bluuebunny/crossref_metadata_2025_split huggingface dataset:
Revealing the Real Picture Behind Safety Performance Statistics
Authors: Cram Robert S. 
Published: December 2007

Abstract
Traditional safety performance continues to be centred round measurements such as Lost Time Injury Frequency Rate (LTIFR) or Total Recordable Injury Rate (TRIR). In themselves, these metrics do not provide an adequate picture of actual safety performance.
Naturally, all organisations want to see a continuous improvement in their safety performance as reflected by a steady decrease in LTIFR and / or TRIR. The downside to such measurements is that they do not take into account normal fluctuations that are inevitable, due to the randomness of accidents and incidents.
All too often, a period of good safety performance is followed by a period of poor performance. It is not uncommon for this to promote an instinctive reaction by management to investigate what has gone wrong and make changes to correct the problem. Unfortunately, in many cases, a clear picture of what is happening is not available, resulting in uninformed decisions being taken.
It is easy to paint a false picture with numbers. This paper describes the issues surrounding misinterpretation of safety performance figures and proposes an alternative metric which can be used not only to measure improving (or otherwise) safety performance but will also accommodate random short term fluctuations in safety figures.
A New Delay Additive for Hydraulic Fracturing Fluids
Authors: Putzig D. E. , St. Clair J. D. 
Published: December 2007

Abstract
A new delay agent has been developed which has hybrid functionality versus previously-reported materials. It delays viscosity development in fracturing fluids based on guar derivatives crosslinked with a variety of common zirconate and titanate crosslinkers under a wide range of pH. The viscosity development can be optimized by adjusting the concentrations of polymer, crosslinker, and delay additive to give the desired profile for a given hydraulic fracturing application.
Parametric Investigations of a Modified SWAG Injection Technique
Authors: Algharaib Meshal , Gharbi Ridha , Malallah Adel , Al-Ghanim Wafaa 
Published: December 2007

Abstract
The natural energy of hydrocarbon reservoirs gets depleted as production continues. The restoration of reservoir energy involves the injection of gas and/or water to support reservoir pressure and to provide a sweeping mechanism. Due to the unfavorable gas-oil mobility ratio, gas injection alone often results in early breakthrough and thus poor sweep efficiency. Water and gas might be injected alternatively, as in water-alternating-gas (WAG) processes, or together, as in simultaneous water-alternating-gas (SWAG) processes, to improve the sweep efficiency. These processes improve the sweep efficiency by stabilizing the displacement front.
In this paper, we study a new design of SWAG process, in which water is injected at the top of the reservoir and gas is injected at the bottom. The difference in water and gas densities provides a sweeping mechanism in which water tends to sweep hydrocarbons downward and the gas tend to sweep the hydrocarbons upward. It is expected that the two displacement mechanisms will work together to enhance the overall sweep efficiency and thus the oil recovery. In this paper, the drive mechanisms responsible for oil production under this injection technique are analyzed. The effects of several design parameters on these drive mechanisms are investigated for both homogeneous and heterogeneous reservoirs. Such parameters include; mobility ratio between water and oil phases, viscosity ratio between gas and oil phases, lateral aspect ratio, location of the water and the gas injection wells, and injection rates of water and gas.
The Wafra First Eocene Reservoir Partitioned Neutral Zone (PNZ), Saudi Arabia and Kuwait: Geology, Stratigraphy, and Static Modeling
Authors: Meddaugh W. Scott , Dull Dennis , Garber Raymond A. , Griest Stewart , Barge David 
Published: December 2007

Abstract
The First Eocene reservoir at Wafra Field was discovered in 1954 and has produced about 290 million barrels of 17-19° API, high sulfur oil. The dolomite reservoir is Eocene/Paleocene age. The average porosity is 35% and the average permeability is 250 md over the gross interval. Well log and core plug porosity values over 45% are common and measured permeability values range up to 5000 md. The First Eocene reservoir has an average depth of about 1300 feet and a gross thickness of about 750 feet. The OOIP is about 9 billion barrels.
The reservoir largely consists of dolomitized packstones and grainstones deposited under arid to semi-arid conditions on a shallow, very gently dipping, low to moderate energy inner shelf or ramp setting in a gently dipping, restricted ramp environment. The presence of some interbedded evaporites suggests restriction was occasionally sufficient for the development of hyper-saline lagoons and sabkhas. The shallowing-upward cycles are capped by mud-dominated rocks, hardgrounds and exposure surfaces that are correlative with gamma ray highs that can be easily correlated across the 20 km length of the field and are the basis for the current sequence stratigraphic interpretation.
Several full field and small, highly detailed reservoir models have been generated using stochastic workflows to assist management of on-going primary development as well as two steamflood test/pilot projects. The reservoir models utilize the new stratigraphic framework and are constrained by over 285 wells with high quality porosity logs and six wells with high quality core descriptions and core plug data. Model properties were distributed by stratigraphic layer and constrained by layer-appropriate data (or transforms) and layer-appropriate semivariograms. The range parameter for the semivariograms models used in full field static models varied between 1100-2200 m with moderate anisotropy in the direction N120°E.
Performance Evaluation of Acid Treatments in Seawater Injectors with Reference to Two Clean-up Techniques
Authors: Beheiri F. I. , Nasr-El-Din H. A. , Rahman M. K. , Shedid S. A. 
Published: December 2007

AbstractAn appropriate post-stimulation clean-up process for matrix acidizing treatments in carbonate reservoirs is essential to ensure that the created wormholes are not damaged by precipitation of the reacted fluids. This paper presents a methodology to compare the performance of the clean-up injection displacement technique with that of the flowback technique. These two techniques were attempted in several seawater injectors in a Saudi Arabian oil field. Several variables that control the flow performance are normalized to accurately evaluate and compare the two post-stimulation clean-up techniques.Based on a well defined criterion, the study analysed historical data from 72 treatments: 42 treatments employing the post-stimulation flowback technique and 30 treatments employing the injection displacement technique. A detailed statistical analysis using actual data from these wells was also carried out.The results indicate that the flowback technique outperforms the injection displacement technique.
Kinetic Study of Crude-Oil Combustion in the Presence of Carbonate Rock
Authors: Saraji S. , Kharrat R. , Razzaghi S. , Taghikhani V. 
Published: December 2007

Abstract
Based upon the reviewed literature, few works have been conducted in regard to the kinetic study of crude oil in the presence of carbonate rocks. However, this study was undertaken in order to obtain modeling parameters such as the Arrhenius activation energy (E) and pre-exponential factor (F) for oil in the presence of carbonate rock. Such values are needed for numerical modeling studies. Also, in this study the effect of different parameters, like oil API gravity, rock type (carbonate/sand) and oxygen enrichment on reaction kinetics were investigated.
A thermogeravimetric analyzer (TGA) was used to conduct non-isothermal thermogravimetric experiments on different crudes ranging from 8-25 °API. Oils were investigated in its original form or mixed with either sand, montmorillonite as clay or crushed carbonate, montmorillonite as clay. Experiments, also, were conducted in atmospheres containing different percentages of oxygen (21-80%) in nitrogen at atmospheric pressure.
It was observed that increasing oxygen partial pressure results in lower front temperatures, more rapid HTC reactions, and more complete reactions. Moreover, Presence of carbonate rock resulted in lower activation energy and frequency factor in HTC region in comparison with sandstone. It, also, was shown that front temperatures for three crude oils used in this study are lower than 600°C and Sarvak limestone rock decomposes at temperatures above 600°C.
Fifty Years of Wettability Measurements in the Arab-D Carbonate Reservoir
Authors: Okasha T. M. , Funk J. J. , Al-Rashidi H. N. 
Published: December 2007

Abstract
The Ghawar field in Eastern Saudi Arabia contains the largest accumulation of carbonate reservoirs in the world. The majority of wells in the field produce from the Arab-D reservoir, an Upper Jurassic limestone sealed by anhydrite. Oil production from the field started approximately 55 years ago. Water injection started in the 1970's. Long before water injection was considered for the reservoir, the evaluation of wettability was considered essential.
Our present day evaluation of Arab-D wettability takes into account a long historical record of wettability measurements and production history. The procedures, results and caveats of the original measurements have changed slightly but they also show a strong consistency fifty years later. Wettability indices obtained from initial tests, Amott, and USBM methods generally indicate neutral to slightly oil-wet character for cores processed and tested in a preserved state. Comparisons with restored state cores did not indicate major differences. Over the years fluids used in coring operations and core preservation have shown little impact on the observed results.
Local variations in wettability indicating mixed wettability and oil-wet tendencies can be observed when tar is present in a significant amount and in areas high on structure. The combination of methods from advanced SEM observations, to qualitative contact angle measurements, to relative permeability results all point to a common wettability value.
Enhanced Coalbed Methane Recovery Using Microorganisms
Authors: Jadhav Madhavi Vitthal 
Published: December 2007

Abstract
Energy consumption in the world is increasing every year with the energy requirement of 5.6% per annum hence forced to find alternative resources like CBM, Gas hydrates, Tar sand. CBM is a natural gas containing 100% methane produced from coal seam reservoirs. CBM is often produced at shallow depths and is often produced with large volumes of water. The methane inside the coal seams can be recovered by two methods i.e., Primary recovery and ECBM recovery. The CBM can be recovered up to 20-60% by primary methods but by ECBM the recovery can be enhanced by 60-80%. To improve the secondary recovery it would be suggested to use methane-eliminating bacteria along with the injection of nitrogen and carbon dioxide. It would assist nitrogen injection by partial pressure mechanism with nitrogen fixing techniques also it fixes carbon dioxide by eliminating methane.
A New Analytical Model of Geomechanics During Nonisothermal Injection
Authors: Kocabas I. 
Published: December 2007

Abstract
A new transient analytical model is presented to study the poro-thermal and poro-elastic stress transients during cold water injection into a hot reservoir. Earlier models have shown that pore pressure and temperature variations during a non-isothermal injection such as waterflooding or even drilling fluid invasion can influence the stress distribution in the field profoundly. Such effects are relatively easier to account for single phase flow or piston-like displacement cases.
In this work, a new solution is developed to further improve the coupling in the case of a non-isothermal Buckley Leveret type displacement. Thus we are able to account for the very important viscosity and relative permeability effects on the stress transients. In the model, first the transient saturation and temperature distributions are solved simultaneously and then transient pressure and stress fields are computed consecutively.
In order to decouple the equations for saturation and temperature from the equation for pressure incompressible fluid flow is assumed. Then, the pressure distribution in the system is obtained by superimposing pressure transient effects on a saturation profile known a priori with its mobilities and diffusivities. Then a plain strain model is developed to compute the poro-elastic and thermo-elastic stress transients for a non-isothermal Buckley-Leveret type displacement.
The results implied that the thermoelastic changes in the cooled zone could affect the surrounding stress fields in a profound manner. For instance for a porous medium with stiff material such as carbonate reservoirs owing to cooling by the injected cold water large scale tensile stresses arise and a major tangential stress concentration develops in front of the cooled zone. The thermally induced viscosity effects can dominate the near wellbore stresses at early times. The relative permeability also affects the stresses significantly in the invaded zone albeit to a lesser extent than viscosity.
Innovation in Drilling Using Replaceable Drilling Bit
Authors: Banerjee S. N. , Gupta Yash 
Published: December 2007

Abstract
In conventional drilling a majority of drilling problems occur during tripping such as key seating and wall sticking. This leads to increase in rig time hence cost is unnecessarily high, especially in deep sea drilling.
Conventional drilling techniques use rotary drill bits which need to be replaced depending on the formations encountered. If the formation is very hard, the bit has to be replaced by a diamond bit. These bit changes unnecessary increase trip time and eventually rig cost. This trip time which can take upto a day, especially for deep wells can be eliminated by using a novel "Replaceable Drill Bit" system.
The concept of replaceable drilling bits is attractive for deep drilling because of the high rig costs and the lengthy round trips needed to replace worn bits. These bits are sturdy, capable of withstanding the high dynamic loads imparted by the vibrating drillstring and are capable of operating with highly abrasive drilling mud containing large amounts of sand and drill cuttings.
Thus an entire hole can be drilled conveniently without frequent tripping operation to change the bit. Maximum efficiency can be achieved by this mechanism during drilling.
The Effect of Hydraulic Vibrations on Initiation of Buckling and Axial Force Transfer for Helically Buckled Pipes at Simulated Horizontal Wellbore Conditions
Authors: Barakat Elie R. , Miska Stefan , Yu Mengjiao , Takach Nicholas 
Published: December 2007

Abstract
An experimental study of the effect of hydraulic vibrations on initiation of buckling and axial force transfer for helically buckled pipes at simulated horizontal wellbore conditions has been conducted. Hydraulic vibrations have been induced inside the drillpipe by interrupting the fluid flow at controllable frequencies.
The results show that the hydraulic vibrations induced inside the drillpipe can reduce the buckling force by 11% to 45%. These results were collected by buckling the pipe with and without vibrations and comparing the loads at which buckling is initiated. It is also noticed that the friction force between the pipe and the wellbore and the stick-slip motion are reduced when compressing the pipe while inducing the vibrations. Regarding the effect of hydraulic vibrations on the axial force transfer, an increase in the axial force transmitted from the top end of the facility to the bottom end of the facility by 30% to 100% was found. This increase depends on the fluid flow rate, frequency of the vibrations, fluid type (i.e. viscosity) and magnitude of the applied top load. It was found that this technique highly depends on the viscosity of the drilling fluid used. Polymers showed a different behavior compared to water.
They were found to have a damping effect on the pressure pulses, therefore are less efficient compared to water.
The results of this study are important for extended reach drilling; i.e., reducing the friction due to buckling of coiled tubing and reducing torque and drag in the case of drillpipes and casing in horizontal wellbores.
Challenges Encountered During a Comprehensive Test Analysis for a Horizontal Well in a Thin, Carbonate Reservoir of the Greater Burgan Field, Kuwait
Authors: Ambastha A. K. , Anderson M. , Gandhi H. , Maizeret P. -D. 
Published: December 2007

Abstract
Mauddud reservoir in the Greater Burgan field is a thin, carbonate reservoir containing light oil in a 10-20 ft target zone with "good" porosity. Matrix permeability is low and natural fracture density can be variable in this reservoir. Thus, this reservoir must be exploited using horizontal wells. Recently, a 2,270 ft long horizontal well has been drilled in an area interpreted to have high fracture density. A comprehensive test program, including flowing and static pressure surveys, modified isochronal test, two buildup tests, and FloScan Imager (FSI) log, has been carried out to evaluate this well.
The material discussed in this paper provides a good basis for evaluating long-term production potential of horizontal wells exploiting tight and thin reservoirs with reservoir pressures close to the bubble-point pressure.
Test data interpretation highlights successful development of inflow and tubing performance relationships, bubble-point pressure estimation as well as quantification of reservoir parameters. This paper describes unique challenges encountered in interpreting transient pressure data from this horizontal well due to multi-phase flow and short production time. Impact of derivative shape on model selection is also discussed. The effects of analysis methodologies based on specific flow regimes vs. total model fitting, single- vs. multiphase production treatment, and assumptions regarding effective well length on the computed values of reservoir parameters emphasize the attention required to obtain meaningful interpretation from horizontal well tests. FSI data was instrumental in interpreting effective length of the well.
Overall, this test program yielded information that was critical in managing sustained production from this well, characterizing the effects of the natural fractures on production behavior, as well as quantifying reserves for this tight reservoir.
Field Trial of an Acoustic Downhole Monitoring System Retrofitted in an Existing Completion
Authors: Fyfe D. , Jarvis L. , Ing Tiang Ting , Farooqui Mohammad A. 
Published: December 2007

Abstract
This paper will discuss the findings from a field trial to evaluate the reliability of a retrofitted acoustic data acquisition system in an onshore well in Qatar for a three month period. The technology allows downhole data to be transferred from multiple locations in the well tubing to the wellhead utilizing acoustic waves. From the wellhead, the data is transmitted to engineers PC through a satellite communication system. This technology eliminates the need for expensive hardware or fiber optic cable used in the conventional downhole monitoring systems.
The field trial was successfully completed after 111 days of continuous data gathering and monitoring. All P/T gauges and the acoustic data transmission devices installed in the well performed excellently. The objectives of the trial were achieved. We not only were able to collect the downhole pressure and temperature data for well performance analysis but were also able to define the flow patterns (such as the slugging effects) occurring in the well due to changes in bottomhole pressure.
This system can be deployed as a temporary installation retrofit in the existing wells utilizing conventional wireline units, or permanently as part of the well completions for monitoring well performance for reservoir management or well performance monitoring purposes. The trial did not cover evaluation of the system under permanent installation mode as part of the well completion. Permanent installations can be considered once more long term experience has been gained from retrofit applications. IT involvement to provide support and the data transmission link is very essential.
The paper will describe the overall system, illustrate the quality and accuracy of real time data obtained during the trial and its utilization for well and reservoir performance evaluation purposes.
MRC Wells Performance Update: Shaybah Field, Saudi Arabia
Authors: Salamy S. P. , Al-Mubarak H. K. , Ghamdi M. S. , Hembling D. 
Published: December 2007

Abstract
This paper is an update of previous SPE technical papers1,2 highlighting the results of 25 Maximum Reservoir Contact (MRC) wells drilled in the Shaybah Field either as new wells or part of a workover strategy to convert existing weak 1-km single lateral wells to MRC wells with reservoir contacts ranging from 5 to 9 km.
Shaybah field, a low permeability reservoir overlain by a huge gas cap was initially developed in 1996 with 1-km single lateral horizontal wells to effectively drain the hydrocarbon while reducing gas coning. A step development approach by increasing the reservoir contact to improve well productivity and performance was the basis for the MRC concept. Results to date from 25 MRC wells have indicated a four-fold increase in well productivities and a three-fold decrease in unit development cost when compared to the one-km single lateral wells. A useful by-product of MRC drilling is the enhancement achieved in reservoir characterization.
In addition to MRC wells, smart technologies such as downhole flow control systems (smart completions), expandable liners, and production equalizers were deployed in Shaybah Field. These technologies have shown major improvements to well performance and recovery. Smart controls assisted in optimizing production from each lateral in a multi-lateral well in the event of premature gas or water coning. In addition, downhole smart completions improved well productivity in multi-lateral wells through an improved well cleanup process. Production equalizers when deployed in high GOR wells reduced gas coning and improved well productivity. To date over 21 expandable liners have been deployed as enablers to a workover strategy to convert single lateral wells to Multi-lateral/MRC wells thereby providing the platform for installation of downhole flow control systems.