bluuebunny/crossref_metadata_2025 huggingface dataset:
An Objective Rapid Screening Tool for Surfactants Used in Foam-Like Dispersions of CO2 into Permian Basin Brines
Authors: Horton R. L. , Wicks J. P. , Prieditis John , Turbeville J. B.
Published: December 2007

Foam-like dispersions of CO2 into brines can reduce the mobility of drive fluids in CO2 floods. To evaluate the effectiveness of such foam-like dispersions, time-consuming laboratory coreflood tests are routinely used. Because of the costliness of such coreflood tests, simple qualitative tests have long been employed to screen potential surfactants. Then only a few of the better candidates are subsequently evaluated in coreflood tests. There are a number of disadvantages of such qualitative tests; therefore we developed, instead, a quantitative screening process. Our quantitative process is based on two simple, quick laboratory tests and a neural network interpretation of the test data. The neural network predicted CO2 mobility reduction values which correlated well with the mobility reductions seen in coreflood tests.
Research and Application of Amphoteric Polymers for Drilling Fluid
Authors: Yabin Niu , Darning Zhang , Pingya Luo , Jian Li , Tongtai Xu
Published: December 2007

As the inhibition ability is not strong enough and the tolefance ability of solid contamination is low for usual polymer drilling fluid, the amphoteric polymer drilling fluid is suggested to solve above problems after analyzing and researching interactive mechanism and components of polymer drilling fluid as well as structure character of polymer molecule. The inherent character of amphoteric polymer molecule makes it not only to have strong inhibition but also to improve rheological property of drilling fluid. The application in 15 oilfields (nearly 4000 wells) in China demonstrates that the amphoteric polymer drilling fluid has strong inhibition, can retard "mud-making" of shale formation, keeps low-solid content and wellbore stable. The amphoteric polymer drilling fluid has excellent rheological property to make full use of jet-bit drilling and achieve significant effectiveness of increasing drilling rate. The obvious results in protection of oil formation have been achieved.
A Compositional Reservoir Simulator on Distributed Memory Parallel Computers
Authors: Ramé Marcelo , Delshad Mojdeh
Published: December 2007

This paper presents the application of distributed memory parallel computers to field scale reservoir simulations using a parallel version of UTCHEM, The University of Texas Chemical Flooding Simulator. The model is a general purpose highly vectorized chemical compositional simulator that can simulate a wide range of displacement processes at both field and laboratory scales. The original simulator was modified to run on both distributed memory parallel machines (Intel iPSC/960 and Delta, Connection Machine 5, Kendall Square 1 and 2, and CRAY T3D) and a cluster of workstations.

A domain decomposition approach has been taken towards parallelization of the code. A portion of the discrete reservoir model is assigned to each processor by a set-up routine that attempts a data layout as even as possible from the load-balance standpoint. Each of these subdomains is extended so that data can be shared between adjacent processors for stencil computation. The added routines that make parallel execution possible are written in a modular fashion that makes the porting to new parallel platforms straight forward.

Results of the distributed memory computing performance of Parallel simulator are presented for field scale applications such as tracer flood and polymer flood. A comparison of the wall-clock times for same problems on a vector supercomputer is also presented.
Surface Network and Well Tubinghead Pressure Constraints in Compositional Simulation
Authors: Litvak M. L. , Darlow B. L.
Published: December 2007

A new procedure for the determination of well production rates from surface pipeline network and well tubinghead pressure constraints is presented.

The well production rates are calculated using simultaneous modeling of multiphase fluid flow in the reservoir, well perforations, well tubing strings, and surface pipeline network system.

The procedure is implemented in an industrial compositional reservoir simulator. It is applicable for both black-oil and compositional reservoir simulations.
A Renormalisation-Based Upscaling Technique for WAG Floods in Heterogeneous Reservoirs
Authors: Christie M. A. , Mansfield Mark , King P. R. , Barker J. W. , Culverwell I. D.
Published: December 2007

A novel and rapid upscaling procedure is described in which: 1) pseudo-functions are generated for each block in a coarse grid; 2) a renormalisation method is used to calculate the pseudo-functions; 3) an empirical viscous fingering model is used to allow for fluid instabilities in unfavourable mobility ratio displacements. Oil recovery predictions are shown to agree well with conventional simulations made on the fine (geological model) grid for unstable, first-contact miscible WAG floods with a range of permeability distributions. In all cases, the result is an improvement (usually a substantial one) over a conventional coarse grid model in which only the absolute permeability of each block is upscaled.
Interactive Reservoir Simulation
Authors: Regtien J. M. M. , Por G. J. A. , van Stiphout M. T. , van der Vlugt F. F.
Published: December 2007

Shell's new Modular Reservoir Simulator (MoReS) has been equipped with a comprehensive and versatile user interface called FrontEnd. Apart from providing a user-friendly environment for interactive reservoir simulation, FrontEnd serves as a software platform for other dynamic simulation and reservoir-engineering applications. It offers to all supported applications a common user interface, enables the re-use of code and reduces overall maintenance and support costs associated with the embedded applications. Because of its features, FrontEnd facilitates the transfer of research results in the form of operational software to end users.

When coupled with MoReS, FrontEnd can be used for pre- and postprocessing and interactive simulation. The pre-processing options allow data to be inputted by means of various OSF/Motif widgets containing a spreadsheet, text editors, dialogues and graphical input. The display of the input data as well as the post-processing of all simulation results is made possible by a variety of user-defined plots of tabular (e.g. timestep summary) and array (simulation grid) data. During a simulation user-defined plots can be displayed and edited, allowing a close inspection of the results as they are being calculated. FrontEnd has been equipped with a powerful input command language, which gives the batch user as much flexibility and control over the input as the interactive user.
Geological Characterization and 3D Visualizations of The Gas Storage Reservoir at Hillsboro Field, Montgomery County, IL
Authors: Udegbunam E. O. , Huff B. G.
Published: December 2007

Geological characterizations, modeling and 3-D computer-generated visualizations of the Ordovician St. Peter Sandstone at the Hillsboro Gas Storage field in Montgomery County, Illinois, are discussed. Petrophysical analyses reveal four distinct hydraulic flow units in six cored wells. Furthermore, four lithologies, identified by thin section petrography, are associated with the various hydraulic units. Fieldwide visualizations of 3-D distributions of petrophysically-derived attributes – reservoir quality index (RQI) and flow zone indicator (FZI) – show considerable vertical variability but lateral continuity. This finding explains why it is easier to expand the gas bubble laterally than vertically. Advantages of the 3-D reservoir description of Hillsboro Gas Storage field include 1) improved definition of the spatial porosity distribution which leads to better estimation of reservoir volumetries; 2) improved definition of reservoir hydraulic flow zones; and 3) development of realistic reservoir model(s) for the simulation and management of the gas storage field.
A New Multi-Phase Flow Model for Horizontal, Inclined, and Vertical Pipes
Authors: Bilgesu H. I. , Ternyik Joseph
Published: December 2007

Multiphase flow conditions occur in a wide range of engineering applications in the petroleum, chemical, and nuclear industries. The design of production systems involving different fluids requires an accurate prediction of the pressure loss. Existing methods rely on the prediction of flow patterns based on observed field and experimental data. However the patterns are not applicable to all conditions and the predicted pressure drops deviate from actual observations.

This paper describes the new model developed to predict pressure drop for vertical, inclined, and horizontal pipes and wellbores. The model is composed of fluid property correlation, flow pattern prediction, and pressure drop determinations.

The model performance is evaluated using published data, The model predictions are also compared with a commercially available model. The overall performance of the model is in good agreement with data. In comparison with the published data, the model predictions resulted in the least average error.
Spatial Delineation of Natural Fractures and Relation to Gas Production
Authors: Caramanica F. P. , Hill D. G.
Published: December 2007

In a Gas Research Institute sponsored study, enhanced formation image analysis was performed on twelve wells in the Antrim Shale, Michigan Basin. The analysis revealed that the abundance of open and partially open fractures as well as their degree of interconnection are controlling factors in gas production. Borehole maps show the interconnection with reference to the borehole.

A fracture factor (Zf) was derived and plotted against gas flow rates for nine wells. Six wells treated with a singlestage stimulation show a linear relationship between (Zf) and Q. Two were stimulated with a two-stage treatment and produced more gas than single-stage wells with comparable values of Zf. The methods of fracture analysis derived for the Antrim Shale should have immediate practical application to other unconventional and tight reservoir rocks.
Using a Mixed Integer Linear Programming Technique to Optimize a Fracture Treatment Design
Authors: Rueda J. I. , Rahim Zillur , Hoiditch S. A.
Published: December 2007

IN1RODUCTION

Well stimulation procedures are designed to reduce the restrictions to flow from the reservoir into the wellbore and increase productivity.1 Hydraulic fracturing in low permeability reservoirs is an important and successful stimulation methodology widely used by the petroleum industry.

The design of the optimum fracture treatment has three basic steps. The first step involves calculating fracture dimensions and conductivity for various fracture fluid pumping schedules. The second step is determining the oil and gas production rates and recoveries using the values of propped fracture length obtained from the fracture treatment design. The third step requires one to determine the optimum fracture treatment design by maximizing the economic benefit of the treatment. Since a fracture treatment design involves selection of fracturing fluids, additives, proppant materials, injection rate, pump schedule, and fracture dimensions, the determination of the optimum combination of all variables can be quite complicated. In this research, we have developed two methods to investigate reasonable combinations of design and treatment parameters to determine the most profitable fracture treatment design. Depending upon the post-fracture treatment production rates, the related expenses, and the economic constraints, the optimum treatment can be easily determined.

The first optimization method is based on a mathematical technique called Mixed Integer Linear Programming (MILP).2 This method can be used to minimize or maximize a desired objective function subject to certain constraints. For this work, we have chosen the objective function to be the discounted net present value due to a fracture treatment. The constraints are related to the fracture dimensions and other items necessary to linearize the fracture design problem.3
Adsorption of Pure Methane, Nitrogen, and Carbon Dioxide and Their Binary Mixtures on Wet Fruitland Coal
Authors: Hall F. E. , Zhou Chunhe , Gasem K. A. M. , Robinson R. L. , Yee Dan
Published: December 2007

A detailed experimental study has been made of the adsorption of methane, nitrtheir binary mixtures, on a wet Fruitland coal at 115°F. Mixture measurements were typically made at nominal gas-phase compositions of 20, 40, 60, and 80 mole percent and pressures to approximately 1,800 psia. These data elucidate clearly the competitive adsorption behavior of the individual components in these mixtures.

The experimental information was used to test predictive methods for describing the adsorption behavior of the pure and mixed gases. Models included various two-dimensional equations of state, as well as more traditional methods, such as the Langmuir and loading ratio correlations and the ideal adsorbed solution (IAS) model. The relative merits of the various models are described. In general, all models perform well for pure-gas adsorption; however, results are less satisfactory for mixtures. The errors in mixture predictions increase as the individual components become more dissimilar in their adsorption behaviors. Greatest (percentage) errors occur for the less-adsorbed component and, in the worst case (nitrogen + carbon dioxide), the predictions for nitrogen show errors of more than 100% at some conditions. Overall, the two-dimensional equation-of-state and IAS models perform comparably, and they are more accurate than the Langmuir model.

The data and modeling results should be of interest in coalbed methane production and, especially, in evaluating potential enhanced recovery operations based on nitrogen and/or carbon dioxide injection into coalbeds.
Bioremediation Evaluation of Surface Soils Contaminated with Organic Compounds
Authors: Tezak James , Miller Jeffrey A. , Lawrence Alonzo Wm , Keffer Ronald E. , Weightman Robin , Hayes Thomas D.
Published: December 2007

Potential environmental impacts of natural gas production have become the focus of increased regulatory activity. Cost effective environmental control strategies are needed for achieving environmental protection of operating and abandoned natural gas well sites and processing facilities. The Gas Research Institute (GRI) has an ongoing comprehensive research program to assist industry in developing cost effective technologies and strategies for attaining the required level of environmental protection associated with natural gas production activities. Bioremediation is hypothesized to be a key remediation strategy.

This paper presents background information on bioremediation; information on biotechnologies that have been proven in other industries and that may be applicable to the natural gas industry; a protocol for assessing the feasibility of bioremediation; and, some preliminary results on some soils that were evaluated using the protocol. Background information related to natural gas production and processing sites and chemicals that are typically used are presented because both are important preliminary feasibility screening criteria. Applications of bioremediation to sites with similar chemicals such as refineries, wood treating plants, and former manufactured gas plants (MGP's) have been used for approximately 30 years, however bioremediation is not widely used to treat wellhead sites or natural gas production and processing sites.

Examples of applications of bioremediation to nonnatural gas industry sites are presented and the similarities, primarily chemical, are presented. The GRI developed an Accelerated Biotreatability Protocol for former MGP sites and it is currently being modified for application to the Exploration and Production (E&P) industry. The Accelerated Treatability Protocol is a decision-making framework to evaluate the potential full-scale biological treatment options. Preliminary results from some soils collected and evaluated using the protocol are presented.
Applications of Exploration Technologies to Reservoir Prediction and Management—Field Examples of South-East Asia
Authors: Duval B. C. , Allen George , Madaoui Khaled , Gouadain Jacques , Kremer Yves
Published: December 2007

The paper describes how modem geoscience techniques, developed for a large part in intensive exploration programs, can be used at the field level to improve reservoir prediction and production planning and also to optimize recovery.

Detailed sedimentological studies have allowed to determine the environment of the reservoir formations and help define the likely shape and size of individual sands and refine the reservoir model. An illustration is given by fields located in the Mahakam delta area of Kalimantan (Handil, Tunu) and in the Gulf of Thailand (Bongkot).

Sequence stratigraphy assists in identifying efficient regional seals which, at field scale, lead to the recomposition of a great number of individual sands (several hundreds in some cases) into fewer flow units, making the system manageable from a reservoir standpoint. This technology was used extensively to delineate the giant Peciko gas field of Indonesia.

The geophysical approach of reservoir parameters and the use of seismic attributes are rapidly expanding. The Yadana gas field in the Gulf of Martaban (Myanmar) is a case in point to show how porosities can be determined from impedances obtained by seismic inversion techniques.

An example from the Bongkot field shows how 3D seismic and direct hydrocarbon indication technology (DHI) are used to deal with complex faulting to optimize deviated well profiles and improve recoveries.
Prediction of Minimum Principal In-Situ Stress by Comparison and Verification of Four Methods
Authors: Harikrishnan R. , Hareland G.
Published: December 2007

This paper evaluates the correlation between values of minimum principal in-situ stress derived from four different models which use data obtained from triaxial core tests or sonic logs. The first method utlilizes a normalized form of the Mohr failure envelope equation fit different lithologies. The second method utilizes sonic log data to predict Poisson's ratio which is used to calculate the minimum principal in-situ stress. The third method uses a fit to the Mohr failure envelope as a function of average rock grain size, which was obtained from detailed microscopic analyses. The fourth method uses the Mohr-Coulomb failure criterion which uses an average angle of internal friction to predict the minimum principal in situ stress. The minimum principal in situ stress values obtained from the four different methods are then compared to actual field mini-frac test data which is known to be the most accurate method to determine the minimum principal in situ stress. The cores and the mini-frac stress tests were obtained from two wells, the Gas Research Institute's (GRI's) Staged Field Experiment (SFE) #1 well through the Travis Peak Formation in the East Texas Basin, and the Department of Energy's (DOE's) Multiwell Experiment (MWX) well located west-southwest of the town of Rifle, Colorado, near the Rulison gas field.

Results from this study indicate that the calculated minimum principal in situ stress values obtained by utilizing the rock failure envelope as a function of different lithologies are in better agreement with the measured stress values (from mini-frac tests) than those obtained from the other three approaches.
An Innovative Model for Drilling Fluid Hydraulics
Authors: Merlo Antonino , Maglione Roberto , Piatti Cesare
Published: December 2007

The hydraulic system plays an active role during drilling operations. Its proper design can accelerate the drilling effort and lower the overall well cost.

It is very important to predict the exact pressure distribution along the well and the circulating temperature distribution in the fluid.

This paper describes an innovative hydraulic computer program developed in Agip.

The program calculates the rheological parameters of drilling fluid based on the viscometer readings.

The rheological models of Newton, Bingham, Power law and Herschel-Bulkley are considered.

The program calculates also the temperature profile of drilling fluid and takes into account the temperature effect on the rheological parameters, when available viscometer readings at different temperatures.

The use of Herschel-Bulkley model and the temperature effect estimation improve the flow modelling capability during drilling fluid circulation and permits to better study and quantify the influence of hydraulic parameters, thus allowing better planning.

It will be also considered case histories with comparison of calculated and field data coming from Agip ultradeep wells experience.
Development of Coated Tubing for Oil/Gas Production in Sour Environment
Authors: Masamura Katsumi , Takeuchi Yuko , Nara Yoshihiro , Nagasaka Tetsuo , Miyagawa Tsuguo , Nakamura Arata
Published: December 2007

To develop inside coated tubing for sour environments, a joint research program has been conducted by Japan Research and Development Center for Metals (JRCM) and Japan National Oil Corporation (JNOC). The aim of this project is to develop a cheap oil country tubular goods (OCTG) with high corrosion resistance in sour environment using new coating technology on carbon steel. Coating facilities by plasma transferred arc hard facing (PTH) process that was applied for tubing, was constructed. Developed coated tubing (5 m long x 89 mm O.D. x 76 mm I.D) and connection was manufactured and tested corrosion resistance and joint performance. Antigalling property and gas tightness is equivalent to conventional joint. Coated tubing and connection evaluated corrosion resistance in dynamic corrosion tester and field test. No corrosion damage was observed after tests. These results suggest that developed tubing and connection can be used in deep sour wells.
Stochastic and Deterministic Reserves Estimation in Uncertain Environments
Authors: Karra Sastry , Egbogah Emmanuel O. , Yang Foo Wah
Published: December 2007

This paper presents a comparison of stochastic and deterministic reserves estimation methods as related to the various stages of development of an oil or gas field, with emphasis on offshore environment. The current debate concerning stochastic and deterministic reserve estimates and definitions is framed with respect to the various stages of field development. Advances in technology in terms of three-dimensional seismic data and reservoir simulation appear to narrow the range of reserves estimates.

Field examples are presented to compare stochastic and deterministic reserves estimates. Stochastic methods are preferable during exploration and pre-development, while both methods can be used in practice to support the decision to proceed with development. In the later stages of development, deterministic methods become more practical as other data become available.

Advances in technology are leading to better deterministic estimates as well as stochastic estimates with narrower ranges. Practices in the industry vary from complete dedication to deterministic or stochastic to a choice of the method depending on the stage of development.

This paper offers recommendations as to which reserves estimation technique is more suitable at specific stages of field development based on data scope and availability.
Determination of the Original-Gas-in-Place and Aquifer Properties in a Water-Drive Reservoir by Optimization Technique
Authors: Chen Ta-Lin , Chen Yeong-Long , Lin Zsay-Shing
Published: December 2007

The purpose of this study was to estimate the original-gas-in-place (OGIP) of a water-drive reservoir using optimization algorithm for Port Arthur field, Texas, U.S.A. The properties of the associate aquifer were also obtained. The good agreement, between the results from this study and those from simulation study, would be demonstrated in this paper.

In this study, material balance equation for a gas reservoir and van Everdingen-Hurst model for an aquifer were solved simultaneously to calculate cumulative gas production. The result was then compared with cumulative gas production measured in the field that observed at each pressure. The following parameters were manually adjusted to obtain: OGIP, thickness of the aquifer, water encroachment angle, ratio of aquifer to reservoir radius, and aquifer's permeability. The procedure was then applied with simplex technique, an optimization algorithm, to adjust parameters automatically. When the difference between cumulative gas production calculated and observed was minimal, the parameters used in the model would be the results obtained.

A water-drive gas reservoir, "C" sand gas reservoir in Port Arthur field, which had produced for about 12 years, was analyzed successfully. The results showed that the OGIP of 60.6 BCF estimated in this study was favorably compared with 56.2 BCF obtained by a numerical simulator in other study. In addition, the aquifer properties that were unavailable from the conventional plotting method can be estimated from this study. The estimated aquifer properties from this study were compared favorably with the core data.
The Asia Pacific LNG Trade: Status and Technology Development
Authors: Hovdestad Wayne R.
Published: December 2007

The Asia Pacific Region is experiencing a period of sustained economic expansion. Economic growth has led to an increasing demand for energy that has spurred a rapid expansion of baseload liquefied natural gas (LNG) facilities in this region. This is illustrated by the fact that seven of the ten baseload facilities in existence provide LNG for markets in the Asia Pacific region. With the three exceptions having been initially commissioned in 1972 and earlier, it is fair to observe that most advances in LNG technology have been developed and applied for this market.

The paper presents the current status and identified future trends for the Asia Pacific LNG trade. Technology development in terms of application to onstream production, processing and transportation facilities, including LNG tankers, is presented. The potential of future advances to applied technology and operational practices to improve the cost-effectiveness of new and existing facilities is discussed. Current design data and methods as actually used are examined in terms of identifying where fundamental research and basic physical data are insufficient for optimisation purposes.

These findings are then summarised and presented in terms of the likely evolution of future and existing LNG projects in the Asia Pacific region.
Case Histories in the Europe/Africa Area Demonstrate Improved Capabilities of FiberOptic Video Camera Technology
Authors: Olsen J. E. , Kristensen R. , Taylor R. W.
Published: December 2007

Cost constraints in the oilfield restrict the performance of remedial services unless a high probability of success can be assured. Unfortunately, a method that could accurately diagnose wellbore problems in a broad scope of oilfield environments was not available, and until the 90's, accuracy of problem assessment was compromised to the point that estimates of remedial success could not be determined. During the 90's, however, a downhole video system that showed promise of providing the sought-after diagnostic accuracy for today's operational conditions was introduced to the oilfield. With the combined capabilities of fiber-optic signal transmission and downhole video camera technology, the system can now provide the oil and gas industry with a diagnostic tool that is rapidly becoming invaluable in oilfield services and is proving the worth of the old adage, "Seeing is believing."

This paper will present a brief overview of the use of the downhole video (DHV) camera technique from its first documented usage until early 1992. The enhancements that have been instrumental in enlarging the scope of its usage since that time will then be discussed. Case histories recorded by the video camera operation in the Europe/Africa area will be presented and analyzed to demonstrate usage and benefits of the system.
Horizontal Well Simulation in the Baram South Area, Offshore Sarawak, Malaysia
Authors: Raub Mohd. Razib Abd.
Published: December 2007

The Baram ‘South’ area is a largely undeveloped fault block in the Baram Field which contains some 154 MMstb of oil.

Due to the elongated nature of the fault block, the moderately high in-situ oil viscosity of 6 cP. and the strong water drive, a horizontal well development has been identified to provide optimum reservoir development in the 14.0 sand. As a result, a horizontal well simulation study to support the requirement for horizontal wells has been carried out. The objectives of this study were to confirm the reserves and performance of the horizontal wells as compared to conventional wells and at the same time understand the key parameters that influence the horizontal well performance. Due to the lack of production history for this reservoir, in addition to no representative core and PVT data, the challenges lay in acquiring the most representative data to be used in the simulation study.

This paper describes the approach taken in the simulation; from utilising core and PVT data from neighbouring fields, establishing a geological layering based on well log correlations and finally the setting up of the simulation model and grid system. In addition, prediction runs and sensitivity studies are also discussed, which identified the key parameters that impact horizontal well recovery and performance.

The base case results confirmed the merits of a horizontal well development as compared to conventional wells. They also support the reserves, watercut and GOR performance of a horizontal well as derived from analytical calculations. However, the simulation gave new insight into the declining gross production. The sensitivity studies highlighted the need to obtain core data and fluid samples during development, for use in future simulation studies.
Structural Integrity of Typhoon Damaged Structures
Authors: Billington C. J. , Ward J. K. , Grimm David F.
Published: December 2007

This paper concerns the integrity reassessment of offshore wellhead platforms damaged by a typhoon, the damage consisting of cracking at joints between the conductor support frames and the main jacket structures. These structures were reassessed to establish the stability and growth rates of the cracks, and the effect of the cracks on the overall stability of the conductor frames and the structures as a whole.

The structures were reanalysed using models that included joint flexibility which had a significant effect on load levels at the critical crack locations. Non-linear ultimate load analyses were carried out at selected joints in order to develop plastic collapse values for a fracture mechanics assessment of crack fracture criticality and growth rates. A series of analyses was carried out to investigate the potential progressive failure of the conductor frame supports and the effect of this on overall structural stability. Remedial measures were considered in detail including crack grinding, chord grouting, member removal and clamping.

The results of the reassessment showed that the analysis including joint flexibility predicted more accurately the crack growth rates. The flexibility considerably relieved member end moments albeit increasing mid span moments and deflections. The progressive collapse analysis showed that a rapid failure in the event of a complete member severance is unlikely and that therefore a planned programme of inspection and remedial grinding can be instituted.

This paper describes the overall assessment strategy and the detailed assessment methods used. It demonstrates the useful role of non-linear finite element analysis and fracture mechanics techniques in minimising the need for expensive underwater structural repairs.
New Findings in Low-Temperature Oxidation of Crude Oil
Authors: Mamora D. D.
Published: December 2007

Clay and sand fines reduced the permeability of sand packs in combustion tube experiments and also provided a large reaction surface area. Consequently, residual oil saturation and hence fuel concentration increased, resulting in high-temperature oxidation (HTO). In contrast, low-temperature oxidation (LTO) resulted from low fuel concentration.

A combustion front temperature of 500°C (932°F) was obtained for HTO runs, compared to only 350°C (662°F) for the LTO run. During HTO, practically all injected oxygen was consumed, whereas during LTO, oxygen moved through the combustion front resulting in the formation of an oxygenated hydrocarbon fuel (atomic oxygen-carbon ratio of 0.3 was measured). As a result of distillation, the viscosity and specific gravity of the produced oil in HTO runs were reduced significantly. In contrast, LTO resulted in an increase in viscosity and specific gravity of the produced oil. A new method was developed to estimate the heat of reaction of oxygenated hydrocarbon fuels.

Kinetic tube experiments showed oxidation of crude oil to consist of two stages: low-temperature oxidation followed by high-temperature oxidation, with reaction peaks at about 250°C (482°F) and 400°C (725°F) respectively. Kinetic and combustion tube experimental results indicated that an oxygenated hydrocarbon fuel was formed during low-temperature oxidation. A new oxidation model for kinetic tube experiments was developed. Oxygen consumption based on the new model agreed well with experimental data.

Before implementing an in-situ combustion project, it is critical to carry out combustion tube experiments using actual crude oil, oil saturation and matrix found in the field to ascertain the type of oxidation reaction. Further, standard kinetic tube experiments may not yield the correct kinetic parameters, since fuel oxygenation is unavoidable in kinetic tube experiments. An alternative approach needs to be found to estimate the heat generated at the combustion front.
Cost Reduction Deriving From Integration of Services Thanks to Slim Hole Rig Design
Authors: Dupuis Dominique , Sagot Andre
Published: December 2007

In respect of Slim Hole drilling, the savings deriving from the application of this technology have to be considered at the level of the well. The Slim Hole technology, thanks to the volumes of hole considered, the design requirements and the construction of a new dedicated rig, has permitted to integrate a cementation system (pumps and batch mixing tanks) an on-line waste treatment system and a comprehensive instrumentation from which are delivered the data to the different players on the rig i.e. mud-logger, driller, tool-pusher, company man. The services deriving from those components usually performed by third party's Contractor are implemented by the Drilling Contractor with its own crew. Futhermore other services like civil engineering (construction of site and roads) and transportation and mud monitoring are similarly performed by the Contractor.

Based on field experience this paper will in the first instance discuss why such globalisation is necessary by technical requirements, then will present the advantages and constraints for the contractor and the increase of risks. The analysis of cost reduction deriving from this scheme will be presented and discussed as well as the benefits for the Operator and the Contractor. The evolution in respect of competence and management of the services for the Drilling Contractor will also be outlined.
Gas Migration: Fast, Slow or Stopped
Authors: Johnson Ashley , Rezmer-Cooper Ian , Bailey Tim , McCann Dominic
Published: December 2007

We review the conflicting literature on gas migration velocities during kicks. We consider the laboratory and large scale test data that shows that for any local gas void fraction of more than 10%, the influx migrates at approximately 100 ft/min. We also review the evidence from field experience that shows that gas can migrate much more slowly (the typical rule of thumb suggests that gas bubbles move at approximately 15 ft/min) and in some cases remain stationary.

We show that the yield stress of the drilling mud which holds cuttings in suspension whilst making connections, can also hold gas bubbles in suspension, and report an experimental study of these gas suspension effects. Significant volumes of gas can be held in suspension during a gas kick, this trapped gas remaining stationary until the mud is circulated out of the well.

We consider the implications of this for well control operations, and present field data where gas was injected into a marine riser, it dispersed and remained stationary until circulated out. We show that a single bubble migration model, which neglects gas suspension, predicts that as the gas rises and expands it unloads the riser. By simulating the gas suspension characteristics we model the field data.

We conclude that gas in moderate concentrations (more than 10%) migrates quickly, typically at 100 ft/min. This migrating influx leaves a trail of suspended gas in the mud that remains stationary. For small kicks in deep wells the entire influx can be distributed, at a low concentration, and remain in suspension until the gas-cut mud is circulated out of the well.
An Advanced Kick Simulator for High Angle and Horizontal Wells-Part I
Authors: Vefring E. H. , Wang Zhihua , Gaard Sigurd , Bach G. F.
Published: December 2007

This paper presents an advanced kick simulation model for high angle and horizontal wells. The model is based on an existing kick simulator for vertical and inclined wells developed over several years. This paper describes the extension of the simulator to handle kicks in high angle and horizontal wells. The new important developments include: 1) consideration of the long horizontal section exposed to the reservoir and therefore the coupling of fluid flow in the horizontal section with the influx from the formation; 2) new models for the gas slip and rise velocities in near horizontal wells, and 3) various models for different gas removal mechanisms. Typical simulation results are also presented to highlight the potential problems when circulating out kicks.

The new models for the gas slip velocities in near horizontal wells are based on the experimental and theoretical work. The gas removal mechanisms include the transportation of gas as large bubbles, in the form of entrained gas, and through gas dissolution in the drilling fluid. Type of gas removal mechanism depends upon circulation rate and mud properties. Models for these mechanisms have been developed based on theory and results from laboratory experiments.
Woodie: A Tool to Support Overpressure Detection
Authors: Cheli Elena , Brancato Calogero , Vagnoux J. P.
Published: December 2007

The quality of a drilling program, that is its reliability and applicability, is essential for the achievement of safety, operational and economical drilling objectives. The most relevant influence, with respect to these objectives, is exerted by a correct evaluation of a formation's pressure regime.

The operative effectiveness of the several methods developed by the petroleum industry for overpressure detection depends highly on the quality and quantity of data that can be accessed and interpreted by experienced personnel.

This paper deals with the description of WOODIE (Well Online Overpressure Detection Interactive Environment) [1], a computerised knowledge based system designed with the aim of supporting the complex task of overpressure detection.

A user-friendly interface allows drilling technicians, not necessarily specialised in overpressure evaluation, to browse and investigate in depth a large amount of information as well as to evaluate results processed by the system.

The WOODIE application is part of ADIS – AGIP's Advanced Drilling Information System [2] – aimed at obtaining better rig-site support, improving the management and reducing cost and risk.
Re-Defining the Exploration Drilling Technique in the North Sea: The First Step
Authors: Ehret J. R. , Carstens Eilif , Johnston Colin , Vagen Per
Published: December 2007

Slim-hole exploration drilling and coring in the North Sea is limited. It is a concept that requires further evaluation. The full economic benefit of slim-hole drilling can be realised with a total slim-hole package, e.g., with sized down subsea BOPs, riser and floating vessel. Also, slim-hole drilling using coiled tubing is a technology requiring further testing.

Prior to expending considerable capital on a fit-for purpose slim-hole floating vessel, the slim-hole drilling technology must be fully proved.

The first step in exploiting this concept is to prove that high quality cores and electric logs can be obtained using slim-hole technology on a floating vessel.

This paper describes a test programme to determine the viability of drilling and coring a slim-hole with coiled tubing and drill pipe from a semi-submersible in the North Sea.
Re-Entry of Existing Wells for Drilling and Completion of Multi-Lateral Wells
Authors: Jones R. C.
Published: December 2007

The interest in the re-entry of existing wells for the purpose of drilling multi-laterals is growing. This paper discusses the options available for drilling multi-laterals. The paper also discusses where completion technology for multi-lateral wells is heading in the future.
A Dynamic Model for Underbalanced Drilling With Coiled Tubing
Authors: Rommetveit Rolv , Vefring E. H. , Wang Zhihua , RF-Rogaland Research , Bieseman Taco , Faure A. M.
Published: December 2007

A model for underbalanced drilling with coiled tubing has been developed which takes into account all important factors contributing to the process. This model is a unique tool to plan and execute underbalanced or near balance drilling operations. It is a transient, one-dimensional multi-phase flow model with the following components: Lift gas system model, multiphase hydraulics model, reservoir-wellbore interaction model, drilling model, models for multiphase fluids (lift gas, produced gas, mud, foam, produced gas, oil, water and cuttings). Various alternative geometries for gas injection are modelled as well as all important operations during underbalanced drilling with coiled tubing.

The model as well as some simulation results from its use are presented in this paper.
Behavior Based Approach to Creating a Strong Safety Culture
Authors: Hubler W. G.
Published: December 2007

The attainment of world class safety by any organization is determined by its ability to eliminate unsafe work practices by its employees and contractors and gain the active involvement of its work force to prevent injuries. This paper begins by outlining foundation concepts of behavior based safety management (Part I). It then describes a behavior based safety process tailored to drilling operations which produces improved statistical and financial results (Part II). Implementation of the process produces greater organizational development and builds the foundation for a deep-rooted safety culture.
A Novel Approach to Initiating Multi-Lateral Horizontal Wells
Authors: Konopczynski M. R. , Hughes John , Best J. E.
Published: December 2007

This paper describes the development and testing of a novel method to initiate multilateral horizontal wells that allows selective re-entry into any of the branches. The benefits of multilateral horizontal wells are reviewed, current methods, their benefits and drawbacks are described, and the criteria for designing a new method and tools for initiating multilateral horizontal wells are listed.

Previous systems designed to initiate multilateral wellbores with selective re-entry have been quite complicated and therefore, costly. This paper describes a system for orienting and cementing pre-cut window sections in a typical production casing string, which provides a positive method for positioning and orienting a retrievable whipstock. This design does not have the capability to conveniently tie back or cement liners in individual lateral wellbores, but it is well suited for application in medium radius and short radius horizontal multilateral wells where bore-hole stability or zonal isolation are not issues.
Dynamics Modeling of PDC Bits
Authors: Hanson J. M. , Hansen W. R.
Published: December 2007

A numerical bit dynamics model has been developed for the purpose of predicting PDC drill bit performance under conditions of a full-scale drilling simulator test. The model accounts for the interaction of the PDC cutters with the bottom hole and side wall rock surface and bit impact energy loss and friction between the bit gage and hole wall. It also accounts for the induced vibration of the main mechanical components of the full-scale drilling simulator. The model has been validated by comparing predicted bit performance with full scale drilling experiments.

Twenty bit designs (15 anti-whirl and five "conventional") ranging from 5 7/8" to 17 1/2" have been used in this validation. The numerical simulator correctly predicts for 18 out of the 20 bits whether or not the bit whirls and the rate of penetration at which the bit stops vibrating in the hole.

This paper discusses the development, numerical implementation, and experimental validation of this PDC bit numerical drilling dynamics simulator.
Environmental Safe Water-Based Drilling Fluid to Replace Oil-Based Muds for Shale Stabilization
Authors: Headley J. A. , Walker T. O. , Jenkins R. W.
Published: December 2007

A recently developed, environmentally safe, water-based drilling fluid has been given its first field trials. The successful field tests have shown that the fluid is indeed very shale stabilizing, has the ability to solve some mud related drilling problems, is easy to formulate and maintain, and is non-hazardous and environmentally safe. These results have corroborated the laboratory testing which had shown that the fluid stabilizes shales by the same mechanism as does oil-based fnuds1.

The drilling fluid, which is based on methylglucoside (MEG), thus has the potential to replace oil-based drilling fluids in many operational areas. The use of this drilling fluid could reduce or eliminate costly disposal of oil contaminated drilled cuttings, minimize health and safety concerns, and minimize environmental effects.
A New Generation of Shale Inhibitors for Water-Based Muds
Authors: Stamatakis Emanuel , Thaemlitz C. J. , Coffin George , Reid William
Published: December 2007

New applications of structurally unique organic cationic materials fOCMs) have provided a highly efficient and economical technology for inhibiting the swelling and yielding of hydratable shales. These OCMs are compatible with all common drilling fluid additives, thermally stable, and environmentally acceptable. The laboratory determined properties and field tests of the OCMs are discussed in detail.
1993 U.S. Beaufort Sea Offshore Exploratory Drilling Achievements: A Case History
Authors: McKay T. W. , Johnson F. C. , Pidcock G. A. , Johnson L. A.
Published: December 2007

This technical paper provides a case history of the exploratory drilling operations undertaken in the Beaufort Sea during the 1993 drilling season. Through a combination of extensive planning, operational teamwork, advanced technology and favorable ice conditions, a total of three wells were completed in one season. The successful completion of this many exploration wells during one season was an historic achievement for both the U.S. and Canadian Beaufort Sea operating arenas.

The operation involved the early mobilization of the drilling vessel "Kulluk" along with associated ice breaking support vessels from a stack location in remote northern Canada, to the drilling locations in Alaska's Camden Bay, offshore from the Arctic National Wildlife Refuge. Logistical support for the operation was maintained primarily from Prudhoe Bay, and the operation was managed from ARCO Alaska's offices in Anchorage.

The 1993 operation was a follow up to a program the previous year, in which a hydrocarbon discovery was made at ARCO's "Kuvlum" location. The paper will document the 1993 operations in which three wells were drilled, and contrast this with the 1992 season in which one well was drilled. The paper will show how advance planning, favorable environmental conditions, and management commitment enabled ARCO to achieve its aggressive exploration drilling goals for this project.