bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Four Geostatistical Methods on Reservoir Description and Flow Mechanism
Authors: Ghori S. G. , Ouenes Ahmed , Pope G. A. , Sepehrnoori Kamy , Heller J. P. 
Published: December 2007

ABSTRACT
Determination of uncertainty in the description of reservoir properties is an important aspect of enhanced oil recovery projects. This paper compares four geostatistical techniques: simulated annealing method (SAM), source point method (SPM), fast fourier transform method (FFTM), and turning band method (TBM) in the generation of property distribution. The four methods are tested and compared by using an exhaustive minipermeameter permeability measured data set, and a tracer flow experiment on a rock sample. The methods are used in conditional simulation, assuming some known permeability data. The conditioned fields are then used in the simulation of miscible tracer flow through the sample rock and compared with the actual tracer concentration curves. The methods are compared on the basis of 1) spatial distribution and the variograms of the generated fields, 2) global error variance, 3) computational cost of generated fields, 4) effect on flow dynamics, and 5) tracer production curves.
Comparison of the four methods has shown that SAM produces the best fit of the experimental variograms without regard to the type of variogram (e.g., trend, etc.). The FFTM and TBM can utilize many types of theoretical variograms. All four methods can produce anisotropic fields. Although the spatial distribution obtained by SAM preserves the main features of the original data better than the other three methods, the global error variance in SAM is 25% more than in SPM, FFTM, and TBM. When considering computer run time and storage, SPM is the most efficient method, followed by TBM, FFTM, and finally SAM.
Finally, the conditioned permeability fields from these methods are used in the simulation of a miscible tracer flow through the rock sample and compared with the actual tracer output curves. It is observed that a very good fit of the simulated variogram to the experimental ones, will not necessarily give a good production history match. Rather, based upon similarity between the simulated and experimental tracer output concentration histories, the best results were obtained with SPM, then TBM, SAM, and finally FFTM.
Risk Assessment Approach to Offshore Safety: Part A—Norwegian Regulatory Philosophy
Authors: Olstad H. T. 
Published: December 2007

Abstract
The Norwegian Petroleum Directorate (NPD) has since the mid-seventies put increasing emphasis on the use of risk analysis techniques in the industry as one of the tools for enhancing safety in exploration and production activities offshore Norway. This approach now forms a cornerstone for updated offshore safety Regulations. In this paper, background internal control obligations of operators are reviewed along with safety supervisory activities of the NPD. The concepts of safety objectives and acceptance criteria as applied to offshore activities are presented. The subsequent use of risk analysis as a tool to highlight areas requiring further attention is discussed. Finally, the "performance-based" nature of the new detailed regulations in defining safety upgrade actions is also reviewed.
Foamed High-Concentration/High-Volume Mud Acid Stimulations at South Belridge Field
Authors: Dominquez F. E. , Lawson J. B. 
Published: December 2007

Abstract
This paper documents the design process and production response of a successful foamed, high hydrofluoric (HF) acid concentration (10% hydrochloric (HCI) acid/5% HF), high volume (150 gal/ft) mud acid stimulation program performed in 1991 on thermal production wells in the Tulare formation of the South Belridge Field. The recommended program was based on the results of laboratory work on Tulare core and a lookback study of a 1989/1990 mud acid stimulation program. In comparison to the prior stimulation program, the 1991 program gave better results; both the total program success rate and the treatment cost per incremental BOPD improved by a factor of 3.
Optimizing the Quality of High-Density Brines for Maximum Performance and Economic Value
Authors: Foxenberg W. E. , Houchin L. R. , Javora P. H. 
Published: December 2007

Abstract
The benefits derived from the use of solids-free high density (HD) brine completion fluids have been extensively documented. The technology to produce and utilize these HD brines was known for many years before they could be made commercially viable. Their use only became economical in the 1970’s when the technology was developed to recondition and re-use these HD brines until fully consumed. Recently, increased competition and cost cutting pressures have resulted in a reduction in quality standards. As a consequence, some operators have begun specifying new brines only. If this trend continues, the actual cost of these valuable salts and the added cost of disposal would be applied to the suppliers price after a single usage. It is this very situation that prevented operators from utilizing HD brines in the 1950’s and 60s. It was not in their best economic interest then nor is it today.
The central problem seems to be the confusion surrounding minimum standards for reconditioned HD brines. Unfortunately, some service companies and operators alike have begun accepting the removal of suspended solids as the exclusive criteria for brine restoration. While the simple filtration of a completion fluid to some arbitrary level may appear cost effective, unseen inherent problems may compromise the functionality of the fluid, be damaging to the formation, complicate normal rig operations, and contribute to unexpected additional cost.
This paper provides guidelines for restoring used brines to new brine standards by addressing both physical and chemical contaminants. Laboratory procedures and operational guidelines are provided that establish methods for identifying problematic contaminants and simulate the brine specific reclamation techniques and field application requirements. Standards for restoring used brines to new/non-damaging compositions are also provided.
Size-Dependency of Hollow Cylinder Collapse Strength
Authors: van den Hoek P. J. , Kooijman A. P. , Kenter C. J. , Khodaverdian Mohamad , Hyland C. R. , McLennan J. D. 
Published: December 2007

ABSTRACT
This paper presents the results of an experimental study of the size dependency of hollow-cylinder (HC) collapse strength in the absence of inner-hole pressure for tight, brittle sandstones. An earlier study on friable Castlegate outcrop sandstone showed that HC strength falls strongly with increasing sample size in this material, implying that small-scale laboratory HC collapse tests may overestimate borehole stability. The present study, however, revealed a much lower size dependency for tight Berea outcrop sandstone and for tight North Sea sandstone. Examination of the borehole shape after testing suggests that breakouts in larger holes grow by a shear mechanism in Berea sandstone, and by a spelling mechanism in Castlegate sandstone. The results for smaller holes in Berea sandstone are less unequivocal: spelling cannot be excluded here as the mechanism for breakout growth.
Optimum Gravel Sizing for Effective Sand Control
Authors: Oyeneyin M. B. , Peden J. M. , Hosseini Ali , Ren Guowu , Bigno Yann 
Published: December 2007

ABSTRACT
Efficient sand control is dependent on the design of the exclusion system and must take into account a number of formation characteristics and production factors which will affect the eventual well performance. For gravelpacking, the design requires the specification of the size of the commercial gravel to use with the final objective being the achievement of maximum productivity over the production life of the well with effective sand exclusion.
To date, a number of formulae have been suggested for gravel size selection, the most popular being the Saucier formula. However in a large number of gravelpacks, operators have reported fines being produced in large quantities, suggesting ineffective bridging by the gravelpack.
A review of the available gravel sizing formulae show that they may be too general and possibly too simplistic to take full cognisance of the depositional environment of the formation sand, the operational conditions to which the gravelpack is subjected, the reservoir fluid, the gravelpack structure, etc.
A project has been initiated in the Department of Petroleum Engineering at Heriot-Watt University to address the problem of determining the optimum gravel size under a range of different operational conditions. The project has the objective of developing a theoretical approach and modelling technique to predict gravel size and also to evaluate particle-pore bridging phenomena, using a series of rigorously defined experiments.
This paper presents the results of the comprehensive experimental investigations carried out to evaluate the bridging effectiveness of various commercial gravels as a function of different operational conditions including the sand sorting and shape.
The experimental studies were carried out using a purposely-built packed column to evaluate the effects of production rate, fluid type, formation sand and gravel characteristics, absolute and differential pressure on the efficiency of the exclusion treatment.
The bridging efficiency of selected gravels were measured. The experimental data generated formed the data base for developing a semi-empirical bridging efficiency equation which assists in the selection of gravel and the prediction of its bridging effectiveness under specified operational conditions. It also allows the design engineer to conduct a sensitivity analysis of the effectiveness of the chosen gravel to a range of variable conditions.
The paper concludes with a description of the computer package being developed for optimum gravel size selection. This package is expected not only to select the optimum gravel size but also predict the eventual well performance.
Case Histories of New Low-Cost Fluid Isolation Technology
Authors: Littlefield B. A. , Fader P. D. , Surles B. W. 
Published: December 2007

Abstract
Texaco has developed a process to shut off steam and water encroachment in production wells. The process involves placing a stable resin system across the zone to be shut off. The resin leaks off into the formation where it polymerizes to form an impermeable plug. The resin plug is stable to temperatures of 700 °F and inert to normal oil field chemicals. The resin is easy to mix, requiring no specialized equipment. The set time of the resin is controllable at any downhole temperature.
The process was tested in Texaco’s Kern River and San Ardo Fields in 1990 and 1991. Thirty-three wells were treated with the resin. Twenty-six of the wells were production wells suffering from water encroachment. The other wells were treated for steam cutting, casing holes, or injection well leaks. About seventy percent (19) of the production wells showed a significant reduction in water production after treatment. Four wells did not show a reduction because the water encroachment zone is above the zone treated. An effective plug could not be made in the other three wells due to highly desaturated or void spaces in the treated zone.
Membrane Filtration of Seawater for Oil Reservoir Injection
Authors: Seland Aina , Bilstad Torleiv , Mehan Surinder , Bakke Rune 
Published: December 2007

Abstract
In the recovery of hydrocarbons from offshore oil reservoirs seawater injection is frequently applied. Unfortunately, the high concentration of sulphate in the injection water may cause problems such as scaling and souring of oil reservoirs. Membrane filtration using nanomembrane can be applied to reduce the sulphate concentration. Nanomembranes have a high rejection of divalente anions and organic molecules with molecular weight above 200. In the present study the separation performance of a NF70-2570 nanomembrane was evaluated. The removal efficiencies obtained for sulphate, magnesium and calcium were greater than 93 %, 47 % and 37 % respectively. The rejection of monovalent anions such as chloride and bicarbonate were in the order of 10-30 % and 30-60 % respectively. The water flux through the membrane decreased from 36.8 l/m2h to 20 l/m2h at Τ = 26 °C after 64 hours of filtration. The required membrane area for the production of 500 m3/day will be in the order of 1000 - 1400 m2.
Determination of Gas Storage in Devonian Shales With X-Ray-Computed Tomography
Authors: Lu Xiao-Chun , Pepin G. P. , Moss R. M. , Watson A. T. 
Published: December 2007

Abstract
The use of X-ray computed tomography scanning with a dual scan technique to study gas storage and transport in Devonian shales is investigated. Dynamic scanning experiments are performed at various gas pressures. Krypton gas is used as the saturating fluid, and its validity in modeling natural gas storage is discussed. Direct evidence of condensed gas in the Devonian shale is presented, and the role of fractures and shale constituents on gas storage and transport is elucidated.
Natural Gas Vehicle Economic Analysis Model
Authors: Matt S. M. 
Published: December 2007

Abstract
As a natural gas utility in the South Coast Air Quality Basin, Southern California Gas has lost load on its system from increasing restrictions on its industrial customers who are classified as "stationary emitters". Air quality data suggests that the majority of the area’s air pollutants are due to mobile sources, particularly automobiles. The utility sought to develop a new market for its product and to help clean the air in its service territory by giving mobile emitters the opportunity to switch to a cleaner burning fuel, by driving natural gas vehicles (NGVs).
The challenge was to prove to regulators that a market development program, in its infancy of creating both a fueling infrastructure and a market for NGVs could be economic to its ratepayers This paper describes the assumptions and structure of the economic model that the utility used to support the filing for the Program.
Application of Biomarkers to Tracing the Source of Oil-Producing Stratum in Oil-Sand Reservoirs
Authors: Chan M. Y. , Altebaeumer F. J. , Brooks P. W. , Sarioglu G. G. 
Published: December 2007

Abstract
Frequently a lack of definite correlation between the cycle performance and the operating strategy has resulted in optimization difficulties for oilsand reservoirs under the Cyclic Steam Stimulation (CSS) recovery process. Oil itself is the ideal substance to be used as the optimization diagnostic tool among the fluids normally recovered in the course of oil production. The preliminary results from this study clearly illustrate this by utilizing a group of chemical compounds found in oils and bitumens, commonly known as biomarkers, as natural tracers. By determining the degree of biodegradation with depth as suggested by the ratios of certain biomarkers, one can reasonably deduce the originating stratum from which the produced oil has originated at the time of sampling. The hypothesis was developed and proven over a 2½ year period using field pilots of the McMurray Formation of the Athabasca oilsand deposits in Alberta, Canada. The approach has the potential to become a cost effective, routine, short turn around time, reliable, direct and continuous monitoring/diagnostic tool for optimizing CSS as well as other recovery processes.
Heavy-Oil Recovery From Thin Pay Zones by Electromagnetic Heating
Authors: Chakma Amit , Jha K. N. 
Published: December 2007

ABSTRACT
There are many heavy oil reservoirs with thin pay zones (less than 10 m). Conventional thermal recovery methods such as steam injection, are not cost effective for these thin reservoirs due to the excessive heat loss through the overburden. In order to minimize heat losses, it is necessary to have the ability to carry out controlled heating of the pay zone. One such way to introduce heat to the reservoir in a controlled manner is electromagnetic heating. This paper describes laboratory studies on electromagnetic heating of scaled thin heavy oil reservoir pay zone models. Combination of electromagnetic heating and gas injection with horizontal wells was studied.
Higher electromagnetic frequencies provide faster heating rate and can overcome problems associated with discontinuity of the media through which electromagnetic waves must propagate in the reservoir. Heat loss can also be minimized with the use of higher frequencies. For moderately heavy oil reservoirs (less than 1000 mPs.s), it is not necessary to heat the entire pay zone. Heating of the wellbore vicinity is sufficient. Oil recoveries as high as 45% of OIIP (Original Oil in Place) were achieved using electromagnetic heating and gas injection compared to estimated primary recovery rates of less than 5%. The results obtained in this work clearly show that electromagnetic heating provides an effective mean of recovering heavy oil from reservoirs with thin pay zones.
Control of Aromatic Emissions From Glycol Dehydrators
Authors: Choi M. S. , Spisak C. D. , Dodd J. A. 
Published: December 2007

Abstract
Glycol dehydration units utilized in natural gas service have been identified as potential sources of aromatic hydrocarbon emissions into the atmosphere. Depending upon the concentration of aromatic content in the natural gas, large amounts of aromatics may be concentrated in the still overhead water vapor vent. Federal and state regulations have targeted glycol dehydration units for emission control on these carcinogenic compounds. In the near future, some states will levy annual fees to operators who exceed maximum daily discharge limits.
Conoco has developed and applied for a patent on a novel addition to the standard glycol dehydration unit that eliminates the emission of almost all of the aromatics and other hydrocarbons. Hydrocarbons, that are normally vented with the water vapor, are recovered as a condensate product or as regenerator fuel.
A prototype of the Aromatic Recovery Unit (ARU) was successfully placed in operation in November 1990, along with a new 30 MMSCFD glycol dehydration unit. Two additional units are now built and in operation.
This paper describes the design and Conoco’s experience with the prototype Aromatic Recovery Unit.
New Oilfield Applications for Electronic Phase Converters/VSD's
Authors: Elmer W. G. , King J. D. 
Published: December 2007

Abstract
New technology has emerged that has removed many of the limitations for the use of single phase power in oilfield applications. Prior to this technology, capacitive and rotary phase converters have been utilized sparingly due to 1) high inrush currents and 2) poor motor efficiencies. The new technology is a computer controlled solid state power conversion process that eliminates these two problems, and provides additional benefits which include variable speed operation and complete motor protection. Actual oilfield applications of the Solid State Phase Converter (SSPC) for fifteen to fifty horsepower motor driven pumping units, compressors, and positive displacement reciprocating pumps are presented, as are other potential oilfield applications.
Improved Specifications for Manufacturing and Inspection of Sucker Rods
Authors: Ott R. E. , Craig B. D. , Beeson Richard 
Published: December 2007

Abstract
In an effort to reduce well failures, Mobil elected to investigate the reasons for rejection rates in new sucker rods. Independent third party inspections indicated a combined 14.3% rejection rate for new sucker rods from all manufacturers during 1990.
Inspection results indicated a variety of rejects led to these failures. However, each manufacturer also had specific problems that led to the rejection of their rods (e.g. cracked pins, hardness variations, etc.).
This paper presents the finding of laboratory analyses of certain sucker rod defects, as well as the resultant development of a comprehensive sucker rod specification.
Results of comprehensive testing of new sucker rod boxes in accordance with API 11B are also presented and discussed.
Completion Techniques Used in Horizontal Wells Drilled in Shallow Gas Sands in the Gulf of Mexico
Authors: Pardo C. W. , Patrickis A. N. 
Published: December 2007

Abstract
Texaco has completed three horizontal wells in shallow gas sands in the Gulf of Mexico. The producing sands in all these wells have relatively high permeabilities and are unconsolidated. This paper discusses the process used to select the completion hardware, drilling fluids, and completion fluids for these wells. In addition, the completion procedure will be discussed in some detail to illustrate the most significant aspects of the completion process. Finally, production histories of the three wells will be presented to highlight the efficiency of the completion system used in these wells.
The Development of Corrosion Inhibitors With Low-Environmental Toxicity.
Authors: Haslegrave J. A. , Hedges W. M. , Montgomerie H. T. R. , O’Brien T. M. 
Published: December 2007

Abstract
This paper discusses the advantages of corrosion inhibitor treatments for oil production applications. It reviews the current direction of legislation concerning the discharge of oil production chemicals into the environment. It details studies undertaken which show that many existing corrosion inhibitors are toxic towards the marine organisms tested. New chemistries have been developed which display excellent corrosion inhibition properties and which are significantly less toxic.
Results of a Large-Scale Refracture Stimulation Program, Kuparuk River Unit, Alaska
Authors: Pospisil Gordon , Lynch K. W. , Pearson C. M. , Rugen J. A. 
Published: December 2007

ABSTRACT
An aggressive hydraulic fracture stimulation program on previously fractured wells in the Kuparuk River Field has increased production by 50,000 BOPD. The Kuparuk River Field is the second largest producing field in the United States with sixty-five percent of the reserves contained in a 20–100 md permeability sandstone. This paper describes results of a series of design improvements in an ongoing refracture program of oil wells in this moderate permeability formation. Over 185 of the 380 production wells have been refractured during the past five years. Long term production data are presented comparing productivities after the initial stimulations carried out in the early 1980’s to the recent refracture stimulations. A twofold improvement in long term productivity is shown with changes in the treatment design: increased job size, different proppant types (ceramic vs. sand), proppant mesh sizes (10/14 and 12/18 vs. 20/40 and 16/20), and fluid types (gelled water vs. gelled diesel). The average productivity increase from 30 to 60 BOPD/net foot pay provided the economic justification for refracturing some wells a second time. Additionally, wells with high flow potential after initial stimulation have been refractured for substantial increases in oil rate.
Microbially Induced Organic Acid Attack in a Sweet Natural Gas-Gathering System
Authors: Dusseault J. W. , Giovanetto R. H. , Schulz J. H. 
Published: December 2007

ABSTRACT
Microbially produced organic acids in contact with mild steel pipelines can cause an accelerated form of corrosion similar in appearance to a CO2 type of attack. While the two types of attack may appear to be similar in nature their corrosion mitigation methods are different. Chemical corrosion inhibitors which are effective in controlling CO2 attack could be rendered ineffective when treating microbially induced corrosion.
This case study outlines the procedure taken in identifying the internal corrosion mechanisms responsible for the microbially induced corrosion (MIC) failures, selection of the treatment chemicals, monitoring techniques, health and safety aspects of chemical programs and the potential environmental impact of such programs.