bluuebunny/crossref_metadata_2025_split huggingface dataset:
Innovative Integration of Subsurface Data and History Matching Validation to Characterize and Model Complex Carbonate Reservoir with High Permeability Streaks and Low Resistivity Pay Issues, Onshore Abu Dhabi
Authors: Salahuddin Andi A. , Gibrata Muhammad A. , Uchida Miho , Al Hammadi Khaled E. , Binmadhi Abdulaziz K. 
Published: September 2015

Abstract
Complex carbonate reservoirs provide many challenges for characterization and modeling not least because diagenetic overprints may lead to increases in heterogeneities on a small scale. This study examines a complex carbonate reservoir from onshore Abu Dhabi where diagenetic overprints have led to the development of high permeability streaks. Additional complication is the presence of a low resistivity pay (LRP), where analysis of resistivity logs has resulted in the calculation of high water saturation which contradicts production tests that confirm dry oil.
This study used a combination of core, thin section, MICP, well logs and dynamic data to develop a holistic and robust reservoir characterization and reservoir model. A methodology was developed specifically to characterize and model the subsurface conditions identified in this field due to the simultaneous existences of high permeability streaks and LRP intervals. The methodology included:
detailed core, thin section and lithofacies description; paleoenvironmental interpretation; high resolution sequence stratigraphy (HRSS) interpretation; diagenetical analysis; reservoir rock typing (RRT); assessment of the relationship between lithofacies, diagenetic processes, and RRT; saturation height function (SHF); integrated static model building, and; flow simulation and history match validation.
Three lithofacies were identified using faunal content, texture, sedimentary structures and Dunham Classification. The depositional setting varied from lagoon to shoal. Reservoir Rock Typing (RRT) defined seven rock types based on capillary pressure trend, pore throat distribution and porosity-permeability. HRSS interpretation recognized three 5th order highstand sequences that separated by two transgressive sequences. This has then allowed the identification of the origin of the high permeability streaks and the spatial distribution within the sequence stratigraphic framework. Detailed geological modeling was then integrated with dynamic data to provide a robust dynamic simulation validation. The combination of static and dynamic modeling can then be used to more accurately calculate OOIP and optimize the current reservoir management plan ensuring optimal sweep efficiency and recovery.
Field Development Strategy through Full-Filed Reservoir Simulation Considering Asphaltene Precipitation and Deposition
Authors: Attar Masoud Seyed , Sedaghat Mohammad H , Kord Shahin , Mayahi Hamid 
Published: September 2015

Abstract
Reservoir simulation is an integrated tool for predicting reservoir performance and proposing development plans. However, in the master development plan (MDP) proposed based on the simulation results, there is always an associated risk that must be minimized. This risk arises from many different sources, one of which is the complexity in petroleum reservoir fluid. On the other hand, asphaltene precipitation and deposition can dramatically affect the reservoir rock and fluid properties.
Asphaltene deposition may cause severe problems during different stages of oil recovery and can affect the reservoir performance through porosity and permeability reduction and wettability alteration. These effects can be modeled in compositional simulation using parameters that are usually estimated from precipitation tests and core flooding deposition experiments. Through a series of experiments, the asphaltene stability envelope and permeability impairment are established for several bottomhole live crude oil and reservoir core samples during pressure depletion and gas injection processes. Using the parameters obtained from the experiments, precipitation and deposition of asphaltene are investigated at field scale by a compositional simulator, and a comprehensive development plan is suggested for the reservoir. Also, the effect of asphaltene deposition on fracture parameters is investigated.
The results show that dynamic and static parameters of asphaltene precipitation and deposition play an important role in the prediction of formation damage and field performance during natural depletion, gas injection and water flooding. Moreover, the results confirm that the permeability reduction due to asphaltene deposition is more considerable in the fractures than in the matrix media.
A Dual Multilateral Completion as an Alternative to Un-Wanted Water Control in Horizontal Wells
Authors: Magzoub Musaab Ibrahim , Hossain M. Enamul 
Published: September 2015

Abstract
Worldwide water production (e.g. also called as un-wanted water) creates huge oil fields problems. An estimate shows that the average of three barrels of water is produced for each barrel of oil. The common practice in vertical wells is to block the water zone and perforate above. However, in horizontal zone if the oil-water contact (OWC) reaches the horizontal section, the well will be abandon. In literature, there are many methods used to delay water break though. Horizontal wells increase the potential of OWC movement due to the phenomena of high velocity of flow near heal compared to toe.
Horizontal wells have been increased significantly for last twenty years and almost replaced the vertical wells. Moreover, horizontal drilling has become a common practice with recent technology and advanced tools. As a result, the technology starts moving towards multilateral wells and extended reach drilling. In addition, some geological and reservoir cases put horizontal well in a challenging position. But still no one can deny advantages of horizontal wells and its contribution to the oil production and increasing exploited reserves. This article addresses the most exhibited challenges faced in horizontal well completions. In addition, the paper proposes the dual multilateral drilling and completion strategy and compares the proposed method with the conventional solution by ICDs and ICVs. A case study is also presented to show the effectiveness of the proposed strategy.
The problem with the existing practice is that the velocity of flow at heal is very high compared with the toe of a horizontal section. This situation causes many problems especially when there is permeability or pressure variations. It becomes even worst when the horizontal section is near the water- oil contact (OWC). The OWC below the horizontal section will be disturbed and this leads to early water break through. ICV is used to choke the heal area or some perforation design technique. All these techniques are based on reducing the production from that area. This article outlines how to tackle this issue using the proposed dual lateral completion while allowing the production to be increased within wider save margin. This method will be useful for enhancing the production and reducing the water break through for a reservoir.
Software-Generated Operating Envelope for Underbalanced Drilling Operations
Authors: Huang Xiaoqian (Christina) , Urdaneta Gustavo , Poletzky Isabel 
Published: September 2015

Abstract
Traditionally, several multiphase hydraulic calculations are required to determine the permissible surface-parameter operating envelope in underbalanced drilling (UBD) operations to estimate how bottomhole pressure (BHP) and the desired underbalanced condition can be achieved. Furthermore, the complexity consists of running several combinations of gas- and liquid-injection rates and overlapping these results with operating constraints, including the operating range of equivalent liquid rates for downhole mud motors, minimum annular velocities for effective hole cleaning, desired BHP, and respective surface-equipment limitations, to visualize a comprehensive spectrum of viable surface parameters. This paper explains and illustrates a novel method for obtaining quick and comprehensive operational envelopes for underbalanced drilling operations.
The model used for pressure-drop calculations considers the effect of geothermal and string temperatures, detailed drillstring and wellbore geometries (including tool joints), formation fluid influxes at several depth intervals, cutting-slip effects, and surface back pressure. This model also enables the evaluation of the behavior of multiphase drilling fluid using different gas correlations.
The system determines bottomhole pressures for several combinations of injection parameters and automatically collects results to generate a permissible operating area (envelope).
Measured times to generate the operating envelope graph and a comparison of the results are evaluated for several methods and wellbore hydraulic simulators; a qualitative evaluation and validation against field data is also included. The method outlined in this paper offers an alternative to automatically obtaining a gas- and liquid-injection operating envelope, which results in a time savings of three orders of magnitude, as compared to traditional procedures and computational solutions.
One of the limitations of the model is that the operating envelope is for a single wellbore depth and provides a representation of the pressure achieved at a fixed depth. Recommended developments will consist of the ability to visualize BHP values for drilling depths, perhaps through a 3D graph.
This paper describes the method used by a multiphase flow simulator to create a graph that aids in determining and visualizing the operational area to achieve a specific BHP, including the hydrostatic and friction-dominant areas of circulation; this development will facilitate the decision-making process while designing the wellbore hydraulic aspects of an underbalanced drilling operation. The benefits of the multiphase flow simulator include a significant time savings to obtain a visual representation of bottomhole conditions and the ability to quickly achieve optimized results by means of a broader sensitivity analysis.
Investigation Of The Stability Of Hollow Glass Spheres In Drilling Fluids In Diverse pH Environments And Assessment Of Potential Field Applications In Saudi Arabia
Authors: Alawami Mohammed B. , Al-Yami Abdullah S. , Wagle Vikrant B. , Alhareth Nasser 
Published: September 2015

Abstract
Low-density water-based drilling fluids formulated with hollow glass spheres (HGS) offer an attractive drilling method. HGS are incompressible lightweight additives with the capability to reduce mud weight down to 41.0 lbm/ft3 (5.5 lbm/gal). Several pressure ratings of HGS are available, and selecting the appropriate rating is essential to avoid formation damage and lost circulation in near-balance conditions. Failure of the spheres could thus lead to catastrophic results.
The objectives of this paper is to evaluate the stability of inhibited water-based drilling fluids formulated with HGS in diverse pH environments, and assess their potential application in Wasia formations in Saudi Arabia. Wasia formation is composed of middle cretaceous clastic rocks with layers of sandstone, shale and occasional limestone. Wasia is an aquifer with a thick unit that crops out in central Najd with a slight eastward dip (Powers et al. 1966). The pressures of Wasia correlate to equivalent mud weights (EMW) of 51—58 lbm/ft3. This range of EMW is lower than that of water, and the use of conventional mud systems could introduce several operational difficulties due to the high hydrostatic pressure they create. The implementation of HGS-based lightweight fluids would lower the hydrostatic pressure in the wellbore, thus eliminating or reducing the frequent loss of circulation experienced in Wasia. HGS-based fluids could also provide greater protection of underground water resources, improve rate of penetration (ROP), and reduce or eliminate differential pipe sticking.
We conducted comprehensive analysis of HGS performance in various pH environments to assess their stability in drilling fluids. Mud characteristics and rheological properties were examined before hot rolling (BHR) and after hot rolling (AHR) to determine the effects of high pressure and high temperature (HPHT) on the system. The duration at which the samples were exposed to HPHT conditions varied from 1 to 4 days to understand the behavior of the mud over time. In addition, two typical formulations were prepared using HGS and conventional additives to evaluate their properties and compare them to the American Petroleum Institute (API) standards.
Hollow glass microspheres were found to be stable in the pH conditions of drilling operations (pH ~9), with a maximum density variation of 0.5 lbm/ft3. At higher pH levels (pH &gt;11), the spheres experienced fractional dissolution due to the reaction of the added NaOH with borosilicate glass. In pH ranges lower than 4, the spheres were found to be extremely stable. The inhibited water-based fluids formulated with HGS produced favorable rheology and stable mud characteristics before and after exposure to the actual downhole temperatures of Wasia formation.
An Integrated Approach to Acquire Formation Fluid Samples in a Challenging Low Perm Carbonate Reservoir Using an Oval-Shaped Pad: Western Desert, Egypt, Case Study
Authors: Kohail Mohammad , Fattah Mohsen Abdel , Helba Adly , Sayed Ahmed M. , Mohamed Hesham Saeid 
Published: September 2015

Abstract
Thinly laminated, low permeability carbonate rocks of the Turonian Abu Roash “D” (ARD) member, located in the north Western Desert of Egypt, provide a challenging environment for recording formation pressures and acquiring clean formation fluid samples. The challenges are partly attributable to reservoir lithological heterogeneity and low permeability in addition to the microporosity pore system. From the operations perspective, locating the probe on the sweet spot, and the difficulty associated with sealing probes on testing tools present major challenges.
To increase the success rate of obtaining valid pressure measurements and fluid samples, a proper selection of the formation tester probe geometry is essential. A series of prejob simulations using various probe types indicated that the use of oval-shaped pads provided distinctive advantages over standard probe types.
This paper includes field examples from the Abu Roash D carbonate reservoir where the oval-shaped pad was used. The wireline microresistivity imager was used to characterize the zone of interest and facilitate the test point selection.
The use of the image log for the pressure point selection in a thinly laminated reservoir and the oval-shaped pad positioned to cover a vertical section of the wellbore enabled the detection of a relatively permeable thin lamination with a mobility of 28 md/cp. This process facilitated the collection of a formation fluid sample for the first time from this reservoir after pumping for more than 1½ hours. A high resolution fluid density sensor was used for fluid identification, which was able to detect low concentrations of residual oil during sampling, unlocking, and eliminating the ambiguity in the understanding of the residual fluid in the Abu Roash D reservoir.
This paper presents the method, selection criteria, and workflow used to acquire formation fluid samples in challenging, low permeable carbonate reservoirs.
Commoditization of Natural Gas, Challenges and Prospects
Authors: Nassar Yehya M. 
Published: September 2015

Abstract
Thanks to its relatively friendly impact on the environment, natural gas usage has evolved to the point that puts forward natural gas as one of the main energy sources worldwide. Aside from the fact that natural gas is widely spreading all over the world and that securing natural gas supply has become a matter of great concern to all energy market players, natural gas still suffers from significant price variations and long-term supply dependency, which results in limited competition, less flexibility and reduced diversity of supply.
In particularly compared to liquid fuels, natural gas lacks certain features required for commoditization. These features are found in the so called “perfect competition” market structure and include among others, standardization or inconsiderable differentiation of the sold product, neglected price margin, diversity of supply, increased cost and hence price stability, availability, and obtainability. In general, product commoditization shall result in a number of benefits not only for the end users, but as well for all involved players along the whole processing value chain.
The aim of this paper is to investigate whether or not natural gas can be classified as a commodity and the forces that are currently affecting this commoditization process.
In doing that the paper will study the effect of natural gas transportation infrastructure costs, long term versus spot market contracts, storage methodologies, LNG compared to natural gas from a commoditization perspective and security of supply requirements. The paper will also discuss the reasons for the increased natural gas price differences worldwide. Finally, it will highlight some of the existing eco-political forces that might affect the pace of natural gas commoditization taking into account the effect of subsidy and trade barriers in certain regional markets on the commoditization process.
Delineation of Paleozoic Tecto-stratigraphic Complexities in the Northern Part of Murzuq Basin - Southwest Libya
Authors: Najem Ali , El-Arnauti Ali , Bosnina Seraj 
Published: September 2015

Abstract
Murzuq Basin is an intractratonic sag basin located in the southwestern part of Libya and considered as one of the major profitable basins in North Africa. The basin has been developed during the Late Precambrian-Early Paleozoic time, which went through various reactivated tectonic events. These events were dominant during the Paleozoic era coincided with regional unconformities and major sea level changes that resulted in complex geological configuration of both structural and stratigraphic. Detailed subsurface analysis implemented utilizing seismic and well log dataset of the concession NC186 to evaluate the main Paleozoic tecto-stratigraphic complexities within the northern part of the basin. This analysis guided to understand the major Paleozoic polyphase tectonic evolution in the area of study. Steep reverse basement faults, folds, positive flower structures and paleohighs and paleolows of glacial topography are evidently indication of the observed large-scale tectonic Paleozoic elements. From this study, the basement faults are anticipated to be genetically related to the Pan African Orogeny in origin and played major controller of all Paleozoic events. These faults are striking NW-SE with a vertical throw up to 300 meters and an oblique fault plane. Late Ordovician glacial valleys encountered in the area with more than seven kilometers of wide, which have eroded more than 500 meters of Middle Ordovician and Cambrian deposits. The incised valleys took place along the strike of the major basement faults in the area. The entire large-scale analyzed elements interpreted to be generated, directly and indirectly, by different tectonic regimes (i.e. compressional, extensional, strike-slip and combination) exclusively during Paleozoic time. Therefore, from the detailed interpretation; six phases are introduced as the main representative tectonic episodes of in the northern part of Murzuq Basin. These tectonic phases and episodes have controlled the petroleum system in the basin and the area of study in particular.
Monte Carlo Model Development for Elemental Analysis Using a Natural Gamma Ray Spectroscopy Tool
Authors: Zhang Qiong , Mendez Freddy , Longo John , Gade Sandeep , Bliven Steve 
Published: September 2015

Abstract
A systematic computational method for obtaining accurate elemental standards efficiently for varying borehole conditions was developed based on Monte Carlo simulations and computational data assimilation. Elemental standards are essential for spectral unfolding in formation evaluation applications commonly used for nuclear well logging tools. Typically, elemental standards are obtained by standardized measurements, but these experiments are expensive and lack the flexibility to address different logging conditions. In contrast, computer-based Monte Carlo simulations provide an accurate and more flexible approach to obtaining elemental standards for formation evaluation. The presented computational method recognizes that in contrast to typical neutron-photon simulations, where the source is typically artificial and well characterized [Galford, 2009], an accurate knowledge of the source is essential for matching the obtained Monte Carlo elemental standards with their experimental counterparts. Therefore, source distributions are adjusted to minimize the least square difference of the Monte Carlo computed and experimental standards. In this work, a natural gamma ray spectroscopy tool is selected as an example and the procedure of obtaining elemental standards through Monte Carlo modelling and data assimilation is demonstrated. A field case study is presented to compare two sets of elemental standards. For future work, the adjusted source distributions will be utilized to generate and validate spectra for varying borehole conditions: tool position, casing and cement thickness and the effect of these conditions on the spectra will be investigated. Given that Monte Carlo modeling provides much lower cost and more flexibility, employing Monte Carlo could enhance the processing of nuclear tool logging data computed standards.
An Essential Periodical Assessment & Performance Revision for Optimizing Sucker Rod Pumping Systems' Operations
Authors: Ali Mira , Mahmoud Rizk , Mahmoud Selim 
Published: September 2015

Abstract
West Qarun (WQ) and North Bahariya (NB) oil leases are being operated by Sahara Oil & Gas Company (SOG); the two leases are located in Abu El Gharadig (A/G) basin in the Egyptian Western Desert with a total of seven oil fields including a total of 58 producing wells “at the time of writing this paper”; According to the nature of silty-sand oil reservoirs in the area with low initial production rates; most of wells had been hydraulically fractured against one or more of the included various hydrocarbon bearing zones; this fact led to necessitating the deployment of an artificial lifting system that is capable of producing the expected initially high rates and then cope with the expected low rates after the routine initial decline in well rate.
According to theoretical sorting criteria and field trials; sucker rod pumping systems proved to be the most suitable artificial lifting system for these wells; but various wells conditions induced the use of several pumping parameters and equipment sizes according to each well conditions.
This paper demonstrates a methodology for initial sucker rod pumping system selection, wide scope for designing required equipment and operating parameters, and the essential periodical revision of pumping performance and assessment of the system within a continuous optimization process that aims to get maximum possible pumping rate and lowest operating costs via reducing the frequency of system failures and modifying operating parameters to the enhanced scheme as per well conditions.
The most difficult part in the evaluation process is obtaining accurate measurements in real time, integrate all available well data in diagnosing well pumping status, discover the tricky signs, and interact with well pumping parameters to reach the optimum status or decide a well intervention job.
The conclusion is summarized in attracting attention to the importance of ensuring the selection of optimum artificial lifting system to the field scale and then keep it operating with optimum design and operating parameters.