bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison of approaches to EMS implementation in two E&P Companies
Authors: Brandon Oliver , Nixon Ashley 
Published: December 2007

Abstract
In recent years there has been an increasing interest in the design, development and implementation of environmental management systems (EMSs) in the E&P industry. In large measure this is due to the much higher profile that environmental issues have attracted in the public mind, and the requirement for organisations to demonstrate their commitment to excellent environmental performance. The introduction and widespread acceptance of ISO 14001 as a model for such EMSs has added a further impetus to the development process, among both companies with a long-standing environmental policy, and those whose environmental awakening has been more recent.
For those whose awareness of environmental issues is well established in management practices, the challenge has been to review systems and align them with the requirements of the Standard. For others, with a more recent environmental awakening, the challenge has been to create an EMS unsupported by a culture of environmental awareness or formalised management.
This paper compares the approach of two quite different companies to the design, development and implementation of their EMSs. In March 1997, Perez Companc S.A., an Argentine company, became the first E&P operator in the world to achieve ISO 14001, when three of their fields in Argentina were certified by DNVQA. Shell Prospecting and Development Peru (SPDP) are the leaders in the development of the Camisea gas field in Peru, and are well advanced in the adaptation of existing environmental management practices as part of their programme of ISO 14001 implementation, aiming for certification in 1998.
The experience of these companies has demonstrated that even though the context differs substantially between the two organisations, there are common features in their respective approaches to the process which may be useful guides to others embarking on similar programmes.
A Multi-Point Flux Discretization Scheme for General Polyhedral Grids
Authors: Gunasekera D. , Childs P. , Herring J. , Cox J. 
Published: December 2007

Abstract
Multi-point flux discretization schemes for triangular, 2D perpendicular bisection, tetrahedral, 3D perpendicular bisection and corner point grids have been presented in the past by Aavatsmark and Verma in several papers. This paper presents a single implementation based on the ideas in the above papers for general 3D structured and unstructured grids, regardless of their method of construction. In this work, multipoint flux (MPF) coefficients are calculated only for cell faces that exceed a K-orthogonality error limit and are supplied to the simulator as an additional list of transmissibilities.
Following a construction or a conversion, all grids are stored in a general unstructured grid data model, where a grid is a collection of cells, a cell is a collection of faces and a face is an ordered list of points. The surface of a cell face is described by the set of triangular facets created by joining the centroid of the face to its edges. Externally generated corner point grids are converted to this data structure before generating MPF terms, which may involve a face splitting step at faults. The permeability within each cell is allowed to be a full tensor at an arbitrary orientation. The K-orthogonality error is estimated at each cell interface and is used to select the transmissibility formula, which is either K-orthogonal type leading to a two-point flux or multi-point type.
The paper presents simulation results for a set of test examples, with and without the use of multi-point fluxes. Comparisons of accuracy and CPU times are also presented to provide an understanding of the efficiency of the scheme.
Technical contributions in the paper include the conversion of corner point grids into a triangular facet based model, an algorithm for calculating multi-point flux coefficients for general structured and unstructured grids and the handling of MPF terms in a simulator.
Fully-Coupled Geomechanics and Fluid-Flow Analysis of Wells with Stress-Dependent Permeability
Authors: Chin L. Y. , Raghavan R. , Thomas L. K. 
Published: December 2007

Abstract
A fully-coupled geomechanics and fluid-flow model is developed to analyze pressure transient problems in stress-sensitive reservoirs with nonlinear elastic and plastic constitutive behavior. For hydrocarbon reservoirs with stress-dependent permeability (stress-sensitive reservoirs), the coupled interaction between geomechanics and fluid production can significantly influence both the stress state and the fluid flow in the reservoir. Therefore, in general the coupling effect can not be ignored when analyzing stress-sensitive reservoir problems. Detailed model formulations and numerical implementation are presented. Practical application examples illustrating various aspects of well behavior analysis of stress-sensitive reservoirs are also demonstrated in this paper.
Integrated Reservoir and Surface Pipeline Network Compositional Simulations
Authors: Litvak M. L , Wang C. H. 
Published: December 2007

Abstract
Effective procedures for the integrated reservoir and surface facility compositional simulations have been developed. Multiphase compositional fluid flow equations in reservoir, well tubing strings, and surface pipeline network system are solved simultaneously. The procedures have been implemented in the commercial compositional reservoir and surface facility simulator VIP.
The equation of state is applied for the phase-equilibrium calculations. New equation of state (EOS) interpolation procedure has been developed (as an option) for simplified phase-equilibrium calculations in integrated compositional simulations. The EOS interpolation procedure can be effectively applied for phase-equilibrium calculations in reservoir, well tubing strings, pipelines, and/or separators. Saturation pressure, recovery factors of hydrocarbon components, and compressibility factors are determined as tabular functions of pressure, temperature, and fluid compositions. The equation of state is applied for the automatic generation of these functions in an initialization step of a reservoir simulation.
The effectiveness and accuracy of the new simplified phase-equilibrium procedure have been confirmed in many full field compositional models and pattern models. The new option significantly reduces the CPU time required for the simulations and it matches results of fully compositional simulations in tested models.
The developed procedures for the integrated reservoir and facility compositional simulations have been applied in many reservoir studies. Their applications in the integrated reservoir and surface facility model of the giant Prudhoe Bay oil field have been demonstrated.
A Generalized Friction Factor Correlation to Compute Pressure Drop in Horizontal Wells
Authors: Yalniz M. U. , Ozkan E. 
Published: December 2007

Abstract
This work investigates the effect of fluid ingress through perforations on flow in a horizontal wellbore and correlates this effect in the form of an apparent friction factor. The investigation uses theoretical and experimental models. It is shown that when there is no influx, the perforations or slots on the well surface cause a reduction in the pressure gradients proportional to their area. The wellbore pressure gradients increase with influx from perforations but unless the ratio of the influx rate to the wellbore flow rate is sufficiently large, pressure gradients are lower than those of an unperforated well. The results of this study are combined to develop a generalized friction factor correlation that is a function of the Reynolds number and the ratios of the influx to wellbore flow rate and the perforation to wellbore diameters.
A New Method for Evaluating Layer Productivity Using a Permanent Monitoring System
Authors: Da Prat G. , Eliseche L. , Iriarte J. 
Published: December 2007

Abstract
A new method is presented for layer evaluation in pumping wells based on the inflow-performance relationship (IPR) determination for each layer contributing to the well production. Both the theory and field examples of the application are explained. The fundamental principle of the method is the IPR determination for each layer that is contributing to the well production. A permanent monitoring system consisting of a permanent gauge and a shut-in valve is installed in the well to discriminate the flow rate from each layer corresponding to a given stabilized formation dynamic pressure. The method is inherently quality controlled: both rate and transient pressure are continuously monitored at the surface during the test to assure stabilized conditions for a valid IPR.
The new method is illustrated with field cases of wells located in the Chihuido de la Sierra Negra oil field, Argentina, which is undergoing a secondary recovery project by water injection. Water is injected and produced from two main layers. Both lateral and vertical displacement efficiency determination have been evaluated from the beginning of the project. In most of the wells, production from the two main zones is combined. A permanent monitoring system was installed in several key wells, and the IPR for each zone was obtained. The rate from each layer was obtained directly using the system. In addition, the reservoir pressure was obtained by direct measurement and an interference test conducted using one of the nearby injectors as the active well.
A relevant conclusion obtained in one of the evaluated wells was that the production of one of the layers was responsible for most of the total production, contrary to the expected results based on conventional methods of assigning layer production based on total production split according to layer petrophysical properties. IPR data fit was done using the Fetckovitch model.
It can be concluded that the methodology presented can be considered as a major breakthrough in testing and evaluation of layer productivity applicable to multilayer completions.
The Integration of Geology and Well Testing for Improved Fluvial Reservoir Characterisation
Authors: Corbett Patrick , Zheng Shi-Yi , Pinisetti Moe , Mesmari Abdallah , Stewart George 
Published: December 2007

Abstract
Fluvial reservoirs are important hydrocarbon reservoirs worldwide. It is the fluvial depositional characteristics that give rise to the complex reservoir architectures/geometries, spatial distributions/patterns, internal heterogeneities/petrophysical properties as well as the connectivity between flow units/channel sands that combine to give great uncertainty in characterising the effective reservoir properties.
Well testing, which measures the dynamic response of the reservoir, is potentially a very important tool for investigating these properties in fluvial reservoir systems. Through the integration of geoscience and engineering, the uncertainty resulting from reservoir description and well test analysis in such heterogeneous systems can be substantially reduced.
This paper reviews the latest techniques developed from the integration of geology and well testing for fluvial reservoir characterisation. Starting from the classification of fluvial systems, deterministic geological models, based on the two end members of fluvial systems (Meandering and Braided), have been mapped out.
A well test interpretation model for meandering channel reservoirs, the Pseudo-channel model has been distilled, which removes the assumption of the uniform formation thickness. Numerical solutions, termed Geotype curves have been derived. A new measure for the reservoir heterogeneity leading to an Effective flow interval has been developed, which shows a significant improvement from the conventional core analysis method. Geoskin as a geological phenomena has been identified and the technique quantifying its value with respect to geology has been developed. A wealth of geological data sets, derived from ancient (outcrops) and modern rivers, have been integrated. Fluvial Flow System Diagnostic Plots (FFSDP) have been developed, with which ten well tests of Tertiary channel sand reservoirs from the Gulf of Thailand have been evaluated.
Based on these studies, a Two-stage diagnostic procedure for well test analysis has been developed. A confident interpretation requires that the tested system should be clearly mapped out prior to the transient data analysis in ensuring the correct selection of the interpretation model. Then the meaningful reservoir parameters can be inverted. The final match to the tested data should be made by the Numerical solution from the defined reservoir system, rather than "force" an analytical model, which are mostly idealised, for the match.
An improved understanding on the scale and limits of the disciplines involved in reservoir characterisation is crucial for the integrated studies. This study gives insights into the integration and scaling of measurements as well as the need for improved geological, petrophysical and dynamic descriptions.
Composite Drill Pipe for Oil and Gas E&P Operations
Authors: Lou Alex Y. , Souder Wallace W. 
Published: December 2007

Abstract
Composite high torsional stiffness, strength and light weight properties are particularly applicable in extended reach drilling. Composite drill pipes can be designed to provide improved resistance to buckling and a reduction of friction and drag while saving 50% of the weight. The horizontal distance can be easily increased 40% from 25,000 to 35,000 feet over the conventional steel drill pipe. In offshore E&P operations, more oil and gas reserves can be reached from a single drill platform. Thus, substantial saving can be realized from fewer, smaller and lighter structures. This is extremely important in deepwater operations, where the platform weight is a major design consideration, additionally, this extended reach capability allows many reservoirs to be tapped from existing structures, which probably will not be developed otherwise. Additionally, real time monitoring of logging while drilling (LWD) and measurement while drilling (MWD) is limited by the rate of transmission of signals to the surface. Current technology utilizing pressure pulses in the mud stream is limited to about 10 pulses per second. Replacing the electrically conductive drill string with one having low conductance, such as a composite drill pipe, would permit deployment of electromagnetic transmission systems and could potentially increase the transmission rate by several orders of magnitude.
Managing the Platform Decommissioning Process
Authors: Griffin William S. 
Published: December 2007

Abstract
Until the summer of 1995 the decommissioning of redundant offshore oil and gas facilities was thought to be just another construction project. Public pressure and the resulting political turmoil from the Brent Spar incident showed there are more factors to be considered than technology and the applicable regulatory regime. The UK authorities did everything required by the regulatory regime and the operator applied good science and technology in arriving at the recommended disposal option, yet the Brent Spar remains today in a Norwegian Fjord.
To discuss "Managing the Platform Decommissioning Process", it is important to review the lessons learned and to consider factors related to decommissioning highlighted by industry's recent experiences.
Field Foam Applications in Enhanced Oil Recovery Projects: Screening and Design Aspects
Authors: Turta Alex T. , Singhal Ashok K. 
Published: December 2007

Abstract
An in-depth analysis was conducted for over forty foam applications in Enhanced Oil Recovery (EOR) projects, and numerous production well treatment operations involving the use of foam in cyclic steam operations and in gas miscible floods, to derive insights on screening and design aspects in such applications. Foam can be used to solve conformance problems caused by either a thief zone or gravity override; The proper identification of the cause, as well as of the production well(s) affected is basic to the definition of the problem. Either blocking/diverting foams or in-depth mobility control foams can be placed through the injection wells. On the other hand, foam treatment in production wells is done mainly to mitigate an override problem. The most important factors in foam assisted EOR projects were determined to be: (a) manner of foam placement in the reservoir (injection of pre-formed foam, co-injection foam and SAG or surfactant alternating gas foam), (b) reservoir pressure and c) permeability. While pre-formed foam are effective mainly in the treatment of the production wells, the co-injection foam and SAG can be employed for solving specific sweep efficiency problems in EOR projects. It is concluded that for designing a steam-foam project (which is essentially a low pressure foam application) a foam quality in the range 45% to 80% should be considered. In this kind of application, a co-injection foam is to be employed and the additives (surfactant and non-condensable gas) are to be injected intermittently (on and off), superimposed on a continuous steam injection. Injection cycles as short as 7 days (2 days-on and 5 days-off) should be considered. Under suitable conditions, an oil rate increase of 1.5 to 5 times, a decrease in water cut by 20 %, and an incremental oil recovery of 6%-12% OOIP can be achieved with such an implementation. At high pressure, such as in gas miscible flooding (CO2 and hydrocarbon gas), foam application can result in excessive mobility reduction factors, and injectivity reduction. Due to this reason, alternate injection of surfactant solution and gas (SAG foam) is favoured over a co-injection mode of placement. Recommendations for laboratory tests in support of a proper design of the field pilot are presented.
A New Two-Dimensional Model for Acid Fracturing Design
Authors: Settari A. , Sullivan R.B. , Hansen C.E. 
Published: December 2007

Abstract
The paper describes a 2-D model of acid fracturing which is more rigorous than current acid fracturing simulators. The equations are discretized and solved along fracture length and across the width (in × and y directions), as opposed to a lumped formulation in the conventional model in which the y-solution is replaced by a mass transfer coefficient Kg. In the 2-D model, correlations for Kg are not needed, and the model uses only directly measurable data. In addition, the model can represent transient effects (Kg variable along frac length and in time) combined with dispersion and thermal effects.
Two models, one for lab experiments and one for field design, were developed. The lab model was validated against results of Roberts and Guin with excellent agreement and compared with the l-D approach on data typical for Phosphoria dolomite. The results show large differences in regions of high as well as low leak-off. Also, acid spending predicted by the 2-D model is higher even when the Kg values are comparable. Correspondingly, the field design model predicts larger spending and frac conductivity.
An example of the field design and post frac history match from the Cottonwood Creek Unit, Washakie County, WY is presented. It shows that the new model is in better agreement with field data. Extensions to a 3-D modeling are also discussed.
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Modeling a Jet Pump with an Electrical Submersible Pump for Production of Gassy Petroleum Wells
Authors: Carvalho P.M. , Podio A.L. , Sepehrnoori K. 
Published: December 2007

Abstract
The objective of this work is to present the concept of the Electrical Submersible Jet Pump (ESJP). It is a new artificial-lift method for application in the petroleum production industry This proposed artificial-lift method uses an electrical submersible multistage centrifugal pump in combination with a jet pump installed in the well bore along the tubing string. Such a method is proposed to allow production of high gas- liquid-ratio petroleum wells using the existing electrical submersible pump technology. While applicable to any petroleum well, the driving force and main motivation for the development of this new technology is deep offshore petroleum production. In this work, also presented is a numerical model developed to simulate the operation of the system. In such a model, the system is analyzed as three coupled subsystems: the electrical submersible pump (ESP), the low gas-liquid-ratio (GLR) multiphase flow in the tubing string, and finally the flow inside the jet pump (JP). Both individual models used for the ESP performance and the multiphase flow inside the tubing string are available in the literature. In this paper we present the modeling of the multiphase flow of fluids inside the liquid-jet gas pump (LJGP), which was developed based on the simultaneous solution of the mass, momentum, and energy conservation equations.
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Gradual Deformation of Continuous Geostatistical Models for History Matching
Authors: Roggero F. , Hu L.Y. 
Published: December 2007

Abstract
This paper presents a new methodology for constraining 3-D stochastic reservoir models to well and historical production data. Based on the inversion framework, this methodology is mainly composed of a new algorithm for gradually deforming continuous geostatistical models and of an efficient optimization algorithm. The gradual deformation algorithm generates a process of realizations which evolve smoothly while preserving the overall statistical characteristics of the stochastic model. Deformation control by a limited number of parameters improves the efficiency of the process. In comparison with other approaches, the number of iterations is significantly reduced.
The deformation procedure can be coupled with an optimization algorithm to obtain automatic history matching capability. The inversion of several model parameters and the gradual selection of a new constrained realization can be performed simultaneously. The analytical gradient method as well as approximated gradients are used to improve the convergence rate of the procedure.
The successful application to a 3-D synthetic case, derived from an actual field case, is described in the paper. The shape of the top structure of the reservoir and the activity coefficient of an aquifer are simultaneously constrained to the historical data recorded for 5 wells. The structural uncertainties are described by a geostatistical model. The definition of the top structure is improved by gradual deformation to ensure the geostatistical consistency of the model during the match of production data. An interference well test case is also presented to illustrate the decrease in uncertainties obtained by integrating a geological description and pressure data.
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