and extra-heavy crude oil) in their electromagnetic properties are non-magnetic dielectric materials with low electrical conductivity. If the electromagnetic field impacts these materials, electro- thermo- and hydrodynamic phenomena take place. The RF-EM fields in the form of waves can penetrate deeply enough - from fractions of a meter to several hundred meters - into oil and gas technological working media

The paper deals with the impact of EM fields on the heavy-oil/bitumen sand deposit and electro-, thermo- and hydrodynamic processes control for enhanced oil recovery. The present paper discusses the technique of RF-EM heating of an oil-bearing layer combined with solvent injection, aimed at increasing heavy and extra-heavy oil recovery rate. Such combined technology expands the displacement area and allows a deeper heating of the layer. This method increases the technical and economic efficiency of field development by treating a producing well in three stages. At the first stage, the well operates as in injector to inject a solvent with simultaneous RF-EM exposure. At the second stage, the well is suspended to ‘stay' without any treatment. Finally, the well is re-commissioned to produce from the layer.

The paper presents a mathematical model for this three-stage iterative process, which describes transfer of mass and heat within the ‘well/ reservoir/ rock environment' system. A numerical simulation was also employed to study the effect of heavy oil production and the relative energy balance. The model estimates the optimum solvent volume and stage duration; the paper also gives a comparative analysis of calculation results for two cases: the one using the suggested combined technique, the other using constant heating without solvent injection.
Experience and Features of Simultaneous-Separate Exploitation Systems Application on SLA Priobskoye Field
Authors: Baryshnikov A.V. , Kofanov O.A. , Sidorenko V.V. , Brezin A.M. , Kremenetskiy M.I. , Kokurina V.V.
Published: February 2011

This paper describes experience gained through the field pilot exploitation of completion systems designed for simultaneous- separate exploitation (SSE) of multihorizon wells in conditions of South License Area (SLA) of Priobskoye oil field. Possibility of particular formation parameters monitoring and control is the main benefit of such systems.

Overview of completion systems for SSE, ways and technologies used for control of multihorizon wells, experience of such systems application and opportunity for future application are also discussed in this work.

Two main points are considered: Simultaneous Separate Production (ОР Д- Russian abbreviation) for production monitoring and control of multihorizon wells and Simultaneous Separate Injection (OP3 - Russian abbreviation) completion system for water injection control in multihorizon injection wells.

A special attention was paid to the long term monitoring of each penetrated formation on different flow regimes. The monitoring was conducted with downhole gauges (flow rate, temperature and humidity). Opportunity of such monitoring is one of the most important SSE advantages.

Described technologies are part of the field intellectualization project. Purpose of this project is identification of the most effective system which enables control and surveillance of multihorizon wells. As a result, the unified system for the exploitation parameters control and monitoring, based on the observation wells network will be created.
Influence of the Linear Filtration Law Breach on the Gas-Liquid Mixtures Influx Into the Well
Authors: Karnauhov M. L. , Skrylev S. A. , Khlus A. A.
Published: February 2011

There are numerous technical papers on fluid flow analysis which address, both Darsi's non-Darsi's filtration law. As for gas wells, as a rule, the quadratic correspondence-«depression squared-flow rate»-is used for the influx calculation.

Practical examples of the well survey (at the Yamburg and other fields in Tyumen) show, that the production curves, by no means always take the shape of a line on the graphs «depression squared-flow rate».

The filtration law breach does not always take place, and if a breach of the law occurs, it happens only in the near region of the well (at the distance of 1,5 ÷ 15 m).

Our calculations also show, that the production curves distortion often occurs not due to the filtration law breach, but due to the fact that a considerable influence of a number of parameters changes is not taken into account: from the reservoir and borehole pressure: such as supercompressibility factor, viscosity, volume factor.

The pseudopressure and pseudotime functions introduction to the calculation while processing the pressure build-up curves improves the calculation results insignificantly, as the corresponding averaging procedures of the mentioned parameters are carried out at the same time.

The influences of all the pointed out factors on the production curves behavior, as well as during the pressure build-up curves measurements in the wells with the hydraulic fracture and in the horizontal wells is particularly special.

The practical examples are given, showing a considerable difference of the reservoir calculation parameters, when the changing of the supercompressibility factor, viscosity, volume factor, while the pressure is taken into consideration.
Shale Gas Development in Canada: The Regulatory Framework
Authors: Beaudoin Y. , Serry J. K.
Published: February 2011

In the fall of 2010, shale gas exploration and development in Canada is just getting started. Engineering advances are making unconventional gas plays more attractive. Provincial governments are looking to tap the economic benefits. Regulators are adjusting existing oil and gas regulations or drafting entirely new legislation. This paper covers a selection of topics for each of the seven Canadian provinces where shale gas development has started or is about to begin. So far, regulation of shale gas is not very different from the regulation of conventional gas exploration and development. Interest groups and regulators are following U.S. trends.
Fundamentals of Methane Hydrate Decomposition
Authors: Ripmeester J. A. , Alireza S. , Hosseini B. , Englezos P. , Alavi S.
Published: February 2011

Constant energy molecular dynamics simulations are used to study the role of mass and heat transfer in the decomposition of methane hydrate. The rate of methane hydrate decomposition in a constant energy simulation is affected by heat and mass transfer arising from the breakup of the hydrate framework and release of the methane gas into the liquid phase. As the hydrate undergoes endothermic dissociation, temperature gradients are established between the remaining solid hydrate and the solution phases. Hydrate dissociation occurs in a concerted fashion with rows of sI cages parallel to the interface decomposing simultaneously. This leads to the release of large amounts of methane gas near the solid-liquid interface which can form bubbles that affect the rate of mass transfer between the phases. These phenomena can affect the rate of methane hydrate decomposition in natural methane hydrate reservoirs.
A Novel Means of Proppant Consolidation
Authors: Wiggins C. B. , Zhang K
Published: February 2011

During fracturing operations, the most important objective is the successful placement of proppant into fracture channels within hydrocarbon bearing formation zones. This is done with the intent of creating a high conductivity channel, allowing hydrocarbons an open path from the far reaches of the reservoir into the well bore area.

However, once proppant has been successfully placed into the formation, it is critical that the proppant remain in place to maintain this high conductivity channel. Achieving this can be complicated by substantial pressure differences between the extremities of the fracture channel and the near wellbore area, with a tendency of flow towards the lower pressure area around the wellbore. The most common means of remedying this problem currently is treating proppants with a resin coating. This coating softens under pressure and temperature, and provides a strong amount of cohesive force to the proppant. However, there are several limiting factors to these types of resin-coated proppants. The most daunting factor in the use of resin-coated sands is likely the price, which can be in excess of four times the price of untreated proppant. This often leads to frugality in the use of resin coated sands, often being utilized only in tail end stages of fracturing events. Another detriment to resin-coated proppants is their temperature and pressure sensitivity. Shallow wells, which often exhibit low pressure and temperature, require substantial amounts of chemical activators to allow resin sand to "set up". These activators can often have a negative effect on fracturing fluids. Extremely cool wells may not even be feasible for resin-coated proppants, requiring excessive amounts of activator. This paper details the development and use of a novel chemical-based system as a means of proppant consolidation. The chemical can be pumped on-the-fly, during the fracturing event, and does not require special types of proppant. It is compatible with most water-based fracturing fluids, and has been used successfully in a number of applications, especially in extremely large, multizonal horizontal applications, with a great deal of success.
Geological Potential for Sequestration of CO2 as Gas Hydrate in the Alberta Portion of the Western Canada Sedimentary Basin
Authors: Cote M. M. , Wright J. F.
Published: February 2011

The Alberta portion of the WCSB has been investigated with respect to the geological potential for the sequestration of CO2 as a metastable, solid crystalline gas hydrate. Based on a coarse-resolution (1 km2) geothermal analysis and industry borehole data, the areas north of Cold Lake and south/southwest of Fort McMurray have been identified as having pressure-temperature (P-T) conditions favourable to the formation and maintenance of CO2 hydrate at target injection intervals of 300-400 m depth. It is estimated that the gross amount of CO2 that could be sequestered as gas hydrate in Alberta is approximately 46 Gt.

The presence of a substantial overburden provides an effective buffer against the propagation of anticipated warmer surface temperatures (due to progressive climate warming) into the ground at depth. Numerical modeling predicts a time frame of between 1000-2000 years for a 3°C change in surface air temperature to effect an increase in ground temperature of 1°C at 300 m depth.

This preliminary regional assessment offers a potential new strategy for the geological sequestration of CO2 in Canada, however considerable additional work is required to advance this idea from concept to practice. Specifically, the acquisition of more reliable ground temperature data and local geothermal gradients, pore water geochemistry, porosity and permeability would be a pre-requisite to the implementation of a small-scale demonstration project in a readily accessible region of northeastern Alberta.
A Novel Chemical Treatment to Enhance Well Productivity in Volatile Oil Reservoirs
Authors: Torres D. E. , Sharma M. M. , Pope G. A. , Ahmadi M. , McCulley C. A. , Linnemeyer H. C. , Gilani S. F.
Published: February 2011

In volatile oil reservoirs, the presence of two fluid phases (gas and oil) near the wellbore is a common problem that affects well deliverability. As the pressure falls below the bubble point the presence of two immiscible phases reduces the oil relative permeability and leads to lower oil production rates. In this paper, we show that the application of fluorinated chemicals can mitigate this impairment associated with gas blocking of volatile oils. We show through laboratory experiments that the treatment not only removes the water from the treated zone, but also modifies the wettability of the rock surface to neutral wet, minimizes capillary trapping and enhances the mobility of oil and gas. The chemical treatment is effective in the presence of connate or flowing water over a range of temperatures. This technique may be used as a curative or preventive treatment in volatile oil reservoirs, potentially increasing oil production rates and recoverable reserves. High-pressure high-temperature (HPHT) coreflood tests were conducted that show that the treatment improved the relative permeability, by a factor of about 1.3 to 2.6 at a GOR of 6000 to 7000 scf/STB in sandstone and limestone cores at low capillary numbers (Nc). Wettability alteration was measured using contact angle and imbibition tests. These tests together with x-ray photoelectron spectroscopy (XPS) analysis were used to screen the selected surfactants. Since this durable enhancement is achieved by treating a small area around the wellbore, it may be applicable in a wide variety of wells.
Mass Diffusion Into Bitumen: A Sub-Pore Scale Modeling Approach
Authors: Taheri S. , Kantzas A. , Abedi J.
Published: February 2011

The increased interest in the production of heavy oil and bitumen has amplified attention paid to solvent-based methods for heavy oil recovery, such as vapor extraction (VAPEX) or miscible flooding.

The diffusion of solvent into oil plays a major role for all the solvent-based recovery methods. Since the diffusion process is governed by the diffusion coefficient, the accurate prediction of mass transfer of the solvent in heavy oil and bitumen is extremely important. The concentration dependency of the diffusion coefficient differs from sample to sample and is determined experimentally in the laboratory. What is measured in the lab as the diffusion coefficient is influenced by different porous medium properties during the solvent injection. Therefore, an effective diffusion coefficient is defined for porous media, which has a dependency on the medium properties.

The main goal of this paper is the prediction of an accurate value for the effective diffusion coefficient from experimentally measured values of diffusion considering the properties of the porous medium.

The medium in this paper can be a micro model pattern, thin section, tomographic image or microscopic picture. The picture is analyzed by an image processing program to distinguish the pore and grain sections. After gridding the pore regions of the picture, virtual porous medium properties are extracted by applying the Navier-Stoke and continuity equations as the governing equations. The diffusion equation is applied to the medium to find the concentration profile of the solvent in the porous medium, and the effective diffusion coefficient of the system is computed from the concentration profile. An extensive investigation of the effects of medium properties on the diffusion coefficient will lead to the capability of predicting the effective diffusion coefficient for other media with different patterns and properties.
Analytical Solutions for Mixed CO2-water Injection in Geothermal Reservoirs
Authors: Wahanik Helmut , Eftekhari Ali Akbar , Bruining J. , Marchesin Dan , Wolf Karl Heinz
Published: February 2011

Concern about global warming is generating interest in reducing the emissions of greenhouse gases such as CO2. One way of reducing CO2 emissions is to replace conventional (hydrocarbon fuels) energy sources for heating buildings by geothermal energy. Recently it was suggested to co-inject carbon dioxide with cold water for simultaneous geothermal energy production and subsurface carbon dioxide storage. Our data correspond to a geothermal energy project proposed for heating the buildings of the Technical University of Delft. After injection of the water/CO2 mixture a complex interaction between physical transport and the phase redistribution of the components, i.e., water and CO2, occurs. This redistribution is usually described in terms of local thermodynamic equilibrium. There are no published complete analytical solutions for 1-D problems involving complex thermodynamics that include CO2 and heat effects in the flow. We take into account the heat effects related to the cold fluid injection and related to the dissolution of CO2.

We give an analytical solution for the model equations for the temperature and for the flow of CO2, vapor and water after combined injection of a cold carbon dioxide-water mixture in a geothermal reservoir. Due to high pressures and temperatures, CO2 is in a supercritical state and it is necessary to determine the phase equilibrium for non-ideal gases. We used a modification of the Peng-Robinson equation of state and an activity coefficient based mixing rule for the thermodynamic calculations. A volume shift procedure is applied to obtain an accurate liquid density. The structure of the solution depends strongly on the injection and initial reservoir conditions. The application of the work is in the effective recovery of heat from geothermal reservoirs with simultaneous CO2 storage. Moreover, the theory provides fundamental understanding of non-isothermal flow of mixtures undergoing mass transfer between phases. The advantage of the analytical model is that it provides a simple methodology to screen injection conditions for optimal geothermal recovery or maximal storage of carbon dioxide.