bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving Fracture Network Model of AB Reservoir through Integration of Seismic Multi-Attributes- A Case Study from Awali Field Bahrain
Authors: Qasim Naji A. , Hermann Behira , Pathak Ravi Kant 
Published: March 2009

Abstract
The upper Cretaceous Ab reservoir within Ahmadi formation at Awali field is considered to be deposited over a broad, gently sloping carbonate ramp. The main reservoir lithofacies are bioclastic packstone, bioclastic packstone/wackestone, bioclastic wackestone and argillaceous wackestone/lime mudstone. The reservoir is characterized with moderate porosity (15%) and low permeability (.1 MD). The average production of wells is about 15 BOPD. However, there is wide degree of production variability due to matrix porosity variation and fracture distribution. The well productivity is relatively high in the areas with high fracture density. Accurate Fracture network model would contribute significantly for efficient recovery from the reservoir. Seismic 2D curvature attribute has been a valuable tool in mapping of fault networks. In the study, seismic curvature attributes along with horizon based and morphological attributes such as dip-azimuth, coherency, edge, 3D curvature have been successfully used together to improve the Ab Fracture network model.
The paper describes the workflow used in extracting Principal curvature attributes from 3D seismic data. The 2D curvature attribute helped in detection of many new fractures having lineaments consistent with the identified faults and fractures. This was followed by a Fracture Seismic Facies Analysis: it consists of fracture-related seismic multi-attribute analysis and statistical classification in order to select optimum set of attributes providing best geologically consistent representation of fractures.
From this Fracture Seismic Facies Analysis, it was inferred that fractures were best represented by facies corresponding to high to mid curvature, high edge and low coherency. The fracture facies so derived was calibrated with FMI & other well information and was used for preparing the improved Fracture network model.
New Techniques in LWD Formation Pressure Testing Enable Real-Time Reservoir Evaluation in Evermore Challenging Environments
Authors: Hahne Ulrich , Pragt Jos , Meister Matthias , Lallemand Marco 
Published: March 2009

Abstract
Wireline formation pressure testing has been routinely used as a valuable reservoir characterization tool and its results are generally well-regarded. On the other hand, LWD formation pressure testing, initially introduced primarily as a drilling safety and equivalent circulating density (ECD) optimization tool, has yet to fully prove its effectiveness in reservoir evaluation, due to perceived data acquisition challenges.
Today, re-entry drilling is used in many aging oil and gas fields to target the remaining hydrocarbon. Formation pressure, fluid gradients and the determination of whether or not compartments are in communication are important information when analyzing such reservoirs in real time for optimum wellbore placement. The cost efficiencies of acquiring formation pressure data while drilling are becoming more influential in the operator's technology selection process, but should not come at the cost of reduced data accuracy or data useability.
This paper discusses new techniques and technologies that facilitate gaining a better understanding of the subsurface while drilling. These include a smart test function, which reduces formation shock while pressure testing in microDarcy formations and avoids sanding in highly unconsolidated formations. Performing optimized test sequences improves the accuracy of the pressure and mobility data and leads to higher operating efficiency. Further to this, LWD pressure testing on wired pipe yields a data density previously only found on wireline. The introduction of extended test times of up to 40 minutes broadens the scope of LWD pressure testing into traditional formation pressure testing applications, such as compartmentalization evaluation or fluid gradient analysis. Longer test times and testing on wired pipe precede future fluid sampling while drilling. Benefits for drilling and subsurface teams are equally important and one of the reasons why LWD formation testing has become a cross-functional discipline. Case histories from the Middle East will be used to highlight the recent technology advances and applications.
Improved Wellbore Delivery in a Deepwater Reservoir via the aid of Logging-While-Drilling Imaging and Formation Pressure Data
Authors: Day Ron , Fisher Ramsey , Plutt Louise Jacobsen , Pardo Nesny , Jebutu Segun , Freitag Hans-Christian 
Published: March 2009

Abstract
As capital costs continue to escalate in the deepwater environment, there is greater pressure on operators to deliver wells in a more efficient manner. This paper will review the drilling and data acquisition strategies to successfully deliver a challenging deepwater development well. First, the well was the longest stepout and highest angle well drilled in the field to date. Second, the well targeted a fault block in a portion of the field that was poorly constrained due to limited offset well control and poor-quality seismic data. Third, the final hole section, 6,000 ft of 12¼-in. hole inclined at 48°, was to be drilled through two pressure ramps, one unstable slump zone, and one pressure regression on its way to the targeted reservoirs.
The evaluation program for the well was solely logging-while-drilling (LWD)-based and included structural dip and azimuth from density and gamma imaging sensors and formation pressures and gradients from an LWD formation tester tool. Real-time formation pressure data and rush processing of the azimuthal density image confirmed that the well had crossed an unexpected sub-seismic fault in the targeted reservoir section. Structural data derived from the density image log and projected fluid contacts based on LWD formation pressure tests were integrated into the existing field model in real time, allowing the team to quickly update its structural model, define the fault block size, and successfully plan and deliver a sidetrack well. A total of 129 pressure tests were attempted with 124 successful tests recorded (96% success rate), all while circulating to maintain wellbore integrity.
The viability and benefits of a fully LWD-based data acquisition program were proven in this challenging application, delivering improved wellbore placement and reduced drilling risk based on real-time evolution of the reservoir model.
Using Formation-Testing-While-Drilling Pressures to Optimize a Middle East Carbonate Reservoir Drilling Program
Authors: Masoud Rashad , Gyllensten Asbjorn , Amari Khalid , Al Belooshi Abdulla , Lawghani Jasim , Salem Gamal , Proett Mark , Aki Ahmet , Eyuboglu Sami , Nabawy Sherif 
Published: March 2009

Abstract
Formation-testing-while-drilling (FTWD) technology was introduced in 2002 and has been used primarily for applications similar to wireline formation testers (WFT). These applications include accurate formation pressures, gradient analysis, formation connectivity, differential depletion, and flow barrier detections. A largely untapped application for FTWD is drilling optimization. The testing practices for drilling optimization are somewhat different than those used for typical WFT applications. In these cases, it is desirable to obtain pressures as soon as possible; and real-time test results are paramount. Combined with other downhole drilling information, such as vibration, torque, and weight-on-bit, drilling parameters can be adjusted to improve the rate of penetration (ROP) and make adjustments to the wellbore stability model in real-time.
This paper reviews a Middle East case study in a carbonate gas reservoir. In part of this field, the reservoir pressure was uncertain due to possible communication with a high-pressure lower interval. Therefore, establishing the actual formation pressure was a priority. By monitoring the FTWD pressure tests in real-time, it was possible to verify the quality and validity of each test. Then, the test data was used to change mud parameters gradually. A composite log clearly indicates how decreasing annular pressures resulted in an increase in ROP.
The method of testing and real-time monitoring results are reviewed and compared with high-resolution memory data from the FTWD tool. Comparison validated the real-time test data. Conclusions are drawn concerning drilling applications and how such test data can be utilized to improve the drilling process.
Uncertainty Analysis of a Fractured Carbonate Reservoir
Authors: Thuwaini Jamil S. , Alwan Khalid A. , Ranjan Amit 
Published: March 2009

Abstract
State of the art methodology using experimental design and response surface techniques were used to perform uncertainty and risk analysis for managing reservoir uncertainties during history matching, production forecasting and production scheme optimization.
In this paper we present the method applied successfully on a complex carbonate fractured reservoir with a long production history with approximately 500 producers and injectors. The simulation model is dual porosity/dual permeability, with 5 million cells. The objective is to quantify the impact of principle reservoir uncertainties on key field performance responses such as cumulative oil production, plateau length and water production using a risk analysis approach. The main uncertainties of the field were fracture connectivity, matrix-to fracture transfer, super-permeability streaks (Super-K) extent and matrix properties in a well spacing of one kilometer.
From field performance experience, main parameters were identified and their responses during the historical production period were analyzed. The impact of parameters on history match quality was analyzed and an appropriate range of uncertainty was selected. A sensitivity analysis was performed to prioritize and rank the key influential parameters impacting production forecast. A novel methodology was applied to convert discontinuous realizations into a more continuous problem. Using the most influential selected parameters, another sensitivity analysis was done to accurately predict the dispersion in the production responses. A polynomial regression equation was derived for each of the main production responses. Finally, probabilistic distributions were generated for key production responses.
This paper will highlight results of the study that helped in giving clear direction in field development planning by identifying and quantifying the main drivers influencing production behavior. Additionally, the results allow for quantifying the key uncertainty of the model forecast and associated risk to be investigated further. The results of the study can also be used for production optimization process by deriving the best operating constraints for highest recovery.
A Successful Full-Field Reservoir Characterization Story Utilizing Pressure Transient Analysis
Authors: Al-Harbi Badr M. , BinAkresh Saud A. 
Published: March 2009

Abstract
This paper presents a successful case history of full-field reservoir characterization. It discusses real cases where transient analysis was a key tool in detecting various reservoir heterogeneities in the early phases of the field development. Pressure Transient Analysis (PTA) is well-known in the oil industry as one of the most important reservoir characterization tools for its ability to provide better identification of reservoir heterogeneities along with its well-proven capabilities in providing rational determination of reservoir parameters such as permeability thickness, skin and productivity index. Many reservoir heterogeneities such as faults, fractures, Super-K were detected along with many others. In addition the paper spots lights on many unique case histories where pressure transient analysis was able to detect an abnormality in the reservoir. The study helped enhancing the development strategy of that carbonate field following other successful studies that were previously conducted on other development fields.
Field Development Strategy Applied to a North African Field using Reservoir Simulation through an Integrated Asset Team Work
Authors: Castro Abel Andres , Fanjul Javier Prieto , Gaaim Abdussalam , Omran Khalid , Gomez Candido 
Published: March 2009

Abstract
An approach to an integrated asset team work to generate a field simulation static and dynamic model to carry out a field development plan revision is presented. A general workflow to assess this goal is developed. Structural and stratigraphic model, fine grid construction, facies characterization, properties distribution, geostatistical realizations to manage geo-static model are presented together with a complete reservoir simulation methodology. H Field is located in Murzuq Basin, SW Libya, in the middle of the southern part of NC186 block. The field was discovered by well H-01 in 2004. H Field is an elongated NW-SE paleo-high. Middle Ordovician sandstones are the main reservoir.
Hawaz formation comprises a distinctive suite of facies associations representing a broad range of environments from low energy shelfal marine sediments deposited largely below storm wave base, through to sub-aerial delta plain channel environments. The depositional environment is characterized by a gently dipping shelf covered by epicontinental sea developing an extensive coastal plain area dissected by fluvial-tidal channels.
Hawaz formation is subdivided into eight (8) units, three of which are the main reservoir (H4 to H6). The top layers (H1 to H3) are very tight with low quality petrophysical characteristics and they are considered for unconventional future development. Geological framework, fault and facies modeling was used in conjunction with observed dynamic performance to determine a representative distribution of reservoir properties. Upscaling process was not performed until the best fit model was achieved. The model dataset was based on twenty (20) existing wells (producers and injectors). Several simulation runs integrating history matching and interactive multidisciplinary work were performed before arriving to the final realization. Predictive runs to perform sensitivity checks on water injection scenarios and additional infill drilling were carried out, too. A combination of peripheral water-leg, structural-edge oil leg and internal line-drive water injection schemes was envisaged. Resistivity logs and RFT interpretation results were combined to define the water transition zone. The proposed revision of the Field Development Plan maximizes the ultimate recovery and requires the drilling of 40 producers and 20 water injectors to reach a 6-year duration production plateau rate of 25,000 bopd. Close work between interdisciplinary team members reduced time and increased the accuracy of the results. Additional wells drilled later on validated the structural and property distribution predicted by the model, as well as the individual productivity indixes. Recommendations for additional field data gathering were included in the final report to improve future model updates.
Inhibition of Th17 Cells Regulates Autoimmune Diabetes in NOD Mice
Authors: Emamaullee Juliet A. , Davis Joy , Merani Shaheed , Toso Christian , Elliott John F. , Thiesen Aducio , Shapiro A.M. James 
Published: March 2009

OBJECTIVE
The T helper 17 (Th17) population, a subset of CD4-positive T-cells that secrete interleukin (IL)-17, has been implicated in autoimmune diseases, including multiple sclerosis and lupus. Therapeutic agents that target the Th17 effector molecule IL-17 or directly inhibit the Th17 population (IL-25) have shown promise in animal models of autoimmunity. The role of Th17 cells in type 1 diabetes has been less clear. The effect of neutralizing anti–IL-17 and recombinant IL-25 on the development of diabetes in NOD mice, a model of spontaneous autoimmune diabetes, was investigated in this study.

RESEARCH DESIGN AND METHODS AND RESULTS
Although treatment with either anti–IL-17 or IL-25 had no effect on diabetes development in young (&lt;5 weeks) NOD mice, either intervention prevented diabetes when treatment was started at 10 weeks of age (P &lt; 0.001). Insulitis scoring and immunofluorescence staining revealed that both anti–IL-17 and IL-25 significantly reduced peri-islet T-cell infiltrates. Both treatments also decreased GAD65 autoantibody levels. Analysis of pancreatic lymph nodes revealed that both treatments increased the frequency of regulatory T-cells. Further investigation demonstrated that IL-25 therapy was superior to anti–IL-17 during mature diabetes because it promoted a period of remission from new-onset diabetes in 90% of treated animals. Similarly, IL-25 delayed recurrent autoimmunity after syngeneic islet transplantation, whereas anti–IL-17 was of no benefit. GAD65-specific ELISpot and CD4-positive adoptive transfer studies showed that IL-25 treatment resulted in a T-cell–mediated dominant protective effect against autoimmunity.

CONCLUSIONS
These studies suggest that Th17 cells are involved in the pathogenesis of autoimmune diabetes. Further development of Th17-targeted therapeutic agents may be of benefit in this disease.
Evaluation of serum cardiac troponin I concentration in dogs with renal failure
Authors: Sharkey Leslie C. , Berzina Inese , Ferasin Luca , Tobias Anthony H. , Lulich Jody P. , Hegstad-Davies Rebecca L. 
Published: March 2009

Abstract
Objective—To determine whether dogs with renal failure have higher serum cardiac troponin I (cTnI) concentrations than healthy dogs.
Design—Case-control study.
Animals—31 dogs with renal failure and 51 healthy dogs.
Procedures—Serum concentrations of creatinine and cardiac troponin I, urine specific gravity, and systolic arterial blood pressure were measured for all dogs. Dogs underwent a standardized physical examination, and any dog with evidence of cardiovascular disease or other nonrenal disease was excluded from final analyses. Dogs were considered to be in renal failure when the serum creatinine concentration was ≥ 3.0 mg/dL, urine specific gravity was between 1.007 and 1.030, and renal failure had been clinically diagnosed.
Results—Dogs with renal failure had significantly higher serum cTnI concentrations (median, 0.35 ng/mL) than did healthy dogs (0.20 ng/mL). The renal failure group also had a significantly higher median systolic blood pressure (156 mm Hg) than did healthy dogs (138 mm Hg), although serum cTnI concentration was not correlated with systolic blood pressure in dogs with renal failure. There was no significant difference in age between dogs with renal failure and healthy dogs, but dogs with renal failure had significantly higher serum creatinine concentration and lower urine specific gravity.
Conclusions and Clinical Relevance—Although dogs with renal failure did not have overt clinical signs of cardiac disease, they had high serum cTnI concentrations, which may have been associated with subclinical cardiovascular disease. The cause of the high serum cTnI concentration in these dogs requires additional investigation.
Evaluation of factors affecting serum IgG concentrations in bottle-fed calves
Authors: Chigerwe Munashe , Tyler Jeff W. , Summers Marin K. , Middleton John R. , Schultz Loren G. , Nagy Dusty W. 
Published: March 2009

Abstract
Objective—To determine the effect of time interval from birth to first colostrum feeding on colostrum intake and serum IgG concentration and the effect of varying colostral volume intake and colostral IgG concentration on the probability of failure of passive transfer (FPT) in bottle-fed calves.
Design—Randomized controlled study.
Animals—104 calves.
Procedures—Equal numbers of calves were randomly assigned to groups and fed 3 L of their dam's colostrum at 1, 2, 3, or 4 hours after birth by use of a nipple bottle. Calves were allowed to feed for 15 minutes, and intake was recorded. A second 3-L bottle feeding of colostrum was offered at 12 hours of age.
Results—17.2% of calves ingested 3 L of colostrum at the first feeding and 3 L at 12 hours of age. Calf age, up to 4 hours, had no significant effect on the calf's ability to ingest colostrum or on 48-hour serum IgG concentration. Colostral intake at 1, 2, 3, or 4 hours had no effect on intake at the second feeding. Probability of FPT in calves ingesting 3 L at both feedings was < 0.05.
Conclusions and Clinical Relevance—Allowing calves fed by nipple bottle to ingest as much colostrum as they can within 4 hours after birth and at 12 hours of age substantially reduced the probability of FPT. Bottle-fed calves that do not ingest 3 L of colostrum within the first 4 hours after birth should be targeted for oroesophageal intubation.
Evaluation of prepartum serum cholesterol and fatty acids concentrations as predictors of postpartum retention of the placenta in dairy cows
Authors: Quiroz-Rocha Gerardo F. , LeBlanc Stephen , Duffield Todd , Wood Darren , Leslie Ken E. , Jacobs Robert M. 
Published: March 2009

Abstract
Objective—To identify serum biochemical and hematologic variables, as measured in the week before parturition, that predict postpartum retention of the placenta (RP) in dairy cows.
Design—Retrospective cohort study.
Animals—1,038 cows in 20 commercial dairy herds.
Procedures—Serum concentrations of fatty acids (FAs), β-hydroxybutyrate, cholesterol, glucose, urea, and calcium and blood leukocyte, neutrophil, lymphocyte, monocyte, and eosinophil counts were determined. These variables were evaluated for an association with development of RP by use of a multivariate logistic regression model. Parity, season of par-turition, existence of twins or dystocia, body condition score, and vitamin E treatment were included in the model as covariates.
Results—High serum concentrations of cholesterol and FAs were associated with an increased odds of RP. There was a 5% relative increase in the odds of RP for each 0.1 mmol/L increase in cholesterol or FAs concentration in the week before parturition. Season of parturition and twinning were also identified as risk factors.
Conclusions and Clinical Relevance—These associations indicated that prepartum energy metabolism contributes to the development of RP. Serum concentrations of cholesterol and FAs may be useful to identify cows with a metabolic abnormality or energy imbalance that might predispose them to RP and should be interpreted in conjunction with clinical risk factors such as twinning, dystocia, or parturient paresis.