bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sand Control in Open Hole Horizontal Wells-Case Histories and Developments
Authors: Rovina Paulo S. , Filho Everaldo Lima 
Published: December 2007

Abstract
The discovery of new fields in the Amazon forest and in deep water offshore Campos Basin led Petrobras to adopt non conventional sand control completion techniques. The main goals were increase productivity, delay gas/water conning and support unconsolidated formations in water injection wells.
This paper will describe the experience acquired running screens in 23 horizontal open hole wells in Brazil. Several improvements were made on the equipment, procedures and in the well design due to the problems faced during the execution of the jobs.
As a result, the main objectives were achieved and new trends were established aimed at deep water fields development.
Improved Productivity Justifies World Record Underbalanced Perforating Operation
Authors: Johnson A. M. , Bakker E. R. , Hungerford K. 
Published: December 2007

Abstract
A Dutch onshore gas well was drilled to a total depth of 5136m along hole (3700m true vertical depth) with a maximum deviation of 89 degrees. The well was completed with 7 5/8" 13 Cr tubing with a 7" cemented liner across the reservoir providing full bore access to the pay zone. Due to the very stratified nature of the reservoir the long term sustained production depended on achieving vertical connectivity with all the layers. In order to achieve this and to maximise productivity a 1 run underbalanced perforating operation was required. Due to coiled tubing limitations in this deep, high pressure well a Hydraulic Workover Unit was selected to deploy and retrieve the guns. A total gross interval of 1026 metres was perforated in one run utilising 3 3/8" deep penetrating guns and thereafter snubbed from the well under live conditions (460 bar at surface). To date it is understood that this is the longest section of guns conveyed, fired underbalanced and deployed out of a live well. This paper addresses the perforating technique selection, the planning and execution process, the major operational learning points and discusses final productivity results which demonstrate the validity of this technique.
Recent Developments in Geoscience for 3D Earth Modelling
Authors: Fontaine JM. , Dubrule O. , Gaquerel G. , Lafond C. , Barker J. 
Published: December 2007

Abstract
This paper discusses recent developments in the domain of Geoscience, which contribute to better 3D modelling of hydrocarbon fields. These techniques integrate geophysical, geological and reservoir engineering knowledge in the construction of a 3D earth model. The 3D-earth model brings consistency between views of the reservoir held by different subsurface disciplines. A common quantitative description of the reservoir is used for all calculations and interpretation studies. Starting with picked horizons and well data, a number of aspects of 3D earth modelling are discussed:
– Anisotropic seismic ray tracing is used for constraining the structural model and estimating uncertainties. – The geological model is constrained by 3D seismic data through geostatistical inversion. – 3D sedimentary modelling generates a 3D facies model incorporating sequence stratigraphic interpretation and geostatistical modelling rules. – Computer-aided history matching quantifies sensitivities through gradient calculation and uses this information to reduce uncertainties in the geological model.
North Sea and West Africa examples will be used to illustrate integrated applications of these various techniques. In conclusion, future integration challenges for 3D earth modelling will be mentioned such as time-lapse seismic (4D), four components seismic (4C), fault modelling, improved links between dynamic data and the initial geological model.
P. 13
Measurement of the Soret Coefficient in Crude Oil
Authors: Georis Ph. , Montel F. , Van Vaerenbergh S. , Decroly Y. , Legros J.C. 
Published: December 2007

Abstract
Very recent works show that thermal diffusion (Soret effect) can have a significant impact on the composition grading of thick oil reservoir. So far, neither satisfactory theoretical models of thermal diffusion nor reliable measurements of thermal diffusion coefficients is available. Lack of knowledge of the magnitude of thermal diffusion may lead to an incorrect estimate of GOC location and to an inaccurate estimation of oil and gas in place. In this paper, we illustrate the potential impact of thermal diffusion on the compositional grading of a real field, outline the objectives the SCCO project and detail the technical achievements realised in this frame. The key objectives of the SCCO project are the following: To measure accurately the Soret coefficients of crude oil samples held in reservoir initial conditions (p 350 bar, T 60 C), to develop appropriate compositional modelling algorithms taking into account thermal diffusion and using reliable values of the measured Soret coefficients. To provide undoubted values of Soret coefficients for testing existing and future theories or correlation laws on the thermal diffusion phenomenon. Practically, Soret coefficients in multicomponent mixtures cannot be measured on ground because thermal and compositional gradients unavoidably induce convective mixing. In the SCCO project, measurements of the greatest accuracy will be obtained performing the experiment in microgravify where buoyancy driven convection is absent. In the present configuration of the hardware, three different complex hydrocarbon samples will be processed. Experimental constraints imposed by the high pressure of the samples and by the microgravity environment require the development of original technical solutions. We describe the miniaturised thermal diffusion cells as well as the dedicated sampling interface with the GC for post flight analysis.
P. 57
Ageing: An Origin for Quicksands and a Predictive Tool for Sand Production
Authors: Razoaki R. , Kageson-Loe N. , Langdon N.J. , Stokken-Ostby G. 
Published: December 2007

Abstract
Ageing is a geotechnical term which describes the changes in compressibility and strength characteristics of granular materials over lime. The process can occur in both naturally and artificially deposited soils through a wide range of diagenitic processes including compression, creep, cementing, weathering and changes in pore water chemistry reflecting physical and chemical changes induced on the material either over engineering or geological time (Atkinson 1993). Ageing has both positive and negative consequences in that the material can either become more stable or more sensitive to subsequent changes in the ambient stress state. Sensitivity of the material is demonstrated by the susceptibility of the material to collapse under an increasing applied shear stress once an initial intrinsic (ageing related) resistance is overcome. Both the amount of collapse and initial stiffness increase with ageing time. Stability is demonstrated by increased shear strength and stiffness, no collapse is observed. The significance of ageing and its dependence on sedimentological properties has been demonstrated on engineering time scales but similar evidence had not yet been previously considered with respect to geological time.
Data is presented from laboratory experiments on saturated carbonate and silicate sands which demonstrate differing sensitivity to ageing over a short time frame under low effective stress conditions. From this it is inferred that ageing and its manifestation is dependent on the compression and creep characteristics of the sediment. The experiments were cdnducted in standard geotechnical triaxial apparatus. The materials were aged under isotropic and anisotropic (Ko) stress conditions.
The phenomena of ageing is described with respect to stress-strain behaviour, effective stress, material stiffliess and collapse potential. Consideration is also given to sedimentological properties and how they influence the ageing process.
In reference to the results presented the paper conjectures to the occurrence of loose/quick sands in geological sequences. These materials have remained stable over geological periods of time but demonstrate sensitivity and collapse brought on by changes in the ambient stress state due to hydrocarbon production. Although these materials tend to be stronger and have been subjected to much higher effective stresses and temperatures than those studied to date they show sufficient similarities in behaviour for inferences to be drawn. It is argued that quick/loose sands are the manifestation of sensitive style ageing over geological time. The identification of those sedimentological parameters which influence sensitivity during ageing will assist in defining those sandstone lithologies most at risk of quick sand conditions.
P. 73
Improved Reservoir Evaluation in Norway Wells from High-Resolution Producibility Measurements
Authors: Jacobsen S.J. , Phillips J. , Cheruvier E. 
Published: December 2007

Abstract
Traditional formation evaluation from well logs is centered around the determination of water saturation, Sw, from which an interpretation of the expected hydrocarbon and/or water production is obtained. At the edges of the saturation range, from approximately less than 30%, and then greater than 70% Sw, these interpretations are generally straightforward. But accurate reservoir evaluation requires that a proper production prediction be made at all calculated saturation values, meaning that the ambiguities plaguing the link between water saturation and water cut in the 30-70% Sw range must be resolved.
This paper discusses Norwegian wells where the essentially static notion of water saturation is converted to a dynamic interpretation of moveable water/hydrocarbon. The outputs of a magnetic resonance logging tool, the CMR Combinable Magnetic Resonance Tool, are analyzed for porosity fractions of free and bound fluids via a link to core- derived permeability. This is combined with the interpretation of resistivity-porosity logging for bulk volumes of hydrocarbon and water to provide a continuous produciblity evaluation of each phase over the extent of the reservoir.
Several case studies in North Sea sandstone reservoirs over a wide porosity-permeability range are presented. The technique is valid for both oil and gas, and examples of each are shown. Production predictions are benchmarked against DST, production, or wireline formation test results in all cases. The complication to NMR interpretation due to significant levels of clay minerals such as chlorite and glauconite in these formations is considered.
The operational issue of increasing the traditionally very slow NMR tool logging speed up to efficient levels is addressed and the continuous producibility estimation is shown to be feasible at "normal" nuclear tool logging speeds.
Conclusions include recommendations on methods of performing the enhanced produciblity evaluation on routine development wells which are not typically cored.
P. 81
Water-Alternating-Gas Flooding in Venezuela: Selection of Candidates Based on Screening Criteria of International Field Experiences
Authors: Manrique E. , Calderon G. , Mayo L. , Stirpe M.T. 
Published: December 2007

Abstract
Water alternating gas (WAG) injection schemes have become an important strategy for improved oil recovery (IOR) technique around the world, and have been the focus of interest in recent years in Venezuela. This drainage strategy is mainly planned according to the major concerns in Western Venezuela oil fields: optimizing gas resources and improving oil recoveries in the region.
As part of the support to identify those reservoirs that will be candidates to WAG flooding in this area of the country, an extensive review was carried out to describe the main reservoir management strategies implemented in WAG pilot, as well as large field projects in order to evaluate international field experiences, before expensive reservoir description, laboratory studies, economic evaluations and WAG pilot projects are carried out.
This paper briefly describes part of this review and also shows some screening criteria for WAG floodings. Data from successfull and unsuccessfull worldwide projects have been analyzed obtaining relevant information about crude oil and reservoir properties as well as gas injection capacities, incremental oil recoveries, among others. All these data have been compiled and the results are presented graphically; the relationship between them is discussed and compared with data of some of the reservoirs proposed for WAG floods in Venezuela.
It has been found that WAG projects must be initiated with injection pressures 24% greater than reservoir pressures unless the formation is deeper than 8000 ft. Additionally, incremental oil recoveries reported by those projects are higher for lower viscosity ratios and do not depends on injected solvent slug sizes. Finally, the authors discuss how this screening was useful as a first look to identify the actual reservoir and facilities of different fields located at the Maracaibo Lake (e.g. B-6-X.10 and VLE-305) and select them for closer investigation and planning WAG pilot projects or "WAG Field Laboratories".
P. 161
Application of a Multisegment Well Model to Simulate Flow in Advanced Wells
Authors: Holmes J. A. , Barkve T. , Lund Ø. 
Published: December 2007

AbstractThe need to simulate advanced wells (horizontal and multilateral wells and ‘smart’ wells containing flow control devices) requires a correspondingly sophisticated type of well model to be implemented in reservoir simulators. The model must be able to determine the local flowing conditions (the flow rate of each fluid and the pressure) throughout the well, and to allow for pressure losses along the wellbore and across any flow control devices. This paper describes an advanced well model in which the wellbore is divided into an arbitrary number of segments. The well model has been implemented in a black-oil reservoir simulator, and the paper describes two case studies which assess the performance of the model and use it to examine the effects of flow control devices on two types of well.
Potential Application of Oxygen-Containing Gases in Heavy Oil Bearing Reservoirs
Authors: Lakatos I. , Lakatos-Szabo J. , Bauer K. , Kosztin B. , Biro Z. 
Published: December 2007

Abstract
In the frame of the laboratory studies the effect of natural and recycled CO2 and different air/CO2 mixtures on chemical composition of crude oil and gas phase, the rheological and interfacial properties, the flow mechanism and the safety measures were analyzed. The tests were performed at reservoir conditions using formation rock, oil and gas samples. The oxygen content of the gas phase and the gas/oil ratio varied between wide limits. Both crude and asphaltene-free oil were used to determine the consequences of the low temperature oxidation.
The main observation of the laboratory studies is that detrimental phenomena using natural and recycled CO2 as a cap gas may not ensue even at long term contact of oil and gas. On the other hand it was also found that the oxygen content of cap gas had completely consumed by the chemical reactions (oxidation, condensation and water formation), and as a result nearly 9 % excess asphaltene formation was observed in both the crude and the asphaltene-free oils. The substantial increase in asphaltene content and the presence of colloidal water resulted in a measurable change in rheological and interfacial properties. Despite these factors the flow and displacement mechanism is ouly slightly influences if the reservoir is of fractured character and the oil is already highly oxidized or is still in prematured evolution state.
As a final statement it was concluded that application of natural and recycled CO2 is a reasonable reservoir engineering and technological concept at the Nagylegyel field. However, in certain cases the chemical reactions can be in-situ regulated without jeopardizing the recovery efficiency by re placing the CO2 or inert gases with oxygen-containing cap gas. In this way the application of the artificial gas cap concept may open new vistas in EOR operations in karstic and fractured reservoirs bearing medium or heavy crude oils even in those cases when natural CO2 or CH source is not locally available.
P. 183
Coiled-Tubing Technology: An Application of High-Pressure Jet Cleaning in a Deep, High-Temperature, Sour Marine Environment
Authors: Morrison D.W. , Hogan R.D. , Coats E.A. 
Published: December 2007

Abstract
High-pressure, coiled-tubing, jet-cleaning technology provided a Mobile Bay operator with a viable option to remove downhole scale and debris efficiently without adversely affecting the formation, the environment, or the well-completion tubulars. This paper will provide a complete and detailed discussion of the surface and downhole equipment needed to perform the high-pressure cleaning application. The paper also provides an overview of the computer simulations created to predict coiled- tubing stresses accurately and the equipment used to collect real-time data on coiled-tubing fatigue, applied pump and hydraulic pressures, tubing drag and buckling parameters, cleaning fluid characteristics, and high-pressure nozzle design.
Historically, well-intervention alternatives have been limited in the deep-sour environment of the Mobile Bay field, which lies off the coast of Alabama in the Gulf of Mexico. Such factors as the sour-gas environment, the great depth of the formations (22,000 ft), the excessive bottomhole temperature &gt;400), the high wellhead pressure &gt;5,000 psi), and stringent environmental regulations, present adverse conditions that challenge the use of conventional well-intervention and workover technology.
Recently, a Mobile Bay operator experienced barium-scaling problems in a deep well (22,000 ft) (Fig. 1). A conventional workover risked formation damage as a consequence of killing the well, and damage to the well's expensive exotic alloy completion tubulars during the pulling and reinstallation process. Conventional rig mobilization and day rates were also prohibitive, as were the associated environmental issues inherent in Mobile Bay operations.
P. 215
Conversion of an Unprofitable Multireservoir Gas/Oil Field Into an Attractive Development Object
Authors: Zakirov S. , Brusilovsky A. , Zakirov E. , Zakirov I. , Piskarev V. , Karlinsky E. , Smirnov B. , Doroshenko J. , Krylov V. , Shepkina N. 
Published: December 2007

Abstract
In 1997 it was fulfilled the production planning project of a field (henceforth called "A"), located in Nadym-Pur-Tazovskiy region of West Siberia (Russia). This field is presented by Valangin (lower Cretaceous) gas-condensate and gas-oil condensate deposits of a complex geological structure with fluid reserves, which are reported to be very hard to be withdrawn. Almost all fields in the North of West Siberia contain high-performing and high- permeable Senoman formations. If Senoman formation is presented and developed, it predetermines appreciable profitability even though the other lower formations are being put into development together with Senoman formation. Therefore, this project is rather unusual from that point of view, that for the first time in this region the opportunity of profitable development technology of the field is considered without using capacity of upper laying donor Senoman formations.
The development of such fields by conventional ways requires the large capital expenditures at a low economic efficiency lying outside of the acceptable profitability. Consequently, the search of new approaches has been required to alter the economic value of the field.
P. 245
4D Seismic: Synergy, Not Just Integration, of Geophysics and Engineering
Authors: Waggoner J.R. 
Published: December 2007

Abstract
Much has been said and published about time-lapse 3D, or 4D, seismic since the last EUROPEC meeting in 1996, most of which focuses on the geophysical processing issues of comparing two 3D images to detect meaningful changes. This is indeed a critical part of 4D, because without a meaningful time-lapse change, there is clearly no useful information derived from the 4D processing. Given a time-lapse change, however, the next issue, and equally critical, is how the change is used to impact reservoir management.
The often stated benefits of 4D include the identification of bypassed oil and untapped compartments. Visual images of the time-lapse change may be sufficient to identify such features in simple cases, but most reservoir production involves changes to fluid saturation and pressure, both of which generally change the seismic response of the reservoir rock. Distinguishing between a pressure change and a saturation change is critical to proper use of the 4D result.
Fortunately, the reservoir engineer often uses a simulator that can be used to model reservoir production and predict pressure and saturation changes. Through a history matching process that incorporates both production and 4D seismic data, an improved reservoir model can be generated that is conditioned to fluid movement between the wells. The improved reservoir model will increase the predictive capability of reservoir simulations, and hence increase the effectiveness of one of the reservoir manager's tools.
By utilising engineering tools and information in the processing and interpretation of 4D data, geophysics and engineering work together in a way that enhances the value of the geophysical result.
P. 301
Reservoir Monitoring Using Time-Lapse Saturation Logs and 4D Seismic Improves Drainage Understanding in the Gullfaks Field
Authors: Instefjord Rune 
Published: December 2007

Abstract
The Gullfaks Field has been in production for eleven years and 2/3 of the estimated reserves have been recovered. The Tarbert and Ness Formations, belonging to the upper part of the Brent Group, contain 44 % of the total STOOIP.
Several 3D reservoir simulation models have been made. Due to the structural complexity and horizontal barriers it has been very difficult to history match these models, especially for the Ness Formation.
Repeated cased hole saturation logs have been collected in two wells located in the same fault block with initially oil filled upper Brent reservoirs. Standard saturation evaluation was not sufficient to understand the flooding pattern between the wells. A method making it possible to distinguish between formation and injection water even though the salinities are fairly equal has been used in this study. This has improved the understanding of the water flooding in the area. As a result of this, one of the wells (B-3) was successfully re-perforated in a thin undrained zone in the Tarbert Formation.
In 1995 a new 3D seismic survey for reservoir monitoring (4D-pilot study) was acquired over the studied area. The most pronounced 4D effects are observed at top reservoir level and at the initial oil/water contact.
One well – drilled in 1997 – confirmed an undrained area as shown by our monitoring tools and our general knowledge. In some areas there is less agreement between the 4D data and other data such as in the area around well B-3, were saturation monitoring was performed simultaneous with the acquisition of the seismic data set. Here the 4D data is not in accordance with the saturation profile in the well.
In 1996 a new seismic data set was acquired over the whole field. This data set is also interpreted for reservoir monitoring purposes. These new data together with earlier collected data will help to locate the remaining oil in the Gullfaks Field.