bluuebunny/crossref_metadata_2025_split huggingface dataset:
Waterflood Improvement in the Permian Basin: Impact of In-Situ-Stress Evaluations
Authors: Nolen-Hoeksema R. C. , Avasthi J. M. , Pape W. C. , Rabaa A. W. M. El 
Published: December 2007

SummaryWe evaluated in-situ-stress magnitudes and directions to support waterflood improvement programs in McElroy field and North Westbrook Unit. In-situ-stress and hydraulic-fracture directions coincided with directional floodwater effects. This information contributed to successful waterflood realignment programs.
Economic Assessment of Applying Advances in Fracturing Technology
Authors: Voneiff G.W. , Holditch S.A. 
Published: December 2007

Distinguished Author Series articles are general, descriptive representations that summarize the state of the art in an area of technology by describing recent developments for readers who are not specialists in the topics discussed. Written by individuals recognized as experts in the area, these articles provide key references to more definitive work and present specific details only to illustrate the technology. Purpose: to inform the general readership of recent advances in various areas of petroleum engineering.

Summary
To obtain optimal results from the fracturing process, several new fracturing technologies can be applied to prevent inappropriate stimulation designs and catastrophic fracture-fluid problems. Despite industry awareness of these technologies, they are not applied routinely because of their added expense. In addition, the benefits are difficult to quantify and often are not clearly understood. In this paper, we present an economic assessment of fracture-treatment quality control, in-situ stress profiling, and 3Dfracture-propagation models that indicates that these technologies increase gas reserves by 10% to 20% for a 5% to 10% increase in the well cost. The application of these technologies is profitable when the formation gas permeability is between 0.001 and 0.3 md.

Introduction
In recent years, hydraulic fracturing research performed by the Gas Research Inst. (GRI) and other industry organizations has generated a wealth of new technology, including the GRI Mobile Testing and Control Facility, the GRI Rheology Unit, FRACPRO (a 3D fracture design program), the Treatment Analysis Unit, procedures for developing in-situ stress profiles, and microseismic processing techniques to determine fracture height and azimuth. Also, field experiments performed on Cooperative Research and Staged Field Experiment (SFE) wells have provided comprehensive data sets for developing and testing new ideas.
Our field research shows that the in-situ stress contrasts between rock layers and fracture-fluid viscosity are often quite different from the values assumed or estimated by the design engineer. Errors in assumed values of the in-situ stress contrast lead to inaccurate reservoir descriptions and inappropriate stimulation designs. Fracture-fluid problems compound the situation through poor proppant transport or fracture plugging with unbrokengel.
Screening of Crude Oils for Asphalt Precipitation: Theory, Practice, and the Selection of Inhibitors
Authors: de Boer R. B. , Leerlooyer Klaas , Eigner M. R. P. , van Bergen A. R. D. 
Published: December 2007

Summary
This paper describes a simple method to screen crude oils for their tendency to precipitate asphalt, which may cause problems during production. The method is based on a thermodynamic model of asphalt solubility, derived earlier by Flory and Huggins. The most important parameters in this model are the Hildebrand solubility parameters for oil and asphaltene, and their molar volumes. The oil parameters can all be correlated with the in-situ density of the crude.
The relative change in asphalt solubility in the crude per unit pressure drop is shown to be highest for light crudes that are undersatu-rated with gas, which usually contain only a small amount of asphaltenes. Hence, the chance that asphalt will precipitate will be greatest for these light crudes. For pressures below the bubblepoint, depres-surising of the crude will cause a rapid increase in asphalt solubility, due to changes in liquid composition.
It is shown that heavy crudes usually will give fewer problems with asphalt precipitation, despite their higher asphaltene content, certainly if the reservoir pressure is close to bubblepoint pressure.
Consequently, the tendency for asphalt precipitation is mainly determined by three parameters: the extent to which the crude is under-saturated with gas, the density of the crude at reservoir conditions, and its saturation with asphalt at downhole conditions.
Apart from the simple screening method, more elaborate methods are described to assess the potential for asphalt precipitation more accurately; asphaltene analysis on produced reservoir fluid and tank oil; n-heptane titration of the tank oil; visual inspection of a bottom-hole sample in a high-pressure cell during pressure reduction; and dynamic flow tests on tank oil after η-heptane addition.
An ultrasonic back scattering technique is described for monitoring the influence of different asphalt precipitation inhibitors. Using above techniques asphalt precipitation inhibitors have been identified that can be applied in the field.
Propped Fracturing as a Tool for Sand Control and Reservoir Management
Authors: Bale Arthur , Owren Kjell , Smith Michael B. 
Published: December 2007

Summary
Hydraulic fracturing has historically been a prime engineering tool for improving well producing rates, either by circumventing near-well damage or by stimulating well performance. This paper describes a somewhat new fracturing application where increasing rate was not the primary goal. In this case, the goal for fracturing was modification of the flow profile to allow a more uniform vertical production profile and thereby maximize sand-free rates over the perforated section of the reservoir. In best cases for such applications, this technique allows perforating of "weak" rock to be skipped, reduces risks of sand production, and allows greater wellbore drawdown through perforated intervals in more competent reservoir rock. This allows better long-term productivity and improved recovery and total project economics. In short, it was hoped that propped fractures would improve reservoir management of the Etive/ Rannoch formations in the Gullfaks field.
Reservoir Compartmentalization Assessed With Fluid Compositional Data
Authors: Smalley P. Craig , England William A. 
Published: December 2007

Summary
Fluid composition is a valuable addition to the battery of "static" data available during reservoir appraisal that can be used to predict the dynamic behavior of the reservoir later in field life. This is because fluid data are not truly static; natural fluid mixing is a dynamic process that occurs over a long (geologic) time scale. Oil compositional differences, especially those that parallel changes in density, should be mixed rapidly by convection; their preservation indicates barriers to fluid flow. Water variations, now measurable on conventional core samples by use of residual salt analysis (RSA), help identify barriers to vertical fluid flow in oil and water legs.
Acoustic Measurements on Cores as a Tool for Calibration and Quantitative Interpretation of Sonic Logs
Authors: Marion Dominique P. , Pellerin François M. 
Published: December 2007

Summary
An upscaling technique is developed for acoustic measurements on cores to present core data as a log for improved comparison between laboratory and sonic measurements. The method combines a laboratory study performed over a wide range of frequency, pressure, and saturation conditions on a series of core samples and construction of a synthetic log that includes upscaling of core measurements at the sonic wavelength and simulation of the log response for various spacing of the tool receivers. A comparison of core and sonic measurements in a carbonate reservoir illustrates the benefit of comparing core and log measurements at the same scale. Agreement between punctual core and sonic measurements is within ± 10%, whereas core data upscaled at the level of sonic measurements are within ± 2% of the sonic. In addition, results of quantitative interpretation of the sonic data in terms of porosity also confirm that sonic measurements can provide accurate estimates of petrophysical properties when properly calibrated with core data.
Legal Problems in Undersea Mineral Development
Authors: Ely Northcutt 
Published: December 2007

As the depth of water in which we can drill increases, the problem of jurisdiction grows more and more complex. What was once the magic number200 meters - has become meaningless. The question is, how do the coastal nations arrive at a fair definition of rights in exploiting the undersea mineral resources of the earth?

Introduction
The subject we shall consider here concerns two questions:To what seaward boundary should the U. S. assert, consistently with this country's international commitments, exclusive American jurisdiction over submarine mineral development?Beyond the limits of national jurisdiction, what international arrangements to govern mineral development are in the best interests of the U. S., and, pending the negotiation of such arrangements, what law governs? In considering these questions we must be aware of other national interests-national defense, navigation, fisheries, protection against pollution, to name some of them.
A nation's jurisdiction can be likened to a bundle of sticks. Landward of a base line, which is the low-water line or straight line joining points along an irregular coastline, the coastal nation has exactly the power that it has on land, a complete bundle of power that it has on land, a complete bundle of jurisdictional sticks. Outward from the base line to the limit of territorial waters, say 3 miles, as our Government insists, or 6 or 12 or more, as other nations claim (there being no formal international agreement on this), the coastal nation has most of the sovereign powers that it has on land. These extend to all four powers that it has on land. These extend to all four elements of the marine environment - the sea bed, the overlying water column, the water surface, and the superjacent air space. This near-plenary control over territorial waters is subject, under international law, to an easement in favor of innocent passage of merchant ships, and warships in peacetime, subject to certain restrictions. Beyond territorial waters, some sticks begin to fall out of the bundle of sovereign powers. Coastal nations, under international law, have some powers beyond the belt of the territorial sea, but these are restricted, extra-territorial powers.* The Convention on the Territorial Sea and the Contiguous Zone provides (Art. 24) that a contiguous zone may be provides (Art. 24) that a contiguous zone may be established to encompass a belt 12 miles wide measured from the same base line from which the territorial sea is measured. In this contiguous zone, the coastal nation may, for example, exercise limited controls to prevent infringement of its customs, fiscal, prevent infringement of its customs, fiscal, immigration, or sanitary regulations "within its territory or the territorial sea". Beyond that, the surface of the ocean is part of the high seas over which the coastal nation has no more power than does any other nation of the world. The freedoms of the high seas include those of navigation, fishing, the laying of submarine cables and pipelines, and of overflight by aircraft.
JPT
P. 237
Snap-Off of Oil Droplets in Water-Wet Pores
Authors: Roof J.G. 
Published: December 2007

Abstract
When oil emerges from a water-wet constriction into a water-filled pore, the interfacial forces are such that a leading portion of the oil may separate into a droplet (snap off). Theory indicates that for a given shape of constriction, there is a minimum size to the protruding portion of the oil that permits snap-off. If the oil/solid contact angle is zero and if the constriction has the shape of the throat of a tore (a doughnut hole), the oil must protrude for a distance of at least seven times the throat radius before snap-off can occur. Experiments were performed in approximately toric constrictions constructed of glass. Liquids used were a dyed mineral oil and a water-ethanol mixture adjusted to the same density as the mineral oil to avoid gravitational effects. Within the limitations imposed by visual distortions through the glass and the liquids, the observations appear to be in accord with the theoretical predictions.

Introduction
Production of oil from a reservoir involves flow of oil through a porous medium that also contains water. Because of the small size of the pores in the reservoir rock or sand capillary forces at the oil-water interface are of considerable importance in determining the nature of the flow through the pores. This report deals with one aspect of such pores. This report deals with one aspect of such How, determining the conditions that must be met in order that the oil emerging from a water-wet constriction will separate (snap off or pinch off) into a droplet in the larger parts of the channel. By applying the fundamental equation of capillarity to oil flowing through certain geometrically describable water-wet constrictions we can calculate the minimum size of the protruding body of oil that will permit snap-off of the oil to give a separate droplet. The theoretical treatment can be checked, at least semiquantitatively, by observations on dyed mineral oil flowing through glass pores previously filled with a water-alcohol mixture. This mixture should be adjusted to give be same density as that of the mineral oil in order to eliminate gravitational effects, which can be large relative to capillary effects in constrictions having an internal diameter of about 2 mm.
Case Study of a Horizontal Well in a Layered Rotliegendes Gas Field
Authors: Catterall S. J. A , Yaliz Ayk 
Published: December 2007

Summary
A horizontal well was drilled in the Ravenspum North field to drain a thin gas column above the aquifer. The field has a significant variation in reservoir quality, with most of the wells requiring stimulation by hydraulic fracturing. The reservoir is formed from a stacked sequence of aeolian dune and fluvial sandstones with a wide permeability range. The horizontal well was chosen as an alternative to stimulation by hydraulic fracturing to avoid water production from the aquifer. The well was successful, flowing at higher gas rates than expected with no water production. Production, core, and production logging data were used to demonstrate greater than expected lateral heterogeneity in the field. The horizontal well was found to be appropriate for the very specific conditions found in one part of the reservoir; however, the overall development strategy of using hydraulic fracture remains the preferred technique.
Construction and Validation of a Numerical Model of a Reservoir Consisting of Meandering Channels
Authors: van Vark W. , Paardekam A. H. M. , Brlnt J. F. , van Lieshout J. B. , George P. M. 
Published: December 2007

Summary
This paper discusses the modeling of a fluvial reservoir system. Construction of a detailed reservoir model was followed by a coarser numerical simulation model. During the history matching of the latter, we found that fluid transmissibilities had to be reduced significantly to reproduce the observed pressure differentials. Fault-related features are thought to be the reason that the sand continuity is so much lower than that predicted with sedimentological considerations only.
Development Planning in a Complex Reservoir: Magnus Field UKCS Lower Kimmeridge Clay Formation
Authors: Leonard A. J. , Duncan A. E. , Johnson D. A. , Murray R. B. 
Published: December 2007

Summary
This paper addresses the problem of how the static geologic description of a complex, low net/gross reservoir can be combined with dynamic production data into full-field reservoir simulation for use in development planning. The discussion focuses on an integrated petroleum engineering study of the LKCF of the Magnus field in the U.K. sector of the North Sea.
The Offshore - An Engineering Challenge
Authors: Russell D.G. 
Published: December 2007

An Interview with D.G. Russell
Offshore petroleum exploration and production on a worldwide basis continuesto expand at an extraordinary rate. Current worldwide production is about 6.5million B/D. The domestic scene, dampened somewhat by the Santa Barbara blowoutand the proposed new operating guidelines, shows signs of a quick return torecord activity. This special Offshore Issue of JPT includes six technicalarticles dealing with many phases of offshore operations. The paper by Lewis G. Weeks, beginning on Page 377, provides an overview of the current offshorepicture. The special JPT feature on the First Annual Offshore TechnologyConference begins on Page 429. SPE and AIME have played a major role indeveloping the Conference, which is cosponsored by nine of the world's leadingtechnical and scientific organizations. Included in the feature is the completetechnical program, with abstracts of some of the papers to be presented. TheSPE program was developed by the sub-committee headed by E. E. Sands, Jr., withUnion Oil Co. of California in Houston. Also included is a complete listing, beginning on Page 441, of the more than 330 technical exhibits that will be ondisplay at the Conference. A certain "mystery" still overshadows theoffshore. Questions such as "How can oil companies pay these high pricesfor offshore leases?" and "Where are the best undeveloped offshoreprospects?" are topics of considerable conversation. To secure an expert'sappraisal of these and other issues, JPT asked D. G. Russell, ProductionManager for the Southeastern Region of Shell Oil Co., to provide readers withhis views. Don is well known to JPT readers for his numerous publications, butis perhaps best known as coauthor of the Society's first monograph, PressureBuildup and Flow Tests in Wells.
Q. What do you think the short (9 months to a year) and long range effectsof the Santa Barbara crisis will be?
A. The over-all effects of the Santa Barbara crisis are difficult to assessat the present time. Certainly there are some short range effects alreadyapparent; for example, the suspension of operations in the Santa Barbarachannel and the postponement of Gulf of Mexico lease sales pending issuance ofnew drilling regulations. As to long range effects, the industry will simplyhave to wait to assess these until the Department of the Interior doespromulgate new drilling and production regulations for the offshoreenvironment.
Q. In your opinion, how do how do most oil company managements view offshoreresources today --- from art economical standpoint? from a technologicalstandpoint?
P. 369
Sand Transport and Deposition in Horizontal Multiphase Trunklines of Subsea Satellite Developments
Authors: Oudeman Pieter 
Published: December 2007

Summary
Gravel packing is unattractive as a way to protect against the effects of sand production in subsea wells because it involves additional completion costs, loss of productivity, and difficulties in subsequent recompletion/well servicing operations. On the other hand, omitting gravel packs means that subsea developments must be designed and operated so that they can tolerate sand production. An experimental study was carried out on sand transport and deposition in multiphase flow in modeled subsea flowlines to address the problem of sand collection in horizontal trunklines, which could lead to reduced line throughput, pigging problems, enhanced pipe-bottom erosion, or even blockage. This study led to the definition of a new model for sand transport in multiphase flow, which was used to establish the risk of sand deposition in trunklines connecting a subsea development to a nearby production platform.
A Study of Diversion Mechanisms by Reactive Water Diverting Agents
Authors: Thompson Karsten E. , Fogler H. Scott 
Published: December 2007

Summary
High water saturations in producing zones of petroleum formations cause problems during both acidizing and production. Water diverting agents are designed to prevent some of these problems by selectively plugging watered-out strata. Reactive water diverting agents are oil-based fluids that provide selective plugging because they react with aqueous formation fluids to form permeability reducing gels. This study used laboratory formulated diverting agents to elucidate the plugging mechanisms that result from in-situ interfacial reactions and gel placement. Our results show the physical characteristics of the media and gels necessary to bring about effective plugging and also the conditions that typically prevent selectivity. Additionally, a simple treatment method called the injection/back-flow procedure is introduced, which helps achieve a highly selective diversion treatment.
Parallel Linear Solvers for Reservoir Simulation: A Generic Approach for Existing and Emerging Computer Architectures
Authors: Bhogeswara Rao , Killough J. E. 
Published: December 2007

Summary
Recent architectural advances in the computer industry focus on the numerical solution of intensive flows, such as in oil reservoirs, on several processors simultaneously. Different computer architectures evolved from connection of these processors: shared memory with a few processors, distributed memory with up to a few hundred processors, and massively parallel with several thousand processors. Oil industry researchers are developing efficient techniques to improve hydrocarbon recovery in reservoirs by use of these computers. In this work, a generic approach is developed to solve the large system of sparse linear equations that arises in reservoir simulation. This approach uses a combination of domain decomposition and multigrid techniques that results in efficient and robust algorithms for sequential computers with one processor and for parallel computers with few to several tens of processors. The efficiency and robustness of these methods is comparable with widely used sequential solvers for problems of practical interest, which include implicit wells and faults. In parallel, these methods prove to be an order of magnitude faster on a 32-node iPSC/860 hypercube.
Hybrid-CVFE Method for Flexible-Grid Reservoir Simulation
Authors: Fung Larry S.-K. , Buchanan Lloyd , Sharma Ravi 
Published: December 2007

Summary
The flexible control-volume finite-element (CVFE) method is used to construct hybrid grids. The method involves use of a local cylindrical or elliptical grid to represent near-well flow accurately while honoring complex reservoir boundaries. The grid transition is smooth without any special discretization approximation, which eliminates the grid transition problem experienced with Cartesian local grid refinement and hybrid Cartesian gridding techniques.
Computer-Aided Real-Time Kick Analysis and Control
Authors: Jardine S. I. , White D. B. , Billingham John 
Published: December 2007

Summary
After early kick detection, the most important activities during well-control operations are correct identification of shut-in pressures, preparation of the kill plan, and careful monitoring of the kill operation. This paper describes the development and application of tech-niques to analyze and to extract the maximum amount of information from surface pressure measurements during shut-in.