bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tapping the Difficult Oil and Enhancing Reservoir Development Strategy to Maximize Recovery From a Matured Waterflood Giant Carbonate Field in The Middle East: Arab C Reservoir Dukhan Field, State of Qatar
Authors: Majid Mohamed Naguib Bin Ab , Troconiz Carlos , Al-Shafei Mohammed Nedham , Luca Gheorghe , Cachi Ariel 
Published: December 2015

Abstract
After 70 years of production, more than 30% of the Arab C STOOIP has been recovered through various mechanisms including natural depletion, water flooding, gas-lift implementation and horizontal well development. Extending production into future years requires a strategic approach, focusing on innovative development optimization in order to target the remaining oil saturation. An aggressive drilling and intervention programme is ongoing to tap into the remaining oil. In addition to coupling evergreen reservoir models and flood-front surveillance, enhanced waterflood and CO2 WAG hold the greatest strategic potential to maximize recovery.
Integration of a recently acquired, high-resolution 3D seismic survey complements the data available for subsurface description and characterization, positively impacting reservoir model history matching metrics. Utilizing the models to set appropriate production and injection targets and vice versa adjusting the models to new data acquired in the field maintains a tight coupling between our models and surveillance monitoring. The evergreen models facilitate optimization of infill drilling locations targeting bypassed/remaining oil for sweep improvements.
Surveillance monitoring of flood-front encroachment and pressure behavior indicates that the permeable and connected beach and shoal lime grainstones of the Lower Arab C are sweeping according to simulation predictions. Conversely, the Upper Arab C exhibits a less favorable waterflooding potential due to the thin-bedded (1-2ft) grain- and mud-prone peritidal deposits that maintain significant lateral and vertical permeability contrasts. Sensitivity tests in our high-resolution full-field models support the addition of a line drive pattern to the existing peripheral waterflood for the Upper Arab C.
CO2 WAG has also been identified and tested in the model as a potential EOR mechanism to improve recovery. Engineering studies are underway to develop the infrastructural requirements for a CO2 pilot. It is envisaged that the combined development strategy of both enhanced waterflood and CO2 EOR will greatly assist in producing the difficult oil and maximizing recovery in the process.
Forward Process-Based Modeling of Submarine Turbiditic Environment: BC-10 OSTRA Case Study
Authors: Ferrandis Javier , Cantelli Alessandro , Jimenez Eduardo 
Published: December 2015

Abstract
Some of the current methods of geological modeling cannot imitate the order and complexity that is observed in nature. It's been recognized among the geoscientist community how a process-based modelling may facilitate a step change in reservoir building capabilities. The advantage in decoupling the grid design from the facies distribution poses a tremendous opportunity to close the gap between the static and dynamic reservoir model. A major advantage is capturing fine-scale heterogeneities (shale drape, amalgamation, etc) which are hard to capture with pixel-based techniques. The goal of process-based geological modeling is to simulate that order by generating rules. These rules make possible to create high-fidelity 3D geological models representing more realistic depositional and stratigraphic events than those that are randomly generated using conventional geostatistical techniques.
In this paper we illustrate the use of surface-based modeling within a submarine-turbiditic environment and the procedure followed to deliver a dynamic model conditioned to production data. The procedure follows development of physics-based methods and rule-base stacking of events to reconcile geological complexities and uncertainties with well performance. We'll present a process combining Design of Experiments and gradient-based techniques to assimilate production data. The method generates complex geometries comparable to those observed in high resolution near-surface seismic datasets. The case under consideration is an oil field offshore Brazil developed with horizontal wells and state of the art surveillance. The proposed workflow has delivered a simulation model that has achieved a good history match to production data in the form of water cuts and pressures.
Extended Abstract: Advanced Multiple Porosity Model for Fractured Reservoirs
Authors: Yan Bicheng , Alfi Masoud , Cao Yang , An Cheng , Wang Yuhe , Killough John E. 
Published: December 2015

Abstract
Much of the hydrocarbon reserves are stored in fractured reservoirs with high heterogeneity worldwide. In such reservoirs there likely exists more than two porosity types, and transient flow likely occurs in the matrix. Dual porosity models can characterize only two porosity types and are difficult to accurately capture the transient flow. This paper discusses an advanced model that allows simulating an arbitrary number of porosity types which accurately captures the transient flow in the matrix.
The proposed multiple porosity model honors any number of porosity types with different properties, such as permeability, porosity and wettability. Arbitrary connection for intra-porosity and inter-porosity flow are designed in an unstructured scheme, and convenient transformation between multiple porosity and multiple permeability formulations is allowed. A flexible porosity subdivision works in a fashion of hierarchical refinement and allows us to characterize the transient flow in the matrix and multilevel fracture sets with different geometry as well. The formulation is designed to allow the proposed scheme to be generalized. To quantify the improvement available with the new formulation, multiple porosity models are compared with single porosity models and analysis of different shape factors are also conducted. Our results show that they can be made to be equivalent under single phase conditions. Moreover, the application of the new model in shale reservoirs is discussed in two phase flow cases considering mixed wettability in shale matrix, and the results show that through a complete inter-porosity connection mode, the flow pathway of gas and water in shale is effectively identified.
A Novel Approach for Modeling Gas Flow Behaviors in Unconventional Reservoirs with Nanoporous Media
Authors: Song Hongqing , Li Zhengyi , Wang Yuhe , Zhu Weiyao , Cao Yang , Killough John 
Published: December 2015

AbstractWith the technology advancement in unconventional reservoirs development, more and more attention has been paid to nanoporous flow which is believed to play a central role in understanding fluid flow behaviors in unconventional reservoirs. Previous studies have performed unconventional reservoir analysis using more conventional reservoir simulation techniques. However, conventional numerical simulation techniques are computationally expensive and do not understand fluid flow behaviors well in terms of theory basis.In this paper, we first present a new motion equation considering diffusion and convection and Lattice Boltzmann method is applied to model the gas flow characteristics to obtain the important parameters in the new general equation. Then the mathematical model of gas flow behaviors in multi-scale medium were proposed and established based on theoretical analysis of transport mechanism via molecular kinetic theory. The pressure distribution equations of radial and linear flow were derived for different flow regimes analytically, and the computation method of the control area of gas well was presented. Additionally, the semi-analytical equations of volumetric flow rate for horizontal fractured wells were obtained. At last through Newton iterative method, the non-linear volumetric flow rate was analyzed, considering various factors such as SRV permeability, unstimulated shale permeability, and diffusion coefficient.Barnett shale production data is used to calibrate and validate this new approach. According to the results, the volumetric flow rate of the gas well increases when the diffusion coefficient grows. Consequently diffusion in unconventional reservoirs with nanoporous media plays an important role. With changing the average pore diameters, different results are simulated and calculated by LBM and the most appropriate values can be confirmed by comparing the experimental results. Besides, the intrinsic permeability of unstimulated shale and permeability of SRV are also found have apparent positive correlation with the gas productivity.
Innovative Integrated Asset Model including ESP Gas Handling and Power Supply Managements, Al Khalij Field case
Authors: Marmier R. , Elazabi S. , Viguerie B. , Pars H. , Venugopal D. 
Published: December 2015

Abstract
Since the start of production, the Al Khalij field, Qatar, has experienced a relatively rapid increase in water cut evolution and decrease in reservoir pressure. The associated consequences bring new challenges to the ESP development concept, increasing ESP exposure to free gas and power requirements. Therefore, operating and maximizing production of Al Khalij field requires not only integrated thermo-hydraulic fluid modeling from reservoir to surface, but also ESP gas handling and power supply managements. Integrated modeling is a cross-functioning simulation, monitoring and decision tool capturing the interactions from reservoir to surface facilities and from today to the end of field life. This paper describes the associated benefits of an innovative Al Khalij field Integrated Asset Model embedded into live data environment and performing production optimization accounting for ESP gas handling (gas volume factor and minimum bottom-hole pressure) and power supply management constraints (ESP motor, variable speed drive and wells and platforms transformers). As for any Integrated Asset Model, the reservoir, the wells, and the network thermo-hydraulic behaviors have been calibrated on the production data. The reliability of the well models to reproduce the measured production data has been demonstrated and is described in this paper. It has even proven capability to detect abnormal hydraulic and electrical behavior of the ESP motor and/or the pump. In the Integrated Asset Model, the intensity and voltage values are calculated at the ESP motor, the variable speed drive and the wells and platforms transformers levels. The electrical load based on these equipments design is used through an innovative workflow to constraint the field production optimization together with the free gas management constraints. The Integrated Asset Model has then been embedded into a live data environment of the field (DOF) for monitoring and automated models management and is used to further optimize the production including ESP free gas and power supply managements, and to anticipate on future debottlenecks.
Depositional Space: Construction and Applications to Facies and Petrophysical Property Simulations
Authors: Souche L. , Lepage F. , Laverne T. , Buchholz C. 
Published: December 2015

Abstract
In the absence of strong diagenetic or compaction trends, the anisotropy and distribution of facies and petrophysical properties are essentially the result of the composition of the paleoenvironment at the time of deposition and of geological phenomena such as erosion, faulting, and folding, which subsequently altered the geometry of the rocks. Understanding and isolating these two parameters (depositional and post-depositional effects) is key to the accurate interpolation and extrapolation of subsurface properties. This requires establishing a mathematical transform between the present-day geometry of rocks and their geometry at the time of deposition. The most common solution consists in relying on the layering and indexing of 3D grids to approximate paleodepositional coordinates. However, it is shown that for both pillar and stair-step grids in presence of tight folds or low-dipping or reverse faults, the variogram ranges, orientations, and facies proportions are significantly distorted when geostatistics are based on cell indexing.
Four essential properties that a rigorous depositional space should honor are then described and the shortcomings of the existing solutions are analyzed. A novel approach in which the representation of a depositional space is independent of a 3D reservoir grid is then introduced, and it is shown that solid mechanics provide a robust and practical way of building such a computational space. The use of depositional coordinates for performing variogram analysis and property interpolation is also exposed. The proposed approach yields facies distributions that accurately honor the model parameters independently from the structural configuration, while accounting for complex stratigraphic and depositional patterns (erosions, onlaps, etc.) and integrating nondepositional trends and overprints. We demonstrate that, in a variety of geological settings, better results are obtained when property interpolation and simulation do not rely on grid geometry and indexing.
Qualification and Optimization of Degradable Fibers for Re-Stimulation of Carbonate Reservoirs
Authors: Sau Rajes , Shuchart Chris , Clancey Byron , Lecerf Bruno , Pavlova Svetlana 
Published: December 2015

Abstract
Advancement in fluid diverter technology has enabled successful initial stimulation of long interval carbonates without mechanical isolation, in excess of 1000 ft. by using in-situ crosslinked polymer systems and viscoelastic surfactant systems. These fluids build viscosity upon reacting with the formation, enhancing diverter performance. However, heavily stimulated, i.e. wormholed, formations require a step-level change in diversion performance to effectively stimulation new intervals, or previously under-stimulated layers. This paper will present the qualification and optimization of degradable fibers for use in re-stimulation of carbonate formations.
The key performance aspects desired and evaluated are: (1) ability to block existing wormholes near the wellbore, as opposed to needing to fill the entire wormhole structure, (2) permeability and diversion capability of resulting fiber bridge, and (3) confirmation of degradation and cleanup in a dry gas environment within a reasonable timeframe. New experimental methods were developed to address these requirements, including gas/fluid degradation testing, bridging tests with slots to represent wormholes and fractures, and bridging experiments with 3D synthetic models of a wormhole structure. To be able to run repeatable experiments, wormholed structures were printed with a 3D printer using high-resolution CT scans from an actual wormholed core plug.
Testing results showed the ability of the fibers to bridge within the wormhole network and provided guidance in designing the fiber diverter stages for already-stimulated wells. Addition of degradable particulates was shown to further improve wormhole bridging and diversion performance. Modeling the wormhole diversion process within advanced stimulation software identified additional optimizations, such as increased stage size and increased fiber concentrations to achieve desired diversion. A related presentation will discuss the successful re-stimulation of three high-rate gas wells (B. Clancey 2015).
An Innovative Methodology for Real-Time Control and Optimization of Dual Injection Increases Efficiency of Carbonate Stimulation in Horizontal Openhole Water Injectors
Authors: Ramondenc P. , Burgos R. , Delgado E. Franco , Resendiz J. T. 
Published: December 2015

Abstract
An innovative methodology using a new bottomhole flow measurement tool and distributed temperature surveying was used to treat two openhole carbonate water injectors using coiled tubing (CT) equipped with fiber optics. The system capabilities were leveraged to control, in real time, the dual injection process and ensure that the treatment covered the entire horizontal section. The new level of efficiency of this approach was proven in the outstanding results of this stimulation campaign.
The method takes advantage of the fiber optics present in a CT string to acquire, in real time, both downhole flow measurements and distributed temperature surveys to identify areas of higher and lower injectivity along the wellbore. It also enables clear and rapid evaluation of the depth to the level that bullheaded fluid would normally reach downhole. The real-time flow measurement is further used to optimize the stages of the treatment that aim at placing fluid across the interval initially poorly covered, as it gives direct feedback of the efficiency of the pumping through the annulus and CT.
Matrix stimulation in water injector wells is often handled in a straightforward way by simply bullheading the treatment from surface. Used within the context of horizontal or highly deviated openhole wells, this frequently leads to an overstimulation at the casing shoe or along the first part of the zone of interest, and a significant section of wellbore is poorly covered or even remains untreated. The new approach not only enables visualizing where the treatment fluid goes, it also gives a new level of control of downhole injection, in real time. This new capability was taken advantage of within the context of long horizontal openhole water injectors, whose previous stimulation treatments left untouched a significant portion of the reservoir, even when complementing bullheading by the placement of treatment fluid with CT. The methodology enabled clear identification of which pumping method was beneficial to which interval. It also proved very efficient, leading to an increase in the injectivity index of the wells of nearly threefold, beyond the expectations based on previous stimulation interventions.
The new downhole flow measurement tool and its use within this innovative workflow address many limitations usually encountered during the stimulation of horizontal or highly deviated openhole water injectors. In particular, the approach enables taking full advantage of the dual injection process, which often proves difficult to control and optimize in real time. The end result is an unprecedented level of efficiency of the process.
Inter-Well Scale Sedimentological Heterogeneities And Facies Architecture Of Upper Jurassic Carbonate Reservoir And Anhydrite Seals: Lessons Learned Using Outcrop Analogues
Authors: John Cédric M. , Hönig Martin R. , Abbott Sunshine , Fraser Alastair J. 
Published: December 2015

AbstractMost regional studies of reservoir and seals focus on large-scale sequences and their architecture. However, understanding flow and geochemical processes happening in the subsurface requires a multi-scale approach from the pore-size to the field-size. Here we focus on an intermediate, ‘inter-well’ scale loosely defined as 100-1000 meter scale. This inter-well scale is crucial as it represents the minimum distance between an injector and a producing well. Hence, constraints on the heterogeneities in the reservoir or within a sealing lithology can guide the production geologist during EOR or CCS operations. In this paper, we present a review of existing outcrop analogues for the subsurface of Qatar that were considered for our study. Out of the different possibilities, we selected outcrops from Wadi Naqab (Ras-Al-Khaima, UAE) as an analogue for the subsurface reservoirs in Qatar, and we focused on mine outcrops in the U.K. as potential analogues to derive the 3D geometry of evaporite-carbonate sequences analoguous to the Hith Formation. The Jurassic limestones at Wadi Naqab appear layer cake at the scale of observation, but we demonstrate here that even though beds rarely pinch out, the facies within bed changes markedly at a scale of &lt;200 meters. For subsurface applications, this could be significant if the change in facies correlates with a change in petrophysical properties. The anhydrite layers at Brightling Mine are mostly composed of nodular, sabkha-type layers, inter-bedded with shallow-water algal limestones and shales. These lithologies are continuous at a 500 meters scale, but scouring impacts on the thickness of the deposits. Again, this could have important mechanical implications during CCS operations, because the interface of different lithologies and their thicknesses control fracture propagation within reservoirs and seals. We conclude that more geometrical heterogeneities exist in both reservoir and seals than previously thought, and that inter-well scale data are needed to inform subsurface reservoir models. We also caution that one of the limitations of using outcrop analogues is that porosity and permeabilities are not preserved during uplift, and thus petrophysical properties within numerial reservoir modelling need to be populated using subsurface data.
Advances in Application of Forward Osmosis Technology for Volume Reduction of Produced/Process Water from Gas-Field Operations
Authors: Minier-Matar Joel , Hussain Altaf , Santos Ana , Janson Arnold , Wang Rong , Fane Anthony G. , Adham Samer 
Published: December 2015

Abstract
Produced and process water (PPW) associated with gas production are often characterized by low total dissolved solids (TDS) and moderate organic content. The oil and gas (O&G) industry in Qatar currently practices disposal of PPW via deep well injection. To ensure long-term sustainability of the reservoir, Qatar operators aim to reduce the PPW disposal quantity by 50%. Recently, Qatargas had initiated a project to recycle process water and thus, reduce disposal volumes, by using commercial advanced water treatment technologies. For future projects/developments, the authors of this paper have proposed and evaluated, through funding by the Qatar National Research Fund (QNRF), an adaptation of forward osmosis (FO) membrane process for PPW concentration, which can be a cost-efficient alternative to achieve 50% volume reduction of PPW.
In the first step of conventional FO, a draw solution (DS) of high osmotic pressure is used as driving force to "pull-in" fresh water from the feed through a membrane into the DS. In the second step, and requiring significant energy, water is recovered from the regenerated DS by various methods depending on the DS used. In this project, brine from thermal desalination plant was used as DS and PPW as feed. Due to the salinity difference between the DS and the PPW, natural osmosis resulted in water permeating from the PPW into the DS, reducing the volume of PPW. Instead of recovering permeated water from the DS, the diluted DS can be directly discharged into the Arabian Gulf bringing an additional benefit by discharging lower salinity brine to the aquatic environment.
Commercial flat sheet membranes and hollow fiber (HF) membranes provided by Singapore Membrane Technology Centre have been tested through bench-scale experiments and the impact of various operating parameters such as DS concentration and temperature was investigated. Results indicated that FO can successfully treat the PPW to achieve the target volume reduction of 50%. The average flux for the HF membranes with pretreated feed was 17 L/m2-h (LMH) using 1M NaCl as DS. Organics passage from the feed to the DS was below detection limits which mitigates the potential concern of organics leaching into the Arabian Gulf.
Appropriate pretreatment of the PPW is required to minimize membrane fouling. Results showed a flux decline of approximately 10% over 5 hours when the PPW was used without pretreatment. The fouling was attributed to the organics present in the PPW. Different pretreatment options were evaluated to reduce membrane fouling including: ceramic membranes, activated carbon; and an organosilica adsorbent. To validate the project concept, long-term experiments were conducted mimicking field conditions. Overall, the results indicated FO is cost-efficient in reducing PPW injection volume and pilot testing is recommended to further demonstrate treatment feasibility of the process.