bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Holistic Approach to Detect and Characterize Fractures in a Mature Middle Eastern Oil Field
Authors: Alhuthali Ahmed H. , Lyngra Stig , Widjaja Danang R. , Al-Otaibi Uthman F. , Godail Loic 
Published: May 2011

Abstract
Naturally fractured reservoirs are recognized as challenging reservoirs to manage. The appropriate balance between production at acceptable oil rate and attaining high ultimate oil recovery is often difficult to find in these reservoirs. A good understanding of the fracture systems is essential for a successful development since the fractures significantly impact reservoir fluid flow and well productivity. Additionally, accurate fracture description in reservoir models is critical for reliable production forecasts.
The main objective of this paper is to demonstrate a holistic approach to detect and characterize fractures in a mature oil field in the Middle East. The study was conducted by analyzing the dynamic data, such as production, reservoir pressure, pressure transient analysis (PTA), production logs, water salinity, drilling mud losses and image logs. The study results included evidence of fracture impact on field behavior, inter-reservoir communication and fracture properties quantification leading to recommendations for future reservoir management strategy and further development.
The evidence of fracture impact on field behavior was evaluated through extensive analysis of well performance of more than 300 wells. The field consists of two reservoirs separated by a thick nonpermeable zone. The Upper reservoir is prolific, while the Lower reservoir is relatively tight and highly fractured. The communication between the two reservoirs was investigated by comparing Lower reservoir wells with the neighboring wells in the Upper reservoir. All available data were taken into account, including the production gas-oil ratio (GOR), reservoir pressure, and water cut profile and produced water salinity, as well as water breakthrough time. A material balance approach was utilized to confirm and quantify the communication between the two reservoirs. Data integration enabled deriving a series of probable links between the two reservoirs used for constructing representative fractures maps. Fracture conductivity was quantified using both pressure transient interpretation and production log results.
The reservoir management team has utilized the study outcome to re-engineer the well architecture in both reservoirs. Additionally, active measures are taken to improve oil recovery from both reservoirs.
Field Application of a Modified Kozeny-Carmen Correlation to Characterize Hydraulic Flow Units
Authors: Nooruddin Hasan , Hossain M. Enamul , Sudirman Sharizan Bin , Sulaimani Thamer 
Published: May 2011

Abstract
Hydraulic Flow Unit (HU) has been used extensively as a technique in permeability modeling and rock typing. Amaefule et al. (1993) introduced for the first time the concept of Reservoir Quality Index (RQI) and Flow Zone Indicator (FZI) by using the Kozeny-Carmen (K-C) model to characterize HU and predict permeability in uncored wells and intervals.
This technique has helped in enhancing the capability to capture the various reservoir flow behavior based on its respective characters. Yet, there are challenges in using the original correlation due to its inherent limitations and over simplified assumptions that prevent accurate HU definitions. This study highlights some of those shortcomings and proposes a modified K-C correlation that enhances the HU characterization.
It is found that the conventional K-C model ignores the inherent nonlinear behavior between the tortuosity and porosity. Hence, handling the tortuosity term in a more representative manner demonstrates a more rigorous correlation that extends the applicability of this powerful technique into more heterogeneous rocks – such as those found in carbonate reservoirs.
This paper presents a reservoir simulation case study that is conducted to validate the applicability of the proposed model as a rock typing technique in a heterogeneous carbonate reservoir in the Middle East region. Relative permeability curves, Leverett J-Function curves and initial water saturation distribution show good agreement within each HU generated using the proposed model.
It is recognized that modified Kozeny-Carmen technique give better matching of initial water saturation model than the conventional technique when compared to open-hole logs which, in turn; adds confidence to initial hydrocarbon-in-place calculations and reservoir behavior predictions. This result will ultimately enhance the prediction of reservoir performance under various scenarios in reservoir simulation.
Tight Gas Petrophysical Challenges in Saudi Aramco
Authors: Forsyth David , Al Musharfi Nedhal Mohammed , Al Marzooq Anas M. 
Published: May 2011

Abstract
Recently, Saudi Aramco upstream activities in unconventional gas, and in particular tight gas sands, have been identified as a focus area. Integral to understanding the potential of tight gas as a resource, is an understanding of the petrophysical characterization of tight gas intervals. This paper presents a review of the petrophysical challenges in the evaluation of tight gas intervals encountered within an existing producing field producing from formation U. This formation can be highly variable and although it can be highly productive, in some areas the geology has produced poorer reservoir quality rock. Production from wells which penetrate these areas can exhibit "Tight Gas" characteristics. Core and log data from existing fields are abundant and cover both good and poorer quality reservoir intervals. The factors which impact the evaluation of these "Tight Gas" intervals, in this relatively well sampled environment, can be generalized to the evaluation of less well studied tight gas formations. The results of this review identify many areas where current techniques and tools fall short of providing an adequate characterization. In particular, the quantification of mineralogy and diagenesis is seen as important, as is the quantification of saturations and accurate measurement of micro-Darcy permeabilities. Areas where current techniques require improvement are highlighted and projects that are in progress to address these issues and improve the evaluation of tight gas are detailed. One area which is highlighted as holding potential is rock typing, which can categorize different types of tight gas interval based on clay content or mineralogy. Three wells have been selected for a fracturing exercise as a proof of concept to assess the production potential. The results of the fracturing exercise are presented relative to the petrophysical evaluation of these wells.
Formation Damage Concern from Water-Base Mud Filtrate in Deep Gas Wells: Case Study
Authors: Ekpe Joseph , Kompantsev Andrey , Khakimov Ayrat , Mohammad Emad , Ganizade Fazil , Madkour Ali , Ashoor Ayman , Al-Ali Ali , Al-Khalifah Fadhel 
Published: May 2011

Abstract
Lukoil Saudi Arabia Energy Limited(LUKSAR) started a Deep ‘Tight Gas’ exploration campaign in the Rub Al-Khali Empty Quarter in 2006 and nine wildcat exploration wells have been drilled and evaluated with one Appraisal well in its Field Fig. 1. These prospective deep gas discoveries in the Empty Quarter have occurred in relatively High Pressure/ High Temperature (HP/HT) horizons at depths between 15,000 and 20,000 feet, where the stress and temperature are extremely high in addition to low reservoir permeability. This has made the exploration activity more challenging.
Well test and clean up results from different completion strategy has not yield convincing results due to many factors. Some of these include: well placement, fluid selection, completions and frac designs. Nonetheless, the starting point in evaluating the success of well operations in the life cycle of a well remains selection of suitable drilling fluid of which its solids and filtrate particles are very friendly to the given reservoir (i.e minimum damage effect). Although the drainage radius of these wells may be several hundreds of feet, the effective permeability close to the wellbore may have a disproportionate effect on the well productivity.
This paper summarizes the challenges encountered in the use of water-base mud (WBM) and the subsequent mud filtrate effect on the reservoir permeability through different test analysis on core samples and logs interpretations. But most importantly the result raises the need for continual research and development in the area of formation damage prevention and avoidance in deep gas drilling of ultra-low permeability reservoirs.
Log-Based Rock Property Evaluation – A New Capability in A Specialized Log Data Management Platform
Authors: Odunlami Tosin , Soroush Hamed , Kalathingal Paul , Somerville Jim 
Published: May 2011

Abstract
Oil and gas companies are increasingly seeking production from more challenging reservoirs associated with costly geomechanical problems. Knowledge of in-situ rock strength is a fundamental element of geomechanical analysis for the oil and gas industry in estimating such elements as wellbore stability, solids production, hydraulic fracturing, bit selection, cap rock integrity, compaction, and subsidence studies. Specifically, this information is critical for successful drilling of directional, highly deviated, and horizontal wells. In production phase, this provides information to maximize the efficiency of wellbore perforations and hydraulic fracturing, and also assess the requirement for sand control equipment.
Log-based rock strength modeling is a technique which enables estimation of in-situ mechanical rock properties from some petrophysical logs. This technique is currently the most popular approach in order to evaluate mechanical rock properties, as laboratory tests are costly and time consuming. The important rock properties which are desired to be determined include; Uniaxial Compressive Strength (UCS), friction angle and cohesion in addition to rock elastic constants (Young's modulus, Poisson's ratio, bulk modulus and shear modulus). This technique has a number of advantages over laboratory measurements of geomechanical properties including (but not limited to): availability of log data, providing continuous property profiles, possibility of modeling weak intervals, low cost, and time effectiveness.
In this study, a comprehensive review of currently available empirical equations developed by different authors is provided. In addition, algorithms for all the equations are developed and subsequently coded into a specialized log data management platform designed for petrophysical and Image log Analysis, thus converting it into a powerful tool for rock property estimation for a variety of rock types and specifications.
Coiled Tubing Sand Clean Outs Utilizing BHA Technology and Simulation Software in Demanding Wellbore Geometries
Authors: Li J. , Green T. 
Published: May 2011

Abstract
Although efforts are made to reduce or eliminate sand production in a producing well, sometimes sand fill is an unavoidable by-product of well conditions and the need for a cleanout intervention is necessary. Various cleanout methods have been utilized in the past, including the use of coiled tubing. Removing sand fill from a well using coiled tubing is one of the earliest applications for CT and continues to be an important service to the industry today.
Historically, coiled tubing cleanouts have incorporated high circulation rates, exotic/costly fluids and reverse circulation to remove solids. Many of these conventional sand cleanout methods often apply excess hydrostatic pressure on the formation, resulting in lost circulation in low formation pressure reservoirs. Incorporating large liner geometries with smaller completion restrictions magnifies the task at hand as the annular velocities are drastically reduced even with higher coiled tubing circulation rates.
Using a specially developed cleanout tool and a computer simulator for solids transport provides an opportunity to optimize the operation for the removal of solids to near 100% efficiency, with all fluidized solids being removed. Simplified operational procedures allow for making a more qualitative decision about the cleanout efficiency.
This paper will show cost effective solutions utilized in Saudi Arabia from 2007 to present by providing an overview of all field cases and job optimization. The main focus of the paper will be to highlight and compare the coiled tubing cleanout job design process, operational procedures, results, and lessons learned from two case studies; the first case study being a successful cleanout, while in the second case study the cleanout objective was not achieved.
Cyclic Pressure Pumping (CPP): A Potential Recovery Method for Fractured Carbonate Reservoirs
Authors: Ikwumonu A. , Rawnsley K. , Bettembourg S. 
Published: May 2011

Abstract
The large permeability contrast between fractures and matrix in highly fractured carbonate reservoirs has been a hindrance to the efficient recovery of the oil from the matrix. Gas oil gravity drainage (GOGD) has been the most appealing option to date. However it is a slow process. Cyclic Pressure Pumping (CPP) is proposed which has the potential of increasing the rate of recovery over GOGD under certain conditions. CPP utilises the fact that due to the much lower permeability in the matrix, the matrix pressure lags behind the fracture pressure during a rapid pressure change. A sudden drop in pressure in the fractures results in expansion of fluids in the adjoining matrix which are discharged into the fracture system. The fluids in the fracture system can then be produced. The reservoir can be re-pressurised by gas injection and depressurised by producing the fluids in an alternate manner.
This process originally called batch gas cycling was suggested in the 50s for improving recovery in non-homogeneous reservoirs over conventional gas flooding. It was tried successfully in a small field in the late 50s. Laboratory experiments in the 70s on low-permeability matrix in contact with high-permeability fractures indicated the effectiveness of the process.
The process was re-discovered during reservoir production optimisation simulation studies in a heavy oil steam injection project in Oman and will be applied to minimise oil loss during steam plant shut downs. Early field observations support the process. The paper presents a study of the process using both dual permeability and single porosity simulation modeling. It also highlights the conditions which are favorable to the process as well as certain practical problems that could be encountered in implementing it.
Error Quantification of Dielectric Spectroscopy on Carbonate Core Plugs
Authors: Zhang Tianhua , Ligneul Patrice , Al-Ofi Salah , Nicot Benjamin , Pairoys Fabrice , Akbar Mahmood 
Published: May 2011

Abstract
The recent introduction of a downhole logging device to estimate rock multi-frequency complex permittivity has motivated the development of corresponding laboratory measurements. Various devices for permittivity measurement are described in the literature. Those instruments generally handle powder samples, millimeter-range thin discs or centimeter-range cylindrical plugs. In carbonate rocks, heterogeneity can be observed from micronic to kilometer scales. Laboratory measurements at similar resolution of the downhole tool can provide useful and justifiable input for the interpretation of the logged data.
A dielectric device which can measure 1.5 in. diameter and 2.0 in. long core plugs with a large coaxial probe is presented in this paper. The repeatability of the measurements are shown to be within 2% of the material dielectric constant value of dry rock plugs and 3% of wet rock plugs normalized with porosity and salinity. The range of confidence for the inferred cementation factor from dielectric measurements is also quantified and the results show that this cementation factor is not sensitive to the brine salinity. Error bars are displayed over dielectric dispersion curves and used as quality control.
Various materials have been tested with this large probe. The measurements on fused quartz, Teflon and ceramic materials match the available published results. Data acquired on pure calcite, dolomite and anhydrite crystals provide a good estimation of the limits of the dielectric properties range for calcium carbonate rocks of complex lithology. In the literature, the properties of these minerals vary over a broad range, which limits their practical use for reservoir characterization.
The design of the probe allows averaging the horizontal heterogeneity of the plug, but by flipping the plug upside down the identification of vertical heterogeneity can be put forward. The heterogeneity can be caused by numerous factors such as lithology, pore system, and fluid saturation variations. The case study presented in this paper shows an example of porosity heterogeneity identified by the dielectric spectroscopy measurements, and confirmed by NMR 1D porosity profiling and CT-scan imaging.
Triple-porosity Models: One Further Step Towards Capturing Fractured Reservoirs Heterogeneity
Authors: Al-Ahmadi Hasan A. , Wattenbarger R. A. 
Published: May 2011

Abstract
Fractured reservoirs present a challenge in terms of characterization and modeling. Due to the fact that they consist of two coexisting and interacting media: matrix and fractures, not only we need to characterize the intrinsic properties of each medium but also accurately model how they interact. Dual-porosity models have been the norm in modeling fractures reservoirs. However, these models assume uniform matrix and fractures properties all over that medium. One further step into capturing the reservoir heterogeneity is to subdivide each medium and assign each one different property. In this paper, fractures are considered to have different properties and hence the triple-porosity model is introduced.
The triple-porosity model presented in this paper consists of three contiguous porous media: a matrix, less permeable microfractures and more permeable macrofractures. These media coexist and interact differently in the reservoir. It is assumed that flow is sequential following the direction of increased permeability and only macrofractures provide the conduit for fluids flow. Different solutions were derived based on different assumptions governing the flow between the fractures and matrix systems; i.e., pseudosteady state or transient flow in addition to different flow geometry; i.e., linear and radial. Some of these solutions are original. The model was confirmed mathematically by reducing it to dual-porosity system and numerically with reservoir simulation and applied to field cases. In addition, the solutions were modified to account for gas flow due to changing gas properties and gas adsorption in fractured unconventional reservoirs.
Application of Advanced Volume Interpretation (AVI) Workflows to Improve Data Quality for Rapid Interpretation
Authors: Badar Muhammad Haseeb 
Published: May 2011

ABSTRACT
This paper discusses the complete interactive 3D seismic volume interpretation workflow, including choices for 3D attributes, and describes a methodology to extract the maximum information from seismic in an integrated visualization and interpretation environment.
Structural and stratigraphic attributes can help analyze the impact of surface features, like sand dunes and sabkha, on near surface and deeper seismic events. Simultaneous 3D visualization of multiple attributes makes this analysis even easier. Understanding the full effect of the surface geology on deeper events helps reduce errors during prospect generation and well proposal. It is very helpful for the seismic data processor to apply accurate static correction and to take this into consideration during seismic data reprocessing and amplitude normalization.
The proposed Advanced Volume Interpretation (AVI) workflows’ interactive, iterative analysis and filtering techniques improved data clarity for better structural and stratigraphic interpretation.
The Application of Real Time Downhole Drilling Dynamic Signatures as a Possible Early Indicator of Lithology Changes
Authors: Al-Shuker Nawaf , Kirby Cliff , Brinsdon Mark 
Published: May 2011

Abstract
While geosteering wells through hydrocarbon producing formations, early and decisive decision making during the real time (RT) drilling process is fundamentally key to whether the particular well is going to be a good producer, or an exceptional hydrocarbon producer.
Typically, within today's modern Logging While Drilling (LWD) tool suites the bulk density and porosity tools are offset behind the drill bit by the motor, Rotary Steering Systems (RSS) and other bottom hole assembly(BHA) components. Offsets will by their nature incur some data time lag period, determined by the ensuing Rate of Penetration (ROP).
By using RT downhole drilling dynamics the decision process tree can be enhanced and quickened. Changes in drilling system dynamics driven by the bit's interaction with the formation, will be a near instantaneous indicator of changes in formation characteristics and properties. The key being this dynamic data is coming directly from bit depth.
These early RT drilling dynamic changes could be used in collaboration with the existing modern Reservoir Navigation Steering (RNS) techniques, to provide earlier decision making.
In this paper the authors will present, discuss and aim to demonstrate and fully explore the relationship and potential usefulness between the RT drilling dynamic signatures and formation bulk density or porosity changes.
Pioneer Application of a Hydraulic Line Wet Mate Connect System in Combination with a Pod ESP in a Dual Lateral Intelligent Completion Well
Authors: Al-Mohanna Khalid , Kilany Khaled , Rooks Mark K. , Iskandar Riza , Shafiq Muhammad 
Published: May 2011

Abstract
This paper describes a case history detailing design, planning, completions, testing and production of the first worldwide Hydraulic Line Wet Mate (HLWM) connect system. The system was installed in combination with a pod type electrical submersible pump (ESP) in an intelligent completion (IC) dual lateral well in an offshore field in Saudi Arabia. In this field, most of the existing wells are horizontal oil producers drilled inside a high Darcy sandstone reservoir. Inflow control devices (ICDs) are run inside the open hole in both the motherbore and the upper lateral as a part of the lower completion. The upper completion includes IC inflow control valves (ICVs) installed in combination with an ESP. The engineering challenges facing such completions stem from the requirement for hydraulic control lines that are required by the IC for operation and how these control lines are installed as they need to pass the downhole ESP. While the hydraulic control lines could be considered permanent, the ESPs are not as they require periodic replacement whenever they fail. Therefore, the challenge of pulling the ESP system because of ESP failures while maintaining the integrity of the hydraulic control lines used for operating the lower IC is paramount. The HLWM connect system provides the solution to the challenges faced when integrating ESP operations with IC (ICVs, multi-port packers, etc.). It provides the flexibility to replace the ESP without having to retrieve the IC, which saves both cost and time.
The HLWM connect system provides connections for hydraulic control lines in a two-stage intelligent well completion and allows combination of IC with an ESP. It can operate in highly deviated wells and allows multiple connect/disconnect cycles during tubing space-out.
The appraisal and acceptance loop of the completion has been closed by having these wells completed, put on production and tested. Approval of technology was achieved and the anticipated benefits are realized by actual performance of the flow control valves (FCVs) in the IC downhole through the HLWM connect system.
Leveraged knowledge from this pioneer installation has provided an insight into HLWM capabilities and implementation. Moreover, it has set the stage for other field's application of this technology within Saudi Aramco.