bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical Motor Power Measurement as the Key for Optimized Rod Pumping
Authors: McCoy J. N. , Podio A. L. , Ott Russ , Woods Mike
Published: June 2009

The development of accurate digital measurement of instantaneous powerduring a pump stroke has made possible a very quick and detailed analysis ofthe efficiency of the pumping system. The efficiency is then used as thebenchmark for determining whether a complete well performance analysis iswarranted from the standpoint of making best use of personnel and economicresources to increase oil production.

In addition, power measurement provides direct information about liftingcost per barrel of fluid and barrel of oil produced, electrical and mechanicalloading of the prime mover, peak power demand, power factor and minimumrequired ratings. These results give operating personnel information regardingpotential problems and give to management a complete picture of thedistribution of pumping costs.

The power measurements are also converted, by the software, to instantaneoustorque and presented as continuous torque curves for the upstroke anddownstroke. This allows determination of the existing level of counterbalanceand provides the most rapid and accurate method for counterbalance adjustmentto achieve lower torque loading on the gear box and reduced energy utilization.One of the principal advantages of this balancing method is that counterbalanceadjustment can be made without need for an accurate description of the pumpingunit's geometry which is often unknown or inaccurate. The effect ofcounterweight displacement on torque and power is observed immediately byrepeating the power measurement after relocating the counterweights.

This paper presents a series of case studies showing the Application ofpower measurement to a variety of pumping systems and components, includingconventional, Mark II, Rotaflexunits and high efficiency motors.
The Physics of Cyclic Deformation and Applications to Coiled Tubing
Authors: Rolovic R. D. , Tipton S. M.
Published: June 2009

The tendency for coiled tubing to grow in diameter due to internal pressure and elongate permanently due to axial loading has been the focus of recent research. These permanent deformations occur in spite of the fact that nominal stresses due to internal pressure and axial loading are well within elastic limits in both the hoop and axial directions. Bending strains that are well into plastic regime are responsible for ratcheting mechanisms in coiled tubing. Progressive plastic deformation can occur under a combination of steady (internal pressure) and cyclic (bending and/or axial) loading. A portion of plastic strain, not recovered in each cycle, may lead to large accumulated plastic strains. A new analytical model capable of predicting ratcheting behavior of this type has been developed and applied to coiled tubing. The model predicted interesting trends, never before noted in the open literature, including incremental decreases in both diameter and length of a coiled tubing section during bending cycles under positive internal pressure. The accuracy of these predicted trends was validated experimentally. The success of the analytical model is based on a new incremental plasticity model that closely conforms to the physics of cyclic plastic deformation. Some elements of the new plasticity model are discussed and predictions are compared to experimental results from complex tests involving variable pressure and axial loading.
Operating in Environmentally Sensitive Areas : International Operators Perspective of Overcoming the Challenge of Waste Management in Eastern Venezuela
Authors: Twynam A. J. , Melchor A. , Page P. W.
Published: June 2009

BP Exploracion de Venezuela (BPV) have been operating in Eastern Venezuela since 1994 under an Operating Service Agreement with PdVSA. BPV operate in the Pedernales and Guarapiche areas which are considered two of the most environmentally sensitive areas within Venezuela. This paper discusses the design and implementation of a Waste Management Strategy having the objective of demonstrating an Integrated Waste Management system that is realistic, leaving no damage to the environment or future risks and recognised by the Venezuelan Ministry of the Environment (MARNR) as a totally acceptable solution.

The waste generated by both drilling and production activities are discussed.

The operating environments of Eastern Venezuela demand a greater investment in environmental compliance and re-quires "better than best practice" solutions to Waste Management issues. A Field Management Plan has been introduced with clear roles and responsibilities for waste handling, waste tracking and reporting systems and clear disposal options.

The model used by BP Exploracion de Venezuela will be of interest to new Operators in Eastern Venezuela, and other environmentally sensitive areas of the Globe.
Safe Techniques of the Perforation System for Oil and Gas Wells
Authors: Zhixin Wang , Junyou Chen , Xianwen Dong
Published: June 2009

The perforation field all over the world has been puzzled by the difficult question that the perforating system goes off on the ground while doing oil and gas well perforating operation. Besides necessary safety education and strictly operating rules, regulations & procedures, the perforating operations should be guaranteed by systematic and necessary safety techniques. This paper analyzed the non-safe factors existed in the perforating operations in the aspect of the dangerous source, safety control and the reliability evaluation of the perforation system, and presented the corresponding countermeasure to each links. All these countermeasure and measurement have been tested and successfully applied for over ten thousands times in more than 4000 wells, goods results have been obtained.
Successful Use of a Synthetic Drilling Fluid in Eastern Venezuela
Authors: Twynam A. J. , Shaw D. , Heard M. , Wilson K. J.
Published: June 2009

Increased drilling performance and low mud consumption rates have made it economical to drill with an environmentally responsible, synthetic drilling fluid in the Orinoco River Delta, Eastern Venezuela. Initially, water based muds were used. Troublesome shales and claystones, coupled with complex tectonic stresses, were cause for numerous hole cleaning and wellbore instability incidents. It was decided to utilize an invert mud with the knowledge that this would inhibit the swelling mechanism of shales and reduce the hydraulic invasion of filtrate into the shale. A synthetic system was chosen for environmental impact concerns, even though the rigs were operating at zero discharge of drilling wastes.

This paper details the reasons for the use of a synthetic based drilling fluid and discusses the planning and implementation of the enhanced drilling fluid programme which ultimately led to a step change in drilling performance. The paper also discusses the utilisation of an Alliance Team and the various Alliance networks to deliver solutions to the challenges faced.

The results have been excellent: zero spills, improved drilling performance and world class consumption rates. Hole stability has greatly improved with mud densities identical to those previously used for near vertical wells. Since introduction of synthetic fluids, mud density profiles are designed relative to balancing pore pressures, as the rock/water base drilling fluid chemical interaction factor has been reduced.

The benefits to operations have been faster completion of wells, lower drilling costs and the ability to plan and operate increasingly difficult wells to better meet demands for production.
A Mortality and Morbidity Study in the Petrochemical Community in Trinidad and Tobago
Authors: Coombs Victor
Published: June 2009

The Caribbean was the first "Global Village", Sugar Plantation doctors were the first Occupational Physicians in the region. This Mortality Study is the first reported study on mortality among petroleum workers in the English Speaking Caribbean. The study population was 5000 workers and 15000 retirees of Petrotrin and its predecessor companies. 1436 death certificates were reviewed during 1979–1990. Cardiovascular diseases and cancer were the top two causes of death. A morbidity study was done in April / May 1997, also a first of its kind. 2339 patient visits made to our medical facilities were analyzed.

Cardiovascular diseases, respiratory diseases and musculoskeletal diseases were the top three conditions presenting. An overview of these two studies are presented as well as a snapshot of a stress survey.
The Use of Critical Body Residue to Predict Produced Water Impact to the Marine Environment
Authors: Rampen W. A. Rondonuwu , Sidharta Henky , Smith J. P
Published: June 2009

Produced water discharge from offshore production facilities has been an accepted practice for many years but the environmental fate and impact of these waters is coming under increased public and regulatory scrutiny. Improvements in effluent water treatment has resulted in improved removal of suspended solids and hydrocarbon fractions, but this is against a background of increasing water volumes, a result of aging reservoirs, resulting in an increased contaminant load to the receiving environment. In addition, advances in analytical chemistry coupled with toxicity testing programs has defined a significant increase in potential adverse impact.

This paper presents the results of LC50 testing for high volume discharges, determination of toxic dose based upon lipid consentrations for determination of critical body residue (CBR) and application of CBR with numerical dispersion modeling to predict acute and chronic toxicity. It was found that acute toxicity even at these volumes causes no significant impact to the environment but the effect of longterm chronic exposure need further review and testing.
Geostatistical Evaluation of QHD 32-6 Oil Field: a DRO in China
Authors: Shih Tai-chang , Yang An-Ping , Cheng Charles T. , Quan Youli , Lu Gou Fan , Wang Ben , Martin D. Lee , Hussey Eric M.
Published: June 2009

The QHD 32-6 heavy oil field in north-central Bohai consists of a series of stacked pay sands in the Pliocene and Miocene at a depth of 1,000 to 1,500 m. To enable the best understanding of the reservoir geology, we have performed geologic, geophysical, and petrophysical studies resulting in construction of a detailed geologic model using advanced geostatistical techniques. The geostatistics evaluation allowed the integration of well logs (as hard data) and 3-D seismic (as soft data) to derive a reliable and detailed 3-D reservoir characterization. The resulting geologic model consists of 18.7 million cells (25 × 25 × 1 m in size), with porosity and permeability values determined for each cell by cokriging seismic attributes to well-log data. The geological model provided input to reservoir simulations, and facilitated the conceptual design of development drilling and production facilities.
Cryogenic Nitrogen as a Hydraulic Fracturing Fluid in the Devonian Shale
Authors: Grundmann Steve R. , Rodvelt Gary D. , Dials Greg A. , Allen Robert E.
Published: June 2009

With proper engineering, liquid nitrogen can be used safely as a hydraulic fracturing fluid. The fluid's extremely cold temperature (−300 to −320°F) will induce thermal tensile stresses in the fracture face. These stresses exceed the tensile strength of the Devonian shale, causing the fracture face to fragment. Because of the extreme temperatures, treated water can be used as a diverter between fracturing stages. This water freezes instantly when it contacts the first treatment zone. This paper discusses the successful application of this technology to stimulate the Devonian shale in Eastern Kentucky.
Transient Pressure Behavior of Composite Reservoirs with Moving Boundaries
Authors: El-Khatib Noaman A. F.
Published: June 2009

A mathematical model is developed for the transient pressure behavior in a composite reservoir-aquifer system with a moving front between oil and water causing the formation of 3 zones. The diffusivity equations for the three zones are coupled with the frontal advance formula of the moving boundary of the water-oil interface. The equations are solved simultaneously in Laplace space using the finite difference method. An iterative procedure is used to estimate the location of the moving front. The solution is then inverted numerically into the real time space using the Stehfest algorithm. The effects of reservoir size, aquifer size, production rate, mobility ratio, skin and wellbore storage are investigated. Results in terms of dimensionless pressures and logarithmic dimensionless pressure derivatives as functions of the dimensionless time are presented. The case of pressure buildup is also investigated.
History and Economics of Flooding a Fractured Lime Reservoir
Authors: Ervin P.S.
Published: June 2009

Kirk field is located approximately 3 miles east of Gorman and 23 miles southeast of Eastland, in Eastland and Comanche counties, Texas.

Engineering studies of waterflood possibilities were commenced in the latter part of 1948. Recommended pilot water injection operations were started in May,1949.

The field was unitized in January, 1950 with all production from Sept. 1,1949 distributed on participation factors based 25 per cent on wells and 75 percent on acre feet.

The producing zone is the lower Marble Falls lime of Pennsylvanian age. Porosities and permeabilities are very low. Oil gravity is 41°API and viscosity of the reservoir fluid is relatively low.

Primary recovery to Aug. 1, 1949 was 643,631 bbl, at which time field production from 103 wells was 80 BOPD at very high GOR. Reservoir pressures were down to 350 psig from 1,300 psig original.

The productive area covered approximately 3,000 acres with estimated average thickness of 11 ft. Primary recovery was estimated to be not over 5.4 per cent of the original oil in place.

Pilot water injection operations indicated efficient waterflooding operations could be conducted although the trend of water movement from the seven initial water injection wells indicated the presence of fractures.

Proposed line drive operations were changed to modified five-spot pattern operations. Subsequent drilling and coring proved the presence of vertical fractures.

Injection of 8,325,000 bbl of water to the end of 1955 resulted in the recovery of 888,000 bbl of oil, or 9.4 bbl of water injected per barrel of oil produced.

Investment of $196,000 resulted in the production of $2,440,000 worth of oil. Deduction of investment, and operating costs of $547,000 over 76 months resulted in a gross revenue to all, interests of $1,700,000 from the waterflood operation or almost $9.00 per $1.00 invested.
Water Flooding Pays Off on Prolific Dora Roberts Lease
Authors: Walters J.D.
Published: June 2009

Introduction

Waterflood operations were commenced on Sunray Mid-Continent Oil Company'ssolely owned Dora Roberts lease, located in the Howard Glassock field, Howard county, Texas, with the injection of water into a Yates sand 90 acre cooperative pilot water flood on Feb. 10, 1952. Production was boosted from 330to 3,281 bbl a day within 16 months after initial water injection. One year later the project attained a second peak production of 3,834 bbl a day. This represents a 1,062 per cent increase in production relative to the normal primary rate of production.

Today, after more than four years of operation, the production is still six times what it would have been under continuation of primary conditions. Cumulative totals indicate that up to July, 1956, 3,485,000 bbl of oil have been recovered through waterflood measures. One barrel of oil has been produced for every 3.78 bbl of water injected into the Yates sand. To date the waterflood operations have recovered an amount of oil equal to that obtained over the preceding 24-year primary period.

Total oil recovery from waterflood operations is expected to surpass 12,500bbl per acre.

Primary Development and Production History

The Yates Sand oil production from the Dora Roberts project, comprising 480leased acres, was obtained in March, 1928. Of 38 wells completed for production from the Yates sand found at about 1,400 ft, the same number of wells were still producing at the time water injection was commenced. Initial production of the wells ranged from 11 to 500 B/D natural.

Production has been obtained from three other formations all underlying the Yates sand formation. In addition to the Yates wells, a total of 49 wells were drilled and completed in the Seven Rivers sand reservoir found at about 1,800ft, the San Andres Lime reservoir found at about 2,600 ft, and the Clear Fork Lime reservoir found at about 3,000 ft.
Water Injection Well Fracture Treatments Benton Field Franklin County, Illinois
Authors: Parkison H.R.
Published: June 2009

Maintenance of desirable water, injection rates has been a problem at Bentonand is a problem to many waterflooding projects. Inability to maintain desirable injection rates is generally the result of plugging by precipitates in the injected water, skin effects incurred during completion, and limited reservoir capacity; Several methods have been used to alleviate this problem in the Benton field and one of the most successful has been hydraulic fracture treating.

Data from 29 fracture treatments of 26 injection wells at Benton show that water injection rates have been substantially increased. Although the behavior of other injection wells mask the effects of increased injection rates in treated wells, total liquid production has been increased in surrounding producing wells without adversely affecting produced water-oil ratios.

Fracture treatments have been varied, but an optimum treatment has not been conclusively indicated. However, results of water-base treating liquids compare favorably with the results obtained from the use of more expensive acid-base and/or oil-base liquids.

The physical nature of the fractures has been investigated by several different injection profiling methods. Pronounced profile changes have not been observed. It appears that existing zones of weakness in the formation have been extended and that a single vertical or horizontal fracture plane has not occurred.

Introduction

Maintenance of desirable water injection rates has been a problem at Benton since the initiation of waterflood operations in November, 1949. The Benton water flood is not unique in this respect, since the problem of maintaining water injection rates is common to many waterflood operations. Considerable effort has been expended in an effort to solve this problem because of its importance to the success of any waterflood project. Inadequate water injection rates create unbalanced flood conditions which reduce flood efficiency, and cause flood life to be extended.
Engineering Analysis of Water Flood Prospects
Authors: Wilson Wallace W.
Published: June 2009

Introduction

The rapid growth of water flooding during the last few years has stimulated the industry to exploit this method of operation to the maximum advantage. Many operators who formerly paid little attention to the secondary recovery possibilities of their properties now realize the importance of evaluating every prospect in their holdings. The impact of this growth of interest in water flooding is easy to see. Well completion practices often are planned for less expensive conversion to secondary operations at a later date; the number of consulting engineers in this field is increasing, as is their backlog of work; and it is increasingly difficult to purchase primary production without some consideration of the potential secondary reserves.

To the average producer, this situation creates some interesting problems. He hears of many successful floods, but of few of the failures. No one, it seems, wishes to announce publicly that his water flood was more productive of experience than oil, and the literature on unsuccessful floods is both meager and carefully clothed with anonymity. All too often, then, the impression is gained that the risks are small, with the rewards stupendous. Such, unfortunately, is often not the case. One also might gain the impression that water flooding is a simple business which involves merely putting an uncertain amount of water down a few of the poorest wells on the lease, with oil certain to appear at others, all of which is accomplished at nominal cost. The basic idea is partially true, but unfortunately, this practice is rewarding only indirect relationship to careful planning or to the bounty of nature in the absence of good engineering.

Success in waterflooding operations begins with the selection of properties to flood which have reasonable chances for profitable operation. A screening process should be used to select only those properties for flooding which have favorable reservoir conditions and the development of those selected should be based on a thorough engineering analysis to seek out any indications of future operating problems in advance of their sudden appearance.
Income Secondary Tax Aspects of Recovery Projects
Authors: Aikman A.E.
Published: June 2009

Introduction

No one need tell you gentlemen that secondary recovery projects and operations are becoming more numerous and important in the oil and gas industry. We all know that unless such projects and operations are undertaken a substantial amount of reserves will be unrecoverable and lost at least as far as our generation is concerned and perhaps to all future generations.

Of course, lawyers especially are cognizant of the fact that the development and changes in the law lag behind the development and changes in business operations and procedures which are necessitated by our dynamic economy. And as so often happens the laws, whether statutory or case law, do not give a great deal of assurance as to the ultimate legal consequences stemming from a particular operation, transaction, or contract. Consequently, lawyers frequently have to draw heavily upon their imagination tempered with judgment and forecast what the courts will probably hold in a particular situation.

What has been said applies in, the field of federal taxation to a greater degree than in other fields of law. The reason is perhaps simple since the field of income taxation is relatively new as fields of law go, and it is an extremely dynamic field which varies in many respects from year to year, all of which may explain why the field of tax law lends itself to more specialization than other fields might.
Contrasting Development, Operation, and Results of Three Waterfloods in Eastern Kansas
Authors: Lollar R.F.
Published: June 2009

The Bush City Shoestring comprising approximately 1,500 productive acres, lies generally in an east-west direction in Anderson county, Kansas. The sand involved is 760 ft deep and is composed of sand and shale layers, resembling in many ways the characteristics of Bradford third sand in Pennsylvania.

According to one published paper and other available data, this reservoir is expected to yield a recovery from water flooding of 2,400 bbl/acre over a period of 10 or more years. The Maracaibo Oil Exploration Corp. has developed and operated an 80-acre tract within this reservoir. We will, attempt to show the difference in application of development and operating practices of Maracaibo's Starit lease vs adjacent property and will show that 3,700 bbl/acre have been recovered in 3.2 years.

A more recent Maracaibo development is illustrated in brief. This area of 31acres, located on the Paola Shoestring, Miami County, Kansas, and referred to as Maracaibo's Phillips-Chandler lease, is an excellent example of good waterflooding practices vs results. It is unique as a test area from a viewpoint of selective shooting, use of Triton X-100, injection of fuel oil prior to water injection, and use of fully automatic pumping wells.

An attempt has been made to design the papers to provide the full story and to show in the final analysis the results of economics involved on the basis of dollars expended vs dollars returned vs time.

Introduction

The following study, relating to our experience with sandstone reservoirs in Eastern Kansas, is submitted in two parts:

Part 1 - Illustrates the planning, development, operation-and net results of Maracaibo's Starit 80-acre lease in contrast to the available data of a 370-acre development adjacent to and on either end of the Starit acreage.

Part 2 - Illustrates, in brief, the characteristics of operations and results of a more recent development, Maracaibo's Phillips-Chandler lease, which has responded splendidly to the employment of good waterflooding procedures and represents some unusual methods of development and operation.
A Resume of the Factors Governing Interpretation of Waterflood Performance
Authors: Calhoun John C.
Published: June 2009

The performance of a water flood is a composite of many separate effects, which fall into a variety of categories. Nature gives many variables through the character of the reservoir rock and fluids and the manner in which they interact. Man imposes additional variables through the wells which are drilled and the manner in which they are completed and operated. In spite of this complexity, we assume at least in principle, that we can resolve all the factors that contribute to a water flood and dissect the entire operation into a series of causes and effects. This is perhaps a brash assumption. Although it may be easy to synthesize a complex situation, the analysis of one can be difficult. To draw an analogy, one may watch a cook and, having noted all the actions taken and the ingredients added, predict to a degree whether or not the cake will be successful. However, it is quite different to taste the finished cake and be able to trace a specific characteristic to a particular cause during the operation of mixing and baking. We say, in effect, that the baking of a cake is an art, not a science.

So it is, to a degree at least, with the water flood. We may plan and watch the operation and predict results in a limited way. Yet, it is quite difficult to trace a given result unequivocally to a specific cause. Generally, there are several equally plausible causes. The fact is that water flooding is also an art, not a science. Of course, it is our hope, as engineers and scientists, that we may be progressing to the place where water flooding operations will be governed entirely by science. In one sense, my remarks are intended to indicate how far we may be along this road. We are probably not even so far along as the cook, for she can bake her cake with some idea of the total factors involved and the role played by each. We do not yet know for sure, so it seems to me, that we have enumerated all the factors that are important to the waterflooding process.
Fresh Water Fracturing in Oil Reservoirs
Authors: Hurst R.E. , Rollins J.T. , Stewart H.A.
Published: June 2009

The use of fresh water as a fracturing fluid in oil reservoirs became widespread in the Permian Basin in 1956,following its earlier introduction in the San Juan Basin. Although water was first used because of its economy, it soon became apparent that water often gave better production increases than oil-base fracturing fluids. Investigations showed that these improved results were caused by the action of fresh water in dissolving and removing salt from treated formations.

Salt occurs in reservoir rocks as matrix material, pore-filling material, fracture-filling material and as fall-out or precipitate from crude oils or brines. The salt content of a core sample can be determined by petrographic study or by chemical tests. Examinations of thin sections of cores show not only how much halite [salt] is present, but also whether the halite is in the form of cementing material, individual crystals, or secondary deposition in pores, channels, or natural fractures.

Fig. 1 is a photomicrograph [X300] of a halitic sandstone thin section from an upper Permian formation. Halite is the cementing material binding together chert and quartz grains. At the upper left hand corner, marked "C", is a chertgrain. The grains marked "Q" are quartz, and the black grains at upper right are magnetite or ilmenite. The arrows point to characteristic cubic openings in the halite. Others are between the arrows and below them. The opening at the right arrow contains a gas bubble. Although many more such openings are in the sample, they cannot be brought into focus at such high magnification.

Fig. 2 is a photomicrograph [x69] of loose quartz sand grains from the same core sample after the cementing halite was removed. This is the effect that can be expected when fresh water is used in treating such a formation.

The presence of halite as individual crystals in the formation is shown in Fig. 3, a photomicrograph [X300] in which both halite and quartz grains are prominent. It is apparent that halite grains may be as large as or larger than quartz grains. Dissolving and removing many such halite grains during a fracturing treatment using fresh water will substantially increase formation permeability.
Drawdown Exploration Reservoir Limit, Well and Formation Evaluation
Authors: Jones Park
Published: June 2009

Drawdown Exploration is the name of a technique that enables the operator to determine from a single drawdown well test the following:ability of the rock to transmit a fluid,darcy-feet of pay connected with the well,well completion efficiency,drainage radius,distance to the productive limit, andbarrels of oil or Mcf of gas connected with the well.

The technique will detect in place hydrocarbons at the rate of 100,000 to about 1,000,000 BOPD or 1,000,000 to about 10,000,000 Mcf of gas per day. If the well will flow for six hours or more and the hazard of sticking the drill pipe is negligible, the test may be run in an open hole before casing is set. A flowing water well may be tested in order to determine whether oil or gas is present at some distance away from the well.

A 1-mile radius explores about 2,000 acres. A 2-mile radius explores about 8,000 acres. The instrumental limitation on the radius of exploration needs further study in the field with a differential pressure bomb. The need for study on the electric analyzer of nonsteady-state flow is also emphasized.

The use of Drawdown Exploration for determining in place oil or gas, water contact, impermeable boundary and well completion efficiency is illustrated by six field examples.

By virtue of discovery, the phrase "Drawdown Exploration" is claimed for exclusive use by Park Jones.

Field Examples

Fig. 1 is for a Texas gas well that averaged 16 bbl of condensate per MMcf of reservoir gas. The curve labelled [P,t] shows the bottom-hole flowing pressure plotted against the logarithm of time, t, in days. The vertical logarithmic scale, Y, on the left side represents the daily rate of P decrease divided by the producing rate in reservoir B/D. The ability of a reservoir rock to transmit a fluid is measured in psi/reservoir B/D and is called the Darcy constant.
A Laboratory Study of Oil Recovery by Solvent Flooding After Water Flooding
Authors: Talash A.W. , Crawford Paul B.
Published: June 2009

Laboratory studies have been made to determine the quantity of oil that may be recovered by application of a solvent flood after water flooding. It was found that substantially all of the oil remaining after water flooding could be recovered by subsequent flooding with a petroleum solvent.

By fractionation and recirculation of the produced effluent it may be possible to reduce the solvent requirements by a factor of two or three.

Introduction

Previous studies have indicated that the oil recovery from porous media may be substantially increased by the injection of miscible fluids. Everett, Goochand Calhoun have suggested that a high recovery could be obtained by displacing reservoir crude with miscible liquids. Results of the study made by Kennedy indicate that the production of oil from depleted oil reservoirs may be substantially increased by the injection of liquefied petroleum gas. Kennedy'slaboratory tests were made using a sand-filled oxygen bottle to simulate a reservoir. The sand was saturated with oil and then flooded with propane. Some of the recoveries obtained by this method were as high as 98per cent indicating that most all of the oil may be obtained by L.P.G. injection.

Offering a and Van der Poel have presented information on the oil to be recovered by circulation of kerosene as a solvent through porous media. They conducted scale model experiments. The study included viscosity ratios of the crude oil to the kerosene from near 1.5 to 5,000. It was found that the oil recovery at breakthrough when flooding with kerosene as a solvent, was equal to those obtained in water flooding at the same viscosity ratio. However, after breakthrough occurred it was found that by flooding with the kerosene [a miscible liquid] the flood becomes much more efficient than the water flood and as a result considerably more oil could be recovered by using the solvent flood than by using the water flood.
Dissolved Oxygen Measurements in Aquatic Environments: The Effects of Changing Temperature and Pressure on Three Sensor Technologies
Authors: Markfort Corey D. , Hondzo Miki
Published: June 2009

Dissolved oxygen (DO) is probably the most important parameter related to water quality and biological habitat in aquatic environments. In situ DO sensors are some of the most valuable tools used by scientists and engineers for the evaluation of water quality in aquatic ecosystems. Presently, we cannot accurately measure DO concentrations under variable temperature and pressure conditions. Pressure and temperature influence polarographic and optical type DO sensors compared to the standard Winkler titration method. This study combines laboratory and field experiments to compare and quantify the accuracy and performance of commercially available macro and micro Clark‐type oxygen sensors as well as optical sensing technology to the Winkler method under changing pressure and temperature conditions. Field measurements at various lake depths revealed sensor response time up to 11 min due to changes in water temperature, pressure, and DO concentration. Investigators should account for transient response in DO sensors before measurements are collected at a given location. We have developed an effective model to predict the transient response time for Clark‐type oxygen sensors. The proposed procedure increases the accuracy of DO data collected in situ for profiling applications.
Removal of Viruses and Indicators by Anaerobic Membrane Bioreactor Treating Animal Waste
Authors: Wong Kelvin , Xagoraraki Irene , Wallace James , Bickert William , Srinivasan Sangeetha , Rose Joan B.
Published: June 2009

Appropriate treatment of agricultural waste is necessary for the protection of public health in rural areas because land‐applied animal manure may transmit zoonotic disease. In this study, we evaluated the potential of using a pilot anaerobic membrane bioreactor (AnMBR) to treat agricultural waste. The AnMBR system, following a conventional complete mix anaerobic digester (CMAD), achieved high removals of biological and chemical agents. The mean log10 removals of Escherichia coli, enterococci, Clostridium perfringens, and coliphage by the AnMBR were 5.2, 6.1, 6.4, and 3.7, respectively, and for the CMAD were 1.5, 1.2, 0.1, and 0.5, respectively. Compared with other indicators, coliphage was observed most frequently and had the highest concentration in effluent samples. Bovine adenoviruses and bovine polymaviruses (BPyV) were monitored in this study using nested PCR methods. All of the CMAD influent and CMAD effluent samples were positive for both viruses, and three AnMBR effluent samples were BPyV positive. The mean removals of total Kjeldahl nitrogen, total phosphate, chemical oxygen demand, total solids, and volatile solids by the entire system were 31, 96, 92, 82, and 91%, respectively, but there was no removal of ammonium. When the AnMBR was operated independent of the CMAD, AnMBR achieved similar E. coli and enterococci removals as the combined CMAD/AnMBR system. The high quality of effluent produced by the pilot AnMBR system in this study demonstrated that such systems can be considered as alternatives for managing animal manure.
Phytase Supplemented Poultry Diets Affect Soluble Phosphorus and Nitrogen in Manure and Manure‐amended Soil
Authors: Pillai Usha P. P. , Manoharan Veeragathipillai , Lisle Allan , Li Xiuhua , Bryden Wayne
Published: June 2009

Understanding P and N dynamics in manure‐amended soil is essential for estimating the environmental impact of manure utilization in land applications. A laboratory incubation study was conducted to assess, (i) the effect of feeding a standard Australian commercial diet, and diets modified with phytase supplementation and reduced nonphytase phosphorus (NPP), on the concentrations of P and N (total and soluble) in the manure derived from layer hens (Gallus domesticusL.), and (ii) the change in water‐soluble phoshorus (PWSP) and mineral N (NH4–N and NO3–N) when used as a soil amendment, applied at rates equivalent to 200 kg ha−1(200N) and 400 kg ha−1(400N). Phytase supplementation increased %PWSPby 8 to 12% in the manures, regardless of the levels of NPP in the diets, and in the manure‐amended soils by 27 to 30% at the 200N application rate, and up to 54% at the 400N rate. Phytase significantly (P <0.05) reduced total nitrogen (TN) content (by 12–31%) of the manures but generally produced greater nitrate accumulation in the manure‐amended soils. Net nitrification, which commenced 4 wk after incubation, was accompanied by a simultaneous decrease in soil pH (by one pH unit) and a concomitant decline in %PWSPThe decline in %PWSPwas primarily attributed to P retention by the soil as it became more acidic. This study suggests that phytase addition not only reduces manure total N content, and increases water‐soluble P, but its effects on manure total phosphorus (TP) and 2 mol L−1KCl extractable mineral N is influenced by the NPP level in the diet.
Effects of Dried Distillers' Grains with Solubles (Wheat‐Based) in Feedlot Cattle Diets on Feces and Manure Composition
Authors: Hao Xiying , Benke Mônica B. , Gibb Darryl J. , Stronks Ashley , Travis Greg , McAllister Tim A.
Published: June 2009

The use of dried distillers' grains with solubles (DDGS) in feedlot cattle (Bos taurus) diets is increasing as the bio‐ethanol industry expands. This study investigated how wheat (Triticum aestivum L.) DDGS‐based diets impact feedlot cattle nutrient and volatile fatty acid (VFA) excretion. Feedlot heifers were fed DDGS at 0 (Control) 20, 40, 60% or 60% + Ca (1% limestone) of dietary dry matter. Feces and manure were sampled monthly over a 133‐d finishing period. Total nitrogen (TN) (feces only), total phosphorus (TP), pH (manure only), and water soluble NH4+ and P contents in feces and manure were higher with 40 and 60% DDGS diets than with the Control. Significant increases in isobutyric, valeric, and isovaleric VFAs (by far the most odorous in manure) were also observed in the feces with 40 and 60% DDGS diets, although there was no change in the total VFA content with diet. Wheat DDGS manure, with higher N and P contents, should be beneficial to crop production. However, it could potentially increase N and P loading on crop lands after application and contribute to greater NH3 emission and malodor intensity while manure is in the feedlot pen. Estimated manure N loss while in feedlot pens also increased significantly with dietary DDGS levels. The small (nonsignificant) differences in total and soluble N and P in feces and manure between 20% DDGS and the Control (0% wheat DDGS) suggest that excess nutrient flow to the environment and malodors can be controlled by restricting wheat DDGS to a maximum of 20% in cattle diets.
Recreating a Functioning Forest Soil in Reclaimed Oil Sands in Northern Alberta: An Approach for Measuring Success in Ecological Restoration
Authors: Rowland S. M. , Prescott C. E. , Grayston S. J. , Quideau S. A. , Bradfield G. E.
Published: June 2009

During oil‐sands mining all vegetation, soil, overburden, and oil sand is removed, leaving pits several kilometers wide and up to 100 m deep. These pits are reclaimed through a variety of treatments using subsoil or a mixed peat‐mineral soil cap. Using nonmetric multidimensional scaling and cluster analysis of measurements of ecosystem function, reclamation treatments of several age classes were compared with a range of natural forest ecotypes to discover which treatments had created ecosystems similar to natural forest ecotypes and at what age this occurred. Ecosystem function was estimated from bioavailable nutrients, plant community composition, litter decomposition rate, and development of a surface organic layer. On the reclamation treatments, availability of nitrate, calcium, magnesium, and sulfur were generally higher than in the natural forest ecotypes, while ammonium, P, K, and Mn were generally lower. Reclamation treatments tended to have more bare ground, grasses, and forbs but less moss, lichen, shrubs, trees, or woody debris than natural forests. Rates of litter decomposition were lower on all reclamation treatments. Development of an organic layer appeared to be facilitated by the presence of shrubs. With repeated applications of fertilizers, measured variables for the peat‐mineral amendments fell within the range of natural variability at about 20 yr. An intermediate subsoil layer reduced the need for fertilizer and conditions resembling natural forests were reached about 15 yr after a single fertilizer application. Treatments over tailings sand receiving only one application of fertilizer appeared to be on a different trajectory to a novel ecosystem.
Uncertainty Evaluation of Coliform Bacteria Removal from Vegetated Filter Strip under Overland Flow Condition
Authors: Guber A. K. , Yakirevich A. M. , Sadeghi A. M. , Pachepsky Y. A. , Shelton D. R.
Published: June 2009

Vegetated filter strips (VFS) have become an important component of water quality improvement by reducing sediment and nutrients transport to surface water. This management practice is also beneficial for controlling manure‐borne pathogen transport to surface water. The objective of this work was to assess the VFS efficiency and evaluate the uncertainty in predicting the microbial pollutant removal from overland flow in VFS. We used the kinematic wave overland flow model as implemented in KINEROS2 coupled with the convective‐dispersive overland transport model which accounts for the reversible attachment‐detachment and surface straining of infiltrating bacteria. The model was successfully calibrated with experimental data obtained from a series of simulated rainfall experiments at vegetated and bare sandy loam and clay loam plots, where fecal coliforms were released from manure slurry applied on the top of the plots. The calibrated model was then used to assess the sensitivity of the VFS efficiency to the model parameters, rainfall duration, and intensity for a case study with a 6‐m VFS placed at the edge of 200‐m long field. The Monte Carlo simulations were also performed to evaluate the uncertainty associated with the VFS efficiency given the uncertainty in the model parameters and key inputs. The VFS efficiency was found to be <95% in 25%, <75% in 23%, and <25% in 20% of cases. Relatively long high‐intensity rainfalls, low hydraulic conductivities, low net capillary drives of soil, and high soil moisture contents before rainfalls caused the partial failure of VFS to retain coliforms from the infiltration excess runoff.
Mercury Adsorption‐Desorption and Transport in Soils
Authors: Liao Lixia , Selim H. M. , DeLaune R. D.
Published: June 2009

Kinetic sorption and column miscible displacement transport experiments were performed to quantify the extent of retention/release and the mobility of mercury in different soils. Results indicated that adsorption of mercury was rapid and highly nonlinear with sorption capacities having the following sequence: Sharkey clay > Olivier loam > Windsor sand. Mercury adsorption by all soils was strongly irreversible where the amounts released or desorbed were often less than 1% of that applied. Moreover, the removal of soil organic matter resulted in a decrease of mercury adsorption in all soils. Adsorption was described with limited success using a nonlinear (Freundlich) model. Results from the transport experiments indicated that the mobility of mercury was highly retarded, with extremely low concentrations of mercury in column effluents. Furthermore, mercury breakthrough curves exhibited erratic patterns with ill‐distinguished peaks. Therefore, mercury is best regarded as strongly retained and highly “immobile” in the soils investigated. This is most likely due to highly stable complex formation (irreversible forms) and strong binding to high‐affinity sites. In a column packed with reference sand material, a symmetric breakthrough curve was obtained where the recovery of mercury in the leachate was only 17.3% of that applied. Mercury retention by the reference sand was likely due to adsorption by quartz and metal‐oxides.
Land Use and Riparian Effects on Prairie Wetland Sediment Properties and Herbicide Sorption Coefficients
Authors: Xu Dani , Meyer Sheila , Gaultier Jeanette , Farenhorst Annemieke , Pennock Dan
Published: June 2009

Sorption of commonly used herbicides by wetland sediment can provide important information for herbicide fate modeling. The influence of sediment properties on herbicide sorption as a result of different land uses in the wetland catchment is unclear. We examined the effects of land use on the physiochemical properties of wetland sediments and the associations between these sediment properties and herbicide sorption characteristics. Bottom sediments were sampled in 0‐ to 5‐ and 5‐ to 10‐cm sections from 17 wetlands under five different land use classes: (i) ephemeral wetlands with no riparian vegetation in a cultivated catchment (ECNR), (ii) ephemeral wetlands with riparian vegetation in a cultivated catchment (ECR), (iii) ephemeral wetlands in a grassland catchment established 4 yr ago (E4G), (iv) ephemeral wetlands in a brome grass catchment established 20 yr ago (E20G), and (v) semi‐permanent (SP) wetlands in a multiple–land‐use catchment. Sediments were analyzed for total organic carbon (TOC), total inorganic carbon (TIC), pH, electrical conductivity, exchangeable cations (EXCAT), total cation exchangeable capacity (CEC), and percent clay (%clay). Sediment herbicide sorption partition coefficient (Kd) was measured for trifluralin, atrazine, 2,4‐D, and glyphosate. The sorption of the herbicides in the sediment increased in the order of 2,4‐D < atrazine < glyphosate < trifluralin. The sorption of 2,4‐D, atrazine, and trifluralin was positively correlated to TOC, EXCAT, and CEC but negatively correlated to %clay. Glyphosate sorption was negatively correlated to pH, TIC, EXCAT, and %clay. Overall, wetland sediments that were recently cultivated (ECNR and E4G) had lower TOC, TIC, EC, EXCAT, CEC, and Kd values (2,4‐D, trifluralin, and atrazine) than sediments that had not been recently cultivated (ECR, E20G, and SP). The ECR wetland sediments had the largest Kd for all four herbicides, suggesting that land use and riparian vegetation have a significant impact on herbicide sorption.