bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tracer Transport in Characterization of Dual-Porosity Reservoirs
Authors: Shinta A. A. , Kazemi Hossein 
Published: December 2007

Abstract
A single-porosity model (SPM) for the tracer response analysis in fractured reservoirs is developed in this paper. This new technique is useful in characterizing fractures in terms of flow anisotropy and quantifying fractures properties such as porosity and permeability. Specifically, tracer response has good resolution and, therefore, its analysis can determine the orientation and conductivity of high permeability fractured systems in the reservoir. This information is highly desirable in improved oil recovery planning and management. The simulator used here is five-point, nine-point finite-difference, two-dimension and two-phase (oil and water) model. In addition to SPM, the simulator conducts a single block simulation (SBS) and conventional dual-porosity calculations. Several options to eliminate or minimize grid orientation effect (GOE) in fractured and unfractured reservoirs are included. These nine-point options appropriately account for the permeability tensor and flow channeling. The SPM is used successfully to characterize an anisotropic confined five-spot pattern in an actual field test.
Effects of Recent Relative Permeability Data on CO2 Flood Modeling
Authors: Prieditis John , Brugman R. J. 
Published: December 2007

Abstract
Results from laboratory tertiary CO2 flooding studies conducted at representative reservoir conditions are becoming available. Predicted CO2 flood performance can be significantly changed by using this data in reservoir models. The laboratory data includes water and oil relative permeabilities when the water saturation is decreasing, residual oil saturations to a miscible flood, residual CO2 saturations, and CO2 relative permeabilities. Predicted oil recovery, CO2 production, and breakthrough times are all influenced.
Unfortunately, much of this data cannot be used in most presently available commercial reservoir simulators. Additionally, there is uncertainty about the proper form for the relative permeability of the miscible (non-aqueous) phase. For example, should the miscible phase relative permeability be based on the gas, oil, or solvent relative permeability or some combination? Texaco has developed a mixing parameter based reservoir simulator that not only uses the new relative permeability data but also incorporates different forms for the miscible phase relative permeability.
This paper describes how the recently available laboratory data and the form of the miscible relative permeability formulation affect predicted CO2 flood performance. Results presented show the importance of using the laboratory data and show what changes in existing simulators may be advisable.
Gas Condensate Well Testing Under the Influence of High-Velocity Flow
Authors: Hernández Héctor , Samaniego Fernando , Camacho Rodolfo G. , Galindo Agustín 
Published: December 2007

Abstract
This paper presents the results of a systematic study of the influence of high- velocity flow on the interpretation of transient gas condensate well tests. A one dimensional radial fully implicit compositional model using the Forchheimer equation was used to obtain the results presented in this work. Drawdown and buildup tests at constant mass rate were simulated. The simulator was carefully checked, since no solutions for gas condensate flow are available in the literature that consider high-velocity flow. Among these tests, in accordance to the method of Camacho et. al., multiphase high-velocity results were graphed in terms of d ppwd/d ln tD vs 1/(tD)1/2, presenting a. positive slope, characteristic of high-velocity flow, that extrapolates correctly to the 0.5 interception value corresponding to Darcy flow. It was found that drawdown solutions graphed in terms of the sandface dimensionless pseudopressure vs log tD show for large times the characteristic one phase slope of 1.151. As expected, high-velocity effects result in an earlier appearance of the condensate phase in the reservoir. It was also found, as already mentioned, that results of this study when properly expressed in terms of pseudopressure show the characteristic behavior for the high-velocity monophasic flow method of Camacho et. al., which allows the estimation of the high-velocity pseudoskin factor and flow capacity. Thus, this method is also valid for conditions of this study as a diagnostic tool for high-velocity flow. It is also demonstrated that the mobility function λt(pw) can be estimated from the derivative of the pressure data.
Simulated Annealing for Relative Permeability and Capillary Pressure From Unsteady-State Non-Darcy Displacement
Authors: Ucan Sezai , Civan Faruk , Evans R. D. 
Published: December 2007

ABSTRACT
An interpretation method using simulated annealing for simultaneous determination of relative permeability and capillary pressure from non-Darcy gas/liquid laboratory corefloods is presented. The effects of gas solubility in liquid and variable rock and fluid properties are considered.
The methodology is first tested by using imbibition and drainage experimental data in the Darcy flow regime and for oil/water and gas/water systems. Relative permeability and capillary pressure curves are generated under different constraints of measurements of core displacement data. Estimated flow function properties are compared with each other. Then the application of the method is illustrated for non-Darcy fluid displacement cases. The method presented here provide discrete values of relative permeabilities and capillary pressure in contrast to spline and other types of prescribed functional representations reported in the literature.
It is demonstrated that entirely different relative permeability and capillary pressure models, such as those based on spline and other types of functional representations, can also be used to match the same recovery performance. If only the recovery curves and overall pressure differential data are used, flow properties can not be obtained uniquely. However, the flow properties can be determined uniquely when transient-state internal saturation profiles and the overall pressure differential data are used. The advantage and convenience of the simulated annealing optimization algorithm are that it does not require the evaluation of first or second gradients of the objective function. Thus, the simulated annealing method converges in all cases without increasing the computational effort and time significantly.
Management of Environmental Impact Studies: A Perspective on the Exxon Valdez Environmental Assessment
Authors: Maki A. W. , Burns W. A. , Bence T. E. 
Published: December 2007

Abstract
New and evolving environmental laws and regulations impose substantial costs and greater potential liabilities on industry. These standards on emissions and assessments of impacts place increasing importance on scientifically based environmental studies. Moreover, technological improvements have provided measurement techniques that detect hydrocarbons that are far below levels significant to the environment. In such situations, it is important for companies and government agencies to design and implement environmental programs that can distinguish meaningful environmental effects due to effluent discharges and spills from those effects associated with natural ecological variation or numerous other factors influencing ecosystems.
This paper describes the environmental-assessment process implemented following the Exxon Valdez spill. This is the most extensively studied oil spill in history and the conclusions drawn from the studies may have a significant effect on future regulations and liability. Unquestionably, large spills can have acute effects; the issue is the ecological significance and duration of those effects.
Conflicting claims have been made about the seventy and longevity of spill impacts in the case of the Valdez spill. This paper summarizes studies that show shorelines, birds, and mammals have essentially recovered in the four years following the spill. They further demonstrate that fish, the most important commercial and subsistence resource present in the area, were minimally impacted.
The paper highlights the pitfalls of studies that do not carefully evaluate spill impacts by using sophisticated and sound scientific techniques or which fail to consider spill impacts within the context of natural variability and other environmental factors.
Protection Measures for Subsea Structures Against External Hazards
Authors: Copsey N. R. , Johnson S. E. 
Published: December 2007

ABSTRACT
This paper reviews the design of subsea developments in relation to possible external hazards. The hazards considered are fishing gear impact, dropped objects and anchor lines. Alternative protection measures are discussed and suggestions are made for the most suitable design approaches over a range of practical situations.
The emphasis in this work is on the application of risk analysis methods to produce ‘fit-for purpose’ designs – avoiding unwarranted costs from over-conservative approaches.
Use of Economic Measures as the Criteria for Optimising Functional Blocks and the Selection of Development Concepts
Authors: Holsen Malvin , King S. D. J. , Steine Gunlaug 
Published: December 2007

ABSTRACT
The paper presents a methodology for optimising offshore hydrocarbon production developments, employing NPV/LCC as an economic selection criteria, including production revenue, throughout all project phases. Combining CAPEX, OPEX and Production Performance into Net Present Value (NPV) gives an opportunity to base decisions upon optimised economics over the field lifetime.
In the early phases of a field development, the methodology analyse all possible solutions systematically. The method analyses the major functions necessary for field production, selecting functional solutions with highest economical potential, and combining the functions into total field development solutions. The methodology utilises aggregated data for CAPEX and OPEX ( a top-down approach), and is often referred to as the ‘Screening Methodology’.
Impregnated Bit Technology Improves Drilling Efficiency in North Sea Conglomerates
Authors: Galletta Antonino , Wapshaw K.G.C. , Wrighton Timothy 
Published: December 2007

SPE Members

Abstract
Historically, the Upper Jurassic Brae conglomerates intrinsic to North Sea Block 16/17 have been drilled with IADC 517 to 617 type roller cone bits. Unfortunately, excessive wear to the cutting structure and gauge area of these bits dramatically limited their useful life and made them uneconomical. Runs shorter than 100 ft with penetration rates as low as 4 ft/hr was not uncommon with these bits. This was true even for roller cone rock bits incorporating enhanced gauge protection.
The decision to employ fixed cutter bits in Block 16/17 was initially frustrated with the inability of existing designs to effectively drill the conglomerates. However, a new fixed cutter design concept utilizing impregnated grit-sized diamonds has greatly improved drilling performance with substantially lower cost per foot.
Field tests have shown average penetration rates of more than 1 5 ft/hr with bit life averaging 400 ft. Penetration rates have remained steady throughout the target interval. Further, no significant gauge wear has been observed, despite the fact the bits were run on turbines.
This paper describes the development of the IADC M841 class fixed cutter bit and its application in these formations. The cost savings achieved with these bits and the future potential of the M841 impregnated diamond drill bit will be analyzed. The laboratory testing leading up to the development of the impregnated diamond bit will be detailed.

Introduction
Block 1 6/1 7, also known as the T-Block, is located about 120 miles from Aberdeen in the Central North Sea (Fig. 1). Phillips Petroleum made the first discovery in the region in 1976 and since then four distinct fields have been identified: Tiffany, Toni, Thelma, and South East Thelma (Fig. 2). Since assuming operatorship of the block in 1986, Agip UK has thus far decided to develop the Tiffany and Toni fields. To date, 20 exploration and appraisal wells have been drilled on the block. Four development wells have been pre-drilled for the Tiffany platform, which became operational in the summer of 1993, and five wells have been drilled through a subsea template installed for the Toni development.
Historically, the Brae conglomerates of the Upper Jurassic sequence of the Central North Sea have proved extremely difficult to drill. The unique combination of a hard and abrasive sandstone matrix with a pebble and occasional breccia conglomerate found in Block 16/17 has made it a particularly difficult area to drill. The formations encountered there have proved impenetrable for both insert roller cone or standard fixed cutter bits.
Since 1 988, Agip UK has been involved in an extensive program to develop a fixed cutter bit capable of drilling the difficult Brae conglomerates of Block 16/17. What resulted was a partnership with a bit manufacturer, which led to the successful development of the IADC M841 type impregnated diamond fixed cutter drill bit,
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An Experimental Investigation of the Formation Damage Caused by Produced Oily Water Injection
Authors: Zhang N. S. , Somerville J. M. , Todd A. C. 
Published: December 2007

Abstract
This paper presents results from an experimental study on formation damage associated with simulated produced oily water injection. Core flooding experiments were carried out with simulated produced oily water containing 40 to 500 ppm crude oil at 1-15 ppm solids (1-10 μm mean diameter) dispersed in brine. The formation damage along the length of a core was investigated and a number of parameters contributing to permeability decline were evaluated.
The results indicate that produced oily water containing oil droplets and solid particles can contribute to the permeability decline observed in the cores. The most severe decline occurred in the first 10-15 mm of the core. Oil droplets with a dimension significantly less than the pore throat diameter also led to permeability decline. The permeability alteration resulting from a combination of both oil droplets and solid particles is more severe than obtained from the systems individually.
Compact Weight-Down Gravel-Pack Floater System with Absolute Isolation System
Authors: Echols R. H. , Thomas P. T. , Oncale R. P. , Fischer Dan , Hubble T. A. , Park D. A. 
Published: December 2007

ABSTRACT
Completion fluids that are introduced to the reservoir during gravel-pack operations often cause formation damage that can substantially reduce production potentials. Most gravel-pack operations employ fluid loss preventive methods to manage this problem. However, in the scenario in which gravel packing is attempted from a floating vessel such as a semisubmersible rig or drill ship, an additional problem, rig heave (wave motion), must also be addressed; the effects of rig heave compound fluid-loss problems and require additional controls in the gravel pack system. Conventional systems have attempted to manage the problem by adding seals and collets for locating the workstring; however, these additions considerably increase the cost of the systems and have not adequately addressed both gravel packing and fluid loss prevention needs.
This paper will describe a new compact weight-down gravel pack system that has been successfully used on floating vessels for gravel packing. The traditional systems that have been used on floating vessels for the same purpose will also be described. Case histories will illustrate how the new system provides solutions to the difficulties normally experienced in offshore gravel packing. Of particular interest are the following advantages that use of the new system provides:
Operational costs are reduced since less rig time is required. Tool reliability is enhanced because of the simplicity of the system. No chemicals are required for fluid-loss prevention. Formation exposure to fluid loss immediately after gravel packing is in most cases eliminated.
Other applications are being proposed for the new system, and these will also be reviewed.
Geology and Hydrocarbon Potencial arctic regions of the West Siberian basin and the Kara sea
Authors: Girshgorn L. , Nemchenkc N. , Rovenskaya A. 
Published: December 2007

Abstract
The northern part of the West Siberian province is mainly a gas producing area. Onshore, gas forms 80% of hydrocarbon production and potential recoverable reserves are estimated at Trillions of cubic meters. The hydrocarbon potential of offshore extensions of West Siberian producing basins may be equally high. Kara Sea basin is a likely target for future exploration interest and development activity.
Arctic part of West Siberian oil-gas basin, including. offshore in the Kara-Sea and West of the Enisei-Hatang depression, is characterized by some peculiarities of geological structure and history and as consequence specificity of oil-gas bearing, that distinguishes this area from the rest West Siberia basin. This region has natural geographical bounderies: on the South it is the main watershead of the plain – Siberian Uvali, on the North it is the continental threshold in the Kara-Sea, on the West and East – these are exposed Hercynian and Cimmerian folded systems.
Specificity of the region may not be detected quite definitely in Geological Map (Fig 1), as the Cenozoic and Cretaceous sediments overlap the tectonicaly heterogeneous northern and southern parts of West Siberian plain by the single common cover. More clear picture gives the Scheme of "Major structures and age of the cover" (Fig 2).
Primary Design Considerations for a Packerless Annular Safety Valve (ASV) System for the North Sea
Authors: Taylor R. W. , Longbottom J. R. , Adams M. P. , White P. M. 
Published: December 2007

ABSTRACT
The trend in the North Sea has been toward installing annular safety valve (ASV) systems for tension leg platform (TLP) completions or for gas-lifted platform production wells. To satisfy the requirements for a highly reliable annular safety system for the Norske Shell Draugen project and an impending Norwegian TLP completion project for the North Sea area, tests were initiated to investigate the feasibility of a polished bore receptacle (PBR)-based ASV system. The nipple system has the capability to handle high hang-weight and/or thermally-induced loads, and the PBR nipple, pre-installed in the casing string, will permit a variety of completion designs that can be determined later in the welldevelopment cycle. Testing verified that 1) only a minimal pressure drop occurred through the system, 2) there were no compatibility problems between drilling/cementing operations and the PBR system, and 3) a PBR casing nipple assembly to anchor an ASV system has the capability to provide a viable alternative to use of a mechanical ASV packer and its related seals.
A Goal-Setting Approach to Offshore Regulations
Authors: Taylor B. G. S. 
Published: December 2007

ABSTRACT
The Offshore Installations (Safety Case) Regulations(1) represent a major step forward in the regulation of offshore safety. Operating Companies have a duty to conform with a Safety Management System and Safety Case prepared by themselves and which has been accepted by the Health & Safety Executive. This approach moves the UK Offshore Industry away from the prescriptive requirements of the past towards a goal-setting approach supported by non-mandatory Guidance.
To underpin the Safety Case Regulations, the Health & Safety Executive (HSE) proposes to enact further offshore specific regulations revoking or replacing existing prescriptive requirements. The new regulations will be expressed, wherever possible, in terms of safety objectives or goals to be achieved, rather than specifying particular precautions. The intention is for these goal-setting regulations to be supported by non-mandatory Guidance to be developed by HSE and Industry.
These aims are in accord with Lord Cullen's recommendations and the Industry takes no exception to them. Nevertheless the Industry has expressed concern that the new Regulations, if not carefully drafted, could undermine the primacy of the Safety Case Regulation rather than support it.
The UK Offshore Operators Association (UKOOA) has played a leading role in informal consultations with HSE and will contribute fully to the debate during the formal consultation phase on these regulations to ensure that they are compatible with and support the Safety Case Regulations which the Industry firmly believes should remain the foundation for improved safety offshore.
Partnering Between a Major Operator and Lead Contractors for Drilling and Well Services Activity
Authors: Schaafsma M. G. 
Published: December 2007

ABSTRACT
Shell U.K. Exploration and Production, Operator in the U.K. sector of the North Sea for Shell and Esso, has adopted a corporate strategy in line with the Drilling in the Nineties concept proposed by Shell Internationale Petroleum Maatschappij B.V. (SIPM) for all Shell Operating Companies. Within Shell Expro the Drilling in the Nineties concept has been broadened to incorporate the drilling, well services and equipment supply areas with the resultant name change to Well Engineering in the Nineties.
This strategy has now been implemented and has substantially changed the modus operandi between operator and contractor with a strong emphasis on long term partnership relations with lead contractors.
This paper summarises the strategy that has been developed, the implications of implementing this strategy; the implications to both a major operator and numerous contractor suppliers; the results to date; and the course of future partnership relations.
Partnering on the Forties Field
Authors: Hazlett K. P. , Helliwell Dennis 
Published: December 2007

Abstract
Four years ago BP was forecasting production from the huge Forties Field in the North Sea would become uneconomic by the mid nineties and progressive shutdown would commence around 1995-96 with the last platform being decommissioned by the year 2000.
A challenge was set to extend the life of the field through to 2010, and as a result of a major review by BP of the cost efficiency of its operations the challenge is beginning to be met. Forties production can now remain viable for much longer than expected in 1989, even after a fall in oil price from $25 to $18 per barrel. Not least of the influences making this extended life expectancy possible are the cost advantages promoted by an innovative Partnering venture between BP as operating company and Brown & Root as contractor.
The Forties Oil Field was discovered in 1970, 110 miles ENE of Aberdeen in 110 metres of water. Recoverable reserves were then estimated at 1.8 billion barrels. Four platforms were designed, constructed and installed and first oil was produced in September in 1975. Peak production of 500,000 barrels per day was reached in May 1978. A fifth platform was installed in 1986 and the 2 billionth barrel of oil was produced in April 1989, an achievement far in excess of original predictions. The estimate for recoverable reserves today stands at 2.5 billion barrels with the current production rate being 140 mbd.
Saving Thistle's Bacon: The Role of Reservoir Management in Optimising a High Watercut Field
Authors: Clyne P. A. , Bajsarowicz C. J. , Jones Kevin , Milne Donald , Richardson S. M. 
Published: December 2007

ABSTRACTAbandonment timing for Thistle is uncertain, and the aim of reservoir management is to accelerate reserves so that value is maximised prior to a target date. In an environment of tight expenditure control, the focus has shifted from large field studies to well reviews, and from infill drilling to rccompletion.