bluuebunny/crossref_metadata_2025_split huggingface dataset:
Downhole Measurement of Methane Content and GOR in Formation Fluid Samples
Authors: Dong C. , Hegeman P. S. , Carnegie A. , Elshahawi H. 
Published: December 2007

Abstract
Formation fluid sampling early in the life of a well ensures that vital information is available for timely input to field planning decisions. For example, in subsea wells, flow assurance is a major concern, and formation fluid samples from openhole logging help operators optimize investment in both upstream and downstream facilities.
When a formation fluid sample is taken from a well drilled with Oil-Base Mud (OBM), the sample contamination by the OBM filtrate is a critical factor for the accurate measurement of the sample PVT properties. The Oil-Base Contamination Monitoring (OCM) technique uses optical means to monitor the buildup of both color and methane absorption signals during sampling. The technique provides real-time analysis of sample contamination. Methane detection is essential for condensates and for lightly colored crude oils; for such fluids, the color buildup becomes difficult to detect, but the high methane content of these fluids makes possible a reliable methane-based OCM algorithm.
Gas/Oil Ratio (GOR) is an important property of crude oil, which has profound value in the design of production facilities. Conventionally, GOR is measured at a PVT lab and may take many weeks before the lab can provide this critical information. In this paper, we describe the development of an in-situ GOR measurement technique, which uses the optical properties of methane and oil components in crude oil. With this technique, GOR can be measured downhole in real time, when the sample is taken and without requiring phase separation.
Downhole GOR has many advantages over the conventional wellsite GOR measurement techniques. It does not require tampering with the sample, which helps the operator maintain the fluid in a single-phase during and after sampling. It can also aid in fingerprinting oils from different layers and provides early indications of GOR that can be compared to PVT lab results.
Both the OCM and the GOR algorithms work well for most crude oils. However, for dark oils, the contamination prediction from methane component and the GOR prediction become unreliable because of the color effect. In this paper, we describe the methodology for downhole GOR measurement and we provide details of a decolorization technique which we have recently developed to remove the color effect of dark oils from the methane, oil and base channels in the LFA* Live Fluid Analyzer tool. This technique significantly improves real-time contamination monitoring and GOR prediction results for dark oils.
The Ec-Factor: A New Correlation for Optimizing Completion Efficiency
Authors: Al Qahtani Abdullah M. , Al Shehri Dhafer A. 
Published: December 2007

Abstract
The optimization of new wells completion designs will increasingly become a critical parameter for reducing development costs and maximizing wells potentials. This is particularly true as more and more reservoirs become mature with their associated complications resulting from increased water cuts and aging facilities.
This paper presents a new method for optimizing the partial completion of oil wells. The optimization criterion is the minimization of well's combined skin due to the partial completion placement, the well deviation angle and the perforation skin effect. These skin components are different from the damage skin that may be negated through well stimulation. That's why the design of well partial completion is imperative.
This work develops and presents simplified correlations for the different skin components associated with partial reservoir completions. The models presented employ uniform and consistent dimensionless variables. This should make the models easier to understand and apply for quantifying the flow efficiency of perforated completions.
The efficiency of a partial completion design is represented here as the completion efficiency factor of a partially completed well, Ec.. This efficiency factor is introduced as an optimizing parameter that can be quantified easily using the newly developed correlations as it captures all parameters affecting partially completed wells for a quick and handy way for engineers for optimizing a well completion. For any reservoir and wellbore geometry, the optimum perforation length is determined for any combination of well and perforation design.
Getting Reliable On-Site H2S and CO2 Concentrations for Anti-Corrosion Measures in Gas Wells
Authors: Williams J. M. 
Published: December 2007

Abstract
This paper demonstrates the importance of valid on-site measurements of hydrogen sulphide (H2S) and carbon dioxide (CO2) in gas wells in relation to corrosion management, notably for the proper selection of tubular goods, where material choice can result in cost changes of millions of dollars.
The problems of loss of H2S during sample storage are well known, providing a strong justification for on-site measurements. This work has looked at the ways to measure and validate both H2S and CO2 on-site. Conflicting values recorded on-site confirm the difficulty of getting reliable H2S and CO2 measurements.
H2S measurements at three gas-condensate wells were made on bottom hole samples involving a special non-reactive wireline sampler service. The intention was to obtain more accurate reservoir concentrations by avoiding anticipated losses through reaction or absorption on the production tubing. However, comparative surface measurements on the separator gas stream gave higher concentrations in nearly all cases, and a thorough investigation of the data confirmed that the separator gas measurements, made using simple equipment, were significantly more reliable.
In addition to the measurements themselves, it is demonstrated that well history, well conditioning and producing interval must be taken into account when interpreting measurements. For example, one test measured H2S production only after an acid fracturing treatment, implying that the original formation fluid contained extremely low or possibly no H2S.
The paper makes recommendations for on-site measurements and their validation including the use of two independent methods for H2S determination.
Simulation of Gas Injection Processes Using Compositional and Multiple-Gas Black Oil Methods
Authors: Al-Awami Amal , Ponting Dave 
Published: December 2007

Abstract
Compositional models are commonly used to simulate recovery processes in which injection gas and reservoir gases have distinctly different properties. Such processes include vapourising miscible drives, condensing miscible drives and low-pressure air injection. Recovery is typically enhanced by changes in fluid properties and a reduction in interfacial tension, leading to a variation of the relative permeability endpoints. These changes are due to mass transfer, in particular the solution of intermediate hydrocarbon components in the oil. Extensions of the black oil model such as that due to Todd and Longstaff can also treat such processes, although the mechanisms considered are rather different – in particular the amount of inter-phase mixing which occurs.
In this paper we attempt to unify these two approaches. The traditional black oil model is extended to multiple gases and property data constructed which yields a measure of the surface tension after mass transfer. Once the surface tension is known, a common end-point shift treatment can be used in both compositional and extended black oil treatments.
Traditional black oil numerical methods based on saturation variables have problems in treating the effect of partial pressure on the amount of dissolved gas when the gas saturation is low. This may be overcome using mass-based variables, but these have typically been less efficient due to the addition of an extra volume balance equation. A reduced mass variable formulation is described which retains the efficiency of the saturation-based approach whilst being easy to generalize to multiple gas components.
The multiple gas black oil and full compositional methods are assessed on some generic examples of gas injection processes.
Application of Multiphase Pumps in a Remote Oil Field Onshore Abu Dhabi
Authors: Saadawi Hisham , Al Olama Sharif 
Published: December 2007

Abstract
A multiphase pump was recently commissioned in a satellite oil field onshore Abu Dhabi. The pump is used to boost the flow from a well, located in a remote desert location, to a crude oil gathering centre, which is located 27 km away.
This paper describes the multiphase pump installations and the unique features of these facilities. Pump specifications and key design considerations are discussed. The paper also addresses the project implementation strategy as well as early operating experience.
Gas Flow Simulation in Discrete Fracture Network Models
Authors: Basquet Rémy , Laurent Jeannin , Lange Arnaud , Bourbiaux Bernard , Sarda Sylvain 
Published: December 2007

Abstract
Advanced characterization methodologies are now able to provide realistic pictures of fracture networks. We recently developed a software to simulate the transient and pseudo-steady-state flows of a slightly compressible fluid in Discrete Fracture Network (DFN) models. This simulator is used to validate the fracture network geometry and to calibrate the hydraulic properties of the fractures via dynamic data obtained from flow meters, interference and well tests. This paper is dedicated to the extension of the methodology to gas cases, taking into account the high fluid compressibility and the non-Darcian effects near the well bore.
The main specific features of our simulator are described and illustrated through demonstrative examples. Our DFN simulation approach is based on an optimised explicit representation for both matrix and fracture media and a specific treatment for matrix-fracture and matrix-matrix exchanges. A pseudo-pressure function is included in the diffusivity equation to take into account highly compressible fluids. The hydrodynamic behaviour of gas fluid flow near the well bore is taken into account via a skin effect proportional to the flow-rate for both matrix-well and fracture-well transmissivities.
This innovative numerical simulator is validated against existing analytical solutions and compared with finite-volume solutions computed with a suitable grid. Then, for application purposes, a complex realistic case involving a multi-scale natural fracture network with small-scale fractures and major objects such as seismic and sub-seismic faults is presented. An interference test is simulated on a representative DFN model and on the equivalent dual-porosity model built thanks to up-scaling procedures. This up-scaled reservoir model is shown to remain consistent with the geological DFN model in terms of gas flow. This example illustrates the practical use of DFN models in our fractured reservoir modelling workflow.
Characterization of Conductive Faults and Fractures Responsible for Inter-reservoir Communication in the Shedgum Leak Area of the Giant Ghawar Field, Saudi Arabia
Authors: Al-Ghamdi Abdullah , BinAkresh Saud A. , Bubshait Saleh A. 
Published: December 2007

Abstract
Pressure Transient Analysis (PTA) was instrumental in identifying and quantifying conductive faults/fractures in the Shedgum leak area. The objective of this study1 is to conduct detailed and integrated pressure buildup analysis for 23 Shedgum producers located inside the leak area in order to accurately estimate important well/reservoir parameters. The ultimate goal was to detect and characterize dominant reservoir heterogeneities such as conductive faults/fractures that may constitute the conduits for vertical fluid flow and inter-reservoir communication.
Additionally, historical water production history inside and around the leak area was also examined in an attempt to provide comprehensive explanation of the water source and flow path. Based on the results of this study, it is believed that water was migrating vertically from lower reservoirs (mainly Hanifa) into Arab-D through conductive faults delineated inside the leak area. Once brought into Arab-D, water then moved laterally towards producing wells, hence, starting the anomalous water production.
Exact Solution and Typical Curve for Commingled Reservoir
Authors: Sun HeDong , Liu Lei , Lu YuanWei , Zhou Fangde 
Published: December 2007

Abstract
The max effective hole-diameter mathematical model describing flow of slightly compressible fluid through a commingled reservoir is solved rigorously with consideration of wellbore storage and different skin factors. The exact solutions for wellbore pressure and the production rate from layer j obtained for a well producing at a constant rate from a radial drainage area infinite and const pressure and no flow outer boundary condition are expressed in terms of ordinary Bessel functions. The numerical computation of these solutions is made by Crump numerical inversion method and the behavior of the systems is studied as a function of various reservoir parameters. The new model is compared with the real wellbore radii model. The new model is numerically stable when the skin is positive and negative. The real wellbore radii model is numerically stable when the skin is positive. Because the curves explicitly include skin factor and other reservoir parameters, the techniques is expected to be more accurate than the real wellbore radii model. The automatic history matching technique has made it possible to accurately determine individual layer properties and wellbore parameters.
Observed Fracturing in a Middle East Oil Well – A Combined Subsurface Study
Authors: Azer Samir , MacKenzie Alasdair , Thiebot Bertrand 
Published: December 2007

Abstract
The paper presents the results of an integrated study comprising different disciplines and scales (core, log and seismic). The study followed the drilling of a well through a Jurassic carbonate reservoir in a NE-SW direction, which was cored near the tip of a NW-SE striking fault. Core and FMI data show a number of open and closed fractures, all striking in a NW-SE direction, contrary to what was expected from the regional structural model.
The structure grew through the Mesozoic with NE-SW extension producing a set of NW-SE striking normal faults and related fractures. A pulse of growth occurred during the Late Cretaceous-Tertiary, followed by continued Tertiary growth. 3D seismic data clearly shows the Lower Cretaceous fault pattern. The faults decrease in throw with depth, and only a limited number cut the Jurassic.
Interference tests show a preferential NE-SW communication pathway between wells. In addition, borehole and core data from other wells show open fractures, which tend to have a NE-SW strike, and a second set of closed fractures orthogonal to these.
The following were concluded from a review of the data: Correlation between core goniometry and FMI image analysis is excellent.The well is located near the tip of a NW-SE striking fault, and is likely to be in the transfer zone between two faults.Two sets of fractures occur in the Jurassic. A fault related NW-SE striking set and a NNE-SSW striking set occurring further away from faults.Fractures occur as near vertical, broken non-mineralized, and completely healed; and tend to occur in swarms.Fractures in the reservoir are likely to provide additional permeability.To intersect the maximum number of open fractures in the Jurassic, wells should be horizontal and oriented WNW-ESE away from faults and NE-SW close to faults.
Seismic Facies Analysis for Fracture Detection: A Powerful Technique
Authors: Bloch Gérard , El Deeb Maged , Badaam Hussein , Cailly Frédéric , Iecante Gael , Meunier Antoine 
Published: December 2007

Summary
Fractured reservoir analysis requires an accurate delineation of fracture corridors, as well as an estimate of the fracture density. Fracture corridors are often closely associated with faults, large and small. 3D seismic data is of great help for minor "sub-seismic" fault detection and characterization, small faults being often expressed as very subtle zones of deformation (discontinuities), with no obvious offset of seismic reflections.
A large number of seismic attributes are known to highlight discontinuities. They can be horizon-based, such as curvature, dip, edge, azimuth or based on the 3D seismic trace variability in a given neighborhood such as "coherence-type" attributes or computed after Fourier or Hilbert transform as instantaneous phase or frequency.
This paper proposes, in a large Upper Cretaceous carbonate reservoir onshore UAE, to use jointly a set of selected "fracture relevant" attributes in a multi-variable statistical process called Seismic Facies Analysis (SFA). The resulting seismic facies map delineates areas spatially oriented towards two directions that are consistent with the general structural knowledge of the field. Analyzing seismic attribute distributions within each seismic facies gives a preliminary interpretation of these seismic facies in terms of fracture density. The validation of this interpretation with well data (BHI, core and dynamic data) delivers an accurate map of fracture occurrence. This map is then used to interpret structural lineaments and constrain stochastic realizations of the fracture model.
Multiphase Flowmeter and Production Logs Diagnose Well Response in an Onshore ADCO Field, Abu Dhabi
Authors: Khoori A. , Bekkousha M. A. E. K. , Pinguet B. G. , Turna E. P. , Koshy T. 
Published: December 2007

Abstract
In early 2002, Abu Dhabi Company for Onshore Oil Operations (ADCO) ran a production-logging program on a high-performance onshore well with an intensive surface welltesting program. This involved running a multiphase flow meter in combination with a calibrated gauge tank and a test separator, in order to qualify the metrological performance of the multiphase flow meter. The objectives were to determine well productivity, establish the flow profile of the reservoir, and assess the performance of the multiphase flowmeter.
This paper describes the benefit of advanced multiphase flowmeter technology and the verification of its performance accuracy against production logs and surface equipment.
In addition to the accuracy computations, the repeatability and linearity of each measuring device were also evaluated. Examples will be given.
The paper also illustrates how this multiphase flowmeter technology improved the diagnosis of the actual well response.
An Improved Method of Slickline Perforating
Authors: King James , Beagrie Bob , Billingham Mathew 
Published: December 2007

Abstract
The BP North Sea Southern Business Unit has successfully incorporated the Schlumberger eFire* electronic firing head system with conventional slickline equipment and perforating guns during a recent trial. Significant benefits were achieved with this system by completing runs quickly and eliminating time-consuming and costly ‘parameter' runs by using conventional memory tools for correlation.
The conventional tools were run within an empty perforating gun housing. During this run the wire was ‘flagged’ at the desired depth and a pass was logged. When logging tools were retrieved and their measurements downloaded, a ‘Tie in Log’ was produced. This was used to correlate the flag on the wire to the ‘Reference Log’. Then 2 7/8-in. HSD* High Shot Density PowerJet* perforating guns were run in hole to the predetermined ‘flag’ depth, and a firing command was sent to the eFire device.
The eFire-Slickline system is an electronic firing head developed for slickline deployment. It is operated by a coded sequence of tension pulses on the slickline wire, which is converted to pressure pulses by a strain sensor in the tool. Following perforating, a ‘disarm’ command is sent and the perforating guns are then pulled out of hole.
Correlation had to be proven for this newly developed system, and this was achieved with the use of a 40-arm caliper over the newly reperforated interval. Results showed that the guns had been fired exactly on depth.
With three 40 ft [12 m] perforating runs capable of being shot in depths greater than 10,000 ft [3048 m] in less than 12 hours, the system proved to be extremely efficient.
Hydraulic Workover for Well Repair and Productivity in Sajaa Field, Sharjah, United Arab Emirates
Authors: Pruitt Randal D. , Ralston Benny , Ali Iftikhar , Van Wynsberghe Dan , Sabine Cedric 
Published: December 2007

Abstract
This is the second half in a two part series on the Sharjah Sajaa gas field repairs. The Sajaa gas condensate field is located onshore in the Emirates of Sharjah UAE. It is producing out of the Thamama limestone reservoir between 11,000 (3,350 meters) and 13,000 (3,960 meters) feet true vertical depth. Reservoir pressure is declining thus creating greater demands on the production strings to prevent collapse from overlying sediments. Sajaa field has had a history of collapsed casing on wells Sajaa 33 and 39 (twice in the same well). In order to investigate the cause of collapse and to prevent further collapse a Peer Assist (Group Meeting) was held in Sharjah to discuss the wells histories and develop a plan forward. Paper One will discuss the CWEAR, READ, casing calculations, the decision tree and well selection. This paper will discuss the live well workover program.
Failure Analysis of Seal Lock Plates in Electric Submersible Pumps
Authors: Samanta B. , Al-Balushi K. R. , Siddiqui R. A. , Al-Araimi S. A. , Al-Habsy Abdullah , Armacanqui Samuel , Al-Hajri Said 
Published: December 2007

Abstract
Electric submersible pumps (ESPs) are used in oil production as effective means of artificial lift. All the major componets of an ESP are put in a long and slender housing. Seal section, located between the motor and the pump, consists of a number of chambers. All the chambers, the base and the head of the seal are connected to the ESP housing through threaded joints between the seal guide and the housing. Lock plates are welded to the housing over each threaded connection to provide additional constraint. The paper presents experimental results to examine different configuration options for lock plates on a type of high power ESP seal housing failed during operation. The paper summarizes the results of mechanical and metallurgical tests, mechanical strength and vibration analyses along with appropriate recommendations. This paper brings into focus the importance and necessity of analyzing even relatively simple and minor components like seal lock plates for safe operation of ESPs.