bluuebunny/crossref_metadata_2025_split huggingface dataset:
Far-Field Hydraulic Fracture Geometry: A Changing Paradigm
Authors: Mahrer K. D. , Aud W. W. , Hansen J. T. 
Published: December 2007

Abstract
The common viewpoint or paradigm of the far-field hydraulic fracture geometry is changing. Data sets compiled over the last decade are incompatible with the conventional picture of a single, bi-wing, planar hydraulic fracture. These data sets include (1) recovered cores, (2) minebacks, (3) microseismicity, (4) overcores and borehole video, (5) treatment pressure response, and (6) surface tilts, in conjunction with advancements in laboratory simulations, studies of natural hydraulic fracture analogues, and improvements in numerical simulations. The single, planar, far-field fracture paradigm finds its roots and development in early theory and simplified laboratory studies that were predisposed to single, planar fracture geometry. Replacing the old paradigm is a new perspective that includes a strong potential for creating multiple, far-field fractures. The implications of multiple, far-field fracturing has resulted in adjustments to completion and stimulation strategies to address and affect the overall fracture geometry.
Minimum Cost Casing Design
Authors: Halal A. S. , Warling D. J. , Wagner R. R. 
Published: December 2007

Abstract
The casing program of most wells represents a significant portion of the total well cost, approximately between 15 and 35%. Hence, any reduction in tubular cost can generate considerable cost savings. This paper presents a novel and efficient minimum-cost casing design technique which employs a recursive branch-and-bound search method together with a streamlined load generator for complex loading conditions. The three-stage technique utilizes effective bounding methods which substantially reduce the search space and speed up convergence. To illustrate the efficiency of the technique in practical applications, a parametric study is presented for an example well which models a geopressured well in the Gulf of Mexico. The results show that a minimum-cost design for most casing strings in this example can be achieved in less than 2 seconds using a personal computer with a 75 MHz Intel 486DX processor. One key outcome of this research is a Microsoft Windows-based implementation of this technique which offers the casing designer a powerful and flexible tool to quickly assess the trade-off between the potential cost savings from increasing the design complexity and the accompanying increased risk.
Non-Stationary Stochastic Modeling Techniques for Reservoir Description: An Application from the Alaskan North Slope
Authors: Thadani S.C. , Novak M. 
Published: December 2007

Abstract
This paper describes non-stationary (multipopulation) Stochastic Modeling techniques that were developed and used to construct regional average velocity and depth surfaces to the top of a key geological marker overlying several major reservoirs from the Alaskan North Slope. The techniques combine average velocities derived from well data with stacking velocities derived from velocity analyses ("VELANS") of 2D and 3D seismic data. In these techniques, the average velocity field is modeled as a mixture of statistically homogeneous (2nd order stationary) populations that are predominantly consistent with variations in the thickness of a near-surface permafrost layer, and other known geological factors. A multi-population Soft Inversion algorithm is used to infer bounds on average velocities at selected locations (away from existing wells) by statistically calibrating the stacking velocities to the average velocities. Stochastic images of the average velocity field are generated using a new (mixture) Stochastic Imaging algorithm - these images are conditioned to the wells, the Soft Inversion velocity bounds, and to the multi-population spatial correlation model of the data. Finally, seismic travel time measurements are used to convert the average velocity images to depth. The results have been "blind" tested at 30 wells - the results indicate significant improvements in average velocity (and depth) estimation accuracy as compared to conventional interpolation techniques.

Introduction
Seismic depth conversion may be defined as the process wherein seismic travel time measurements to selected geological horizons are converted (or "migrated") to depth using an inferred spatial velocity field. One class of Stochastic Modeling approaches to seismic depth conversion, typically images depth (measured at the wells) and seismic travel time (measured at and away from the wells) as co-variables, using methods such as external drift and Cokriging/Cosimulation. Such methods typically require significant well control for inference of the underlying spatial auto and cross correlation models for the co-variables; the spatial velocity distribution is modeled only implicitly, and local precision of the estimated depth surfaces relies primarily on the conditioning provided by the well control. In many applications, stacking velocities derived from velocity analyses ("VELANS") of 2D and 3D seismic data are readily available. These stacking velocities often correlate with average velocities, and constitute an important (densely sampled) source of "soft" conditioning information away from the wells, which can augment the available well and seismic travel time information in constructing the desired depth surfaces. This has lead to the development of another class of Stochastic Modeling approaches for seismic depth conversion, wherein the spatial average velocity distribution is explicitly modeled and imaged.
P. 67
Improving Management of Oil and Gas Assets Through Derivatives
Authors: Stibolt Robert D. 
Published: December 2007

Abstract
As markets for futures, swaps, and options have grown and matured in the oil and gas industry, the question of how companies should make use of such financial derivatives naturally arises. The simplest models of risk versus return in modern finance theory are based on a world in which the costs of external and internal financing are the same and all risk is either systematic or can be diversified by shareholders. In this simplified world, derivatives must be viewed as purely speculative instruments that can add nothing to shareholder value. However, in the real world of financial distress, imperfect information, and misaligned management/shareholder risk attitudes the use of these instruments can add significant value. This paper explores the sources of this potential for value creation, including a look at improving organizational alignment, information consistency, capital structure, and management of real assets.

A Strategic Decision Perspective on Derivatives
Derivatives have been receiving a great deal of attention recently, both in the financial press and in political circles. This attention has resulted from a number of highly publicized financial catastrophes in which even relatively sophisticated companies have lost millions of dollars. It is understandable that enlightened executives would react to this series of financial catastrophes by avoiding any involvement with these sometimes complex financial instruments. This initial reaction is quite reasonable in that outright speculation in markets not directly connected with a firm's core strategies cannot be justified from a shareholder perspective.
However, further investigation of the problem reveals dimensions that might cause these executives to reconsider their initial reactions. In most cases, derivatives cannot be avoided because they are already embedded in the day to day business of managing a firm's real assets. Examples that cannot be ignored include the valuable mid-month natural gas swing options that producers often give away at no charge to marketers or customers and the option value of undeveloped real assets.
Even as it becomes evident that derivatives cannot be avoided, critical management questions must still be addressed:–Are derivatives just a zero-sum game?–Are derivatives dangerous?
While the first question involves a fuller discussion that comes later, the second question can be addressed immediately. Derivative transactions fall into three distinct categories, only one of which appears to consistently lead to financial trouble. Perhaps derivatives can be used profitably and trouble avoided by better understanding these categories and the types of transactions associated with them.
Separator Design and Operation: Tools for Transferring "Best Practice"
Authors: Lawson P. N. E. , Little L. M. 
Published: December 2007

Abstract
Maintaining flexibility in the design of separation systems is a key consideration in coping with the uncertainty in fluid properties, reservoir performance and production profiles. There is an increasing need to improve our understanding of how different separation schemes perform over a range of operating conditions. This paper outlines two recent approaches that BP Exploration have been developing in the area of separator design and operation. The first addresses the need to understand the ‘operating envelope’ of a separator. In contrast to the conventional method of sizing a separator for a number of design cases, the operating range of a separator can be presented as an operating envelope. This concept will be demonstrated as a potential method for taking account of reservoir uncertainty and as a means of identifying operating flexibility. A parallel development is the construction of a database which captures information on BP Exploration’s Production Separators. In addition to design and current operating data, ‘case histories’, incorporating details on retrofits and design changes, are being collected as a means of transferring ‘Best Practice’ in separator design and operation across the BP Exploration operating Assets world-wide.
The Displacement of Oil from Porous Media by Micellar Solutions
Authors: Sharifi Fereidoon , Osoba J.S. 
Published: December 2007

Abstract
The increasing need for oil in today's world has focused attention on increasing the efficiency of displacing oil from reservoir rock. Recently the oil industry has become interested in oil recovery using miscible fluids.
The purpose of this investigation was to study the effectiveness of micellar solutions in recovery of oil from porous media. The models used were linear sandstone cores, a linear model packed with various sands and a five-spot model packed with various sands and a five-spot model packed with sand. Models saturated with water packed with sand. Models saturated with water and different viscosity crude oil were subjected to micellar solution injection. Experiments were performed for both secondary and tertiary recovery performed for both secondary and tertiary recovery conditions.
One hundred percent oil displacement by micellar solution injection was observed for all but one system. This exception occurred when a small slug of micellar solution was injected into a sandstone core and displaced with a Dow pusher. A small amount of oil was observed at pusher. A small amount of oil was observed at the outflow end of the core when small samples were cut from the core and examined.
The laboratory experiments indicated that micellar solutions are an effective means of oil displacement. These solutions are effective because of their miscibility with the oil, controllable mobility, their stability in the presence of reservoir crude oil, water and rock, presence of reservoir crude oil, water and rock, and finally their incomplete removal of contacted water.

Introduction
Complete recovery of crude oil from an oil-bearing formation is not possible if the crude oil is displaced by an immiscible fluid such as water. Capillary forces retain part of the oil in the pores even though many pore volumes of the immiscible displacing fluid are passed through the system. To recover the oil trapped in the pores, the capillary forces must be zero. There are no capillary forces if the displacing fluid is miscible with the crude oil.
For the past decade the oil industry has been interested in displacing oil from reservoir rock using miscible fluids. The miscible process has been used in fields when technically process has been used in fields when technically and economically feasible.
A few years ago a micellar solution was developed that was miscible with oil and water. In 1967, this solution was described by Marathon Oil Co. To displace oil from reservoir rock, a micellar solution and then water were injected into a formation. The method was reported to result in a 100 percent displacement of oil. Micellar solutions used in this process consisted basically of three components: hydrocarbon, surfactant and water. In addition, a small amount of electrolyte and cosurfactants (e.g., alcohol) were sometimes used.
Laboratory and Field Evaluation of the Role of Drill Solids in Formation Damage and Reduced Horizontal Well Productivity
Authors: Burnett D.B. , Hodge R.M. 
Published: December 2007

Abstract
This paper examines the role of drill solids in causing formation and completion damage in horizontal openhole completions. Drill solids are routinely kept to a minimum in drilling fluids, mainly to improve drilling properties. However, these drill solids, even at low concentrations, represent a significant source of insoluble particulates that become incorporated in the drill-in fluid filtercake. Not only is the potential for formation damage greater, but these filtercakes laden with insoluble drill solids can be deposited on screens resulting in reduced productivity through screen plugging.
The objective of this paper is to illustrate the effect of drill solids contained in drill-in fluids on formation damage and well screen plugging and to emphasize the importance of minimizing solids, not only to maintain the desired drill fluid rheology, but also to effect better filtercake cleanup. New laboratory test methods have been used to study formation damage in a 2-foot long horizontal wellbore model incorporating dynamic filtercake deposition on natural and synthetic core material. The model measures formation damage in radial flow. Formation damage tests with drill solids were performed for both water based and synthetic based drill-in fluids. Testing was also performed to simulate prepacked screen damage using a variety of commercially available drill-in fluids and common resin-coated gravel sizes. Results of these tests with laboratory-prepared fluids have been compared against the performance of field fluids and will eventually be correlated with field well performance.

Background
The use of horizontal wells to maximize recovery of oil and gas has become commonplace. However, operators frequently find horizontal wells do not provide the expected productivity after completion. While cased hole completions exploit perforation techniques to bypass the zone of formation damage caused by drilling, the openhole completions commonly used in horizontal wells do not provide a means of bypassing this damage.
Previous work has discussed formation damage caused by drill-in fluids. Often, these studies have concluded that formation damage is caused by solids invasion into the rock or from damage caused by incompatible fluid filtrate. Some investigators have presented evidence that DIF filtercakes did not penetrate into rock matrices. Fraser's study showed ESEM photo images of different types of DIF filtercakes tightly compacted onto formation rock surfaces. He found very little filtercake invasion in the rock matrix. Burnham and Browne have discussed the concept of "lift off" pressure that can be used characterize the behavior of DIF filtercake on formation rock. Their studies suggest that "formation damage" can be caused by too "tight" a filtercake on rock surface.
P. 749
Gel Formation and Thermal Stability of Gels Made From Novel Water-Soluble Polymers for Enhanced Oil Recovery Applications
Authors: Eriksen O.I. , Daasvatn K. , Vigerust B. , Braen T. , Olafsen K. , Ahmed I. , Moradi-Araghi A. , Hamouda A.A. 
Published: December 2007

Abstract
This paper will describe the details of experimental conditions and will present gelling systems for potential water shut-off and profile modification applications under hostile environmental conditions.
A range of copolymers of acrylamide with an experimental comonomer has been prepared to evaluate gelation of the polymers and thermal stability of the gels under hostile environmental conditions. The experimental monomer was obtained using commercially available chemicals by a simple synthetic route. Gels of high thermal stability have been revealed with polymer concentrations below 1 weight %. The polymer was dissolved with crosslinker in synthetic North Sea water (SNSW). The crosslinking systems include phenol with formaldehyde (HCHO) or hexamethylenetetramine (HMTA). The results were evaluated after aging for 30 days at 120 C. The thermal stability of the gels depends not only on chemical composition of the polymers and the crosslinker, but also polymer and crosslinker concentrations used for gelation. For one of the polymers, viscometric study of gel formation was carried out in addition to the studies of gel stability.
In this work, statistically designed experiments were used to determine which variables had the most significant effect on thermal stability of the gels so that the optimum gelling composition could be determined. These variables include polymer composition, polymer solution viscosity and concentration as well as the crosslinker concentration. A ranking of the gels was made according to an overall gel quality parameter based on gel strength and degree of syneresis. The results illustrate the advantage of using experimental design during testing and evaluation of synthetic polymers.

Introduction
The amount of residual oil can be up to 40–70% in oil producing fields. To increase the production from off-shore fields, sea water is injected into the formations. The sea water follows the high permeability zones in the reservoir, and after some time, a water break-through may occur, and the result is a higher water to oil ratio. In such a case, it is desirable to plug high permeability zones in the formation by using water soluble polymers. Generally, a solution of the polymer along with an appropriate crosslinking system, is injected into the formation. With appropriate placement techniques the polymer solution can permeate into and form gel in the regions having the highest permeability. However, for near-wellbore applications on deep off-shore fields, the salinity and the temperature limit the use of many currently available water soluble polymers for enhanced oil recovery applications in these regions.
Polyacrylamides with phenol/HCHO as crosslinking system have been used successfully for plugging or permeability reduction, but the thermal stability of gels from polyacrylamide is very poor above 90 C in sea water due to extensive syneresis.
Sweep Efficiency in a Two-Dimensional Miscible Slug Injection
Authors: Bieber M.T. 
Published: December 2007

Abstract
A series of laboratory experiments was conducted in which oil was displaced from a porous medium by a solvent slug driven by a porous medium by a solvent slug driven by a miscible fluid.
Two dimensional displacements experiments were carried out on a consolidated porous media representing one fourth of five spot. All fluids were miscible together. Among the variables investigated were slug size, viscosity ratio and sweep efficiency.
Such research with simple fluids was undertaken to provide basic information both for the laboratory study of more complex fluids in the same porous media and for the development of a numerical model capable to predict performance of miscible slug injection.

Introduction
As the amount of oil to be recovered is determined by the fraction of reservoir contacted by the flood the main purpose of all secondary recovery processes now under investigation is to improve the sweep efficiency of the injected fluid.
Sweep efficiency is largely determined by the fluid mobilities so the study of this last parameter is a step towards a better recovery. parameter is a step towards a better recovery. Several processes tend to improve mobility ratio between oil in place and driving fluid, they can act: on injected fluid viscosity,-on in place fluid viscosity, or: on permeability to injected fluid. In order to have a good displacement efficiency and a good sweep efficiency, all the different secondary processes use slug injection.
For miscible processes, a slug will be injected to reduce oil viscosity and mobility ratio between oil and driving fluid will be reduced.
Others recovery processes use non newtonian fluid injection, a slug of polymer solution or of foam will decrease the permeability of the reservoir to a displacing fluid and improve mobility ratio.
In order to investigate the simple physical phenomena related to flow of fluids with very phenomena related to flow of fluids with very different mobilities ratios, we conducted a laboratory research in a two dimensional porous media.
We studied the injection of slugs using simple miscible fluids.
The Theory And Practice Of Monitoring And Controlling Dumpfloods
Authors: Davies C.A. 
Published: December 2007

Abstract
The term dumpflooding usually refers to the technique of maintaining the pressure of an oil reservoir by allowing a high pressure potential water source zone to flow naturally into the oil zone. The reason for using this technique is primarily related to its cheapness both in initial capital expenditure and in the routine operating expenses. This technique becomes particularly important in isolated areas where particularly important in isolated areas where there is insufficient ground water.
There has been a problem in monitoring the rate at which the wells transfer water from a high pressure potential zone to a low pressure pressure potential zone to a low pressure potential zone. This is due to the fact that potential zone. This is due to the fact that there are two zones open to the well bore which cannot be readily monitored independently.
The theory of dumpflooding has been developed and due to the complexity of solving the resultant second order differential equations, a computer program has been written and presented to assist analysts in monitoring the dumping rates.
A technique has also been developed which permits monitoring of the actual fluid injection rate, within an acceptable accuracy, and also permits the determination of well bore properties of both the source zone and the injected zone from simple fluid levels and periodic fluid travel logs.

Introduction
The technique of injecting water into an oil producing reservoir for either pressure maintenance or secondary recovery is a well-established process in the worldwide oil producing industry.
The methods available for obtaining water for injection purposes are numerous and the economics associated with purposes are numerous and the economics associated with the injection project usually dictate which source should be used. The source of water used is dependent usually on the quality and quantity of water available. For instance, the sea or rivers may be used, when available, but treatment costs are often very high. Subterranean water is often of better quality but quantity and/or accessibility usually involve large capital expenditures for wells and pumps.
This paper deals with probably the cheapest and most effective method of injecting water into an oil reservoir, that is, dumpflooding.