bluuebunny/crossref_metadata_2025_split huggingface dataset:
Well Deliverability of Undersaturated Coalbed Reservoir
Authors: Thungsuntonkhun Witsarut , Engler Thomas W. 
Published: December 2007

Abstract
The production mechanism of gas from a coal reservoir is different from conventional gas reservoirs. For example, a typical coalbed reservoir first produces water until reservoir pressure decreases below the desorption pressure at which time gas begins producing. Furthermore, as gas is desorbing, the matrix shrinks and reservoir permeability changes with time. Due to these dissimilarities the conventional method to calculate the inflow performance curve cannot be applied to coal reservoir.
This paper presents a method to calculate the Inflow Performance Relationship (IPR) curve for undersaturated coal gas system based on a Fetkovich-type approach. A new concept to predict the coal gas inflow performance includes matrix shrinkage effects for the entire production sequence. The production sequence is divided into three parts in response to the production mechanism of coal reservoirs. In the first part, the IPR for water is calculated as single-phase production. Followed by multiphase production of water and gas. Last the third part is single-phase gas production. Previous work, considered this stage as single-phase gas production like a conventional gas reservoir; however, this work demonstrates permeability increases at lower reservoir pressure resulting in an increasing production rate for given well bore flowing pressure (Pwf).
Several field examples were evaluated with this new method, Deerlick Creek Field in Black Warrior Basin, and Cedar Hill Field in Fruitland Coal San Juan Basin. In both examples, an improved match of IPR data was achieved. Subsequently, a better prediction of well performance is proposed for undersaturated coalbed methane reservoirs.
Stimulating Oil and Gas Wells With PGDBK Gas Generators
Authors: Banahene A. O. , Pepe D. C. , Lueck W. R. 
Published: December 2007

Abstract
PGDBK Technology is used for the stimulation of oil and gas wells to enhance productivity. The pulsating pressure generated upon combustion of caseless cylindrical powdered charges overcomes the tensile strength of formation rock to create multiple fractures1. These fractures, with horizontal and vertical orientation, extend more than 100 feet in diameter from the wellbore. Combustion of PGDBK generators takes place near a selected pay zone in a well under a hydrostatic column sustained by a tamp fluid.
Through a combined effect of mechanical, thermal, and chemical actions, the use of PGDBK increases pressure communication between the extended reservoir and the wellbore. The pressure pulsating action of generated non-combustible gases erodes fracture walls keeping the flow channels opened for a long period of time without propping agents. High temperature generated through the combustion process cleans the wellbore region of heavy hydrocarbons, reduce the viscosity of oil and enhance relative permeability of oil to water. Additional oil is also recovered through the reduction of the surface tension by the chemical actions of the combustion products.
The in-situ process ends with a negative pressure gradient towards to the wellbore, washing impediments from flow channels. Wells are immediately swabbed or circulated to remove debris, equipment re-installed, and well brought back on line.
This paper describes the PGDBK stimulation technology. It further presents case studies of successful field applications in three different USA sedimentary basins in the summer of 2000 and recent treatments in Russia.
Resolving Differences Between Core and Welltest Permeability in Basal Colorado Sandstones, Canada: The Role of Rock Heterogeneity, Relative Permeability and Formation Damage
Authors: Potocki Dan 
Published: December 2007

Abstract
Welltest permeabilities are about 1 to 3 orders of magnitude lower than average core permeabilities from the same well for gas bearing Cretaceous Basal Colorado channel sandstones in south-eastern Alberta, Canada. The large differences coupled with local anomalously poor production from rock with high core permeabilities have raised uncertainty in both geologic and engineering communities regarding the reliability and representativeness of welltest and core permeabilities, respectively. Differences between core and welltest permeabilities are related to the core analyses, sampling and averaging techniques, and welltest interpretation procedures. Core absolute permeabilities are optimistic in part due to the effects of clay dehydration, rock decompaction, biased oversampling of high permeability intervals, and absence of relative permeability effects. Welltest effective permeabilities have been underestimated for gas wells producing minor amounts of water by wrongly assuming single phase gas flow in permeability calculations. The sum of these features creates the large differences between core and welltest permeability.
Streamline-based Production Data Integration Under Changing Field Conditions
Authors: He Zhong , Datta-Gupta Akhil , Yoon Seongsik 
Published: December 2007

Abstract
Recently streamline-based flow simulation models have offered significant potential in integrating dynamic data into high-resolution reservoir models. A unique feature of the streamline-based production data integration has been the concept of a ‘travel time’ match that is analogous to seismic tomography and has allowed the use of efficient and proven techniques from geophysics. In this paper we propose a ‘generalized travel time’ inversion method for production data integration that is particularly well-suited for large-scale field applications with changing conditions. Instead of matching the production data directly, we minimize a ‘travel time shift’ derived by maximizing a cross-correlation between the observed and computed production response at each well. There are several advantages with our proposed method. First, it is general and extremely computationally efficient. The travel time sensitivities can be computed analytically using a single streamline simulation that can be orders of magnitude faster than a conventional reservoir simulator. Second, it is very robust and the minimization is relatively insensitive to the choice of the initial model. Finally, it is field-proven because we utilize efficient techniques from geophysical inverse theory.
We demonstrate the power and utility of our proposed method using synthetic and field examples. The synthetic examples include a large-scale 3D example with quarter-million grid cells involving infill drilling and pattern conversions. The field example is from the Goldsmith San Andres Unit (GSAU) in West Texas and includes multiple patterns with 11 injectors and 31 producers. Starting with a reservoir model based on well log and seismic data, we integrate water-cut history for 20 years in less than 2 hours in a PC.
Characterization of West-Africa Submarine Channel Reservoirs: A Neural Network Based Approach to Integration of Seismic Data
Authors: Arpat B. G. , Caers J. , Haas A. 
Published: December 2007

Abstract
Advances in deep water drilling technology have cleared the path for new domains of hydrocarbon exploration along the Atlantic margins. Such deep marine settings are generally characterized utilizing seismic data while in development phase. Yet, interpreting facies information from seismic amplitude data requires an extensive and tedious work of an expert geologist/geophysicist. This process is not only costly in terms of work hours but also invites human inconsistencies into interpretations. This paper attempts to solve the above problem by proposing a neural network based automation method that learns how to relate the seismic data to facies objects like channels. The neural net training is based on the manual/CAD interpretation of a small portion of the available seismic amplitude data by an expert geologist/geophysicist. The trained neural net is shown to be able to automatically detect channel body features in the remaining portion of the data. As the case study, the paper includes a West-Africa submarine channel reservoir where the expert interprets a seismic amplitude data set of a turbidite sequence and where the neural network manages to estimate channel facies morphologies from seismic data.
Improved Reservoir Characterization of a Mature Field through an Integrated MultiDisciplinary Approach. LL-04 Reservoir, Tia Juana Field, Venezuela
Authors: Márquez L. J. , Gonzalez M. , Gamble S. , Gomez E. , Vivas M. A. , Bressler H. M. , Jones L. S. , Ali S. M. , Forrest G. S. 
Published: December 2007

Abstract
The LL-04 reservoir is located in the northeastern section of Lake Maracaibo and is part of the prolific Bolivar Coastal Field (BCF). Since its discovery in the late 1920's, this reservoir has produced over 520 MMSTB of oil from shallow (&lt;3000 feet), unconsolidated fluvial and fluvial deltaic sandstones of the Miocene Lagunillas and La Rosa formations. Production is complicated by the heterogeneous nature of the sediments, low oil gravity (12° - 19° API) and water coning and channeling. A multidisciplinary team consisting of engineers, geologists, geophysicists and petrophysicists was assembled to characterize and simulate the field. The objective of the team was to develop a reservoir management plan for the LL-04 Field that would increase daily production and ultimate recovery. Available data included 3-D seismic, openhole logs from over 600 wells, four cores and production and pressure measurements. All available data were used and honored in the interpretation process. Pressure measurements and production history were integrated with the seismic interpretation, log analysis, core descriptions, log correlations and deterministic mapping to define the reservoir compartments. Seven reservoir regions were defined. The original oil in place (OOIP) was increased by 44% as a result of this rigorous study. Also, 80 workover/recompletion candidates and 25 areas for infill drilling were identified.
Optimization of Rates of Penetration in Deepwater Drilling: Identifying the Limits
Authors: Hemphill T. , Murphy B. , Mix K. 
Published: December 2007

Abstract
Deepwater drilling in the U.S. Gulf of Mexico [GOM] is usually characterized by very narrow pore pressure / formation fracture gradient [PP / FG] windows. In GOM deepwater drilling, firm control over Equivalent Circulating Density [ECD] is required to help ensure these fracture gradients are not exceeded to reduce lost circulation and minimize expensive non-productive rig time. With the high daily operational cost of deepwater drilling, operators are pushed to drill as fast as possible, yet maintain a stable borehole and remain within the pressure bounds of their particular drilling situation. For these reasons synthetic-based drilling fluids [SBM] are commonly used.
Occasional hole pack-offs of large cuttings around the BHA during connections precipitated a study by the operator and drilling fluids service provider to thoroughly study the problem and recommend courses of action to help improve hole cleaning efficiency and optimize drilling operations. With the calculations of hole cleaning efficiency levels for various cases studied, accurate ECD predictions were made, and safe operating windows in terms of ROP were identified. These results were then applied on 2 GOM deepwater wells drilled with SBM having water depths between 2800 and 8800 ft. In this paper, the hydraulic studies and the field results are described and recommendations for future deepwater drilling operations are offered.
Demonstrations of Real-Time Borehole Seismic from an LWD Tool
Authors: Underhill W. , Esmersoy C. , Hawthorn A. , Hashem M. , Hendrickson J. , Scheibel J. 
Published: December 2007

Abstract
A new technique provides conventional borehole seismic measurements in real time while a well is being drilled. The system consists of a logging-while-drilling (LWD) tool with seismic sensors positioned near the drill bit, a seismic source at the surface, and a measurement-while-drilling (MWD) system for real-time telemetry. The seismic source is fired during pipe connections, seismic data are processed downhole and check-shot information is sent to the surface.
Borehole seismic tools conveyed by wireline cable have been used for a variety of applications including seismic time-depth mapping, and reflection and transmission imaging of subsurface structures. Although wireline borehole seismic services are mature, they are unable to provide all the benefits that are sought in real time while drilling. This is particularly the case when borehole seismic surveys are conducted to help make drilling and well construction decisions, such as steering and deciding on casing and coring points. The new service provides standard borehole seismic information in real time that can be exploited for drilling optimization, cost savings, and safety improvements. Check-shot (time/depth) data are used to place the bit on the seismic map to help well navigation and casing point selection and to avoid drilling hazards, such as pore pressure, seen on the seismic. Real-time seismic velocities can be used to update pore-pressure predictions from surface seismic. Ultimately, the real-time velocities will be combined with look-ahead images, formed from the seismic reflections from horizons ahead of the bit, to provide a direct measurement of the distance to a marker of interest.
In 2000, a field-test campaign conducted with experimental tools in the Gulf of Mexico demonstrated the first known real-time check-shot technique with an LWD tool. We will show the results and further describe the status of the service.
Early Kick Detection for Deepwater Drilling: New Probabilistic Methods Applied in the Field
Authors: Hargreaves David , Jardine Stuart , Jeffryes Ben 
Published: December 2007

Abstract
This paper documents the development and field test of a sensitive new kick detection system. The detector uses a Bayesian probabilistic framework to make good decisions based upon noisy drilling data. It works on any rig type, but brings particular improvements to kick monitoring for deepwater drilling, especially in high heave conditions. The approach offers sensitivity improvements over existing systems, while maintaining a low false alarm rate.
Effects of Fluid Flow in a Porous Cuttings-Bed on Cuttings Transport Efficiency and Hydraulics
Authors: Cho Hyun , Shah Subhash N. , Osisanya Samuel O. 
Published: December 2007

Abstract
The study of effective cuttings transport and accurate prediction of drilling hydraulics has been a major concern for decades in the drilling industry. It is inevitable for deviated wells and long horizontal wells to have a considerable amount of cuttings-bed in the annuli. Common problems with most of the existing models are that they do not consider the drilling fluid flow through a cuttings-bed.
A new mathematical model is proposed to identify the effects of fluid flow in porous cuttings-bed and the differences of relative velocities between cuttings and carrier fluid on drilling hydraulics. The carrier fluid flows through the cuttings-bed, forming a porous matrix in which porous media itself is moving or stationary depending on the force balances. This model also considers the pressure losses of carrier fluid flowing through porous media in a cuttings bed layer. This paper specifically describes the model development (including changes in axial forces in continuity and momentum equations due to changes in a deviated well angle), the solution, and simulation results. In order to ensure a comprehensive understanding of the effects of parameters affecting cuttings transport efficiency, a simulation of the hole cleaning mode is performed. This study provides a method to predict cuttings transport efficiency accurately, and to precisely estimate friction pressure losses in deviated wells (hole deviation angle: 30 to 60°), which have the most unstable cuttings bed characteristics.
Gas Hydrate Formation in Drilling Mud Characterized With DSC Technique
Authors: Herzhaft Benjamin , Dalmazzone Christine 
Published: December 2007

Abstract
Gas hydrates have been studied by petroleum industry for more than 60 years, but up to now, the major part of the research was linked to the problem of oil transportation, prevention or remediation of pipe lines plugging. The development of deep offshore drilling has extended gas hydrate problem to drilling muds area. The consequences of hydrate formation in drilling muds can be dramatic: loss of mud rheological properties, accumulation of hydrate crystals leading to plugging of the lines, the BOP or the annular, interruption of the drilling operations and even destruction of rig equipment. To prevent these problems, operators must use drilling muds (WBM or OBM) with thermodynamic inhibitors of hydrate formation as salts and glycols, which cause important problems of density adjustment, corrosion and toxicity. The usual way to determine the thermodynamic conditions of hydrate formation in drilling mud formulations is to use batch reactors or thermodynamic models validated from PVT experiments on simple or model fluids.
An innovative methodology was elaborated using Differential Scanning Calorimetry (DSC) to determine the thermodynamic equilibrium properties and kinetics of hydrate formation in mud formulations, particularly in the presence of large amounts of mineral. This technique allows the measurement of heat transfers as a function of time, temperature and pressure and thus detects phase transitions. We have shown recently that this rapid, versatile, easy to use technique permits to determine the dangerous zones for hydrate appearance. We present here new results of hydrate characterization. Using DSC, hydrate appearance in several drilling muds formulations (WBM or OBM) was shown and quantified. The influence of gas composition i.e. methane or natural gas on hydrate formation has been studied for different mud continuous phases, the effectiveness of several inhibitors was measured. A methodology using isothermal experiments to quantify kinetics of the formation of hydrate was proposed, the bubbling of gas into the measuring cell allowing to simulate agitation and progressive gas incorporation. Effect of time and temperature are by this way quantified. Through this work, DSC has proven to be an efficient technique for characterizing hydrate formation in drilling muds.
Obtaining Successful Shoe Tests in the Gulf of Mexico: Critical Cementing Factors
Authors: Harris Kirk , Grayson Gary , Langlinais Joey 
Published: December 2007

Abstract
Approximately one out of six casing shoes in the Gulf of Mexico (GOM) require a cement squeeze job after primary cementing. Numerous theories exist regarding the causes of high shoe-test failure rates, but failure is often attributed to problems associated with the primary cementing job.
A GOM database containing information about more than 4,000 shoe-cementing operations was reviewed to find correlations between the success/failure rate and industry-accepted best cementing practices. The results confirm some correlations between the cementing process and shoe-test success; however, no single cementing parameter has an overwhelming effect on shoe failure. Of the industry-accepted best cementing practices, the GOM database shows the following factors to be most important for shoe-test success: (1) pipe movement, (2) maintenance of circulation during cementing, (3) accurate displacement volumes, (4) centralization, and (5) application of foam cementing. The cementing parameters that appear to have less effect on shoe-test outcomes were (1) mud properties, (2) displacement rates, (3) spacer volumes, and (4) application of a hesitation squeeze at the end of the primary cement job.
The review of the GOM database also showed that deeper casings are more susceptible to shoe-test failure, as are wells in deeper water. The data shows a constant rate in shoe-test failures since 1993 and a large variation in success between operators.
Chipping Resistant Polycrystalline Diamond and Carbide Composite Materials for Roller Cone Bits
Authors: Fang Z. , Griffo A. , White B. , Belnap D. , Hamilton Rob , Portwood G. , Cox P. , Hilmas G. , Bitler J. 
Published: December 2007

Abstract
Cemented tungsten carbide and polycrystalline diamond are the most critical materials used for roller cone bit cutting structure. Chipping and catastrophic breakage are the primary failure modes for the materials and hence the limiting factor of service life of a drill bit. Chipping and fracture resistance can be improved at the expense of hardness and wear resistance of the materials. This trade-off between wear resistance and chipping resistance hinders the development of super hard materials for demanding drilling applications. Functionally designed composite materials of polycrystalline diamond (PCD) and cemented tungsten carbide (WC-CO) that offer enhanced chipping resistance without significantly sacrificing wear resistance are studied and reported in this presentation.
Specifically, one example of the functionally designed composite materials is a honeycomb structured composite of polycrystalline diamond (PCD) and WC-Co and its application for diamond enhanced inserts for roller cone bits. The PCD/WC-Co composite takes advantages of high modulus and superior wear resistance of diamond, while it mitigates chipping and cracking using the tougher WC-Co as cell boundaries. The overall engineering properties and performance are superior to that of pure PCD.
Another example of functionally engineered hard materials is double cemented (DC) tungsten carbide. Double cemented tungsten carbide has 50% or higher fracture toughness than conventional cemented tungsten carbide at equivalent wear resistance. When compared to tool steels, DC carbide has equivalent fracture toughness but much higher wear resistance. Field tests of honeycomb structured diamond enhanced inserts (CDEI) demonstrated the controlled chipping characteristics and longer durability of components as compared to conventional homogeneous PCD materials with comparable wear resistance. DC carbide also exhibited excellent damage tolerance during field tests in demanding applications where excessive heat checking and fracturing of inserts are common failure modes.
Field Development Utilizing Rotary Steering Technology
Authors: Grini Morten , Rice Bill , Stromberg Svein 
Published: December 2007

Abstract
The Jotun Field is located approximately 165 kilometers offshore Norway in 127 meters of water. Jotun development drilling was executed from a wellhead platform with a fit for purpose new build drilling rig. All production wells were planned as complex directional, horizontal producers in Paleocene, Heimdal sandstones at a depth of approximately 2050 meters TVD SS.
Reservoir target complexity dictated tortuous directional well paths often resulting in azimuth changes in excess of 90 degrees at high angle, horizontal inclinations. Target tolerance ± 1m was common place at measured depths out to 6000 meters. Directional control and well tortuousity were critical well design considerations.
An agreement was reached between Esso Norge AS and Baker Hughes Inteq to utilise AutoTrak™ steering technology on all 12 1/4 inch intermediate and 8 1/2 inch horizontal hole sections on the Jotun B Platform. Drilling commenced in April 1999. This was the first field to be developed using rotary steering technology.
To date, 1 water injection well and 14 horizontal production wells have been drilled on Jotun B. This paper provides a history of drilling performance utilising rotary steerable technology on the Jotun B Platform.
The following topics are discussed: Well design considerations and complex 3-dimensional well pathsDrilling performanceAutoTrak™ tool performance and reliabilityRotary steering hole conditioning benefits