bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unlocking the Hidden Potential of an Upper Jurassic Carbonate Reservoir After 46 Years of Field Discovery: A Case Study in Offshore Abu Dhabi
Authors: Maalouf Christophe Bassem , Hernandez Hernandez Jose , Zidan Maher , Uijttenhout Mattheus , Al-Jaberi Salem 
Published: November 2017

Abstract
After a long history of unsuccessful appraisal wells, a new phase of reservoir appraisal focusing on data gathering for reservoir and fluid characterization led to positive results. Fluid sampling, acid recipe, formation pressure, and horizontal drilling were key factors for the successful appraisal. This reservoir is now a significant upside for the field development plan.
During the early phase of field development, careful data gathering plan was designed to characterize the reservoir. The plan included coring, logging, reservoir formation pressure, downhole fluid analysis, fluid sampling, conventional Pressure, Volume, and Temperature (PVT) studies, and asphaltene and flow assurance studies. After collecting downhole oil samples, a compatibility study with acid recipe was performed and many chemical additives were tested to find the optimal one. A horizontal drain was drilled to maximize the reservoir contact. The well was tested with drill stem test (DST).
Reservoir formation pressure acquired in 4 pilot holes at locations covering the reservoir confirmed fluid mobility, initial reservoir pressure, and possible oil pool limits. Downhole fluid analysis and sampling allowed the characterization of the reservoir fluid properties. Conventional PVT, asphaltene and flow assurance studies confirmed light oil with good flow potential. However, the compatibility study with existing acid recipe showed a high increase in fluid viscosity. This could prevent the well from flowing after matrix acidization. Naphta, among many tested chemical additives, proved to be the best to resolve the viscosity increase. The horizontal drain was successfully acidized with the new acid recipe and the well flowed oil during DST for the first time, 46 years after the field discovery. The well was tested through separator at different chokes before the main pressure build-up (PBU). The well was shut-in for 78 hours. BU analysis showed that reservoir permeability is in line with previously collected cores.
Although earlier appraisals were successful in upper reservoirs, a classic approach to reservoir appraisal of this thin oil reservoir failed. Our approach of carefully planning the data gathering sequence, testing acid and oil compatibility, proved essential to understand the past failures, correct the shortcomings, and carry on a successful appraisal.
Appraising Unconventional Play Potential in Egypt's Western Desert
Authors: Salah Mohamed , Ibrahim Mazher H. 
Published: November 2017

Abstract
With the increase of Egypt's domestic demand for energy, economical production from unconventional reservoirs is a great challenge to maintain production's annual decline. This has spurred interest in the development of unconventional resources, such as tight reservoirs and shale gas, particularly because of the enormous success in North America that brought unconventional resources to the forefront of the discussion on the future of energy. The country has launched studies to evaluate, explore and appraise several prospects for unconventional gas in Shoushan-Matrouh and Abu Gharadig basins. Exploratory pilot data wells were drilled and completed in the appraisal program for collecting the required data to evaluate the reservoirs qualities, demonstrate the availability of reserves, and identify optimal technology to maximize productivity and set the foundation for future development of these unconventional plays. Logs, core testing, and analysis service data were performed on or collected from these wells. Laboratory testing was conducted to understand the complex mineralogy and variable rock fabric. Geomechanical rock properties derived from advanced petrophysical analysis of newly acquired high-definition triple-combo full-wave sonic logs and core samples were combined to develop sophisticated models. These understandings helped reduce uncertainty and the lessons learned from this work and presented in this paper helped define completion and stimulation technologies for horizontal wells.
This objective of this paper is to review of the results and share lessons learned related to the recent appraising activities of unconventional plays in Egypt's western desert, evaluate these unconventional resources to unlock their potential. In addition, this paper present the challenges of development, highlight the best strategies required for field development to capitalize on the promising potential of these reservoirs through an integrated advanced workflow. The results from this study will shed light on the results of recent unconventional gas exploration and appraisal activities, which indicate that the western desert of Egypt holds substantial resources of unconventional gas. This unconventional gas can help to change the slope of production rates in the country positively and set the foundation for future development of these plays.
Determination of Fluid Connectivity in the Middle Marrat of the Jurassic Fields of North Kuwait using Oil Fingerprinting
Authors: Dekker R. , Tegelaar E. , Perrotta S. , Miller S. D. , Le Varlet X. , Hasler C-A. , Narhari S. R. , Rao J. D. , Neog N. , Dwindt A. A. , Al-Haidar S. , Dashti Qusem 
Published: November 2017

Abstract
The primary objective of the present study is to determine the fluid connectivity in the Middle Marrat of the major Jurassic fields in North Kuwait. Understanding fluid connectivity on both geological and production time scales has a direct impact on static and dynamic reservoir modeling, history matching, fluid property variations during production and zonal allocation of comingled production.
123 light oils and condensates were analysed using multi-dimensional gas chromatography (MDGC). The resulting so-called fluid fingerprints were interpreted in the context of a complex geological framework resulting from extensive sedimentological, petrographic, and structural geology studies. A detailed description of different fluid families allowed reconstruction of reservoir connectivity on a geological time scale. Fault transmissibility was reconstructed from the distribution of fluid fingerprints of samples taken during well tests or/and early production representing the fingerprint of the initial fluids in place. Also, the significance and extent of baffles to vertical fluid flow like anhydrites or low permeability streaks could be evaluated.
In time-lapse-geochemistry, fluid fingerprints are monitored during production. Changes in fluid fingerprints were interpreted in terms of fluid movement from other reservoirs along fault systems. These changes in fluid fingerprints matched the changes in fluid properties observed during the well testing. In other examples, changing relative contribution of different separate flow zones that are commingled in the subsurface were recognized.
The results are used to update/constrain the 3D static & dynamic models. Results help to understand connectivity, fluid flow and Pore Pressure Prediction (PPP) for new wells to be drilled.
Coupled Multi-Reservoir Multi-Network Production Optimization of an Onshore Middle-Eastern Reservoir with Sour Gas Reinjection for Miscible EOR
Authors: Pathak Varun , Palaschak Chelsea , Kumar Anjani , Eastick Rob , Schulz Ralf , Al-Hadhrami Abdullah 
Published: November 2017

Abstract
Integrated reservoir & production modelling can be extremely beneficial in conducting production forecasting for complex systems consisting of multiple reservoirs, fluid mixing, and complex production networks. These forecasts are even more valuable in scenarios such as sour gas separation, compression, and re-injection into multiple oil and gas reservoirs. The challenges in performing such work include modelling of the reservoir and fluid complexities while correctly representing the reservoir and production network, and optimizing the entire system together. Such tasks have been a daunting proposition for the petroleum industry because of the technical and logistical shortcomings in the traditional approach of integrated modelling where several tools are coupled together explicitly.
In this study, a new, fully-coupled implicit tool was used to model an onshore middle-Eastern asset with multiple reservoirs, each with unique fluid, and multiple networks. The asset uses complex fluid mixing in the integrated network, multi-stage separation followed by gas sweetening, compression and re-injection of compressed sour gas into the reservoirs. A multi-fidelity approach was used throughout the modelling workflow, incorporating reservoir and production related uncertainty in the forecast and optimization process. For example, some reservoirs were modelled with refined numerical discretized models, some with upscaled numerical discretized models and some with decline curves. A total of 16 reservoirs linked to a single production system were modelled as an integrated system. Unique compositional fluid models were used for each discretized reservoir, as the reservoirs had distinct fluid phase behavior during primary production and under miscible enhanced oil recovery.
Consequently, an integrated system was built that contained numerical discretized and decline curve reservoirs, fluid complexities, high fidelity wells, and a production network with gas separation, sweetening and re-injection. The oil production and recycled gas injection were optimized using rules and long-term forecasts were generated.
Throughout the work, several production and reservoir engineers collaborated and shared data on the single multi-user, multi-disciplinary tool using a relational database – which solved the logistical challenges associated with modelling such large-scale projects where the use of traditional methods can often lead to communication breakdowns and data discontinuities.
Repeatability of a Highly Stable Permanent Seismic Source Evaluated Through Long-Term Operation at the Aquistore CO2 Injection Site
Authors: Nakatsukasa M. , Ban H. , Kato A. , Worth K. , White D. J. 
Published: November 2017

Abstract
Time-lapse seismic is often used for reservoir monitoring. Although some case studies have been reported, especially for offshore oil fields, similar onshore Abu Dhabi studies have been limited. Onshore monitoring challenges are mainly due to hard carbonate reservoir rock, in which fluid displacement invokes only minor changes in rock properties. Moreover, complex near-surface structures create strong surface-related noises such as surface waves and elastic scattering. These noises significantly degrade the repeatability if repeat data are recorded with positioning error of 1 meter. To address the problems above, permanent reservoir monitoring has been spotlighted recently. Although permanent receivers are widely used for seismology, few studies of permanent seismic sources have been reported. In this study, we demonstrate a permanent source, Accurately Controlled Rotational Operated Signal System (ACROSS), which has a fixed position and excites highly repeatable seismic waves by rotating an accurately controlled eccentric mass. We deployed ACROSS at the Aquistore CCS test field onshore in Canada and recorded the wavefield with permanent receivers buried underground. The ACROSS system was operated several times throughout one year. The data acquired in a continuous 45 day operation were analyzed to calculate variation of amplitudes. The result indicated that we had obtained very stable waveforms with less than 3% variation if the data is stacked sufficiently. We also compared the two datasets acquired at different times of the year by calculating the normalized root mean square (NRMS) as a repeatability index. The histogram showed that the peak of NRMS distribution approached ~15% with only front and back mute processing. These results support our conclusion that an ACROSS system has potential to be used for reservoir monitoring in onshore fields by providing highly repeatable data for an extended time period.
Moving Toward Smart Monitoring and Predictive Maintenance of Downhole Tools Using the Industrial Internet of Things IIoT
Authors: Temer Elias , Pehl Hermann-Josef 
Published: November 2017

Abstract
While all other industries are aligned with the digital evolution, oil and gas operations have also taken advantage of the importance of the digital transformation, especially in the actual context. Our industry is arguably in a new wave of the digital oilfield, with a growing consensus toward "smart" operations and "predictive" maintenance instead of the "reacting better" approach, which is not adequate in the new industry conditions and has been proven as an inefficient approach. Oil and gas operators and services companies have a major opportunity to increase efficiency and reduce operational costs through better asset tracking and predictive maintenance, combined with operations and technology expertise. This paper will focus on the maintenance management of downhole equipment, evolving in an unforgiving downhole environment, which in the case of equipment failure, can cause high financial losses. It will also present a use case and opportunities and challenges of smart monitoring and the predictive equipment maintenance approach, which is supported by newer technologies, such as the industrial internet of things (IIoT) and data analytics that use machine learning (ML) algorithms compared to the traditional, reactive approaches to equipment maintenance.
Integrating Microgels and Low Salinity Waterflooding to Improve Conformance Control in Fractured Reservoirs
Authors: Alhuraishawy Ali , Wei Mingzhen , Bai Baojun , Almansour Abdullah 
Published: November 2017

Abstract
The recovery from fractured reservoirs is usually low. The areal heterogeneity is one result of the fractured reservoir. Low-salinity waterflooding (LSWF) and preformed particle gel (PPG) have recently investigated by some reserchers. The main objective of this study was to determine whether the combining technologies can improve conformance control in fractured sandstone reservoirs. Semi-transparent five-spot models made of sandstone cores and acrylic plates were built. The effect of low-salinity waterflooding on oil recovery was studied. Models were designed with three parallel open fractures. Sodium chloride (1.0, 0.1, 0.01, and 0.001 wt. % NaCl) were used for brine flooding and 1.0 wt. % NaCl for preparing swollen PPG. Two microgel concentrations, 2000 PPM and 5000 PPM, with 850 micrometer particle size were used. Three cycles of low-salinity water were injected after the second conventional brine injection was completed. Oil recovery factor, water cut, injection pressure, microgel extruded pressure, fracture pressure (Pf), monitoring pressure (P1 and P2), and water residual resistance (Frrw) were measured. The interwell connectivity also was investigated. Laboratory experiments showed that the oil recovery factor, injection pressure, and the Frrw increased when the concentration of injected brine changed from conventional salinity to low salinity and the areal sweep efficiency was improved. The tortuous wormholes resulted highrer oil recovery than the straight wormholes and the oil recovery decreased as number of fratures and fracture width increased. The microgel concentration had a signicicant effect on plugging effeciecny; therefore, the 5000 PPM Microgel showed higher plugging efficiency than 2000 PPM. The result showed the interwell connectivity between the injector and producer decreased when low salinity waterflooding applied and increased the interwell connectivity between the injector and the monitoring points. The plugging efficiency, stabilized injection pressure, fracture pressure, monitoring pressure, and water residual resistance factor—all increased when the salinity of injected water decreased. Furthermore, the microgel strength decreased as brine concentration decreased. However, lower salinity water caused the incremental oil recovery factor to increase. Thus, there is a limitation in increasing the plugging efficiency under low salinity water. This limitation occurred when the brine injection pressure was less than the PPG’s extruded pressure. Combining two different EOR technologies can improve displacement and sweep efficiency and, in turn, enhance conformance control.
Evaluation of Late Cretaceous Cenomanian Petroleum System in Offshore Abu Dhabi with Geochemical Analysis
Authors: Kojima K. , Yamanaka M. , Taniwaki T. , Amo M. , Chiyonobu S. 
Published: November 2017

Abstract
Identification of hydrocarbon generating source rocks and evaluation of their potential are essential in the exploration and development of hydrocarbon resources. For an offshore oil field in Abu Dhabi, we conducted geochemical study using crude oil and core samples from Upper Cretaceous Cenomanian carbonate rocks. The study objectives are 1) correlation of crude oil and source rock with biomarker, and 2) evaluation of the source rock potential.
The Cenomanian carbonate rocks of the oil field are composed of shallow marine porous limestone and deep marine lime mudstone. This Cenomanian lime mudstone was believed as source rock of the crude oil in the interfingered Cenomanian porous limestone reservoirs. However, the origin of crude oil has been poorly constrained with geochemistry yet. In this study, we carried out geological description and RockEval pyrolysis analysis of core samples to evaluate source rock potential of the lime mudstone. Then, biomarkers such as hopane, sterane and compound specific isotopic ratio of n-alkane were analyzed to correlate the source rock and the crude oil samples with GC/MS, GC/MS/MS and GC/C/IRMS for high resolution biomarker measurements and robust interpretation.
As a result, the biomarker fingerprints of the crude oil in porous limestone and the organic material in the lime mudstone show significant similarity. It proves that the crude oil in the porous limestone is migrated from interfingered organic rich Cenomanian lime mudstone. In addition, the lime mudstone shows excellent source rock property (Total Organic Carbon exceeding 4%, Hydrogen Index &gt; 600mg/g TOC) and categorized as Type I/II source rock deposited in marine environment. Furthermore, the biomarkers effectively constrain the maturity of source rock which is difficult to evaluate with Vitrinite Reflectance and RockEVAL analysis. Consequently, the timing of hydrocarbon generation and the area of effective source rock will be interpreted based on our study result with higher confidence.
This study deepens understanding of Cenomanian petroleum system in offshore Abu Dhabi. The result suggests the advantage of biomarker application not only in oil-source correlation but also in source rock maturity analysis.
The Effect of Ba2+ & Sr2+ on EOR Efficiency in Carbonate Reservoir During Low Salinity Waterflooding
Authors: Park Hyemin , Park Yongjun , Yeonkyeong Yeonkyeong , Kim Joohyung , Lee Wonsuk , Kwon Oukwang , Sung Wonmo 
Published: November 2017

Abstract
When low-salinity water containing SO42- is injected into carbonate oil reservoirs, rock dissolution and in-situ precipitation occur as chemical equilibria are progressed, altering both permeability and wettability. The Ba2+/Sr2+ ions present in the formation water as impurities chemically react with the SO42- ions, and BaSO4 and SrSO4 are precipitated. In addition, when injected low-salinity water including SO42-, either dissolution of Ca2+-containing minerals or CaSO4 precipitates are occurred. These reactions can cause a serious impact on the efficiency of enhanced oil recovery (EOR). Therefore, the main purpose of this study was to identify EOR efficiency induced by low-salinity waterflooding (LSWF) when Ba2+/Sr2+ were present in a carbonate oil reservoir.
From the results of the effluent analysis and material balance calculation with the produced Ba2+, Sr2+, and Ca2+ concentrations, when Ba2+/Sr2+ concentrations were low, permeability was improved because of rock dissolution predominating over in-situ precipitation. These results concurred to the permeability change which was calculated with the measured pressure data. Also, in the analysis of wettability alteration through the measurements of contact angles and relative permeabilities before and after LSWF, higher concentrations of impurities consumed more SO42- in precipitating BaSO4 and SrSO4, resulting in weaker wettability alteration due to the reduction of sulfate activity. These phenomena ultimately influenced EOR efficiency, i.e., the oil recovery was greater as Ba2+/Sr2+ concentration were lower. Therefore, applying LSWF containing SO42- ion to carbonate oil reservoirs is not always a desirable EOR method when Ba2+ or Sr2+ is present, as an impurity, in the formation water.
Ways for Optimizing and Increasing Reliability of Centrifugal Compression Systems in Oil and Gas Industry: Case Study in Sultanate of Oman
Authors: Hatmi Khalid Al , Mashrafi As'ad Al , Balushi Sa'Ud Al , Al-Kalbani Haitham , Shaikh Mohammed , Vakili-Nezhaad G. Reza 
Published: November 2017

Abstract
Rotating equipments reliability and performance have evolved in the recent decays. Manufactures continue to produce more sophisticated machines. Those equipments form a central part of any oil and gas plant. Compressors in particular considered being a major investment for any company. For any operator, keeping the compressors performance and reliability is a very major task which requires an intense OPEX spending in some cases.
This study was conducted to focus on the common issues which are related to centrifugal compressors in Oil and Gas Industries with the aim to increase the reliability and performance of this type of compressors and to form a kickoff for compressors low performance root cause analysis. Also, it will serve as a quick reference for engineers and operators to troubleshoot and optimize compression system.
The common compressors issues identification and short listing of this study was not limited to literature review instead a detailed analysis of an existing centrifugal compressor system was carried out and common issues were reported. These issues were shortlisted to focus only on the process related aspects which are liquid carry over, surge, improper system configuration, variation on inlet gas properties and pressure impacts on the performance.
An existing compression system has been selected to study the effects of the listed issues. The performance and reliability of these compressors were checked and monitored for the last three years.
To meet the objective of this study, a detailed analysis was conducted to solve these issues and optimizing the system. The study includes theoretical analysis and field troubleshooting and trials). Theoretical aspects of the work with regard to the compressor efficiency, power consumption as well as other important issues are examined based on thermodynamic analysis of the systems.
The theoretical analysis concluded that the reliability and performance of the compressor system can be increased through a number of recommendations including optimization of the suction and discharge pressure, continuous process monitoring, enhancing inter stage scrubbers’ efficiency and maintaining the gas molecular weight through compressors stages. In addition, some recommendations are given which are applicable during the design stage such as recycle line location, drain system design, seal system design and scrubbers internals accessibility. The recommendations of the theoretical analysis are under long term field trials to ensure their applicability and sustainability. The results from this study are projected to be generalized for similar type of compression system in the industry. This paper will be of interest to anyone who designs or operates multistage compression systems.