bluuebunny/crossref_metadata_2025_split huggingface dataset:
Confronting the Simulation of Fluid Flow in Naturally Fractured Carbonate Karst Reservoirs
Authors: He Jie , Killough John E. , Gao Sunhua , Fadlelmula Mohamed M. , Fraim F. Michael 
Published: November 2016

Abstract
Flow simulation in carbonate reservoirs presents many challenges due to the frequent occurrence of vugs and natural fractures therein. In conventional reservoir simulation practices, fluid flow in vugs and fractures is usually assumed as Darcy flow, and permeability values are estimated for vuggy regions and fractures. Although such estimations are often accomplished in reasonable ways, no physical or mathematical basis exists for them, and even the assumption of Darcy flow itself is questionable.
In this paper, we propose a novel workflow for the simulation of fluid flow in naturally fractured carbonate karst reservoirs. The workflow is based on simulation results of a single-phase transient Brinkman model, which provides the correct and complete description of the coupled flow in vuggy and fractured reservoirs by unifying Stokes flow in vugs and fractures with Darcy flow in the rock matrix. The new workflow proceeds through an iterative procedure by increasing the permeability values of vugs and fractures without the disadvantages of accurately estimating them, and attains the final simulation results when a convergence pattern is observed.
The novel workflow is implemented and compared with the conventional approaches in commercial reservoir simulators. The workflow is first applied to single-phase flow simulations in a fine-scale 3D geological model which is generated using the multiple-point geostatistical modeling technique, and then extended to immiscible two-phase flow and other multi-phase cases. Simulation results show that in most cases our new workflow yields higher production rate predictions than conventional approaches. This is due to the fact that the permeability values of vugs and fractures estimated by conventional methods are usually lower than the permeability values required for the iterative convergence of the new workflow. The results also have further implications on the history matching process that more focus should be put on fracture geometry, i.e. fracture width and half-length, since the use of fracture permeability alone has lost its physical meaning in the novel workflow according to the Brinkman equation.
People Development Framework
Authors: Mahmoud M. A. 
Published: November 2016

Abstract
This work describes ADCO's Discipline Development Frameworks (DDF); which helps the implementation of a Competency based approach to employee development by grade and discipline across all assets. In addition to ensuring the consistency of skills across ADCO, such Development Frameworks provide structured development programs and monitoring mechanisms, thus enabling a one ADCO Vision. Such effort informs and encourages career paths, and a "lifelong learning culture" through this master guide referred to as the "Discipline Development Framework (DDF). This DDF is therefore, a comprehensive career development framework for all employees, which ensures a high caliber workforce.
The process of the DDF starts with the refinement of ADCO's Career Ladders. Following this detailed identification of appropriate skills levels, the DDF is developed by Subject Matter Experts (SMEs) in the Discipline. This is double checked internally, refined and benchmarked with other OPCOs and the Industry at large. Following this, the DDF emerges; identifying core competencies, Support, Behavioral and all related Soft Skills essential for all disciplines, job grades. The skill levels (Awareness, Knowledge, Skill, Mastery and Expert Levels) for each are highlight. Mixed and blended development initiatives are also identified.
An outcome is therefore a master career guide document that provides clarity to employees, ensures consistency of development within ADCO, minimum standards and transferability by grade and discipline across all assets and functions. It also aids morale and increases employee retention since there is the knowledge of clear progress and strategic support for such. The DDF also ensures a centralized and harmonized approach to learning & development.
PTA and Well Performance Assessment of Dry and Liquid Rich Gas in Unconventional Tight Sands: A Middle East Case Study
Authors: Al-Shawaf Ali , Al-Momen Mohammad , Issaka M. B. , Filipi I. , Lewis C. 
Published: November 2016

Abstract
Saudi Aramco is actively appraising the numerous unconventional shale and tight sand opportunities located across the kingdom of Saudi Arabia. The early phase of the unconventional gas program in the company has been directed towards exploration data gathering activities through drilling, coring, open-hole logging and completion of shale and tight sand gas resources. Due to the ultra-tight nature of these reservoirs, several vertical and horizontal wells have been drilled and completed with multistage hydraulic fractures to be able to produce them. Initial flow back tests, in addition to long term pressure build-up, have already been conducted on some of these wells, the analysis of which will help to characterize and better understand these tight hydrocarbon reservoirs.
This paper discusses the results of pressure transient analyses and modelling performance of two unconventional tight sand wells. An Integrated workflow was developed for reservoir characterization and fluid flow modeling using well test analyses and a simulation tool designed specifically for unconventional reservoirs. Post fracture flowback data along with available petrophysical interpretation, geological and geophysical analyses and 3-D hydraulic fracture models were used to build and calibrate single well numerical models. For the purpose of comparison, two wells were selected: one from a dry gas reservoir, while the other was from a rich gas-condensate reservoir.
Metrology of a Dataset Acquired with an Optical Fiber in a Horizontal Well
Authors: Leclercq Marion , Hubans Christian , Suaudeau Eric 
Published: November 2016

Abstract
Acquiring a seismic profile data in a well using conventional geophone technology requires sensors to be lowered down the well. Unfortunately it is expensive and it involves the production interruption. The Distributed Acoustic Sensing (DAS) is a known alternative to this system for vertical seismic profiles, with the benefit that it can stay after the acquisition, even while producing. The quality of this type of measurements for reservoir monitoring is studied here.
In 2014, several lines were shot around a horizontal well in a carbonate area in Middle East with the DAS technology (walk above and lines in different directions from that of the well, some of them shot several times, some of them while producing, some with the production shut down). First this dataset was used to provide a 2D image of the reservoir below the horizontal part of the optical fiber. It also enabled a comparison of the measurement while producing or not and gave a dataset for repeatability evaluation.
Unfortunately, this dataset is not usable as a VSP for the vertical part of the well, due to coupling issues and directivity of the signal. Nevertheless, in the horizontal part of the well, dense spatial sampling opens the door to detect very small details in the reservoir, below the conventional seismic imaging capacities. However, separating the up-going wavefield from the down-going wavefield is challenging.
The comparison of the repeated lines shows whether this technology is satisfying in terms of repeatability for 4D surveys or not. It is also possible to measure the difference of the direct and reverse paths which are both recorded. Since the equipment varies along the well, it gives information about the quality of the coupling, for e.g. with or without casing. Finally, it shows whether it is necessary or not to shut down the production while acquiring the dataset.
It is already known that optical fibers can be used for VSP and reservoir imaging, but this experiment is the perfect dataset to evaluate the quality and to extract all the potential of this type of measurement especially in terms of reservoir monitoring. Thanks to the lessons learnt from this experiment, it will be possible to optimize the acquisition design of future surveys to improve the signal quality.
Innovative Wireline X-Ray Diagnostic Service Reduces Risk During Well Interventions: A Case Study
Authors: Spannuth Melissa , Achihai Radu , Angel Juan , Gunn Spencer , Johns Jack , Singleton John 
Published: November 2016

Abstract
During well intervention activities, one of the biggest challenges faced is uncertainty about the downhole hardware. Carrying out interventions without understanding the state of downhole equipment can be time-consuming, expensive and ultimately unsuccessful. There are several diagnostic techniques available to assess the state of downhole hardware, but none offer an efficient and reliable solution, particularly if the well fluid is opaque. Recently, an X-ray based wireline tool was introduced for providing downhole imaging, regardless of the well fluid. We will present a case study in which this new tool was run in a brine-filled onshore gas storage well in the Netherlands. In this case, the X-ray images provided measurements of the inner- and outer-diameters of a coiled tubing disconnect to millimeter-scale accuracy. These X-ray images and measurements verified the operator's fishing plan and they successfully retrieved the fish on the first attempt. In general, the quick and reliable visualization of downhole objects provided by X-ray imaging reduces the uncertainty and concomitant risk associated with well interventions, resulting in a higher success rate, less downtime, and lower cost.
An Integrated Reservoir Modelling and Evolutionary Algorithm for Optimizing Field Development in a Mature Fractured Reservoir
Authors: Sambo C. H. , Hematpour H , Danaei S. , Herman M. , Ghosh D. P. , Abass A. , Elraies K. A. 
Published: November 2016

Abstract
In upstream oil and gas industry, infill drilling is a vital practice to increase the productivity as well as recovery factor of hydrocarbons. It concerns with the implementation of accurate and reliable reservoir models in order to evaluate the reservoir behaviour response effectively and be able to predict its future performance. Given the nature of reservoir response of naturally fractured reservoirs, optimal well locations are extremely important to ensure the economic viability of infill drilling programs. However, optimal placement of infill wells in fractured fields is challenging.
In this study a reservoir modelling-optimization workflow for fractured reservoir is developed. Firstly, an integrated static and dynamic reservoir model has been developed and validated using history matching process. For the purpose of maximizing economic recovery, an infill well placement optimization project has been considered for this field to find the best possible locations of infill wells, two different optimization approaches were adopted and implemented on reservoir model. The first method is an exhaustive method which uses the concept of design of experiment to search all grids available in the model in order to locate the best possible well locations. The second method is automatic optimization using Genetic Algorithm. That depends on the principle of natural selection as proposed by Darwin
The genetic program was coupled with the reservoir flow model to re-evaluate the chosen wells at each iteration until obtaining the optimal choice. The proposed location of wells has improved Net Present Value (NPV) by + 10% higher than the base case without infill wells. Examining two different optimization approaches used in this work, the genetic algorithm program gave results similar to the results that were obtained by an exhaustive method with much less computation time which is a great issue mainly for large size fields or fields which possess condensate gas and require the use of compositional simulators.
Redesigning Completions to Overcome Downhole Flow Assurance and Corrosion Impacts in a Giant Field, Offshore Abu Dhabi.
Authors: Aouda Abdel Hakim , Daghar Tariq al , Odeh Nadir , Morrow Timothy , Troshko Andrey 
Published: November 2016

Abstract
A new generation of sophisticated wells are to be drilled in a giant offshore field in Abu Dhabi. These extended reach wells will reach and produce remote areas of the field from artificially built islands. The first maximum reservoir contact (MRC) pilot well was drilled successfully with 20,000 ft total depth and a 10,000 ft producing interval completed with inflow control devices (ICDs). The well started producing dry oil at reasonably high flow rate and uniform contribution from each ICD compartment. After a relatively short period of dry oil production water break-through occurred and started causing unexpected downhole flow assurance concerns, especially at the locations of the ICDs. Production logging along with caliper data showed severe corrosion around water producing ICD nozzles and high gamma ray readings in the water producing intervals, suggesting that scale had precipitated behind pipe either in the near wellbore rock (believed to be unlikely based on the history of scale precipitation in the field) or on the outside of the completion (thought to be more likely).
An investigation was launched to determine the cause of the corrosion around the ICD nozzles and improve understanding of the influence of ICD flow dynamics on scale deposition and material corrosion, with the objective of developing a suitable mitigation method for scale and corrosion in future MRC/ICD wells. The study results showed that high wall shear stress developed in and around the water producing ICD nozzle area are at the origin of the corrosion in the pilot well, and that low-to-moderate wall shear stresses on and around the wire-wrapped screen sections of the ICDs could be the cause of the scale deposition. Consequently, the completion design for future wells with ICD completions has been revised to mitigate the risks of flow induced corrosion.
This paper will present results of the laboratory study into the influence of ICD flow dynamics on corrosion rates and mineral scale precipitation and discuss strategies for mitigating both concerns via the design of the ICD.
Water Alternating Gas WAG Optimization Using Tapered WAG Technique for a Giant Offshore Middle East Oil Field
Authors: Khan Mohammad Yunus , Kohata Akihiro , Patel Harshad , Syed Fahad I. , Al Sowaidi Alunood K. 
Published: November 2016

Abstract
An extensive study was conducted to evaluate enhanced oil recovery (EOR) potential of a giant, offshore, Middle East oil field. The subject field contains a very large reservoir with light oil and has a long production life extending beyond 100 years. Primary recovery began in 1968. The field has been under water flooding with pattern injection since 1982. In order to sustain oil production and increase the ultimate recovery, EOR will likely be implemented at some future time. Miscible gas injection with a water-alternating-gas (WAG) injection scheme is considered to be the most suitable method among the currently available technologies. The WAG injection process is a well-established EOR technique with several successful field applications around the world. This paper describes Water Alternating Gas (WAG) Optimization through Tapered WAG technique (more gas is injected earlier and then reduced over time) and its impact in the subject reservoir.
The primary focus of this study is to estimate the benefit of miscible WAG EOR for the subject reservoir. Finely-gridded, compositional, mechanistic, 2D cross-sectional models as well as 3D sector models were constructed and used for the evaluation. One non-hydrocarbon (CO2) and two hydrocarbon ("associated" and "lean') miscible gases were tested as injectants. The study encompasses different geological areas in the same reservoir and addresses key design parameters including well spacing, optimal WAG operating scheme, and timing of WAG application. In this paper, we will focus on formulation of optimal CO2 WAG operating scheme.
As part of optimization of the miscible WAG application, a concept of Tapered WAG was tested. A typical WAG application consists of injection of water followed by gas injection. Each cycle of water and gas injection is of fixed duration. In Tapered WAG concept, the durations of gas injection varies with longer gas injection earlier and reducing with progressive WAG cycles. Such miscible WAG application, termed as Tapered WAG, was found to be more effective than the Uniform WAG application where the water and gas injection cycle durations are same.
The Tapered WAG technique reduces response time i.e. oil bank arrives earlier. It also uses gas injection more efficiently, i.e. produces more incremental oil per unit of injected gas. Findings were applicable to both a homogeneous (low and relatively Uniform perm) and heterogeneous (high perm with high perm streaks dominant) areas of the reservoir.
Successful Application of a Mechanistic Coupled Wellbore - Reservoir Dynamic Simulation Model to History Match and Plan Cleanup Operation of Long Horizontal Wells
Authors: Syed Fahad I. , Al Saadi Sami , Khedr Osama , Khan Mohammad Y. , Yusuf Rahel , Thakur Kapil K. 
Published: November 2016

Abstract
Cleanup of an extended reach horizontal well with maximum reservoir contact is challenging especially when a large amount of mud is lost into the reservoir formation. During the well cleanup operation, not only the existing completion fluid needs to be unloaded from the wellbore, but also the drilling fluid that invaded into the formation needs to be back-flowed to minimize formation damage and regain well's capacity.
This paper describes the successful application of a mechanistic wellbore model coupled with a near wellbore dynamic reservoir simulation model to history match clean-up operation of a maximum reservoir contact (MRC) well. The coupled model was simulated for a sequence of events starting from mud loss during a stuck liner incident, followed by subsequent well cleanup using coiled tubing unit (CTU) with nitrogen to recover large amount of drilling mud invaded into the pay zone, to PLT run along the long lateral for assessing flow profile. The PLT flow profile was used to calibrate the reservoir model in terms of skin factor, matrix and relative permeability.
Given the transient flow nature of well unloading operation, the coupled model is best suited to simulate oil and mud movement from reservoir through porous media, into the wellbore together with nitrogen, and then being lifted to the surface with the changes in PVT properties (density, viscosity, solution GOR). The coupled transient multi-phase flow model is able to achieve good history match on mud invasion into the wellbore reservoir region, thus providing good insight on the key operational and reservoir parameters influencing cleanup efficiency. The tuned model predicts the total cumulative liquid, oil and water phase volumes with fair accuracy. This study shows the importance of transient dynamic simulation in history matching and predicting well cleanup and the recovery of the invaded mud from the formation. The key benefit from the study is that the model is a very useful tool for designing the most economical and efficient cleanup operation in terms of total operational/rig time, injectant selection and the volume, as well as the operating parameters.
Optimizing CO2 Floods Using Rate Control with Smart Wells Under Geologic Uncertainty
Authors: Sharma M. , Taware S. V. , Datta-Gupta A. 
Published: November 2016

Abstract
Carbon dioxide flooding (continuous or WAG) is a proven and effective EOR technique resulting in improved oil recovery in various types of reservoirs. However, the complex displacement mechanisms in CO2 flooding, in particular adverse mobility and gravity segregation can reduce its effectiveness. It has been demonstrated earlier that by adjusting the well rates, we can manage the flood front and improve the sweep during waterflooding. In this paper, we present the application of rate optimization to CO2 flooding in order to maximize areal and vertical sweep, and minimize CO2 recycling by delaying CO2 breakthrough.
Field-scale rate optimization problem for CO2 EOR processes involve complex reservoir models, production and facility constraints and geological uncertainty. We propose an efficient approach for computing optimal rates for CO2 flooding with application to smart wells completed with inflow control valves (ICV). The approach is based on equalizing the arrival time of flood front at the producers within a selected sub-region to maximize the areal sweep efficiency under hierarchy of production and facility constraints. An additional ‘norm’ constraint on the arrival times is also included to achieve high viscous-to-gravity ratio (VGR) to minimize gravity segregation. The ‘optimal’ strategy is decided based upon the trade-off between maximizing sweep and accelerating production. We use streamlines to compute the analytical sensitivity of arrival times with respect to injection/production rates. Analytical gradient and Hessian of the objective function are also derived, making the approach computationally efficient for field-scale applications.
The approach has been demonstrated using a synthetic 2D example and a 3D benchmark field case. The results clearly demonstrate that rate optimization can improve sweep, delay CO2 breakthrough and increase oil recovery for the same amount of CO2 injection. In addition, we demonstrate the potential of our approach for WAG flooding in the 3D benchmark field case. We incorporate geological uncertainty via a stochastic optimization framework based on the combination of the expected value and variance of a performance measure from multiple realizations.
Tectonic and Eustatic Control on Mishrif Regional Reservoir Distribution
Authors: Vogel Koen R. , Follows Edward J. 
Published: November 2016

Abstract
This article exclusively relies on data from published literature.
The development of a foreland basin in the Mesopotamian Basin of South Iraq during the deposition of the Mishrif resulted in facies stacking patterns reflecting the development of a flexural bulge.
Paleogeographic reconstructions rely on carbonate facies as depth indicators, whereby rudist biostromes and coarser bioclastic debris define Shoal Complexes that separate restricted lagoonal deposits from open marine sediments. Ahmadi-Rumaila-Lower Mishrif sediments deposited into a N-S trending basin also showing evidence of precursory foreland basin tectonics: the increasing thickness of Lower Sequence deposits to E and NE reflects an increase of accommodation space in these areas. A disconformity separates the lower and upper Mishrif sequences, and represents the initiation of the flexural forebulge. The lower sequence (Mishrif mC, mB2) is characterised by a N-S oriented platform margin Shoal Complex, while during the upper sequence (Mishrif mB1, mA), a NW-SE orientation prevailed. The origin of the regionally deeper facies at the start of the Upper sequence reflects eustatic sea level rise, after which foreland basin tectonics significantly changed the paleogeography of the basin and enabled the rudist Shoal Complex to spread over a wider area. The Mishrif caprock at the top of the Upper Sequence represents a major regional exposure.
Alpine 1 tectonic activity, previously associated with the Khasib, Tanuma, Sadi and Hartha Formations in the region, actually initiated earlier, impacting the upper and to a lesser extent lower Mishrif sequences. The activity is interpreted in a foreland basin setting, with structural styles similar to but smaller scale than that seen later in the Alpine 2 Zagros emplacement.
Local structuration effects along pre-existing lineaments likely reactivated in different orientations due to the rotating stress fields. NW - directed push leading into Alpine 1 on N-S oriented structures may have resulted in transpressional strike slip related uplift. Such local uplift cannot however explain the observed facies stacking patterns, particularly in the Upper Mishrif.