bluuebunny/crossref_metadata_2025 huggingface dataset:
Gingival Status of Brazilian Renal Transplant Recipients Under Sirolimus‐Based Regimens
Authors: Cota Luís Otávio Miranda , Oliveira Ana Paula Lima , Costa José Eustáquio , Cortelli Sheila Cavalca , Costa Fernando Oliveira
Published: November 2008

Background: Although the prevalence of gingival overgrowth (GO) in calcineurin‐inhibitor (CNI) immunosuppressive regimens has been well documented, to the best of our knowledge data from sirolimus (SIR) regimens have not been described. We sought to investigate the gingival status of renal transplant recipients under SIR‐based regimens with regard to the prevalence and potential risk variables associated with GO.

Methods: A cross‐sectional study was conducted at a public hospital in Belo Horizonte, MG, Brazil. Of 886 transplant recipients, an eligible sample of 144 subjects was selected. Medical, pharmacologic, and periodontal variables were recorded for each subject. GO was assessed through visual inspection and was evaluated in relation to variables of interest by univariate and multivariate analyses.

Results: Although not clinically significant, 20.8% of the samples had GO, with a mean GO score of 5.0% ± 3.98% (range, 0% to 19%) and mean GO score per papilla of 0.378 ± 0.361 (range, 0.1 to 1.9); the percentage of papilla affected by GO was 14.35% ± 9.86% (range, 5% to 45%). The multivariate final model, excluding periodontal variables, showed that the concomitant use of calcium channel blockers (P = 0.033) and the interaction between time since transplant and previous CNI use (P <0.001) were associated with GO. Adding periodontal variables to the model improved its accuracy and retained papillary bleeding index as being strongly associated with GO (P <0.001).

Conclusions: GO was observed in a considerable number of subjects under SIR‐based immunosuppressive regimens, although the relationship was not clinically significant. Findings point to the importance of cooperation between medical and dental health care personnel in the maintenance of renal transplant recipients under SIR‐based immunosuppressive regimens.
The Effect of Laser Therapy as an Adjunct to Non‐Surgical Periodontal Treatment in Subjects With Chronic Periodontitis: A Systematic Review
Authors: Karlsson Marcus R. , Diogo Löfgren Christina I. , Jansson Henrik M.
Published: November 2008

Background: The objective of this study was to systematically review the evidence on the effectiveness of laser therapy as an adjunct to non‐surgical periodontal treatment in adults with chronic periodontitis.

Methods: A search was conducted for randomized controlled trials comparing the outcome of periodontitis with laser as an adjunct to scaling and root planing in the treatment of chronic periodontal disease. The electronic databases, PubMed and Cochrane Central Register of Controlled Trials, were used as data sources. Screening, data abstraction, and quality assessment were conducted independently by three reviewers (MK, HJ, and CDL). The primary outcome measures evaluated were changes in clinical attachment level, probing depth, and bleeding on probing.

Results: The search resulted in 25 abstracts; four randomized controlled clinical trials were included. Four different laser methods were used; consequently, it was impossible to conduct a quantitative data synthesis leading to a meta‐analysis. All studies included a limited number of subjects.

Conclusions: No consistent evidence supports the efficacy of laser treatment as an adjunct to non‐surgical periodontal treatment in adults with chronic periodontitis. More randomized controlled clinical trials are needed.
The Effect of Smoking on Periodontal Health of 15‐ to 16‐Year‐Old Adolescents
Authors: Heikkinen Anna Maria , Pajukanta Riitta , Pitkäniemi Janne , Broms Ulla , Sorsa Timo , Koskenvuo Markku , Meurman Jukka H.
Published: November 2008

Background: Smoking is a severe risk factor for periodontal health in adults, but data on the effect of smoking on periodontal health in teenage populations are sparse. The aim of this study was to investigate the effect of duration and quantity of smoking on periodontal health in teenagers and possible differences between genders.

Methods: The oral health of 501 adolescents (15‐ to 16‐year‐old boys [n = 258] and girls [n = 243]) was examined. A structured questionnaire about self‐reported smoking and health habits was filled out, and bitewing x‐rays were taken. Clinical examinations included measuring periodontal indexes, such as visible plaque index, bleeding on probing, root calculus (RC), probing depth, and attachment loss. Results were analyzed by generalized linear logistic regression.

Results: Twenty‐five percent of boys and 27% of girls were smokers. The boys and girls who smoked had higher RC values than non‐smokers (P <0.001). The adjusted scores for smoking boys and girls were 17.3 (95% confidence interval [CI]: 8.6 to 31.7) and 13.6 (95% CI: 5.5 to 29.7), respectively. The adjusted scores for non‐smokers were 10.4 (95% CI: 5.7 to 18.3) and 7.7 (95% CI: 3.3 to 17.3), respectively. Smoking boys and girls also had more periodontal pockets ≥4 mm than non‐smokers: the score for boys was 4.6 (95% CI: 2.2 to 9.1), and the score for girls was 5.4 (95% CI: 1.1 to 23.2; P <0.001).

Conclusion: Smoking significantly impaired periodontal health in teenagers.
Advanced Glycation of Type I Collagen and Fibronectin Modifies Periodontal Cell Behavior
Authors: Murillo Jesse , Wang Yao , Xu Xiaoping , Klebe Robert J. , Chen Zhihua , Zardeneta Gustavo , Pal Sanjay , Mikhailova Margarita , Steffensen Bjorn
Published: November 2008

Background: Advanced glycation end products (AGEs) have been linked to pathogenic mechanisms of diabetes mellitus. However, little is known about the contribution of protein glycation to periodontal disease in patients with diabetes. Therefore, this study investigated whether glycation of type I collagen (COLI) and fibronectin (FN) modified the behavior of human gingival fibroblasts (hGFs) and periodontal ligament fibroblasts (hPDLs).

Methods: Procedures for rapid in vitro glycation of COLI and FN used methylglyoxal (MG). Formation of AGEs was analyzed by changes in protein migration using sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and Western blotting with antibodies specific for MG‐glycated proteins. Experiments then characterized the effects of glycated FN and COLI on the behavior of hGFs and hPDLs.

Results: MG glycated COLI and FN in <6 hours. Confirming the specificity of the reactions, antibodies specific for MG‐induced AGEs reacted with glycated FN and COLI but not with control proteins. In cell culture experiments, glycated FN was significantly less efficient in supporting the attachment of hGFs and hPDLs (P <0.05). Moreover, the morphologic parameters, including length, area, perimeter, and shape factor, were altered (P <0.001) for cells on both glycated proteins. Finally, cell migration was reduced on glycated FN and COLI (P <0.001).

Conclusions: MG treatment efficiently glycated COLI and FN, providing a new tool to study the effects of diabetes on periodontal disease. The substantial effects of glycated COLI and FN on hGF and hPDL behavior indicated that protein glycation contributed to the pathogenesis and altered periodontal wound healing observed in patients with diabetes.
Improved Method for Compositional Modeling Using a Fine Scale Geological Description Within Gas Injection Pattern in Carbonate Reservoir
Authors: Obeida Tawfiq , Gibson Adrian , Al-Hashemi Hussain , Baruah Bikram
Published: November 2008

The objective of this paper is to address the challenges that are frequently encountered in simulation studies when using local grid refine (LGR) within upscaled models. The difficulties mainly arise due to the unreliability of populating the fine grids with reservoir properties and attributes.

Dynamic modeling of a pilot is an important task to predict fluid flow and reservoir behavior which is a major step of pilot design. Dynamic models usually have many limitations when it comes to geological description due to the upscaling of fine-grid static model. Using local grid refinement (LGR) alone for the pilot area within a coarse dynamic model also would not enhance reservoir description of the pilot area without a realistic reservoir description. This work was aimed to provide an improved method for the proper simulation of pilot project in order to optimize the design of the pilot injector, borehole location and length. Furthermore, the model would be used to plan an efficient reservoir monitoring program including an optimized well data gathering with sponge coring for defining the remaining oil saturation.

To overcome these limitations, the proposed method introduces a special fine scale LGR covering the pilot area within the upscaled dynamic model. Whereas the upscaled model has 36 layers, the LGR contains exactly the same fine-scale layering scheme and reservoir properties as the static model with 160 layers. Thus, it eliminates the upscaling process within the LGR. This process will ensure a better quality history match, for example the TDTs and RSTs derived saturations when compared against the fine layer LGR from the dynamic model.

The dynamic model in this study is a large sector model (Nx 167, Ny 98 and Nz 36) with a detailed LGR (Nx 130, Ny 145 and Nz 160). The fluid properties were calculated from a 10-components equation of state (EOS). After the addition of the LGR, the model history match was updated. Several prediction cases were then studied to optimize well location (injector and observation wells) in order to convert the existing inverted five-spot gas pattern into water injection line-drive. Several saturation maps and profiles were generated to predict the breakthrough time for each observer and utilized to design the future pilot monitoring program. The new data will be utilized for future updates of the history match and performance of pilot under the optimum scheme of sweep and thus well spacing.
Pipeline Construction Challenges in Brownfield
Authors: Thabet Hussein Ahmed Bin , Murad Mahmoud Mohamed , Azouz Amr Mohamed
Published: November 2008

ADMA-OPCO is the pioneering offshore Oil and Gas Producer in Abu Dhabi, UAE dating back to the 1950s. ADMA-OPCO operates more than 1500 km of sub sea pipeline network, built over the years as part of the progressive development in Umm Shaif and Zakum fields.

ADMA-OPCO vision is to work effectively as one integrated team to produce hydrocarbons from offshore areas aspiring to excellence in all aspects of the business.

This paper identifies ADMA-OPCO current key challenges being faced in and around existing developments, "Brownfields" considering the additional challenges imposed by the extensively busy oil & gas market.
Better Contracting in Oil & Gas Markets - Finding Mutually Acceptable Ways of Securing the Best Supply Chains in a Tight Market
Authors: Nouwailati Kenan
Published: November 2008

Oil companies and their suppliers need to design and implement contracts to build new production capacity quickly IOCs, NOCs/Host Governments, and Major Suppliers have different perspectivesThey all need to deliver complex and technically challenging projects on time, while guaranteeing quality and controlling costsAlthough their interests sometimes diverge, operators and suppliers share the need to improve the effectiveness and clarity of their contracting approachesThere are 8 levers that can improve project contracting for all parties
Using Crystallized Superabsorbent Copolymer for Plugging High-Permeability Channeling and Vugular Communication
Authors: Albidrez Patricia , Dalrymple Eldon Dwyann , Vasquez Julio , Adokpaye Anino E.
Published: November 2008

As fluids are produced from a reservoir, zones of higher permeability and corresponding higher flow rates create channels for the preferential movement of fluids. This can result in diminished sweep efficiency when there is premature communication between an injector and a producer. Crystallized superabsorbent copolymer (CSC) is a water-swellable (but not water-soluble), 100% crystalline synthetic polymer. CSCs are resistant to degradation by CO2 and bacteria and have a temperature range of 70 to 275°F. In addition, rigless placements can be made on current injection tubulars. This eliminates the expense of using a workover unit (Griffen 2000). This paper addresses the uses of CSC in the Permian Basin for the treatment of vugular communication, lost circulation, and near-wellbore remediation problems.
Deployment of a Rotodynamic Multiphase Pump in a Remote Hilly-Terrain Oil Field in Saudi Arabia
Authors: Hamoud Amir A. , Boudi Adnan A. , Al-Qahtani Saeed D. , Al-Dayil Nasir
Published: November 2008

Multiphase boosting technology can provide a cost-effective option for developing remote and marginal oil field discoveries, by reviving dead oil wells and increasing the production from active wells. The implementation of the multiphase technology at the remote field is a new strategy to obtain increased production and flow assurance from the operator.

This paper describes the implementation of a rotodynamic (helicon-axial) multiphase pumping (MPP) system at a remote, hilly-terrain onshore oil field in Saudi Arabia. The process conditions, the MPP package scope of supply, the MPP installation setup and operation will be discussed in detail.
TAML Level 3 Tri-lateral with Sand Control Application for Saudi Aramco
Authors: Refai Ibrahim , Assal Anwar , Fould Jeremie , O'Rourke Tim , Haque Muhammad Habib , Akram Nawaf Sayed
Published: November 2008

A number of the wells reach there economical production limit and are consequently abandoned or mothballed until viable solutions are available to enhance there production to an economically feasible level. The Hawtah field (see Figure 1) discovered in the late 1980s is located 180 km south of Riyadh, the capital of Saudi Arabia (figure 1). Hawtah is one of several small fields located along the Hawtah Trend (others are Ghinah, Hazmiyah, Nisalah and Umm Jurf). The Trend runs approximately 30 km east to west and 50 km north to south. Production in Hawtah comes from the Unayzah sandstone and consists of Arabian super light (50° API) sweet crude oil.

Hawtah field is a mature and depleted reservoir, and in order to maintain economical levels of production a combination of several technologies is being applied.

Due to the poor natural production from the vertical cased and perforated completions in Hawtah and little associated gas, electrical submersible pumps (ESPs) have been used in Hawtah to enhance production since early 1990's.

Existing wells are standard 9-5/8" vertical cased wells with perforations through the thin producing interval with ESP set in the same casing. Due to the low productivity of this type of completion, and high water cut a work-over program was initiated by Saudi Aramco in the late 90s to re-complete these wells as horizontal producers using various sand control techniques.

While converting from vertical, cased and perforated wells to single horizontal producers has helped to improve production, multilateral wells are needed in Hawtah to achieve and maintain economical production rates from these wells. In addition sand control solutions are required to safely deploy several branches off one main vertical well.

This paper will describe the history of the well HWTH-34 and workover's performed during its life span. It will also discuss the latest achievement deploying Saudi's first TAML Level 3 multilateral completion of a tri-lateral well.
Field Development Plans Optimization by Modeling Fluids Flow Impact and Assessing Intelligent Wells on Reservoir Performance
Authors: Elrafie Emad , Al-Qahtani Ghazi D. , Agil Mohammad , Rincon Alexander , Colomar François-Michel
Published: November 2008

The understanding and accuracy of modeling fluid flow behavior in naturally fractured carbonate reservoir is critical in predicting reservoir sweep efficiency, remaining drilling targets and evaluating field development alternatives. The use of appropriate complex wells design such as Horizontals, (H) Multi-laterals (ML) and completion technology such as equalizers (ICD) or Inflow Control Valves (ICV) are of equal importance.

The approach presented in this paper is based on detailed integrated analysis of all available well data including logs, production, pressure transient analysis (PTA), fracture distributions, well flow profiles (PLT) etc, to provide a first-line insight of the fractured reservoir fluid flow mechanism. These first-line insights provide the basis to develop mechanistic or concept reservoir simulation models to fine-tune fluid movement understanding in fractures, reservoir matrix, well types (H, ML) and completion placement to field development strategies. Sector modeling provides further insight to well design in field areas of different rock quality and fracture density. Well type and completion strategy alternatives for each identified field area including intelligent smart well completions are developed and tested in each sector model. The combined developed understanding of fluid flow mechanisms, well type and completion strategy are rolled up and implemented into a full field simulation model, fine tuned through history match and prediction processes.

This paper describes the methodology used to study a number of naturally fractured carbonate reservoirs through the integrated "Event Solution"1 study approach. The methodology presented in this paper was applied on a number of large Middle East carbonate fields. The fields studied have naturally fractured reservoirs with two distinct fracture systems. Namely, fracture corridors or clusters and diffuse or layer-bounded fractures. Diffuse fractures are typically horizontal (layer-bounded fractures) inter-connect with the fracture corridors which are normally vertical to sub-vertical. This fracture system combination forms a highly conductive fluid flow and pressure medium which is responsible for observed water movement as well as pressure propagation from the aquifer/injectors into the reservoirs.
Integrity Management during Design Stage
Authors: Baby Reji
Published: November 2008

The surging cost of Crude Oil has provoked oil and gas exploration and production to higher levels than expected. The wells that were previously considered abandoned for less GOR is now profit earning facility. Exploration and exploitation of new wells are at full swing and the time frame between identifying prospective wells and commission of a facility has shortened much. Planning, development and production of new facilities and systems / equipment needed for its support must take into account how operation and maintenance requirements are met into the design. Omitting the human factor and ergonomics (fitting the workplace to worker) in design has compromised the safe and efficient production, reliability, availability and maintainability of facilities leading to injuries to personnel and damage to equipment as well as costly retrofit. In the race to start an early production, integrity of assets has to be ensured in design, technical and operational phases for long term operational benefits.
Charge and Structural Timing in Relation to Hydrocarbon Prospectivity for Paleozoic Reservoirs in Abu Dhabi
Authors: Alsenani Haitham Saleh , Taher Ahmed , Alzaabi Mohammed Rashed , Stone Gary C. , McAllister Niall
Published: November 2008

Structural timing in relation to hydrocarbon charge timing has a significant impact on hydrocarbon prospectivity for Khuff and pre-Khuff reservoirs in Abu Dhabi. Maturation of Silurian source rocks began more than 150 million years ago and continues on until today in some parts of Abu Dhabi. A mix of structural growth histories is also observed with some very old structures pre-dating source rock maturation and other very young structures related both to emplacement of the Semail Ophiolites and Zagros uplift. Some of these young structures are located in areas where charge had already finished before the structure formed. Comparing the growth history of each individual structure to the Silurian source rock maturation history at each structure location can explain much of the observed Paleozoic gas distribution that has been observed by exploration drilling. This study investigates the impact of growth timing on the presence of hydrocarbons. It is believed that the use of this analysis substantially increases the confidence in assessing prospect risk ahead of drilling.

In this paper, we reflect on our efforts to undertake comprehensive investigations of the geology of the region. This discussion will cover the methodology which is used to perform the analyses of the growth history. Measuring the growth from seismic sections and from depth contour maps were the two basic methodologies applied.

The interpreted growth histories are compared to the tectonic history of the basin. Basin modeling to understand the timing of source maturation was a separate study, but the results of that work will be shown and the growth history will be compared to the charge history. Examples from Abu Dhabi fields are provided in this study to illustrate our concepts.
Using a Digital Plant Architecture to Prevent Abnormal Situations
Authors: Dennant Andrew
Published: November 2008

The wealth of data available from intelligent field instruments frequently goes unused. This is a waste of the investment in smart devices and, more importantly, does not allow the operator to optimise the performance of the asset. In the worst case it does not allow the user to prevent an abnormal situation (i.e. an emergency). This paper will explore, through concept and case study, how plant performance can be optimised and abnormal situations prevented through the use of intelligent alarm and alert routing.
Using Closed Loop Adaptive Control to Optimise Plant Operations
Authors: Dennant Andrew
Published: November 2008

Studies show that over two thirds of all control loops are poorly tuned or in the wrong mode (e.g. Manual instead of Automatic). Modern control system technology can not only identify poorly-performing loops but also identify the root cause of the problem. In many cases this is poorly-maintained field equipment, such as a badly-maintained valve. Early identification of such a field problem will allow maintenance to fix the problem in a timely way, improving the profitability and throughput of the plant and allowing the loop to be put back into Auto. In many cases the field equipment is operating perfectly, but the loop is poorly tuned. This may be for a number of reasons; the most common are that the loop parameters have not been changed since the plant was commissioned and that different tuning parameters are required in different modes of plant operation. The ultimate goal of loop tuners is the ability to automatically tune all loops in real time all the time, matching the tuning parameters to the process conditions. This presentation will show how this can be easily achieved using modern automation technology.
An Innovative Approach in Tracking Injected Water Front in Carbonate Reservoir off Shore Abu Dhabi
Authors: Amer M. M. , Al-Farisi O. , Hiraiwa T. , Attia M. , Al-Habshi A. , Madjidi A.
Published: November 2008

For pressure maintenance purpose peripheral wells have been used to inject sea water into a carbonate reservoir offshore Abu Dhabi. The injected water preferentially follows the path of the of higher permeability zones, since injection is done into formation water below oil water contact. Though the sea water front movement in the reservoir has been estimated indirectly via numerical reservoir simulator, successes of direct methods have been limited by the injection volume and environmental effects.

Direct spatial measurement of the injected sea water front within the reservoir is important to evaluate the efficiency of pressure maintenance by peripheral water injection, also considered an important step in tuning simulator parameters, and optimizing the Field Development Plan (FDP).

Although there is strong water salinity contrast between the injected and original reservoir water in this field, resistivity-based methods can be affected by variations in the reservoir rock cementation factor, while cased hole logs can be affected by environmental effects such as hydrochloric acid effect commonly seen in carbonate reservoirs after stimulation.

This technique that utilizes open hole Pulsed Neutron Sigma measurement of Logging While Drilling (LWD) enables petrophysicists to distinguish and determine injected water separately from formation water, independent of Archie-based resistivity method. Also this technique provides a new methodology to calculate cementation factor (m). Successful application of this technique in an offshore Abu Dhabi carbonate reservoir is presented here.
New Methodology for Optimized Field Development Plan, Why Do We Need To Introduce Dynamic Rock Typing "Case Study for Simulation Model Improved Accuracy and Reliability"
Authors: Al-Jenaibi Faisal , Hammadi Khaled , Salameh Lutfi
Published: November 2008

The initial hydrocarbon (Oil and Gas) in-place represents the asset volume of ADNOC that is required estimation at high accuracy level with minimum uncertainties to avoid any future risks with fields' development plans. Moreover, accurate estimation of the reserves that can be produced during the field life cycle is critical as it is directly impact the CAPEX and OPEX of different field development phases.

Fields developments are usually selected based on the techno-economic evaluations of the outcome from the full field simulation studies using representative models. Accordingly, management decision for fields' development is totally dependant on the accuracy of the used simulation models.

Worldwide, there are many simulation models successfully demonstrating good history match profiles, nevertheless, several of these models are utilizing unsupported parameters, such as representative capillary pressure and relative permeability curves. In addition to the adverse impact on the predictive reliability, massive convergences problems that are encountered and participating in slowdown the models performance and decreasing accuracy. Subsequently, incorrect Long Term Development Plans "LTDP's" profiles will be generated.

Therefore, in order to ensure achieving more representative asset volume estimates, a new procedure has been setup, established and successfully validated through different fields. The main objectives of the new procedure are to enhance model initialization with minimum gap in terms of hydrocarbon-in-place between the static and the dynamic models below the range of 1.0 %, to achieve more accuracy of the expected movable oil and gas with respect to water flooding (Current Development Plan) and future Gas/WAG flooding (LTDP), to eliminate high risk of assessment of modeling the actual gas/water breakthrough timing, recovery factor, sweep efficiency and fields measured matching parameters, and to cut down potential risks of under/over estimating the water/gas influx fronts in the reservoir.

Quality match is essential in order to prevent utilization of non-measured parameters such as irreducible water saturation (Swc's), also to eliminate utilization of unproven permeability multipliers. Moreover introducing a new capillary pressures (Pc) designing concept will contribute in reducing convergences problems as well as providing more consistent dynamic model setup (dynamic model rock typing).

Based on the results from several simulation studies which were introduced to the new procedure framework, the new procedure managed to demonstrate its capability to design the most reliable capillary pressure profiles. These profiles are essential for simulation models to ensure quality match of lateral and vertical oil and gas distribution in the field which represents the most extremely improvement match achieved when compared with other used method.
Large Hole LWD Compressional Sonic, New Age of High Quality Seismograms in Offshore Abu Dhabi, U.A.E.
Authors: Mercado Gary , Al Farisi Omar , Boyd Douglas
Published: November 2008

Generating a full section synthetic seismogram requires compressional sonic and density logging of the entire wellbore from TD to surface. Offshore Abu Dhabi, this is often difficult to achieve in the shallowest portion of the hole given the large 17.5" borehole size, possible formation collapse resulting in stuck tool condition, and uncontrolled free flowing water zones. Attempts to acquire sonic data through 13 3/8" casing met with mixed results while density logging was considered not an option. Acquiring logging while drilling (LWD) sonic data offers an alternative to wireline acquisition less restricted by adverse borehole conditions.

Uncertain whether LWD or wireline provides the best quality sonic data in a large diameter hole and accepting the risk of lost in hole occurrence, both types of tools were consecutively run followed by wireline density in a 17.5" diameter hole. Formation characteristics varied from clean high porosity limestones and dolomites, to tight anhydrites and shaly limestones. Compression travel times ranged from 55 usec/ft to 155 usec/ft.

A comparison between wireline and LWD sonic logs in a large diameter hole is presented. Sonic data quality, signal coherence and operating environments are reviewed and compared. The technical evaluation shows LWD sonic technology can replace wireline sonic in large holes when hole stability is an issue. However, neither tool provides high quality data under all conditions encountered.
AVO Application in a Carbonate Offshore Oil Field, U.A.E.
Authors: Ikawa Hidemasa , Mercado Gary , Smith Adrian
Published: November 2008

Amplitude Variation with Offset (AVO) is a well known technique as a direct hydro-carbon indicator in clastic gas fields. Carbonate reservoirs usually have a more rigid rock framework making them more difficult to see the changes in elastic parameters based on differing types of fluid saturation. An AVO Pilot Study has been conducted in 2007 to investigate the ability to detect fluid fronts in a producing Lower Cretaceous carbonate oil field, using pre-stack seismic data acquired in 2001. Assessing the position of injected water is a critical factor for future in-fill well location optimization and provides additional support for reservoir fluid movement prediction when coupled with reservoir surveillance and simulation data. The study was conducted in a small pilot area that includes a recently drilled well, where necessary data were available for a modeling. The modeling study was performed utilizing log data to assess the degree of seismic change due to fluid substitution based on Biot-Gassmann equation and synthetics have been generated to compare with actual seismic response. In addition to the conventional AVO technique, other techniques have also been tested such as Elastic Impedance and simultaneous AVO inversion followed by Lambda Rho / Mu Rho(LMR) transforms.

The results of the pilot study were validated with the known well fluid status in the pilot area. Mapping of the different water-oil-gas fluid response using the LMR technique shows a reasonably good agreement with currently known well saturations. It is, however, difficult to discriminate reservoir sub-layer water-cut percentages due to data resolution limitations. Generally, the results of the analysis indicate potential to identify hydrocarbon to water fluid contents, with the above constraints.
Managing Mature Indian Offshore Fields – A Case History
Authors: Mitra N. K. , Kumar Adesh
Published: November 2008

Mumbai High, Neelam and Heera fields, located in Western Offshore of India, are 20–30 years old and matured. Multi disciplinary approach in utilizing modern technology in every step of a well from planning to execution has been adopted in brown field development of these mature fields, Static and dynamic model building with state of art technology has been undertaken to bring out the subsurface picture more vividly. Technology has helped in drilling of ERD wells to far of places from existing platforms in complex subsurface architecture. Well placement technology with online monitoring at base (Virtual Reality Center) has improved proper well steering though thin sweet zones. In area of well completion also higher level multilateral technology has been adopted to monitor and control individual reservoir performance.

Typically, redevelopment project implemented in Mumbai High during 2000–2007 will increase recovery by 4% from 28% by 2030. About 200 wells have been completed in last 5 years. Similar project is under implementation in Heera field and envisages increase in recovery by 3.4%. In last 3 years about 91 wells in Neelam and Heera fields have been completed with latest technology.

Future initiatives are: –application of intelligent wells and smart platforms (3 Nos. of smart well platforms i.e. 1 in Mumbai High and 2 in Heera field installed),–challenge in produced water handling (plans are in vogue for processing capacity enhancement, application of swellable elastomer to reduce water inflow whilst increasing oil production) from high water-cut wells,–application of micro fracture simulation to assess the effects of water injection (FMI Logging).–Enhanced Oil Recovery (EOR) pilot to target residual hydrocarbons for increasing recovery.

The present paper describes in detail about the management of these matured fields to achieve higher recovery and future initiatives.
Challenges in Highly Sour Gas Environment Containing Elemental Sulphur
Authors: Girgis Magdy
Published: November 2008

BACKGROUND

To compete with more conventionally produced gas, wet sour gas is transported from the well head to the gas sweetening units in carbon steel pipelines. Sour gas corrosion can lead to pipeline pinhole leaks which pose hazardous consequences to people, wild life and pollution to the environment. Corrosion is usually controlled through chemical inhibition in combination with frequent batching and pigging programs.

In the presence of elemental sulphur corrosion rate can exceed 30 mm/y. Most of the mitigation methods designed to manage and maintain the integrity of carbon steel downhole tubing and pipelines present in itself some of the toughest technical challenges.

This paper outlines specific corrosion challenges related to the use of sulphur solvents; frequent pigging and inspection programs; corrosion monitoring, the use of lined carbon steel materials and some case histories. The paper also addresses the challenges associated with well acidizing on sulphur corrosion in surface and subsurface operations
Delivering Efficiency in Performance by Exploiting Advanced Management Information Systems for Well Integrity Processes
Authors: Al Ashhab Jamal , Khreibeh Hana Abu
Published: November 2008

Well integrity data is one of the most critical data types in oil production companies. Since this data is a valuable asset, ensuring its availability and reliability must be taken into consideration to avoid unsafe situations and potential catastrophic consequences. ZADCO has recognized this concern and thus makes continuous use of Information Technology to streamline its business processes.

This paper outlines the best practices for data management implemented by the Well Integrity Team to boost its business performance. These practices ensure achievement of effective and efficient business processes to cope with today's dynamic, fast-paced business environment. The deployment of Information Technology and its capabilities designed appropriately to serve the business, management and organizational needs result in robust Information Systems that achieve business objectives and save resources, effort and time.
Removal of Overburden Channel Effects through Channel Velocity Modeling and Prestack Depth Migration for an Oil Field Offshore Abu-Dhabi
Authors: Takanashi Mamoru , Kaneko Mitsuyoshi , Monzawa Nobuaki , Imahori Seiichi , Ishibashi Toshihisa , Sakai Akio
Published: November 2008

To generate refined depth structure for a very gentle Cretaceous reservoir on an oil field offshore Abu-Dhabi, we conducted channel velocity modelling and prestack depth migration (PSDM). The target reservoir structure on a vintage prestack time migration (PSTM) contains pull-up and push-down artefacts, induced by a couple of overburden channel velocity fills. These artefacts hindered correct representation of gentle depth structure at the target.

Detailed interpretation on the PSTM volume delineates overburden channels in three upper Cretaceous formations. One of them, Fiqa channel, generates small pull-up and the others, Halul and Lafan channels generate push-down below each formation, caused by higher and lower velocity channel fills, respectively. These artefacts overlapped at some locations.

Analysis of synthetic PSTM stack from forward modelling reminded us that a low-velocity channel produces obvious pushdown below the channel. The shape of push-down become smaller but wider with depth and offset. The resulted push-down in full-offset stack also changed with depth. A "true" channel velocity and implementation of PSDM eliminates push-down at all depths and offsets.

Bearing in mind the phenomenon confirmed on the forward modelling, we first produced channel velocity model for the target field data. With the assumption that the depth structure at a layer just below channels is flat, time thickness of channel and the amount of push-down at the layer below the channel could determine the channel velocities. Then, we estimated three channel velocities by channel time thicknesses and the amount of pull-up/push-down at the top Mid-Cretaceous shale, Nahr Umr formation that located just below these channels. On the overlapped area, a linear inversion provided each channel velocity. An application of PSDM with the channel velocity model successfully mitigated the artefact at target depth structure.
Challenges for Integrated Permeability Modeling Incorporating Conceptual Fracture Model in the Jurassic Carbonate Reservoir in a Mature Oil Field, Offshore Abu Dhabi
Authors: Kojima Haruo , Umezawa Yoshihiko , Salman Salman Mohamed , Hosani Khalid E. , Masuzawa Tsutomu
Published: November 2008

"A field" located in offshore Abu Dhabi has produced oil from the Jurassic carbonate reservoirs for 20 years under water injection scheme since 1997 after 10 years gas injection with maximum 20% water cut in some wells. The previous geological model was composed of box shaped fault pattern at down flank area derived from 2D seismic interpretation and mostly considered matrix reservoir properties with unsatisfied history matching quality, especially water cut behavior. In order to improve quality of static/dynamic models, geological model was mainly upgraded focusing on the following subjects: Fault re-interpretation was carried out with reference to analogy from adjacent oil fields, regional tectonic history and dynamic production performance. Radial fault pattern at crestal part in the domal structure was newly introduced.Since well test permeability was obviously greater than static permeability model derived from core plug measurements, fluid flow contribution by fractures was suspected. Hence, fracture density data from cores was reviewed and it is found that more fractures develop at selective layers and near the re-interpreted fault locations. Time-lapse water saturation data confirmed that water movement appeared at low matrix permeability intervals with higher fracture density. A conceptual fracture model was finally established based on the currently available data, and utilized to generate fracture permeability.

These approaches provided multi realization results to assign higher permeability at specific layers and locations related to faults/fractures reconciling well test permeability, although uncertainties remain on the fault interpretation due to lack of 3D seismic data.

It is very difficult to assess each realization and uncertainty including fracture permeability, therefore iterative loops between the geological model and reservoir simulator based on multi-realization models were required to generate a reasonably integrated permeability model. This collaborative process fully incorporating new geological model is in progress and the preliminary updated reservoir simulation using an essence of the conceptual fracture model suggested that matching quality was successfully improved compared with the previous model, particularly water cut behavior.
ADCO's Experience and Lessons Learnt in Managing Major Project Bu Hasa Facilities Development
Authors: Al Jaberi Adel , Hussain Mohamed
Published: November 2008

The objective of this technical paper is to share ADCO's experience during project execution – both in terms of technical and project management issues. It is also highlighting the challenges faced, achievements and lessons learnt during execution of the project and addressing issues related to changing market conditions in terms of availability of quality manpower, vendor assistance during commissioning, falling dollar value, maintaining production during construction and changeover.

The Bu Hasa facilities development project scope is to upgrade the existing Bu-Hasa oil production facilities and centralize the processing units in a new location and to design the system for the new forecasted produced fluid in order to meet the crude oil output specifications. The project includes also building new units / systems for water & gas injection for reservoirs pressure maintenance.

The existing central processing facilities at Bu Hasa consist of four (4) Central Degassing stations (CDS's), which are old and scattered at different locations. These stations independently receive process and export crude through main oil line (MOL) pumping station. Existing auxiliaries such as fresh water supply, produced water disposal, instrument air compressor station, power generation facilities, central control room etc. are also scattered at different locations. The new oil / gas and associated facilities (utilities) will replace the old and centralization of these facilities will be achieved under the Facilities Upgrade.

To maintain oil production from wet wells, facilities are required to handle a high water cut and ensure export crude oil is properly desalted; 20 PTB as total chloride content, and almost water free; 0.1% vol. BS&W.
Phanerozoic Plate Reconstructions of the Middle East: Insights Into the Context of Arabian Tectonics and Sedimentation
Authors: Johnson Christopher A.
Published: November 2008

The geodynamic events that shaped the Arabian plate and its hydrocarbon systems are illustrated in new animated plate reconstructions that include non-rigid deformation. The reconstructions illustrate the genetic relationships between hydrocarbon systems development and regional tectonostratigraphy. Important genetic controls include plate motions, tectonic events, basin formation and subsidence histories, deformation and uplift, eustasy, sediment supply and stratigraphic packaging (sequences), facies and depositional patterns, and paleolatitude (climate). Viewed synchronously in a regional-scale animation, the causes, feedbacks, and interrelationships between these factors are illuminated. The linkages between tectonics, stratigraphy, and eustasy are also clearly laid out in a logical context, where they can be viewed and evaluated together as a system.

Arabia during the Phanerozoic was situated at the northern rim of Gondwana, where repeated Wilson cycles created and destroyed a number of ocean basins (Proto-, Paleo-, and Neo-Tethys). Through this process, the Arabian platform experienced repeated marine transgressions across a low-relief continental platform. Relief controlled facies development and continuity. Therefore an understanding of the relief, where and when it developed, and the forces driving its creation and destruction are critical to mapping paleogeography, facies patterns, and play fairways. Relief can be driven by various factors, including thermal, flexural, or structural mechanisms, each of which have characteristic scales in space and time. Key Phanerozoic events involve relief creation through interaction between regional tectonic forces, basement structural fabric, erosion, and sedimentation. Thus it is critical to recognize the regional influence of tectonic events along the northern margin of Gondwana.
Sweet and Sour Gas Injection as an Enhanced Oil Recovery Method in Abu Dhabi Offshore Oil Fields
Authors: Uchiyama Ryoji , Yamada Yutaka , Ishii Hiroshi , Salameh Lutfi A.
Published: November 2008

Oil production from two adjacent offshore fields, ARF and GAF, started in 1989 and 1995 respectively in conjunction with sweet gas injection, followed by sour gas injection in 2001. The application of sweet and sour gas injection as an EOR method and transition of these reservoirs' behavior to date are discussed. Reservoir fluids in these fields comprise two types: Arab A reservoir is a highly under-saturated black oil reservoir with low GOR. This reservoir has applied the high pressure gas miscible drive method as an EOR. On the other hand, Arab C reservoir is a near critical fluid reservoir with high GOR. This reservoir has applied the gas cycling method, i.e. gas injection into the gaseous phase at the crest of the structure. Miscible displacement can be achieved by gas injection taking advantage of the naturally occurring fluid properties. Since commencement of production/injection, the produced fluid property has been monitored to optimize reservoir management. The historical transition of the fluid property is important in understanding the behavior of injected gas into the reservoirs. H2S/CO2 content is one of the simplest parameters to investigate the behavior of injected gas in reservoirs. The fluid data with H2S/CO2 content is used to validate the reservoir simulation models. Since the allocation of the gas injection volume to each reservoir is essential under the limited amount of the total gas, the optimum allocation is necessary and has been determined through sensitivity studies using the validated models.
Exploring Organisational Understanding and Capability through Crisis and Emergency Exercises
Authors: Evans David
Published: November 2008

This paper explores the relationship between understanding the "trigger" events which result in emergencies and crises and the capability of organisations to respond to such events. Traditional exercises are often expensive and fail to deliver value to an organisation; they take people through the steps but do not challenge the underlying assumptions and cultural values. Using information gathered from over 21 years of experience, including running some of the world's largest commercial exercises, the author analyses techniques for using exercises as a basis of establishing risk management as a proactive element of mitigation within an organisation.

The establishment of effective programmes for exercising crisis and emergency response can deliver valuable insights into the culture and capability of an organisation. By researching the underlying factors, presenting information in realistic scenarios and ensuring the balance of opportunity and vulnerability is explored; exercises can deliver both experiential learning to participants as well as independent feedback to managers on the status of the organisation.

It suggests an approach to training and exercises that can result in a marked improvement in the ability of an organization to reduce its risk profile.