bluuebunny/crossref_metadata_2025 huggingface dataset:
A Single-Stage Acid Treatment to Remove and Mitigate Calcium Carbonate Scale in Sandstone and Carbonate Reservoirs
Authors: Nasr-El-Din H. A. , Al-Saiari H. A. , Al-Hajji H. H. , Samy M. , Garcia M. , Frenier W. , Samuel M.
Published: December 2007

Combining scale inhibition with matrix stimulation in a single treatment has always been a challenge due to potential formation damage. This concern has been historically prominent in carbonate reservoirs, due to the accelerated precipitation of the scale inhibitor at very low pH values. Earlier experience in combining acid stimulation with scale inhibition in carbonate reservoirs has been reported with limited success.

This paper presents recent development in combining acid stimulation and scale inhibition treatments in sandstone and carbonate reservoirs. The combined treatment utilizes a newly developed scale inhibitor (a polymer-based inhibitor) that offers full compatibility with a wide range of the commercially available acidizing systems, including hydrochloric acid, mud acids and chelating agents.

This treatment minimizes the number of well interventions, significantly reduces well maintenance cost and improves the work-over efficiency. At least one scale inhibitor squeeze treatment is eliminated with every acid stimulation treatment. In addition, there are other inherent advantages including: effective inhibitor placement and better coverage of the target zone.
Injection of Incompatible Water as a Means of Water Shut-Off
Authors: Nasr-El-Din H. A. , Raju K. U. , Hilab V. V. , Esmail O. J.
Published: December 2007

This paper describes laboratory and modeling work to utilize high-sulfate pit brine and calcium chloride solutions as a means to the permeability of water producing zones. The study included compatibility tests, coreflood experiments, and scale prediction to calculate SI and SA at surface and reservoir conditions. The pit brine contains sulfate ions at 120,250 mg/L and its TDS is nearly 400,000 mg/L. Three solutions that contained calcium chloride at 10, 20, and 30 wt% were prepared. Coreflood tests were conducted using carbonate core of 100 to 1,100 md. Tests were conduced at 200°F (reservoir temperature) and overburden pressure of 2,000 psi. Most coreflood tests were conducted at 1 cm3/min. The pressure drop across the cores was monitored during these tests.

Compatibility tests indicated instantaneous precipitation of calcium sulfate when pit water and calcium chloride brines are mixed. Scale predictions are done for 10, 20 and 30 wt% CaCl2 brines with pit brine. The maximum super-saturation at 200°F for CaSO4 occurs at 45, 60 and 70 vol% of pit brine for 10, 20 and 30 wt% of CaCl2, respectively. Predictedmaximum anhydrite is nearly 55, 81 and 97 g/L for the three CaCl2 brines, respectively. Coreflood tests indicated that maximum core plugging occurs when pit brines is injected into cores saturated with CaCl2 brines. The degree of core damage depends on the injection rate. Core flood results were explained in terms of thermodynamics and viscous fingering effects, which occur when a less viscous fluid displaces a more viscous fluid in porous media.

Water production is a serious concern for oil and gas companies. On one hand, there is a cost required to lift this water, and to perform separation, treatment, and then disposal. In addition, water production causes scale, corrosion and emulsion problems. Therefore, every effort should be made to minimize excessive water production.Currenttechniques that rely on chemicals (cross-linked polymers) are expensive and in some cases these chemicals are not environmentally friendly. The technique described in this paper is simple, and utilizes simple and green chemistry. It can be used to plug water-producing zones in carbonate and sandstone reservoirs.

This paper introduces a simple, effective technique that can be used to reduce the flow into high permeability zones. This technique can be used to minimize drill string sticking that occurs during drilling and reduce the amount of produced water during production Coreflood tests indicated that this technique is very effective in reducing the permeability of reservoir cores.
Selection and Deployment of a Scale Inhibitor Squeeze Chemical for the BP Miller Field
Authors: Poynton Neil , Kelly Caroline , Fergusson Alasdair , Ray John , Webb Phil , Strong Allison
Published: December 2007

The BP operated Miller field arguably produces the most severe barium sulphate scaling waters in the world. There is an operational need to carry out scale squeeze operations almost continually in order to maintain the oil and gas production.

In this paper, we will present the challenges overcome proposing and in applying a new downhole product in this challenging environment. The paper will describe the selection process and test protocols needed to identify suitable squeeze inhibitor chemistry and review the laboratory data generated for a specific chemistry.

A pre-requisite in assuring the performance of a squeeze chemical on the Miller asset is the ability, for the supplier, to guarantee a 24 hour turn around time for residual inhibitor analysis. The conventional detection method for the type of chemistry selected is the hyamine test, which is time consuming and can be inaccurate. This paper will also include results from the Baker Petrolite High Performance Liquid Chromatography (HPLC) method for residual analysis, developed for detection of polymeric scale inhibitors in produced water. This method has the advantage of producing accurate results in a very short time frame.

The paper will also review the actual deployment of this chemical in the field, and demonstrate how the implementation of the selected chemistry resulted in immediate annualized operational savings to BP of an estimated $2.9MM on a single well.

The results of Squeeze V modeling are also reported, demonstrating how the squeeze applications are being optimized to bring even larger operational savings to BP by improving the squeeze lives on selected wells.
How Scale Inhibitors Work: Mechanisms of Selected Barium Sulphate Scale inhibitors Across a Wide Temperature Range
Authors: Sorbie K. S. , Laing N.
Published: December 2007

Scale inhibitors (SI) have been applied very successfully over many years in oilfields to prevent the formation of mineral scale. Both barium sulphate and calcium carbonate scales may be prevented using inhibitors, although in this work we will focus on the more difficult barite inhibition problem. A number of publications have appeared discussing the mechanisms by which barium sulphate scale inhibitors operate to prevent or retard scale formation. The mechanisms are discussed here in terms of (a) nucleation inhibition where the scale proto-crystals forms but are then disrupted or redissolved by the action of the inhibitor molecules, and (b) crystal growth inhibition where the inhibitor is thought to adsorb or interact with the active crystal growth sites (growing edges or spirals) hence retarding or stopping the crystal growth process. Both of these mechanisms are consistent with the inhibition of mineral scale at "threshold" levels, typically for MIC = 0.5 – 20 ppm (MIC = minimum inhibitor concentration for a defined level of inhibition for a given test procedure). The MIC is always considerably below stoichiometric values in terms of the scale inhibitor to mineral scale molar ratios. It is known that most inhibitor types from the small molecular phosphonates (e.g. DETPMP) to polymeric species (e.g. PAA, PVS, PPCA) actually operate through both of the above mechanisms although one of these may predominate for specific species. Previous work has established that, broadly speaking, smaller phosphonates operate principally as crystal growth inhibitors and polymeric species work mainly as nucleation inhibitors.

A number of factors are known to affect the inhibition efficiency (IE) of scale inhibitors against barite formation, the main ones of concern here being pH, temperature and the calcium and magnesium levels in the scaling brine mixture. The general observed effects of these factors have been described in the literature and will be discussed in detail in this paper. However, no complete description of the mechanism of barite inhibition has appeared which clearly and consistently explains all of the observed effects of these parameters for different scale inhibitor types. It is the central aim of this paper to present a complete and consistent set of mechanisms for barite inhibition which may vary in degree for different inhibitor types. Our proposed mechanisms are based on a wide range of observations from the open literature analysed with our own experimental and modelling results.
Avoiding Drilling Equipment Downtime – Four Case Studies
Authors: Sattler Jeff , Reed Bob
Published: December 2007

Occasionally, equipment issues drift out of focus as long as the drill bit keeps turning to the right and no "incidents" are recorded, particularly when activity levels and utilization rates are high. Unfortunately, it sometime takes a significant event to regain compliance with established operating and maintenance policies and procedures.

Investigations were undertaken as a result of events that occurred on four rigs. This paper will outline these incidents, describe the root causes determined, and delineate recommended steps that might be taken to prevent similar events.
Applications and Case Histories of Geared Turbodrilling in the North Sea
Authors: Beaton T. , Seale R. , Van Den Bos M. , Salomons G. , Strang G.
Published: December 2007

Over the years, drilling technology in the Dutch sector of the North Sea has evolved in an attempt to overcome many drilling challenges. Gaz de France’s 12-1/4" hole section, in the K12 field, has been a very active arena for technological advancement and new product development. Many new drilling systems and new drill bit designs have been tested and developed through this complex drilling interval. However, even with all of the advanced technology utilized in drilling this section, many operational difficulties remain, due to the variety of formations, the directional requirements, and the length of this interval. Until recently, this section was drilled using a variety of different products, including roller cone and PDC drill bits, on both downhole motors and rotary drive systems.

In an effort to improve the performance through this interval, another new technology was introduced to this drilling program, the geared Turbodrill. This new downhole drive system is capable of producing very high mechanical power at the bit, both high torque and relatively high RPM. The high power of this new tool, in conjunction with aggressive PDC drill bits, has proven to provide excellent performance in this challenging environment. This paper will detail the development and characteristics of this new geared Turbodrill, and also analyze recent North Sea case histories that included the 12-1/4" hole section through the upper Cretaceous chalk down to the upper Permian Zechstein formation.
Increased Net to Gross Ratio as the Result of an Advanced Well Placement Process Utilizing Real-Time Density Images
Authors: Al-Fawwaz Abdullah , Al-Yosef Osama , Al-Qudaihy Dia , Al-Shobaili Yousef , Al-Faraj Hassan , Maeso Carlos , Roberts Iwan
Published: December 2007

Development drilling operations in the Zuluf Field / Khafji Reservoir (offshore Saudi Arabia) involve targets near the flanks of the main structure, where oil-filled sands are sandwiched between overlying gas and underlying water. Horizontal well technology is utilized to increase the reservoir footprint. This article relays recent geosteering examples in the Khafji Sand bodies. Demonstrated results show significant gains in well productivity through an advanced well placement procedure relying on real-time geosteering.

An asset team implemented a process of well placement in order to maximize the reservoir contact while drilling1. The process involves continuous exchange of information between the well site and the office-based teams to allow fast and informed decisions. The success of the well placement process has been enhanced by preparation prior to drilling, continuous interpretation of the real time data while drilling and integrated teamwork throughout the project. A key technology in the well placement process is the use of realtime borehole density images in addition to the standard LWD data. Continuous interpretation of the image data (providing bed dip and thickness) and correlation of the LWD data, with the offset well data and geological models, provided the information necessary to maximize the reservoir contact "net pay" along the horizontal lateral section.

A series of wells have been drilled using the advanced well placement process. Examples illustrate how real time interpretation of the data by the team increased the net to gross ratio from 35% to 50%. The resultant increase in production demonstrates the value and the necessity of the process in the ongoing development of the field.
A Case History: The Effective Use of Jarring Accelerators in Stuck Pipe Situations
Authors: Broussard Andre N. , Dacanay Julius U. , Pewitt Gregg A. , Walters John L.
Published: December 2007

The use of jarring accelerators in drilling assemblies has been technically substantiated for many years.1-6 However, the practical applications and actual effectiveness of drilling jar accelerators are not well documented or transparent. This paper provides a case history comparison of stuck bottom hole assembly situations in eight offset wells of similar geology and the effectiveness of drilling jar accelerators when included in the drilling assembly.

The location of the wells in this comparison is the Mak-Ban geothermal field in the Philippines. While the primary focus of this paper will illustrate the actual effectiveness of the drilling jar accelerator, operational theory and field applications of the tool will also be explained. This paper will document that the use of jarring accelerators in conjunction with drilling jars not only eliminated the number of occurrences per that the drilling assembly could not be jarred free, but also reduced the amount of jarring time required to free a stuck workstring. The analysis data for this paper was obtained directly from documented daily drilling reports and comparisons will be made between those wells drilled without using drilling jar accelerators and those wells drilled using drilling jar accelerators. The two primary comparison measures will be jarring time required on stuck pipe incidents per well and lost-in-hole occurrences per well. Theoretical data comparisons for stuck point displacement, impact and impulse will also be drawn for each stuck situation utilizing the proprietary jarring analysis software package discussed in Wang et al.1
The Role of Knowledge, Tools and Systems for Drilling Analysis
Authors: Lagreca Alejandro J. , Damski Carlos , Peden James M. , Nakagawa Edson Y.
Published: December 2007

This paper proposes a methodical structure to embody current expertise for the analysis of drilling data. This structure is based on two aspects: (1) the review of published literature, representative of present-to-day efforts to perform such tasks and (2) the use of the Methodological Pyramid Concept, to illustrate what elements typify a methodology.

The review of published works revealed that several key aspects of the analysis of drilling data are not clear, for example:Actual use of drilling data is still unclear and under debate;Most of the available engineering tools limit the range of applications to drilling performance estimators;The proposed methods of analysis vary depending upon the needs of individual organizations or processes using the concept of "method and methodology" indistinctly;Various sets of concept and theories from internal and external sources of drilling engineering knowledge have been used to develop existing methods and engineering tools.

Under this scenario, it seems that more effort is needed to unify current approaches to analyze drilling data i.e. within the scope of an independent field with common goals, theories, methods and tools that can support the decision-making process. For this purpose, the methodological pyramid was chosen as a convenient model to outline these efforts. By allocating some of the reviewed approaches within the elements of such a pyramid, and contrasting their different ideas where necessary, a Methodology for Drilling Analysis was formalized. It is believed that this methodology is a convenient framework for defining the goals and scope for an area of drilling expertise named Drilling Analysis and the evolving future role of the Drilling Analyst.
Jack-Up Mobilization in a Complex Soil Environment Including Mitigative "Swiss Cheese" Operations
Authors: Kostelnik Andre , Guerra Mike , Alford Jake , Vazquez Jose , Zhong Jack
Published: December 2007

Proposal

This paper presents the planning and execution to effectively mitigate the risk associated with uncontrolled leg penetration. Planning reviews the soil analysis work used to understand the hazards and the development of solutions for obtaining a suitable jack-up foundation. Execution describes the procedures used to implement the mitigation plan at the hazardous sites.
A New Method to Measure the Downhole Pressure in UBD
Authors: Zhou Yingcao , Gao Deli , Wang Guangxin , Zhai Hongjun , Zheng Zhongwen , Liu Yonggui
Published: December 2007

Underbalanced drilling (UBD) has gained strong momentum in recent years because of a number of advantages of the technology, including reduced formation damage and minimized lost circulation. UBD is mainly applied in exploratory wells in China, especially in deeper gas exploratory wells. Due to the inaccuracy of pore pressure and the complex nature of water, oil, gas, and solid multiphase flow in the UBD system, it is very hard to remain the UBD condition. Furthermore, conventional MWD or LWD can’t be used in multiphase flow annulus to measure the downhole pressure. Although EMWD is an ideal tool in UBD, its cost is too high. There have been many calculation algorithms or mechanistic models about multi-phase in UBD, but it is still not easy to gain accurate results. In this paper, a new tool is introduced, which was designed to measure the annulus pressure near bit during UBD, and the data is analyzed after round trip to gain the actual value of downhole pressure. Compared with the data about pore pressure gained through logging, the actual underbalanced pressure differential can be acquired. This is an effective approach in deeper gas exploratory UBD, especially in Daqing oil field, in which the change of deeper pore pressure isn’t obvious. Two deeper gas exploratory wells have been completed successfully by using this method with the tool. The design, manufacture and testing of the tool, as well as field problems encountered are reviewed in this paper.
Use of Cement As Lost Circulation Material - Field Case Studies
Authors: Fidan E. , Babadagli T. , Kuru E.
Published: December 2007

Cement is one of the most common lost circulation materials (LCMs). Various types of cement have been used as LCMs in the past. Recent developments in cement technology and the understanding of lost circulation have produced custom-designed applications utilizing effective cement types and compositions. Applications also vary depending on the drilling fluid type and its properties. Custom-designed applications include thixotropic and ultrathixotropic cement slurries; slurries containing cello flakes, mica, and CaCO3 for mechanical bridging; unique spacers and surfactant packages; and foamed cement for controlling loss.

Selection of proper cement type and injection procedure calls for specific information such as formation properties, wellbore conditions, and thief zone characteristics. Laboratory experiments are recommended in this process. Field observations are also critical in making the final decision for selecting the optimum treatment fluid train and application strategy.

This paper discusses the process designs and application of various cement types as LCMs. Solutions to four problematic field cases are provided. The conditions that require cement as an LCM and the criteria for selecting the best cement compositions are outlined along with optimal strategies.
Multistring Analysis of Well Growth
Authors: Aasen Jan A. , Aadnøy Bernt S.
Published: December 2007

This paper presents simple models to describe casing loading and wellhead movement during the completion (mechanical) phase and the production (thermal) phase. A wellhead-drop incident is investigated. The theory is simple, and the formulations are suitable for hand-calculation or spreadsheet. The presented models are suitable both for conventional and HP/HT (high-pressure/high-temperature) wells.

This paper also investigates an abrupt wellhead drop of several feet for an offshore well. The incident took place during wellhead cooling following a routine shutdown. The expected wellhead cooling contraction did not occur. After a cooling period the wellhead suddenly released. A corroded segment of the surface casing collapsed and the wellhead dropped.
World Longest Expandable Open Hole Clad & Open Hole Liner with Swelling Elastomer Deployed in Yibal Horizontal Well
Authors: Al-Balushi H. M. , Al-Rashdi M. H. , Al-Shandoodi M. H. , VanNoort R. H.
Published: December 2007

PDO has successfully installed the longest open hole clad and longest open hole liner with swelling elastomers in a Yibal horizontal oil producer well. The main objective of installing expandable liner combined with swelling elastomers was to efficiently isolate the water producing features/fractures that are dominating majority of the 957m of reservoir section.

This one horizontal well replaces five vertical wells at cost of two vertical wells. In addition to the cost reduction, the surface location construction constraints in the field do not allow drilling five wells from different locations to reach the required targets. Therefore the introduction of such well type allows drilling five well targets from one surface location.

The overall value Drivers for drilling and completing this well with expandable liners/clads with swelling elastomers were as follows:▪Restore some symmetry to the water flood process for proper surveillance and management.▪Vertical wells are uneconomic for establishing symmetry as they are only good for targeting oil sweet spots (reduced number of wells as a result).▪Allow for more & longer perforation intervals.▪Proper selective zonal isolation.

The bigger ID provided by the expandable tubular allows for running larger OD smart completion to control the production from specific perforation zones.

Initially 305 m of 5-1/2" x 6-1/8", Open Hole Clad was set at TD (2541 m), then a 687 m Open Hole Liner was tied back to the 7" liner.

Based on 6 arm caliper log, both expandable liner and clad were coated with 4mm and 5.5 mm thick swelling elastomer to achieve optimum annular sealing, covering total length of 425 m isolated interval. Initially perforated well with 4 intervals to produce from different zones. There are further 7 'blank' intervals between elastomer sections for future perforations.

The paper covers a brief background of the Yibal field, detailed technical planning and execution phases for drilling and completing the well with expandable technology & application of swelling elastomers.
Expandable Liner Hanger Application in Arduous Well Conditions Proves Reliability: A Case History
Authors: Cantu Joseph , Smith Pete , Nida Ron
Published: December 2007

Proposal

In an effort to increase production in the gas fields of East Texas, horizontal wells have become the standard, as they have in many regions worldwide. Many times the horizontal section is preceded with a drilling liner to cover the build section of the well and isolate weaker fracture gradient zones prior to penetrating the production interval. Previously, many operational challenges were encountered during liner installation, resulting in costly shoe and liner top remedial operations or the inability to reach the total depth of a hole section. Primary among the hurdles are successfully deploying the liner across the weaker zones and negotiating the hole angle.

With the recent advancements made in the field of solid expandable tubular technology, several innovative products have developed from the core technology. One of these products is the expandable liner hanger. This product has been proven to greatly enhance liner operations in the well construction industry.

Expandable liner hangers offer many novel features not available or applicable to conventional liner hangers. These features include radial geometry and a hanger / packer body construction with no moving parts. The primary benefits of this system are superior seal, improved installation reliability, and a significant reduction in time required to complete the installation and to resume drilling operations. These benefits and others derived from the features listed above will be discussed in detail in this paper including results from a recent case history in the Mossy Grove field of East Texas.
GTL: Is it an Attractive Route for Gas Monetization?
Authors: Rahman Osama Abdul , Al-Maslamani Mohamed
Published: December 2007

The conversion of natural gas into synthetic fuel is an active area of development. Today, many large and independent oil companies as well as engineering contractors are involved in either research, pilot plants, or demonstration units with the objective of reducing capital and operating cost of this technology.

Beside the technology, the economic factor of the GTL process remains the major element in the application of this process. The major factors affecting the economics of the GTL process is the gas price and the capital cost. The GTL process could be an attractive way to monetize stranded gas reserves where the application of pipeline or LNG Technology is not techno – economically feasible, because the gas is either very far from the market and/or the gas reserve can not support a world scale LNG plant.

Fuel produced from the GTL process is practically sulfur and aromatics free, accordingly, exhaust emission from the GTL products is not an area of concern. As an example, exhaust emission pollutants from GTL diesel oil is much below those required by most stringent present and planned (future) specifications. However, carbon release cycle (from GTL production to consumption) is an active area of research and studies.

The availability of natural gas at reasonable price, present crude oil price and the environmental benefits of using fuel products derived from natural gas has led to the realization of many commercial scale GTL units at different parts of the world particularly in Qatar which is targeting to be the centre of the GTL projects. These worldwide projects are at different stages of implementation.

In this paper, an attempt was made to present the above consideration in more details for the GTL process as a route for gas monetization including a broad brush economic comparison with LNG production as an alternative competing route.
Separator Profiling: Kuito FPSO Case Study
Authors: Pearson Ken
Published: December 2007

The Kuito field, discovered in April 1997, lies offshore Cabinda Province in Angola's deep-water Block 14, a 1,560-square-mile concession. Kuito was Angola's first deep-water oil field to come on stream in December 1999, two and a half years after discovery. Kuito oil is produced via an FPSO chartered through SBM of Monaco and Sonangol on behalf of operator ChevronTexaco.

Kuito is a heavy oil ranging from 18 – 22 API. The FPSO presently has two oil production trains with a maximum throughput of 100,000 bbls. oil per day. Three phase, horizontal, gravity separation vessels are used to separate oil and gas from unwanted produced water and solids prior to transportation. Kuito production separators were designed with traditional, single point transmitters for interface and bulk level measurement. These level transmitters were capacitance type instruments mounted inside the vessels in stilling wells. Following production start-up, separation problems began to emerge, these were manifested in numerous process upsets and shutdowns. Kuito oil can form emulsions quickly and calcium naphthenate, or ‘Kuito Gunk’ as it is referred to on the FPSO, is produced at higher temperatures and if allowed to cool solidifies. The point instrumentation was unable to detect these emulsion and naphthenate layers resulting in the instrumentation becoming fouled and ceasing to function. The separators were operated ‘blind’, utilising tri-cocks located on the side of the vessel and as the instrumentation was installed in stilling wells inside the vessel it was impossible to maintain them without shutting down and depressurising the vessels. This paper describes how nucleonic profiling instruments were retro-fitted to the vessels and shows, with the aid of real time on line screen shots how operations were able to identify the different layers within the separators. This enabled oil production uptime to be increased and chemicals, emulsion breakers and defoamers, to be pro-actively dosed before the plant became unstable.
Benefits of Developing Knowledge Sharing Communities
Authors: van Unnik A.
Published: December 2007

Computer systems used to capture and retrieve knowledge that can be made available in digital format can only contain a fraction of the corporate knowledge. In implementing Knowledge Sharing the computer systems are complemented by Knowledge Sharing communities in which people share what they know and what they need to know.

Forming knowledge sharing communities locally is a practice that has many advantages but is more often than not limited to a small pool of colleagues with similar interests. Knowledge sharing through large virtual "communities of practice" makes available the practical and theoretical knowledge of many experienced professionals who need not sit in the same office, building or site. Modern communications technology and software can make this wider knowledge sharing an easy and low-cost reality.

Putting the knowledge of a larger community of professionals to use via a community network will benefit the business and reduce costs. Approaches taken and value measurements will be presented.

For the participants the knowledge sharing communities act as an on-site aid to continuous learning for professionals. This leads to new concepts for Knowledge Sharing and for Learning: WorkPLACE Learning.
Succession Planning – A Multi-Purpose Tool
Authors: Al-Marzouqi Yehay , Rathbone Mike
Published: December 2007

Context

During the year 2000 ADCO recognized that the lack of a formal system by which successors could be identified for leadership team posts was a weakness in its corporate business strategy.

Many consultancies offered "off the shelf" solutions but given the unique circumstances of not only the region but also its position in the industry as a leader, ADCO decided that it would recruit an independent contractor during 2001 to design and develop an ADCO specific system to match the needs of the company and its culture.
Nationalisation: Issues in Learning and Development
Authors: Aldred Deborah , Lees Martin
Published: December 2007

The ADNOC (E&P) group's Emiratisation targets have highlighted the need for competency development of UAE nationals. One issue within development is the nature and delivery of training. This in turn raises the important issue of the language of instruction, technology and business and the concept of English language competency. Another issue is that underlying any instructional methodology are sets of beliefs and values. Any mismatch between these and those of trainees has implications for the value/uptake of that training. Insights from a unique empirical study with a group of UAE nationals provide information about their preferred learning styles and cultural values. The findings have implications for understanding and optimising the learning and development process within the workplace, and illustrate the value of research within such a context. Setting competence descriptors and objectives are not the only considerations when developing a competent workforce.
Value of Quality Management in E&P Business Improvement and Integration
Authors: Al Mulla Badria
Published: December 2007

The paper presents an integrated model for Quality and Performance Improvement (Q&PI) Framework that has been established within ADCO (Abu Dhabi Company for Onshore Oil Operations) Petroleum Development Division (PDD) to ensure a continuous improvement in core activities. It highlights triggers and challenges which were behind the serious need for an integrated business model that will help the division in clarifying its vision in line with ADCO Business Strategy, and translate that vision into a set of business operational and measurable objectives.

The achievements of Q&PI Framework in unifying and integrating all the divisional business units around a common understanding of business key strategic drivers are presented. The critical business objectives that can be continuously assessed and upgraded toward achieving the business vision with minimum business/technical uncertainties are exemplified, indicating a significant improvement in a typical E & P environment.
Faults, fracture corridors and diffuse fracturing: ranking the main structural heterogeneities within onshore Abu Dhabi fields
Authors: Bockel-Rebelle Marie-Odile , Hassall John K. , Silva Fernando P. , Lozano Jose A. , Al Deeb Maged , Salem Salem El Abd , Vesseron Marc , Al Mehsin Khalil
Published: December 2007

One of the most challenging issues within Abu Dhabi onshore fields is the definition, characterization and modeling of the main structural heterogeneities. Integration of structural, geometrical and dynamic understanding is the key to defining what is important from a field development and production viewpoint, since it may affect the economics of the fields.

A consistent analysis and approach is essential to be able to compare the fields taking into account the three different types of fracture (i.e. faults, fracture corridors and diffuse fracturing), and the potential geological events that postdate the fracturing (fluid circulation, diagenesis).

Diffuse fracturing was commonly described across most fields based on core observations and image log interpretation. However, this fracture type alone cannot explain the behavior of many wells.

A new look at the data reveals that several fields exhibit fracture corridors and/or subtle faults. Integrating the well behavior suggests this fracture type may have a significant impact in some fields. Unfortunately, this style of deformation is often below the seismic detection threshold.

The recent acquisition of 3D seismic across most of the Abu Dhabi onshore fields reveals all fields are faulted at the seismic scale. The fault style is often characterized by small throws. Recent improvements in seismic resolution reveal that what was previously interpreted as one fault is in fact made of numerous fault segments separated by relay areas. This new interpretation has obvious implications for the dynamic behavior of these fault zones. Indeed great discrepancies of the fault zone behavior are observed and discussed using six example fields which encompass a wide variety of carbonate reservoirs with varied depositional environments and reservoir properties. Given such a range of reservoir properties, faults and fractures with similar properties might be expected to have very different expressions in the way they affect fluid flow.
Inter-reservoir Communication Detection via Pressure Transient Analysis: Integrated Approach
Authors: Akresh Saud Bin , Al-Obaid Rashid , Al-Ajaji Abdulaziz
Published: December 2007

This paper presents a successful integration of pressure transient tests, production, and seismic data to detect inter-reservoir communication between Hanifa and Arab-D reservoirs in the southern dome of Abqaiq field in Saudi Arabia.

Even though Hanifa and Arab-D reservoirs are separated by about 300 feet of impermeable Carbonates, the two reservoirs are in pressure-fluid communication through conductive faults/fractures in the heavily faulted/fractured area of Abqaiq field.

Late time pressure anomalies on the log-log plots were observed on several field examples of transient tests in Hanifa reservoir and some were interpreted as external effects of pressure support from the communicating Arab-D reservoir. Simulation modeling was used to further analyze such pressure responses.

Better reservoir management decisions and more focused development strategies can be achieved through the utilization of the quantitative pressure transient analysis of those tests.
Petrophysical Measurements From Drill Cuttings an Added Value for the Reservoir Characterization Process
Authors: Egermann P. , Doerler N. , Fleury M. , Behot J. , Deflandre F. , Lenormand R.
Published: December 2007

Permeability and porosity are necessary for reservoir characterization and cuttings can provide quick and cheap measurements. In this paper, we present the first applications of the method on real reservoir characterization cases and the comparisons with logs and core data.

We first recall the method of permeability measurement from cuttings, which is based on a pressure pulse applied on a cell filled initially with cuttings saturated with viscous fluid and trapped gas at atmospheric pressure. The permeability is derived from the transient response of the oil invasion into the cuttings by using a numerical model. We also measured the porosity from dry drill cuttings using the routine helium technique. These methods were tested and validated by using various samples of crushed rock samples of known permeability and porosity. Both measurement techniques are fast, require light conditioning, are applicable over a large range of permeability and need only 1 ml of sieved rock to be realized.

Field applications of the drill cuttings measurements (permeability, porosity, T2 distribution) have been undertaken on various types of rocks (dolomite, carbonate, sandstone) obtained under several drilling conditions (WBM, OBM). The representativity issue of the cuttings towards the native reservoir is of primary importance and was checked by using adequate cleaning procedure and the preparation techniques and by comparing the consistency of the porosity measurements obtained from cuttings with other data (cores or logs). The overall results demonstrate the added value of K and ϕ measurements in addition to the data that are already collected in routine.
Bayesian Uncertainty Reduction for Log Evaluation
Authors: Spalburg M. R.
Published: December 2007

The evaluation of petrophysical logs in terms of rock and fluid compositions can be ambiguous in the presence of possible complex lithology types, deep invasion effects, etc. In such circumstances the evaluation results tend to be strongly influenced by the choice of petrophysical evaluation parameters such as rock and fluid density, acoustic and electrical properties. In addition, different lithology types may require the use of different interpretation models or equations. Given these total or partial unknowns a rigorous log evaluation needs to scan through all possible combinations of evaluation parameters and models to determine which combinations of rock and fluid component abundances explain the measurements. It may be obvious that such an exercise can result in multiple solutions and that some type of Monte Carlo analysis is an appropriate mechanism to sample through all the combinations. The amount of calculations required to do this using a regular Monte Carlo analysis scheme is prohibitive large: in the order of 10^20. An implementation of a Bayesian inference method based on a Markov Chain Monte Carlo algorithm dramatically reduces the amount of evaluations required to some 1000 to 10000 per log increment. Any available geological, geophysical or production derived knowledge can be incorporated in the MCMC evaluation as a modification of the prior probability distributions for the evaluation parameters and models. The resulting properly correlated rock and fluid component abundances also enables the calculation of tool response probability distributions for (not yet) acquired logging tools and enables a quick analysis of the potential evaluation uncertainty reduction by those tools. A few carbonate and sandstone application examples illustrate log evaluation uncertainty with respect to rock mineral composition and oil/gas saturations and how the ability to predict the range of possible measurement results for possible additional logging tools can help optimize data acquisition programs.
Integration of 3D Seismic & Dynamic Data Improves Interpretation of Structural Features
Authors: Al Rougha Hamad Bu , Al-Henshiri M. Yousef , Khouri Naeema , Arisaka K. , Sultan A.
Published: December 2007

Well tests are often used to investigate reservoir heterogeneities such as fractures, conductivity of faults, and matrix permeability. Attributing a measured pressure response to a particular geological feature is problematic, as many different solutions will fit the same pressure response. Data integration is the key to understanding well pressure transients and the underlying geology controlling them.

A recently acquired and interpreted 3D seismic survey indicated the reservoir contained numerous strike slip faults. To reduce the uncertainty associated with reservoir characterization, a multidisciplinary team comprising of geophysicists, geologists and reservoir engineers selected an area of the reservoir to focus their efforts. The integration of the 3D seismic with dynamic data provides a possible means of validating the interpretation.

Anomalous transient pressure data were identified on five wells. Initial interpretations proved ambiguous with several possible geological reasons. Close examination of the 3D seismic data indicated in each case the presence of a fault. Faults were found to be the likely structural anomalies that have been detected by seismic and well test data. The fault throw, conductivity and its distance to the wellbore were estimated. The transient pressure data enabled us to evaluate the faults as sealing.

Once the integration perception was adopted, and high quality data became available, concerns with the 3D seismic interpretation data and the uncertainties associated with pressure transient data that were initially ambiguous began to make sense.
Best Practices from Super-Giant 3D-OBC Seismic Survey, Offshore Oil Field Abu Dhabi
Authors: Hagiwara Hiroshi , Belaid Kamal , Lilley Graham , Corless Denis , Al Kaabi Musabbah , Ajlani Ghiath , Ebed Atef , Suwaina Omar , Shimada Nobusuke , Najia Walid , Bu-Alrougha Hamad
Published: December 2007

This paper presents the best practices and the lessons learnt from a comprehensive offshore 3D ocean bottom cable (OBC) seismic survey, which was successfully carried out over a super-giant offshore production oil field in Abu Dhabi by an integrated multi-disciplinary team from three different companies. This work highlights a wide range of challenges and achievements throughout the steps, from the feasibility study, data acquisition, processing, interpretation and advanced reservoir characterization studies.
Pressure Transient Derivative Signatures In Presence of Stratiform Super-K Permeability Intervals, Ghawar Arab-D Reservoir
Authors: Gill Harmohan S. , Al-Zayer Rayed
Published: December 2007

This paper describes case studies of observed pressure derivative signatures in the presence of stratiform Super-K permeability intervals in Ghawar field, Arab-D oil reservoir. The case studies (presented in order of increasing complexity) include: 1) an open-hole vertical well intersecting the Super-K interval, 2) a slant horizontal well intersecting the Super-K interval and, 3)a horizontal well at the top of a layered reservoir, not in contact with the Super-K interval and separated from the Super-K interval by low permeability layers.

The stratiform Super-K permeability intervals in Ghawar can be visualized as being like horizontal pancakes of multi-darcy permeability. Since these Super-K intervals are not continuous but rather show up as patches of high permeability, the typical effect on the pressure derivative of a vertical open-hole well is that of a radial composite system.

The most complex derivative signature is observed when a horizontal well is separated from the non-intersecting Super-K interval by low permeability layers. It is very easy to misinterpret this derivative signature without integrating all the available geological and production log data.

The derivative signatures are demonstrated by numerically simulated responses of actual case studies. The importance of identifying these pressure derivative signatures is illustrated in this heterogeneous, multiphase, layered, reservoir where data quality is sometimes poor due to wellbore phase redistribution.
Comparing the Accuracy of Fluid Saturation Derived from Different Logging Measurements: Past, Present and Future Methodology
Authors: Belgaied Adel , Al-Farisi Omar , Al-Ghusain Subhi , Al-Muntheri Hiyam , Al-Marzouqi Mariam , Petricola Mario
Published: December 2007

Obtaining the water and hydrocarbon saturations in any reservoir are one of the main applications of many logging instruments. Resistivity has been used with relative success in many fields and can be considered the main open-hole "saturation" measurement, even though true formation resistivity remains elusive. Pulsed neutron capture is the basic cased-hole "saturation" measurement when formation water salinity is known and high enough. While either one has its own limitations, they often agree well enough that they reinforce the user confidence in their respective accuracy. Thus, they are generally considered adequate for reservoir management decisions.

Occasionally, acquiring and comparing a large number of different measurements that respond to fluid distribution in the formation shows that two measurements dose not give the same answer. As a result, Petrophysicists face the task of reconciling and explaining those discrepancies to extract additional and valuable information.

In this paper, we review the principles, advantages and limitations of a certain number of measurements acquired in both open and cased hole. We briefly review how data was handled in the past and the way it is handled today. We then review how discrepancies are reconciled today and make suggestions and recommendations as to which measurements are the most appropriate for various types of environments.

In the last part of the paper, we are suggesting new ways to acquire, process and interpret log data. Logs free of environmental effects will be obtained through the acquisition of auxiliary measurements that define the Wellbore environment accurately. Models are used to evaluate and correct for the environmental variations that are not resolved by in-built sensors. Tool planners are expanded to become true artificial experts that recommend the right measurements for a given formation and borehole environment. In addition, the uncertainty on the logs, parameters and models will be propagated to the output uncertainty in a meaningful and representative manner.