bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiscale Data Integration Using Markov Random Fields and Markov Chain Monte Carlo: A Field Application in the Middle-East
Authors: Malallah Adel , Perez Hector , Datta-Gupta Akhil , Alamoudi Waleed 
Published: December 2007

Abstract
Integrating multi-resolution data sources into high-resolution reservoir models for accurate performance forecasting is an outstanding challenge in reservoir characterization. Well logs, cores, seismic and production data scan different length scales of heterogeneity and have different degrees of precision. Current geostatistical techniques for data integration rely on a stationarity assumption that is often not borne out by field data. Geologic processes can vary abruptly and systematically over the domain of interest. In addition, geostatistical methods require modeling and specification of variograms that can often be difficult to obtain in field situations.
In this paper, we present a case study from the Middle East to demonstrate the feasibility of a hierarchical approach to spatial modeling based on Markov Random Fields (MRF) and multi-resolution algorithms in image analysis. The field is located in Saudi Arabia south of Riyadh and produces hydrocarbons from the Unayzah Formation, a late Permian siliclastic reservoir. Our proposed approach provides an efficient and powerful framework for data integration accounting for the scale and precision of different data types. Unlike their geostatistical counterparts that simultaneously specify distributions across the entire field, the MRF are based on a collection of full conditional distributions that rely on local neighborhood of each element. This critical focus on local specification provides several advantages: (a) MRFs are far more computationally tractable and are ideally suited to simulation-based computation such as MCMC (Markov Chain Monte Carlo) methods, and (b) model extensions to account for non-stationarities, discontinuity and varying spatial properties at various scales of resolution are accessible in the MRF.
We construct fine scale porosity distribution from well and seismic data explicitly accounting for the varying scale and precision of the data types. First, we derive a relationship between the neutron porosity and the seismic amplitudes. Second, we integrate the seismically derived coarse-scale porosity with fine-scale well data to generate a 3-D field-wide porosity distribution using MRF. The field application demonstrates the feasibility of this emerging technology for practical reservoir characterization.
Experience in Developing a Web Base Workflow to Enhance Competency
Authors: Ming Yeow Lei 
Published: December 2007

Abstract
How do one ensure consistent work quality and process in a large organization with multiple projects and a wide range of technical staff with various competencies and experience ? A web base Production Technology workflow was developed to meet the challenge. Production Technology work process was mapped, reviewed, validated, improved and integrated with other subsurface related disciplines in field development i.e. Geophysics, Geology, Petrophysics, Reservoir Engineering, Drilling and Petroleum Economics. The web base workflow was then implemented across the organization. Steps taken in the mapping, review, validation, improvement and integration process, learning points and benefits of developing such a system are discussed in this paper.
The workflow was categorized into issues identification, term of reference, data acquisition, processing, interpretation, model and archive for all disciplines. Knowledge and experiences of all Production Technologists in the organization was compiled and mapped. A high level workflow was first developed. Points of integration with other disciplines were identified. A "drilled down" process was used to detail out each step until the lowest level consisting of guidelines on each work step.
Steps in preparing the workflow consist of: –Preparing a high level work flow–Appointing each engineer to prepare a specific work process covering well completion design, material selection, sand control, well flow modeling, completion fluids, cement evaluation, wellhead & Christmas trees, artificial lift, etc.–A review process to improve the work flow and formulate the best way to put it in a web base format–A validation process with selected projects to ensure all steps are considered and realistic–The web site was implemented across the organization–Encouraging project teams to follow the work process
Learning points includes: –in-house experiences are more important with consultants as facilitator to compile and integrate the process–fitting workflow of different disciplines in the same categories needs flexibility–engineers working on daily business can contribute to corporate initiatives–concentrated and focus workshop sessions speed up the process
Benefits of the web base workflow includes: –a reference point for engineers to perform their job–more efficient mentoring and guidance from experienced engineers to young engineers–a reference point to quality check work and approve Field Development Plan–one point data base to compile work experiences, company standards and previous work reports for reference
Alternative Economic Criteria for Superior Project Analysis
Authors: Schaaf Robert , Hashim Hosnia 
Published: December 2007

Abstract
Economics performed by projected cost per unit analysis will give better insight into the merits of an oil production project than conventional measurements. This alternative economic metric can easily be used to determine if the project meets the objectives of a particular oil company. The proposed method will give pertinent values to see if return on investment, return on capital employed, operating expense, and cash flow goals will be met. As an additional benefit, cost per unit analysis also incorporates all the accounting pseudo charges. The inclusion of all actual and financial impacts will give a clearer picture as to the outcome a project will achieve. The calculations are not dependent upon predicting future oil prices or assigning a time value to money. Conventional economic measurements (net present value (NPV), internal rate of return (IRR), profitability indexes) can be misleading as to the actual benefit the project has for an oil company. They require that you predict oil prices and, in the case of NPV, assign a time value to money. These typical economic measures were designed to compare one project against another. High IRRs for capital investments can be due to initially high oil production and/or high tax regimes that allow for accelerated depreciation. A good NPV is sometimes achieved just by the large size of a project. Examples will be shown how projects with excellent NPVs and IRRs turned into disastrous economic failures despite performing close to prediction. Using the alternative method described in this paper would assist in avoiding costly mistakes and will help achieve the financial goals a company aspires.
Evaluation of a New Opportunity in a Matured Oil Reservoir
Authors: Al-Enezi Hamdah S. , Al-Qattan Raghad A. , Sinha Satyendra P. , Roe Stan E. 
Published: December 2007

Abstract
Matured oil reservoirs may have to be reviewed for unproduced mobile oil that has been compartmentalized by stratigraphy or structure. This paper presents such a case study in which the reservoir is more than 55 years old with no current producing wells within the case study area. A new well recently penetrated this reservoir and the unexpectedly higher oil column triggered this review. The reservoir is characterized by thin sandstone reservoirs with a strong, active aquifer. The workflow included a geological overview of the reservoir architecture and production/completion history of past completions. The detailed geological model was constructed incorporating the cased-hole oil saturations. This led to the building of a non-scaled-up, concurrent, 2-phase, 3D reservoir model for simulation using Frontsim. The fluid flow trend and the drainage pattern were analyzed by simulating the performance of assumed completions and re-completions of all the existing wells that penetrated this reservoir. The review resulted in the identification of a viable completion strategy to deplete the remaining oil trapped in this reservoir.
An Oil Market Without OPEC!
Authors: Zaid Alforgi M. 
Published: December 2007

Abstract
Oil prices rarely reflected those of a free market. The history of the oil industry documents several instances of monopoly and price fixing. In the last decade however, globalization and the ensuing economic policies raised the possibility that the oil market may finally be free from production and price controls. This paper will analyze the oil supply and demand patterns under scenarios of free market and will predict short and long-term price patterns under these conditions.
Scale Mitigation Enhances Safety and Production
Authors: Lewis D. R. , Zainalabedin K. A. , Al-Habib N. S. , Al-Beaiji T. M. , Al-Qahtani A. M. , Nasr-El-Din H. A. 
Published: December 2007

Abstract
Calcium carbonate scale represents a significant safety and operational problem in offshore carbonate fields operated by Saudi Aramco. Scale can form on any surface where the pressure drop is sufficient for the produced fluids to form the scale and unload entrained solids. These solids will deposit on wellhead equipment such as the wellhead surface valves, piping, well tubulars and may plug the perforations.
Well safety is jeopardized by hindering the operation of critical safety valves such as subsurface safety valves (SSSVs) and surface safety valves (SSVs). Further, scale buildup can cause backpressure problems in the tubing as the pipe internal diameter is reduced. Identification of scale in impacted wells requires periodic inspection and repair.
This paper presents Saudi Aramco&#39;s experience in eliminating calcium carbonate scale by treating existing scale using HCl acid. Scale mitigation was initially attempted using an encapsulated inhibitor placed in the rat hole of vertical wells. This method had a limited treatment effective life and Saudi Aramco has moved to using inhibitor squeeze treatments. Chemical squeezes places inhibitor (phosphonate-based) directly into the formation of wet oil producers and is now the currently employed method of long-term prevention of scale.
Case studies using both methods of scale mitigation are discussed as well as future plans to improve the effectiveness of these treatments.
Investigation of Asphaltene Precipitation onset Conditions for Kuwaiti Reservoirs
Authors: Gholoum E. F. , Oskui G. P. , Salman M. 
Published: December 2007

Abstract
Asphaltene Onset Pressure (AOP) conditions were measured for Kuwaiti Reservoirs fluid samples at reservoir, wellhead, and well-bore temperatures along with the saturation pressures by performing a series of pressure depletion tests using the mercury-free, variable volume, fully visual JEFRI-PVT system with laser light scattering. Asphaltene Deposition Envelope (ADE) and P-T phase diagram were developed. Asphaltene onset conditions were also investigated using different precipitants with Stock Tank Oil (STO). A number of titration experiments were performed on the STO using different alkanes and CO2. Our investigation has revealed that CO2 is the most effective asphaltene precipitant followed by alkanes (C1 to C7). To investigate the molecular structure of the asphaltene molecule, advanced analytical techniques such as 1H and 13C NMR and IR spectrometers have been utilized. It was concluded that the total number of carbon atoms was 220 of which 120 were associated with aromatic and the rest were aliphatic rings. The number of aromatic and naphthenic rings were estimated to be 42 and 114 rings respectively.
The Development Of Al Khalij - A Complex Carbonate Field, Offshore Qatar
Authors: Marion Dominique , Noman Rashed , Al-Othman Ibrahim J. , Leschi Pierre 
Published: December 2007

Abstract
The Al Khalij field, located offshore Qatar, was discovered in 1991 and put into production in 1997. The field is original in many aspects. It is one of the few carbonate reservoirs with a stratigraphic closure, the oil being trapped in the upper part of a monocline due to a lateral variation in reservoir facies. In addition, the reservoir lies within the capillary transition zone and consists of a succession of highly conductive oil bearing layers ("drains") in between matrix layers of poor permeability.
Due to the complex reservoir architecture and the large uncertainties in the reservoir dynamic behavior, the field has been developed in several stages to improve understanding and minimize risks.
This paper will discuss on the development of Al Khalij field and will illustrate how advanced technological solutions were applied to overcome complex geological and reservoir problems in order to enhance reservoir performance and well productivity. More specifically the paper will illustrate how: ➢High-resolution 3D seismic has revealed additional areas for development, which were previously considered to be uneconomic.➢Innovative well design in a stair-step manner was implemented to intersect productive layers and increase drainage efficiency with a limited number of wells.➢Stimulation and completion techniques were adapted to optimize productivity while limiting water production.➢Water injection was implemented in the field after validation of its effectiveness through pilot water injection, including tracer test, and through reservoir simulation studies.
Whole Core Analysis - Experience and Challenges
Authors: Honarpour M. M. , Djabbarah N. F. , Sampath K. 
Published: December 2007

Abstract
Whole core analysis is critical for characterizing porosity and directional permeability in heterogeneous, fractured, and/ or anisotropic rocks. Whole core measurements are essential for heterogeneous reservoirs because small-scale heterogeneity may not be appropriately represented in plug measurements. For characterization of multi-phase flow properties (special core analysis) in heterogeneous rocks, whole core analysis is also required.
Few commercial laboratories are equipped to conduct routine measurements on whole cores up to 5 inch in diameter and up to 8 inches long, and importantly, under simulated reservoir net confining stress (NCS). Special whole core analyses are rarely conducted because of difficulties associated with establishing a representative water saturation in drainage capillary pressure experiments and measuring directional effective permeability. Electrical properties are also measured occasionally to determine saturation exponents for situations where resistivity tools are utilized in horizontal or highly deviated wells.
In this paper we provide an overview of routine and special core analysis measurements on whole cores. Results from selected heterogeneous sandstone and carbonate rocks will be discussed. We will also show how the results relate to data obtained from plug analysis at the same depth, with particular emphasis on directional absolute permeability, directional effective permeabilities, trapped fluid saturation, and the effect of net confining stress. Finally, we will describe a novel whole core apparatus and provide examples of capabilities of the system.
In this paper, we will present: Recommended techniques for the determination of directional absolute, effective permeability and establishing initial water saturation in whole cores;Improved understanding of the effect of scale (sample size) on the measured properties;Description of a novel whole core apparatus with measurement of fluid saturation distribution using in-situ saturation monitoring.
Robust Reservoir Characterisation of UAE Heterogeneous Carbonate Reservoirs
Authors: Shedid Shedid A. , Almehaideb Reyadh A. 
Published: December 2007

Abstract
This study is conducted to test and evaluate the use of current methods of reservoir characterization, namely the permeability-porosity correlation, the J-function, and the Reservoir Quality Index (RQI) concepts, for reservoir description of heterogeneous carbonate formations. These approaches were compared with a new technique developed in this paper for improved reservoir description of carbonate reservoirs. This technique is called the Characterization Number (CN) technique and it is based upon considering fluid, rock, rock-fluid properties and flow mechanics of oil reservoirs.
To compare these reservoir characterization techniques, measurements of porosity, absolute permeability, oil and water relative permeability and irreducible water saturation for 83 actual core samples extracted from eight different wells for a new oil reservoir in the U.A.E. are obtained. These experimental data are used first to develop a permeability-porosity correlation. Then, the J-function and the RQI concepts along with the newly developed CN approach are applied and evaluated for reservoir description of the UAE carbonate reservoir under investigation. The results show that the Reservoir Quality Index concept is capable of identifying the flow units while the J-function concept is quiet poor. Also, a more refined identification of flow units is obtained by using the newly-developed Characterization Number. This improved description for the Characterization Number approach may be attributed to the consideration of rock/fluid properties of flowing fluid(s) and flow dynamic conditions of its containing formation.
Planning is Critical for Underbalance Applications with Under-experienced Operators
Authors: Divine Ron 
Published: December 2007

Abstract
The benefits of a properly executed Underbalance Operation (UBO) can result in a well of higher quality and value than that of a conventional well, if proper planning and execution is achieved. This paper discusses the importance of detailed planning when undertaking a UBO and the consequences when conducted improperly.
UBO has demonstrated numerous times that:
Higher penetration rates (&gt;2X) can be realized Higher productivity (&gt;2X) can be achieved Higher reserves recovery are achieved
UBO has proven to reduce development costs, on multi-well projects. The timing for this cost reduction depends largely upon:
the well construction staff in charge of the operation the rate of knowledge transfer from the experienced personnel (service technicians) to the operator the utilization of the information by the operator.
The current knowledge base of UBO is miniscule compared to conventional Overbalance Operation (OBO) knowledge. Access to this knowledge base and implementing the value of the knowledge are critical to expansion of the technology and the establishment of credible operating practices. Global industry organizations such as the International Association of Drilling Contractors (IADC), Society of Petroleum Engineers (SPE), and Gas Technology Institute (GTI) have dedicated significant time and resources to promote the exchange of knowledge and develop safe operating practices of UBO. These organizations should be accessed to reduce the learning time for companies considering the use of UBO equipment and services.
The critical keys to achieving the benefits of UBO, are planning and execution. Several real case histories are presented, which demonstrate the impact of critical planning and execution on project cost. Accessing the knowledge base and implementing lessons learned will enable the user to achieve a successful UB Operation.
Innovative Technology Advances Use of Electromagnetic MWD Offshore in Southern North Sea
Authors: Brett Peter , Weisbeck Denis , Graham Robert 
Published: December 2007

Abstract
The underbalanced drilling campaign undertaken by Shell U.K. Exploration and Production (Shell Expro) offshore in the Southern North Sea has been on the cutting edge of UBD technology since its inception in 1997. Electromagnetic (EM) telemetry systems were incapable of performing in the Southern North Sea due to the depth and nature of the formations. However, recent enhancements to the technology have greatly expanded the scope of EM telemetry. The use of this technology has potential for expanding the scope of underbalanced operations possible in the Southern North Sea.
A fundamental advantage of the EM telemetry system is the capability to transmit data independently of wellbore hydraulics. For example, down-hole pressure data can be transmitted to surface during pressure buildup tests and flow tests. Data can also be transmitted during trips, during connections, with pumps on or off, etc. The transmission of data is unaffected by loss of drilling fluid returns, the use of air, air-mist, foam or other multi-phase drilling fluid mediums generally associated with underbalanced drilling practices. The down-hole instrumentation can also be interrogated or reprogrammed at any time by direct communications protocol, which is completely independent of the rig or drilling activity.
A new, innovative twist to enhance the use of EM telemetry involves the use of insulated casing to reduce signal attenuation and further expand the application of the technology where it has been previously out of reach. This paper discusses rationale for the use of EM telemetry in the Southern North Sea basin and the results of a recent successful field trial of the technology.
Design and Operational Considerations to Maintain Underbalanced Conditions with Concentric Casing Injection
Authors: Mykytiw C. G. , Davidson I. A. , Frink P. J. 
Published: December 2007

Abstract
Underbalanced drilling (UBD) has the potential to add value by maximizing productivity and ultimate recovery by reducing formation damage. The benefits of UBD are of course dependent on the ability to maintain underbalanced conditions throughout the entire life of a well, especially during the drilling phase. The ability to maintain underbalanced conditions is complicated because real UBD wells are rarely, if ever, in a "steady-state" condition and are subject to constantly changing or transient flow behavior. Improved understanding of the transient flow behavior will increase the ability of the rigsite engineer to maintain the desired bottomhole pressure and thus minimize potential formation damaging, overbalanced periods. This paper illustrates how detailed transient analysis provides a rigorous engineering basis for selection of the appropriate methods, to maintain optimum downhole conditions by minimizing bottomhole pressure instability.
Methods to mitigate destabilizing transient effects with drill pipe injection are relatively well understood, due to extensive case histories, but less experience is available with concentric casing (CC) injection and thus less is known on options to control pressure instability.
The UbitTS transient flow simulator is used to optimize design and operational parameters to minimize well slugging tendency and pressure instability when the concentric casing injection technique is employed. Reference is made to a generic test well, but the methodology has application to all UBD operations considering CC injection.