bluuebunny/crossref_metadata_2025_split huggingface dataset:
Permeability Anisotropy Measurement on Whole Cores—Analytical Solution and Application
Authors: Al-Yousef H. Y. 
Published: December 2007

Abstract
This paper presents an analytical solution for the steady-state flow problem for the anisotropic permeability measurement. It also describes a practical procedure that implements the solution to evaluate permeability anisotropy. The procedure requires a few steady-state measurements of flow rates and pressure drops at different directions from which the maximum and minimum permeability values and their directions can be determined. The application of the new solution and the proposed method is demonstrated by measurements on whole core samples. Comparison between results obtained using the new solution for the anisotropic case and the existing solution for the isotropic case is discussed.
Reservoir Screening and Sensitivity Analysis of Waterflooding With Smart Wells Through the Application of Experimental Design
Authors: Esmaiel T. E. H. , Fallah S. , van Kruijsdijk C. P. J. W. 
Published: December 2007

Abstract
This study demonstrates the feasibility of creating a response surface proxy model, using experimental design and analysis, to facilitate Monte Carlo simulation, uncertainty analysis and screening of performance forecasts. In particular we applied the technique to assess the value of smart wells in waterflooding a heterogeneous reservoir and to examine the sensitivity to geologic, production and economic parameters. This was achieved through the generation of proxy models using various d-optimal designs with a full factorial design for comparison. The models were further validated with independent simulations to verify the predictions.
The computationally efficient proxy models allowed Monte Carlo analysis to determine sensitivities and the quantification of an increase in expected value through the use of smart wells. The improvements in simulation speed were in the order of 1,000 to 10,000 times faster. In the examples studied we found that the negative impact of geological features on the waterflooding performance could be almost entirely mitigated through dynamic flow control with smart wells operating under rate constraints.This provided an options value due to reduced risk in addition to an increase in the expected NPV.The Monte Carlo analysis also allowed the quantification of the value of information in collecting additional data to reduce the uncertainty in reservoir properties and the resulting reduction in NPV uncertainty.
Analysis Behind Casing: A Window for Improved Reservoir Management of a Mature Bahrain Oil Field
Authors: Murty C. R. K. , Zubari H. , Srivatsava A. , Ramamoorthy R. , Rampurwala M. A. 
Published: December 2007

Abstract
Management of mature oil fields requires accurate formation evaluation information. The ability to acquire essential data through casing adds a new dimension to reservoir characterization and affects the reservoir development of a mature oilfield like the Bahrain field. New logging tools and technology fill the gap in evaluation, especially for monitoring water saturation changes over time and for detecting bypassed oil pockets across the zone.
In this paper we present the results and validity of a logging through casing run in a depleted well completed in a sandstone reservoir in the Bahrain oilfield. The reservoir has a complex lithology of high-permeability sandstone with thin interbeds of siltstone and shale, erratically deposited but prolific in oil production. The objectives of the data acquisition were to monitor oil depletion through casing and to study the effect of lithology on the water encroachment pattern across the zone.
In this paper we describe the interpretation procedures and data validation of the information obtained from an advanced suite of logs run through casing. The paper also focuses on how this new information has resulted in a review of potential further development of this pay in one part of the field.
Investigation of Thermal Gas-Oil Gravity Drainage (GOGD) in Fractured Carbonate Reservoirs
Authors: Ayatolahi S. , Boukadi F. , Wadhahi M. , Maamari R. , Bemani A. 
Published: December 2007

Abstract
In Oman, it is known that the oil content in matrix porosity in fractured carbonate oil reservoirs exceeds more than 90% of the oil originally in place. Minimal recovery factors during the primary stages of production are due to the nature of these carbonate reservoirs; geometry and extent of the fracture network, matrix permeability, wettability tendency, as well as the nature of the fluid system. The occurrence of a strong water drive, in some of the fields, becomes even more detrimental to primary recovery.
The Omani oilfield of Qarn Alam, with a naturally-fractured Shuaiba carbonate reservoir, is at the center of this investigation. Its reservoir contains 213 million cubic meters of heavy crude (16 oAPI and 220 cp) with an expected ultimate oil recovery of 2% of STOIIP, under primary depletion. Intensive theoretical and experimental studies are carried out in an attempt to quantify potential gains from the Gas-oil Gravity Drainage (GOGD) mechanism that is taking place in the reservoir. Investigations will be undertaken to validate the theory that the combined effects of matrix accessibility to the trapped oil by hot gas, oil viscosity reduction, and the possible oil bank formation are contributing to a higher oil recovery factor during GOGD.
Using Gradients to Refine Parameterisation in Field-Case History Match Projects
Authors: Cominelli A. , Ferdinandi F. , De Montleau P. C. , Rossi R. 
Published: December 2007

Abstract
Reservoir management is based on the prediction of reservoir performance by means of numerical simulation models. Reliable predictions require that the numerical model mimics the known production history of the field. Then, the numerical model is iteratively modified to match the production data with the simulation. This process is termed history matching (HM).
Mathematically, history matching can be seen as an optimisation problem where the target is to minimize an objective function quantifying the misfit between observed and simulated production data. One of the main problems in history matching is the choice of an effective parameterization: a set of reservoir properties that can be plausibly altered to get an history matched model. This issue is known as parameter identification problem and its solution usually represents a significant step toward the achievement of an history matched model
In this paper we propose a practical implementation of a multi-scale approach to identify effective parameterizations in reallife HM problems. The approach is based on the availability of gradient simulators, capable of providing the user with derivatives of the objective function with respect to the parameters at hand. Those derivatives can then be used in a multi-scale setting to define a sequence of richer and richer parameterisations. At each step of the sequence the matching of the production data is improved. The methodology validated on synthetic case and has been applied to history match the simulation model of a North-Sea oil reservoir.
The proposed methodology can be considered a practical solution for parameter identification problems in many real cases. This until sound methodologies, primarily adaptive multi scale estimation of parameters, will become available in commercial software programs.
Wettability Index Determination by Nuclear Magnetic Resonance
Authors: Looyestijn W. , Hofman J. 
Published: December 2007

Abstract
Knowing the wetting condition of a reservoir at an early stage is crucial for selecting optimum field development options. Paying insufficient attention to the wetting condition e.g. assuming water wet behavior) may result in incorrect STOIIP estimates, and in unexpected dynamic behavior, e.g. under water flooding.
A novel method is presented to determine the in-situ wettability of rocks from NMR logs. The method is based on the fact that fluids experience additional relaxation when in direct contact with the rock surface. A reduction of the oil relaxation time away from its bulk value is generally known as a qualitative wettability indicator. Through detailed modeling of the NMR response, this concept has been further developed to provide a quantitative wettability index. It is based on a model for the microscopic distribution of the crude oil and the wetting state of the rock at any given overall saturation. The method requires an NMR measurement on a sample containing two reservoir fluids, i.e. brine and crude oil. Multi-acquisition schemes including diffusion effects make the interpretation more robust, but a normal NMR acquisition suffices and can be made with all available NMR tools (wireline and LWD).
The new NMR based method has been extensively verified on core data against standard wettability tests. Application to NMR logs from several fields, and in particular carbonates, show continuous profiles of varying wettability, ranging from fairly oil-wet, through intermediate, to waterwet, all in line with the available core data.
Operating Experience With Dual and Triple Slimhole Injectors in Coalinga
Authors: Zahedi A. , Johnson R. 
Published: December 2007

Abstract
The Coalinga field is one of the oldest oilfields in California and has been under production for over 100 years. The Temblor sands comprise the major reservoir in Coalinga at a depth of 500-2200 ft, with porosity of 33%, oil gravity of 12-14 API, and air permeability of 0.7-3 darcies. Each Temblor sand is at a different stage of drainage and thermal maturity requiring different steam injection rates in each zone.
A significant number of slimhole injectors have been drilled in Coalinga dedicated to single zones as a way to control steam injection in multiple-zone steamflooding. Nearly 200 slimhole injectors were drilled at Coalinga from 1988 to 2002.
Dual and triple string slimhole injector designs were used in West Coalinga as a cheaper alternative for conventional dual and triple zone injector completions. However, operating problems with some of the slimhole wells have negated much of the cost savings.
Currently all triple slimhole injectors are shut-in as most of them have experienced near surface tubing failures and subsequent steam migration to the surface. Some of the dual and triple slimhole injectors drilled in close proximity to each other at Coalinga have experienced steam migration out of the perforated zones into nearby zones due to low quality cement placement in the triple completions.
Monitoring and operation of the triple injectors has been a difficult task due to their surface equipment design. This has shown that operational and monitoring design related issues need to be addressed in detail prior to field implementation. This paper discusses the performance history of slimhole design injection wells in Coalinga. It reviews advantages and disadvantages of dual and triple slimhole injectors, compares single and multiple string slimhole injectors with similar conventional injectors, and shows general field examples of historical slimhole operational and monitoring issues.
Better Results Using Integrated Production Models for Gas Wells
Authors: Harms L. K. 
Published: December 2007

Abstract
While each engineering discipline may have a piece of the puzzle to find the best solution for achieving optimized production rates and economics, we can only hope to achieve the best results if we use a total system (reservoir to sales point) approach. Relatively simple to use software tools are available to help and can be easily applied, especially on gas wells. However, effective use of these tools will require the engineering disciplines to break down silos, possibly compromise on using their "favorite" tools and work together. Examples and case histories on gas wells are shown to demonstrate how each discipline looks at solving problems and how better solutions are found using an integrated production model (IPM).
An Experimental Investigation of Reaction-Transport Phenomena During Co2 Injection
Authors: Egermann P. , Bazin B. , Vizika O. 
Published: December 2007

Abstract
The injection of carbon dioxide in depleted petroleum reservoirs or in aquifers is a promising way to cope with the short-medium term issue of greenhouse gas emissions mitigation. Several coupled physical and chemical processes may occur during the injection depending on time and location within the reservoir. Far field regions are facing long term reaction in a situation where flow of gas and water at a reduced rate may induce near fluid-rock equilibrium. In contrast, near well-bore regions are subjected mainly to gas at a high flow rate where dissolution/reprecipitation phenomena may increase/decrease drastically the injectivity.
The purpose of this study is to investigate experimentally the various situations in representative reservoir conditions with the objective of achieving knowledge and data for future physical and numerical modeling and reservoir numerical simulations of CO2 re-injection. Experiments consist in the co-injection of CO2 and brine in carbonate cores (limestone). The temperature and pressure conditions are such that the CO2 is in supercritical state. Results show that the flow rate and the composition of the fluids initially present in the core play a major role in the fluid-rock interaction leading to various non-uniform dissolution facies and in some cases to re-precipitation and permeability reduction. These phenomena have been observed and quantified using various non destructive techniques (NMR, CT-scanner) and chemical analyses of the producing fluids, leading to a comprehensive understanding of the coupled mechanisms taking place.
Career Development System; A Giant Nascent
Authors: AbouHeif M. 
Published: December 2007

Abstract
A pioneer local attempt presenting new experiences and valuable contribution to the oil and gas industry careers and competences development.
Businesses used to partner with employees to carry out employees’ career planning and development. Times have changed. Now, businesses are coming to view career development primarily as the employee's responsibility. However, proper guidelines, procedures and systems are furnished and huge resources are made available by the businesses to help employees in their career planning and provide managers with the right judgment tools.
Such resources and capabilities are usually not available to the national and local companies. Tailoring a precision "Career Development System" to suite the local environments and compete, at the same time, with the multinationals' capabilities is not an easy task.
The Career Development System: Tells employees where they stand;Shows employees their possible career paths;Helps employees to choose the career path that best matches their competences, ambitions and vision;Describes a detailed step by step procedure to develop competences and to move up the ladder from one position to the other in each career path;Supplies the necessary follow-up sheets and forms to help each manager and employee in taking timely & correct career decisions and, at the same time, guarantees the fairness and the proper implementation of each procedure.
Our company's "Career Development System" has passed through many stages starting from the "need rise" stage, the "system building" stage, the "validation & revision" stage, the "implementation" stage, up to the "evaluation" stage.
This paper goes through all these different stages, describing the difficulties of each stage, suggesting solutionsbased on our gained experience and offering some picked examples from our system. As a conclusion, this paper also describes the positive impact of this system on all our business aspects.
We wish to present our experience to all national and local companies in our area to help setting the example and simply say that WE DID IT.
Integration Tools to Streamline Reservoir Management and Field Development Workflows for Mature Fields in South Oman
Authors: Naguib M. A. , Shahin E. , Moore J. 
Published: December 2007

Abstract
Enhancements in software, hardware, expertise, data collection and interpretation have continued to improve the industry's ability to build detailed 3D geologic and dynamic flow models of the subsurface and to take rational reservoir development decisions. There continues, however, to be much skepticism about the ability of the same process to contribute to day to day reservoir management and optimization of mature assets.
This paper describes how a truly integrated approach can shorten the planning and study timeframe and reduce uncertainty for reservoir management in such mature assets. Also presented is a system which links on-line (real-time and near real-time) downhole, surface and corporate data to ensure that reservoir, well and facilities models are constantly updated to reflect actual operating conditions. Using this "always current" encapsulation of the production system (between reservoir and delivery point) we perform a wide range of tasks to manage the asset performance: surveillance activity planning, production optimization, facilities optimization and debottlenecking, production forecasting and allocation.
The system integrates a number of existing software applications, and reduces the number of complex engineering tasks. It is being applied in a number of operational environments and the results of some are presented: Workflow and examples for integrating dynamic simulation output with static model and production data.Tool for waterflood pattern analysis and integration with well and production historyLive visualization of SCADA/DCS data via PI system and integration with reservoir understanding to provide a tool for accelerated identification of optimization potential
This integration process has a very positive impact on reducing the processing time for each task, and the visualization formats assist communication within the multidisciplinary reservoir management team. Embedding these tools in the reservoir management and field development process aids decision making and accelerates production thereby increasing the value of these mature fields.
Water-Free, Drill-In Fluid Dramatically Improved the Producibility of Sensitive Sandstone Reservoirs
Authors: Al-Ammari S. M. , Phillips J. E. , Ogunsola A. , Al-Mumen A. A. , Ezzat A. M. 
Published: December 2007

Abstract
New water-free, oil-based drill-in and completion fluids were recently utilized to drill a sensitive sandstone reservoir.Lower fluid densities were required to safely stabilize the wellbore compared to water-based fluids previously used in the offset wells.Avoiding excessive overbalance pressures eliminated differential sticking, minimized hole enlargement, and significantly reduced formation damage.Upon reaching the target horizontal depth, clean treated oil was circulated to remove the wallcake and solids-free viscosified oil was used as the completion fluid.Two horizontal wells were successfully drilled and completed with pre-pack and expandable screens. Quick clean up was achieved without stimulation.Sustained production rates of these wells exceeded expectations and improved productivity indexes were achieved.
The systems used were chemically non-reactive with the rock minerals and reservoir fluids and were less invasive to preserve the native state of the rock along with its natural wettability. Based on the reservoir rock morphology and the calculated pore throat size distribution, the bridging particles type, size distribution, and concentration were selected to rapidly establish a tight thin wallcake and prevent the invasion of fine drilled solids deep into the formation.
Comparative laboratory data was generated using natural core samples and different types of fluids.Some of these fluids reduced clay hydration and swelling, but failed to totally prevent dislodging and mobilization of fines.Authegenic clays were present as pore filling fine particles in some cores.Destabilizing these fines and forcing them to move choked off the interconnections between the pores as clearly shown in the thin sections studies.
This paper discusses the reservoir rock sensitivity data, the drill-in fluid formulation and its formation protection characteristics, and the field applications and production data.Also presented are the recommended guidelines for designing and monitoring the quality of this type of drill-in and completion fluids in the field.
Tipping Point Leadership, Discipline Quality Experts and Quality Assurance in ADCO
Authors: Gyllensten A. 
Published: December 2007

Abstract
"Tipping-point leadership" is a modern management approach designed to overcome resistance to change and improve performance. In ADCO the introduction of Discipline Quality Experts builds on the idea that in any organization there are people, procedures and systems that has a disproportionate impact on performance - like hitting the kingpin in bowling brings down all the other pins!
This is particularly important in Petroleum Development, the core of modern Oil & Gas companies. Although highly technical such organizations are now often "Asset focused" and as a result functional skills may suffer. This causes dilemmas for a learning organization, which is also trying to grow significant numbers of young national staff and integrate them in their midst. In ADCO Discipline Quality Experts in key disciplines like Geoscience, Petrophysics, Reservoir- and Petroleum- Engineering are located in a Quality and Performance Improvement Department (QPID) charged with conducting gap analyses on a continuous basis to monitor critical business areas and suggest new opportunities for change to maximize the value of existing assets. Peer Reviews, Discipline Forums and Balanced Scorecards are utilized to monitor individual and team performance contracts and monthly Project Boards review the business value of major projects and studies.
The Discipline Quality Experts provide Asset teams with expert advice and consultation in areas that directly impact short and long term activities. They conduct quarterly reviews to ensure that Field Development Plans meet the business targets and are in line with Shareholders’ guidelines. They play a key role in the introduction of minimum standards for competency assurance and foster a challenging and motivating learning environment for all staff. They also lead the discipline coordination meetings to ensure the transfer of "Best Practices" across Asset teams.
This paper will illustrate the approach taken in applying these principles to the Petrophysics Discipline in the Petroleum Development Division (PDD) in ADCO.
Mechanics of Borehole Ballooning in Naturally-Fractured Formations
Authors: Lavrov A. , Tronvoll J. 
Published: December 2007

AbstractThe mechanics of borehole ballooning caused by opening / closing of a single fracture intersected during drilling in a naturally-fractured reservoir is explained by means of a coupled analytical model. Equations governing borehole ballooning are summarized for different types of fluid rheology. The effects of various parameters on the fluid flow during a ballooning event are analyzed numerically. Shortcomings of the developed modeling approach are outlined.