bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Critique of Selected Case Studies in Environmental Geophysics
Authors: Wilson M. J. , Muir S. G. 
Published: December 2007

ABSTRACT
The intelligent use of environmental and geotechnical engineering geophysics enhances one's understanding of site conditions in an integrated data collection program. Engineering geophysics includes a variety of analytical methods which, when calibrated with geologic and engineering data, improves the understanding of subsurface conditions. Examples of where the appropriate use of geophysical methods improved the interpretation of the data are presented.
The most commonly known use of geophysics in oil and gas operations is surface seismic reflection surveys and used for downhole electric logs in oil and gas wells used for well completion. Geophysical survey uses in environmental liability assessment are significantly varied. Geophysical surveys can be utilized to locate buried underground fuel storage tanks, drums or pipelines. Geophysical methods can be used to verify the depth to groundwater, and in some situations to assist in the definition of groundwater contamination plumes. Another important application is the post-installation due diligence evaluation of groundwater monitoring systems.
A critique of selected case studies will demonstrate strengths and limitations of the various surface and subsurface geophysical methods.
Injection Safety Valve Solutions for CO2 WAG Cycle Wells
Authors: Sides W. S. 
Published: December 2007

ABSTRACT
Unlike the offshore production industry, there are presently no regulations that dictate the use of subsurface safety valves in land completions. However, due to the increase in the number of fields moving toward CO2 injection as a means of tertiary recovery and the potential for injury or environmental damage, many producers have decided to install subsurface safety valves in their CO2 injection wells.
This paper will address why these wells need to be protected, discuss the parameters that must be considered in the selection of a tubing retrievable safety system and cover the unique features of the following types of safety valves.
Surface controlled
Flapper check
Fixed choke-velocity
Variable orifice-velocity
Pressure differential operated
An injection well safety system is necessary to shut-in the well in the event of a catastrophic failure such as accidental well head damage, injection line leaks or tubing separation. A catastrophic failure would result in the release of CO2, wellbore fluids and reservoir fluids possibly containing H2S.
Using a Unique Acid-Fracturing Fluid To Control Fluid Loss Improves Stimulation Results in Carbonate Formations
Authors: White D. J. , Holms B. A. , Hoover R. S. 
Published: December 2007

ABSTRACT
Achieving effective fracture lengths in carbonate formations by fracture acidizing has long been a recognized industry challenge. Severe fluid loss is generally considered a major factor limiting the effectiveness of acid fracturing treatments. A unique new acid fracturing fluid has been developed to control fluid loss. It has been tested in numerous laboratory and field studies. Test results confirm that this new fluid system improves live acid penetration in carbonate reservoirs by controlling acid fluid loss.
This paper discusses the technical basis for the development of this new fluid system. Laboratory test results are included. It also describes the results of field case histories in which the new system was successfully utilized in the Permian Basin of West Texas and the Williston Basin of North Dakota to control acid fluid loss in carbonate acid fracturing. Production comparisons show a substantial improvement in well performance from these wells following treatments that utilized this new system.
The Development of a Low-Cost Thermally Stable Polymer/Surfactant System for Steam-Sweep Efficiency Improvement
Authors: Cooke R. W. , Eson R. L. 
Published: December 2007

ABSTRACT
The estimated 100 billion barrels of heavy oil reserves in the U.S. have responded well to thermal Enhanced Oil Recovery (EOR) during the past 30 years. However, in the current low price environment for heavy oil, new and novel low cost EOR methods must be developed to maintain and hopefully increase the production of heavy oil in the U.S. and throughout the world.
This paper documents the efforts of a 2-1/2 year, two phase project conducted in two areas of the Midway-Sunset field near Bakersfield, California. Successful applications of a novel high temperature stable polymer/surfactant gel system utilized in conjunction with the injection of steam and carbon dioxide have been demonstrated. This process has been tested in nine cyclic steam stimulation treatments, as well as in two continuous steam drive injectors and has shown the ability to effectively divert steam and correct the inherent inefficiencies due to steam channeling and steam override. This process utilizes a specially developed low cost, high temperature stable polymer/surfactant gel solution that holds the promise of substantially reducing the costs associated with current methods utilized to improve sweep efficiencies in thermal projects.
Surveillance of South Belridge Diatomite
Authors: Patzek T. W. 
Published: December 2007

Abstract
This paper illustrates the surveillance methods used in Shell's 1-1/4 and 5/8 acre (0.5 and 0.25 ha) waterfloods in the South Belridge Diatomite field: (1) computer-assisted monitoring of injection pressures and rates, (2) online databases with well tests and allocated production and injection data, (3) step pressure tests in numerous water injectors, (4) a geological database with cycle markers and directional surveys, (5) sonologs, and (6) salinity tests. Methods (1) – (4) require use of custom software to be practical.
The geometry of waterflood patterns in the Diatomite (well spacing compared with length of hydrofractures, injectors in-line with or offset from producers, and pattern orientation relative to the direction of maximum in-situ stress) influences the rate and frequency of coupling between the injectors and producers. It is shown that wells in the "direct" 1-1/4 acre patterns are less prone to coupling than the "staggered" ones because a "linkage potential" (defined in the text) is higher.
The proximity of hydrofractures in the 5/8 acre staggered patterns makes the injector-producer coupling unavoidable if the patterns do not follow the direction of maximum in-situ stress. The coupling develops in the N20°±5°E direction, probably along the cycle tops. The step pressure tests of many injectors in waterflood Phases I through III have shown that hydrofracture extensions are common and we are currently unable to predict the "correct" injection pressures for individual wells. It is concluded that to avoid reservoir damage, each injector must be controlled individually. Injection pressures can be increased with time by trial-and-error, but the injection rate must be kept below a safe limit to preclude excessive damage if the hydrofracture is extended.
New Low-Cost Resin System for Sand and Water Control
Authors: Fader P. D. , Surles B. W. , Shotts N. J. , Littlefield B. A. 
Published: December 2007

ABSTRACT
Technologies for sand1,2 and water3,4 control have been developed, patented and successfully field tested in the Kern River Field, Bakersfield, California, using a modified furan resin. These chemical resin systems are stable to temperatures over 700°F, are inert to oilfield chemicals, are environmentally safe, involve very low material and placement costs, are applicable to wells with almost any downhole temperature, and require production interruptions of a few hours rather than days.
Analytical Inflow Performance Relationships for Three-Phase Flow in Bounded Reservoirs
Authors: Wiggins M. L. , Russell J. E. , Jennings J. W. 
Published: December 2007

ABSTRACT
The performance of oil wells producing water during boundary-dominated flow was investigated to develop a better understanding of multiphase flow and its effects on single well performance. This understanding can assist the petroleum engineer in predicting the pressure-production behavior of oil wells producing under boundary-dominated flow conditions.
An analytical Vogel-type inflow performance relationships (TPR) was developed from the multiphase flow equations. This relationship is based on the physical nature of the multiphase flow system and contributes to a better understanding of the pressure-production behavior of an individual well. The analytical IPR was verified using simulator information for three-phase flow. The analytical IPR provides a method for the petroleum engineer to develop individual IPRs for each reservoir.
New Analysis Technique Provides Effective Fluid-Loss Coefficients
Authors: Lee W. S. 
Published: December 2007

ABSTRACT
The minifrac procedure used in the oilfield services industry is a one-step procedure. The most important information one tries to obtain from minifrac testing is an effective fluid loss coefficient, CEFF, which is the average of the early time fluid loss coefficient, Cvc, and the late time fluid loss coefficient, Cw. Since Cvc could be much larger than Cw, this procedure works reasonably well only if the early fluid loss period, commonly referred to as spurt time, Ts, is short compared to the overall job time. However, since the spurt time is sometimes on the order of several minutes, which is in the same order as the minifrac pumping time, this method tends to overestimate the magnitude of CEFF, resulting in the overdesign of a job treatment when spurt time is large.
A mathematical algorithm has been developed in this paper to determine both the Cvc and Cw, TS and spurt volume, VSP from the conventional minifrac treatment such that they can be adequately used to design the full-scale treatment.
Joint Analysis of Pressue and Surface Tilt Data Improves Constraints on Interpretation of Hydraulic Fracture Growth
Authors: McDaniel B. W. , Underwood P. L. , Garvin T. R. , Wood M. D. , Hunter R. J. 
Published: December 2007

ABSTRACT
Surface response to fracture growth (as measured by an array of tilt meters) is now being analyzed jointly with formation pressure response data to more accurately determine the result of fracture growth during stimulation treatments and for fracture closure after shut-in.
Previously, interpretations of fracture growth behavior during and after injection have depended primarily on observed trends of the treating pressure (or net pressure) response vs time. For some wells, this analysis is improved by prefrac pump-in tests and analysis of pressure decline following shut-in. However, as with well test analysis, determination of fracture parameters from a single pressure record in the wellbore will yield no nu nique solutions. Moreover, important parameters such as azimuth and inclination of the induced fracture plane cannot be interpreted from treating pressure data.
In recent years, determinations of fracture azimuth and dip have been achieved by fracture mapping based on measuring surface displacement with arrays of high gain tilt sensors. Now, more accurate fracture mapping can occur because the tilt data are being jointly analyzed with the net treating pressure response during the fracturing operation. This has yielded more highly constrained three dimensional projections of fracture growth and geometric parameters.
This paper will discuss such fracture mapping applications and present several field examples.
Frontiers-Exploratory or in Improved Recovery
Authors: Galloway George H. 
Published: December 2007

This is a good time to talk frontiers. I doubt if many of us can think of a time when more of them seemed to forcibly impact our daily lives. Look at only a partial list, and I'm starting with things in general and not unique to this industry. Like them or not, we're crossing some frontiers in morality, in the stability or lack of it in the higher educational institutions, in space technology, in racial relations, computer sciences—You can arrange them in any order of importance you choose.
And look at the industry we're in and its new frontiers. Within the last few years and more particularly within the last one the crude oil supply characteristics for North America have gone through radical reappraisal. In addition to that frontier which is geographic, we seem to have an abnormal amount of frontiers to cross this year in political thing like the import quota, the safeguards against oil spills, and many other volatile issues with which the federal and various state governments understandably feel they must concern themselves. All of these things seem to provide a complicated environment within which to try to talk very convincingly about the future of this business we're in.
I do feel though that I probably couldn't stimulate you with anything electrifying along the lines of your symposium theme on improved recoveries, so I thought we might examine some relationships here first thing this morning that perhaps will put the problem of improved perhaps will put the problem of improved recoveries within the context of the larger problem confronting the industry. It is problem confronting the industry. It is the same on I heard stated from my earliest days of working in this oil business. Where is all the oil we will need to come from, and can we get it profitably?
Some of you may remember, others will have to take my statement on faith, that the problem was considered just as formidable twenty y ears ago as it is today, may be worse. I guess I will say at the outset that the answer is probably much the same today as it turned out to be then, and this answer is the title I selected: "Frontiers-Exploratory or in Improved Recovery." Said in simpler terms, some new things are going to turn up whether they are manifested in new places and new ways to find new sources, or whether in new places and new ways to get more oil out of the sources we have already found.
Comprehensive Evaluation and Decision-Making Analysis Techniques of Oilwell Production Operation Methods: Theoretical Models and Applications
Authors: Zhang Qi , Li Zongtian , Li Binghui , Jiang Huanbin , Son Datong 
Published: December 2007

ABSTRACT
We present in this paper a complete set of theoretical models and systematic techniques for comprehensive evaluation and decision-making analysis of oil well production operation methods (POMs). They are the key components of production engineering project scheme for a reservoir block unit. As a systematic approch, our models and techniques take the reservoir geological research, reservoir engineering design, and development and production conditions as the basis, the whole reservoir or block unit as the research object (not a well only), the performance simulations of oil well production under development as the core, use the concepts of system engineering, and consider comprehensively various restricted conditions.
The main content in our techniques cover (1) a set of theoretical models for comprehensive evaluation and decision-making analysis of oil well POMs; (2) an oil well production performance simulator of every POM under various developing phases and a computation modle for technological and economical indeces; (3) an application of three-stage fuzzy-math judgement in the evaluation and analysis of POM; (4) a complete set of commertial computer softwares.
Through the practical applications of three re-References and illustrations at end of paper, presentive reservoirs in China's ZhongYuan, ShengLi and Dagang oilfields, the paper gives a detailed description of procedures of our models and techniques.
Use of Well Management Schemes for Rate Forecasts
Authors: Lo K. K. , Holden C. W. 
Published: December 2007

Abstract
In this paper, two well management schemes are proposed for rate forecasting of production streams under multi-level rate constraints. Each rate stream may be obtained from decline analysis, simulation or other means and may represent that from an individual well, a group of wells, or a separate field. In the first scheme, the well management problem was formulated as a linear programming (LP) problem and solved by the standard Simplex method. Although the solution is rigorous, the computer time for repeated solution of the problem over many time steps can be excessive. A second, approximate scheme was developed that gave results in close agreement with the LP results (within 5%) for most cases. In addition, this scheme reduces the computing time for a solution by about a factor of 4, which makes it more suitable for incorporation in a reservoir simulator. A computer program, based on the approximate scheme, was developed and used for predicting rates for several North Slope reservoirs. A second computer program, using the LP approach, was used to check the accuracy of the approximate scheme as well as another approximate scheme proposed in the literature.
In addition to being a stand-alone tool for rate forecasting, the approximate well management logic has been incorporated in a black-oil reservoir simulator with an explicit formulation. With this type of formulation, the well management logic ensures that the field oil rate is maximized at every time step in the simulations provided lift gas is unimportant.
Analysis of Multi-Feedpoint Geothermal Reservoirs
Authors: Schroeder R. C. 
Published: December 2007

Abstract
A new technique is described to analyze fluid production from geothermal reservoirs with multiple feedpoints. The analysis method can be used to determine the enthalpy and flow rates for reservoirs that are liquid in the undeveloped state but two-phase when produced. The analysis method can also be used to determine the formation or fracture properties associated with each feedpoint, such as permeability and porosity. Sample calculations are given for a well having multiple feedpoints and two-phase flow in the reservoir. The presence of non-negligible amounts of gas in the fluids is not included in this report.
Effective Maintenance Management in Production Operations
Authors: Wisdom W. L. , Gibson R. B. 
Published: December 2007

Abstract
When Tidelands Oil Production Company took over operation of portions of the Wilmington Field, they found field maintenance being performed in a reactive, "fire-fighting" mode. Eighty percent of work was unplanned and unscheduled. Preventive maintenance occupied less than 5% of mechanical and electrical/instrument man-hours worked. Maintenance work force productivity was low.
This paper describes how this company remedied this situation through supervisory training and implementation of a manual, and later computerized, maintenance management system. Operating in a more effective "planning/scheduling" mode, unscheduled work is now well below 20% and preventive maintenance occupies as much as 40% of mechanical and electrical/instrument man-hours. These improvements were accomplished while operating with manpower well below historical levels.
Reservoir Surveillance for the Alberta Lease, North Midway Field: Surveillance and the Total Energy Balance
Authors: Janssen L. D. 
Published: December 2007

Abstract
In 1989 and 1990 during the development program of the Potter sands on the Alberta lease, 21 TOW's (Temperature Observation Wells) were drilled on the 40 acre Alberta Lease in the North Midway Field for use in a high density surveillance program. Since that time, temperature surveys have been obtained from the TOW's on a monthly basis.
The temperature data was used to create temperature log profiles as well as temperature maps on various subzones throughout the Potter sand. The profiles and the maps were used to identify cold areas within the reservoir which aided the cyclic steaming policy. After identifying the cold spots in the reservoir, massive group steaming was utilized to uniformly preheat the reservoir areally and vertically prior to continuous injection.
The temperature log profiles and temperature maps were also used to identify steam movement downdip into the water column and preferential steam movement into channel sands. The temperature log profiles were integrated to calculate the average monthly reservoir temperature, fractional reservoir heat retention, average monthly temperature, and heat losses to the overburden and underburden layers.
With the data above, only two pieces of information were needed to calculate a total energy balance. These were the producing fluid heat losses and casing annular vent heat losses. Systems were installed to measure and record the data necessary to calculate these heat losses, and then, a total energy balance was calculated from the above data.
Optimizing Steamflpod Performance in Dipping Reservoirs
Authors: Kumar Mridul 
Published: December 2007

ABSTRACT
A comprehensive, three-dimensional, numerical model study was conducted to optimize steamflood performance of dipping, heavy-oil reservoirs. Results show that a reduction in steam (heat) injection rate after steam breakthrough is much superior to the constant rate injection. A linear rate reduction is preferred, when rate reduction is initiated at steam breakthrough. However, if the rate reduction is started after the entire project area is covered with steam (which is the case for several existing projects), an exponential rate reduction is preferable.
A line drive configuration with rows of injectors and producers along the direction of the dip and injectors located near the downdip edge of the patten is preferred. This configuration better utilizes gravity override and drainage and recovers significant additional oil over conventional pattern drives, especially for higher viscosity oils. For confined systems, single-pattern results agree well with multi-pattern (up to six patterns in the direction of dip).