bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capillary Trapping Mechanisms in Water-Wet Laminated Rocks
Authors: Huang Yaduo , Ringrose P. S. , Sorbie K. S. 
Published: December 2007

Summary
Most flooding experiments in sandstone cores are carried out either in almost homogeneous samples or in core samples of uncertain heterogeneity. As a result, the interaction of small-scale sedimentary heterogeneity with the fluid mechanics of water-oil displacement cannot be adequately understood or quantified. Because most clastic sediments show some degree of lamination, this might be expected to have a significant influence on both oil displacement efficiency and residual/remaining oil saturation.
This paper reports results from low-rate, drainage/imbibition floods in a 20 × 10 × 1- cm water-wet slab of cross-laminated heterogeneous eolian sandstone. The distribution of porosity, permeability, initial water saturation and residual oil saturation were monitored with computerized-tomography (CT) scanning techniques. The low-rate imbibition floods show that between 30% and 55% of original oil may be trapped in isolated high-permeability lamina. This work shows the importance of recognizing the role of core-scale heterogeneity in the laboratory measurement of waterflood behavior (i.e., the interaction of capillary forces with rock structure, particularly lamination). The practice of performing high-rate floods on rock samples assumed to be homogeneous is unwise and can lead to erroneous conclusions. The results of this work have major implications for (1) two-phase petrophysical measurements; (2) assessment of residual/remaining oil, and (3) multi phase-flow scaleup.
Mechanical Treatment of Weighted Drilling Muds
Authors: Bobo Roy A. , Hoch R.S. 
Published: December 2007

Abstract
Maintenance of desirable plastic flow properties of weighted drilling muds may be greatly simplified by use of centrifugal classification to control the drilled solids content. The new application of a decanting type centrifuge to separate and reject the low density solids from the weighting material results in a drilling mud of greatly improved quality with lower values of yield and rigidity.
Its practicality and economy has been proven in field operation. The degree of separation of light and heavy solids is not limited by the machine, but by the particle size distribution of the solids in the mud. Removal of the low density component of drilling mud that makes chemical treatment necessary permits a marked reduction in chemicals.
The main uses of the centrifugal process are the treatment of muds while drilling, the reclaiming of discarded muds, cleaning up of workover muds, and the reduction in lime content of mud for completion.

Introduction
Drilling mud in any circulatory system is made viscous and difficult to pump by gradual accumulation of drilled solids which pass through the shale shaker and are continually reground. In a weighted mud containing a large proportion of barite by volume, the amount of drilled solids that may be tolerated is greatly reduced. Much effort has been expended to control by chemical treatment the effects of such solids. Though chemical treatment is quite effective, the time eventually comes at deeper depths after enough drilled solids nave entered the system when a portion of the mud must be discarded and replaced with water and more weighting material. Once begun, this process is generally continued at frequent intervals with resultant high maintenance costs.
A New Method for Representing Multiple Wells With Arbitrary Rates in Numerical Reservoir Simulation
Authors: Peaceman Donald W. 
Published: December 2007

Summary
A new equation is presented for calculating the equivalent wellblock radii, req, for all nw wells in a reservoir that fully accounts for arbitrary well rates and the interaction between wells. The data required for the new equation may be obtained in a preprocessor by calculating nw single-phase pressure distributions. Then, an accurate req can be calculated for each well at each timestep, even under conditions where well rates vary with time.
Shale Oil Recovery by In-Situ Retorting-A Pilot Study
Authors: Burwell E.L. , Sterner T.E. , Carpenter H.C. 
Published: December 2007

Results of this in-situ combustion experiment, conducted by the U. S. Bureau of Mines near Rock Springs, Wyoming, to produce shale oil from oil shale, indicate that a combustion zone can be established in a fractured oil shale body by using air injection and a propane burner. During the six-week period that combustion was maintained, 8,000 gallons of oil was produced. produced. Introduction
This paper describes an in-situ combustion experiment conducted by the U. S. Bureau of Mines in the Green River oil shale formation near Rock Springs, Wyo. The experiment was designed to study the engineering problems associated with the establishment, maintenance, and control of a self-sustaining combustion zone in the oil shale and the use of this process to produce shale oil. A 20-ft-thick section of the oil shale located from 68 to 88 ft below the surface of the ground was ignited by use of a propane burner in the central well of an expanded five-spot development pattern. A combustion zone was established in the formation and maintained with little difficulty for a 6-week period, at the end of which time air injection and the combustion phase of the project weld terminated. Several thousand phase of the project weld terminated. Several thousand gallons of shale oil were recovered and stored for analysis. Permeability loss at the injection well and high viscosity of shale oil were problems experienced by other investigators during oil shale retorting, but were not encountered during this test.

Geology
The combustion experiment was performed in the Tipton member of the Green River oil shale formation near Rock Springs, Wyo. The Tipton member in the area of the test-site has a 2-percent dip to the west and a general geologic strike to the north, Green River oil shale is a dolomitic marlstone with a finely laminated structure consisting of an intimate mixture of organic and inorganic materials. The mineral portion ranges from 92 weight percent of shales having an oil yield (as determined by Fischer assay) of 10 gal/ton to 60 weight percent of those having a yield of 75 gal/ton. It consists largely of dolomite, calcite, feldspars, quartz, and illite clay. In the leaner shales cementation is primarily inorganic; however in rich strata it appears that the organic material is the principal cementing agent principal cementing agent Both the porosity and the permeability of oil shale are extremely low because the solid, essentially insoluble organic material serving as a cementing agent blocks the major portion of any pores that might be present. present. Site Preparation
Since the success of any in-situ combustion oil recovery experiment in oil shale depends directly on the ability of air, combustion gases, and produced oil to move through the shale formation, produced oil to move through the shale formation, the first part of the site preparation consisted of an intensive fracturing program. Fracturing techniques that were investigated included electrolinking, hydraulic fracturing, and explosive fracturing.
P. 1520
Identification of Parameters Influencing the Response of Gas Storage Wells to Hydraulic Fracturing With the Aid of a Neural Network
Authors: McVey D. S. , Mohaghegh Shahab , Aminian Khashayar , Ameri Samuel 
Published: December 2007

SummaryPerforming hydraulic fractures on gas storage wells to improve their deliverability is a common practice in the eastern part of the U.S. Most fields used for storage in this region are old, and the reservoir characteristic data necessary for most reservoir studies and hydraulic fracture design and evaluation are scarce. This paper introduces a new method by which parameters that influence the response of gas storage wells to hydraulic fracturing may be identified in the absence of sufficient reservoir data. Control and manipulation of these parameters, once identified correctly, could enhance the outcome of frac jobs in gas storage fields. We conducted the study on a gas storage field in the Clinton formation of northeastern Ohio. We found that well-performance indicators before a hydraulic fracture play an important role in how good the well will respond to a new frac job. We also identified several other important factors.The identification of controlling parameters serves as a foundation for improved frac job design in the fields where adequate engineering data are not available. Another application of this type of study could be the enhancement of selection criteria among the candidate wells for hydraulic fracturing. To achieve the objective of this study, we designed, trained, and applied an artificial neural network. The paper will discuss the results of the incorporation of this new technology in hydraulic fracture design and evaluation.
Allocation of Costs Between Petroleum Liquids and Gases
Authors: Hunter E.E. 
Published: December 2007

Introduction
Petroleum producers have been engaged for many years in supplying several different types of materials from the leases they operate. Some leases produce crude oil and casing-head gas, others produce gas-well gas and condensate, and still others produce all four of these materials. Therefore, the problem of allocating costs between these intermingled products is not a new one.
While in some fields gas has been the dominant product, most producers have been interested principally in oil. Consequently, little has been done about the cost allocation problem by oil producing companies. For accounting purposes, these companies have generally considered gas a by-product, and whatever realization was obtained from it was accounted for as a reduction of producing costs, which were all considered to be applicable to crude oil. The inadequacy of this procedure under present day conditions, and the need for a more realistic approach to the problem of accounting for costs, can probably be illustrated best by a brief review of the growing importance of gas in the economic structure of the industry.

Need for Allocation
Known natural gas reserves in the United States approximately doubled during the 10 years ending with 1952, rising to a total of nearly 200 trillion cu ft at the beginning of 1953. In terms of heat value the 200 trillion cu ft of gas is approximately equal to the combined heat content of the 28 billion bbls of crude oil and the 5 billion bbls of condensate in reserve at the beginning of 1953. However, the heat units produced in the form of oil in 1952 were almost twice as great as those produced in the form of gas - a good indication that there is much more room for expansion in production of gas than for crude oil.
The rapid growth in demand for gas since the end of World War II has brought about a substantial increase in the wellhead price, despite increasing reserves. In the Southwest, for instance, the price doubled in the period from 1943 to 1951, rising to an average of approximately 5.6 cents a thousand in the latter year. Marketed production of gas in the United States had increased to a rate of about 7.5 trillion cu ft in 1951 and over 8 trillion in 1952. The increase in demand thus indicated has been close to 12 per cent a year since 1946, more than twice as great as the rate of increase in demand for crude oil.
Analytical Solution of the Tracer Equation for the Homogeneous Five-Spot Problem
Authors: Almeida A. R. , Cotta R. M. 
Published: December 2007

Abstract
The Generalized Integral Transform Technique (GITT) has been successfully employed in various heat and fluid flow problems. This paper describes the first application of the GITT in petroleum reservoir simulation problems.
The two-dimensional tracer equation for the five-spot pattern is solved analytically by means of this approach, with the usual assumptions of steady-state single-phase flow and unit mobility ratio. The solution is compared, in a wide range of situations, with alternative analytical (when possible) or numerical (finite differences) solutions, as well as with experimental data from other sources.
Liquid Fuels From Oil Shale - A Critical Review
Authors: Rubel A.C. 
Published: December 2007

Abstract
Shale deposits of northwestern Colorado contain more than 100 billion barrels of recoverable shale oil from which, by processes now developed, high quality liquid fuels, gas, sulfur, ammonia, and petrochemical products may be produced.
Experience during the past two years indicates that in the immediate future we face an increasing dependence upon crude supplies outside of the United States.
Studies conducted by the National Petroleum Council indicate that a considerable proportion of this shale oil may be recovered and processed into products equal to those from natural crudes on the Pacific Coast at a cost closely approaching current prices from natural crude.
It would therefore seem to be in the public interest for the petroleum industry and the Defense Department to thoroughly explore the possibilities of developing this great resource as a supplement to our domestic crude supply.
Immediate industry study on an expanded pilot plant scale is suggested.

Introduction
Probably the greatest concentration of potential energy to be found any place in the world lies in the oil shale deposits of the Green River Formation in northwestern Colorado. Those deposits are capable of producing billions of barrels of high quality liquid fuels, as well as large quantities of ammonia, sulfur, coke and fuel gas.
There is a definite need to provide a larger available and dependable reserve of liquid fuel within our own territorial limits to augment our domestic production and, in case of war, enable us to be independent of imports if they are denied us by enemy action.
It would therefore seem to be prudent and sensible for both the oil industry and the Defense Department to take a very careful look at this vast resource.
The history of oil from shale is old. Liquid fuels from this source have been produced in Europe, particularly Scotland, for over a century. Because of the high cost of production, it has attracted little attention in the United States, although immediately following World War I rapidly declining reserves directed the attention if the U. S. Bureau of Mines and several companies to oil shale as a potential source of liquid fuels.
Drillstring Component Mass Imbalance: A Major Source of Downhole Vibrations
Authors: Dykstra M. W. , Chen D. C-K. , Warren T. M. , Azar J. J. 
Published: December 2007

SummaryA study consisting of surface and downhole field experiments, theoretical analysis, and numerical modeling has shown that mass imbalance of drillstring components is a major source of downhole lateral vibrations. Factors that contribute to imbalance include bore misalignment, initial curvature, and gradual wear during service. Field experiments were conducted on the surface to quantify drill-string component mass imbalance for modeling purposes. Tests focused on drill collars. Lateral displacements of collars were measured while each was rotated in the derrick, and results were interpreted with simple models. All collars were unbalanced to some extent. A similar procedure can be used in the field to identify nearly balanced collars for use near the bit. Field experiments conducted downhole used a bull nose in place of a bit to evaluate drill-string vibrations without the bit as a source. A pendulum assembly with stabilizers 65 and 95 ft from the bull nose was used. Simultaneous surface and downhole measurements of accelerations were made. Lateral shocks caused by collar/wellbore collisions were measured at various locations in the drillstring at rotary speeds that caused the collars to whirl. Acceleration magnitudes were heavily influenced by local formation strength. Backward whirl of the drill-string was observed while rotating both on and off bottom. It was identified through downhole measurements, and was associated with sudden, dramatic increases in surface torque.
Simple Procedures for Imposing Constraints for Nonlinear Least Squares Optimization
Authors: Carvalho R. , Thompson L. G. , Redner R. , Reynolds A. C. 
Published: December 2007

Abstract
Nonlinear regression methods (least squares, least absolute value, etc.) have gained acceptance as practical technology for analyzing well-test pressure data. Even for relatively simple problems, however, commonly used algorithms sometimes converge to nonfeasible parameter estimates (e.g., negative permeabilities) resulting in a failure of the method. To avoid this problem, the optimization method must be constrained. Several methods for constrained optimization exist, but nonlinear least squares with penally functions used to impose constraints is usually the algorithm of choice for pressure transient analysis problems. With some experience, penalty functions can be used effectively, but their use requires the user to determine the weighting given the penalty function. Moreover, if initial estimates are far from the solution, non-physical estimates of the parameters may still be obtained.
The primary objective of this work is to present a new method for imaging the objective function across all boundaries imposed to satisfy physical constraints on the parameters. The algorithm is extremely simple and reliable. The method uses an equivalent unconstrained objective function to impose the physical constraints required in the original problem. Thus, it can be used with standard unconstrained least squares software without reprogramming and provides a viable alternative to penalty functions for imposing constraints when estimating well and reservoir parameters from pressure transient data.
In this work, we also present two methods of implementing the penalty function approach for imposing parameter constraints in a general unconstrained least squares algorithm. Based on our experience, the new imaging method always converges to a feasible solution in less time than the penalty function methods.
Permeability Continuity of Laminae in the Calvin Sandstone
Authors: Robertson R.W. , Caudle B.H. 
Published: December 2007

Laboratory tests that were conducted to determine the continuity of laminae in a sandstone outcrop in Oklahoma revealed that such laminae would probably have adverse effects on miscible displacement operations in a sandstone reservoir.

Introduction
The existence of thin, horizontal strata in sandstone rocks has long been recognized by geologists. These same permeable layers of consolidated sand grains have recently been identified in sandstones that appeared outwardly to be homogeneous. The existence of the microstrata seems to be accepted even though a detailed study of their areal extent has not been attempted. One reason for this neglect may be that the thin strata have in the past been considered relatively insignificant in relation to the larger strata in the formation. It is now thought, however, that these thin layers may be very important in the way they affect some of the processes used to recover petroleum from the sandstone reservoir. Holden and petroleum from the sandstone reservoir. Holden and Sprinkle found the laminae to exist in several water-deposited sandstone formations along the Gulf Coast and inland to Oklahoma. The laminae examined by Holden and Sprinkle were found to differ radically in permeability, with adjacent ones having ratios as high permeability, with adjacent ones having ratios as high as 10:1. If the laminae are continuous over a long distance, the extreme permeability differences would most probably affect the recovery of petroleum obtained probably affect the recovery of petroleum obtained by the replacement of one fluid with another. This would include miscible secondary recovery operations and also primary operations in which the energy source is solution gas drive. Holden, in his investigation, found the laminae to exist in the Calvin sandstone of Oklahoma. The Calvin is a highly permeable, well consolidated sandstone, and because of this, we selected it for this study of the continuity of microstrata. The laminae in question are about 1 mm and larger in thickness. A Calvin sandstone thin-section is shown in Fig. 1, which indicates the relative dimensions involved. Dye was injected into the sample before the thin-section was taken.
JPT
P. 661
Principles of Engineering Design Applied to Writing on the Job
Authors: Hay-Roe Hugh 
Published: December 2007

It's no secret that plenty of engineers dislike having to communicate in writing and feel that they don't do a very good job. They may blame deficient language skills, when in fact the biggest problem is something else entirely. The unrecognized No. 1 problem is this: the writing techniques we learned in college were never meant to satisfy the needs of readers in industry.1,2
A practical solution to this problem was developed by Melba Jerry Murray, an industrial editor. She worked with the engineers of a major oil company to create a systematic procedure for writing to management and professional colleagues.3 Murray noticed that most engineers communicated effectively in conversation but dropped the ball when they started to write because they went back to the approach they learned in college. She solved that problem by using the conversational transfer of information as a guide for designing memos, letters, and reports of any length. It works like this:Get to the point. Tell your readers what you want from them, or to offer them, in plain business language.Answer, in sequence, any questions that your readers would ask in response to your main point. (See the left side of Table 1 for an idea of how this works.) Now you have a reader-oriented summary of your message. To use it as is, skip ahead to Step 7. But for long reports, articles, or proposals, proceed with the next step.Use the summary (Step 2) to develop a reader-oriented topic outline. This will ensure that you get away from the old outline shown on the right side of Table 1.Develop a main-point outline. In the outline, every heading you wrote for your reader-oriented outline is followed by a sentence containing the main point for that section of the document.Assemble illustrations that will support and explain your text. Send a set of the illustrations, attached to a copy of your main-point outline, to everyone who will have to approve your document.Arrange a prewriting conference to get approval of the proposed content.Compose the complete text. (For several reasons, the worst way to do this is to write it out in longhand.)Edit and polish the completed draft.
This approach appeals to engineers because it is logical and systematic. Managers receive the full impact of your ideas without having to search around with a highlighting marking pen for essential points buried in the text. Any engineer-writer who has the habit of sandbagging readers with big words can relax and write simply. Plain language reduces the chance of making embarrassing errors.

References
Barabas, C.: "Technical Writing in a Corporate Culture: A Study of the Nature of Information," Writing Research Series, Ablex Publishers (1990) 18. Medawar, P.: The Threat and the Glory: Reflections on Science and Scientists," Oxford U. Press, Oxford, U.K. (1991) 233. Murray, M.J. and Hay-Roe, H.: Engineered Writing: A Manual for Scientific, Technical, and Business Writers, PennWell Books, Tulsa (1986) 292.
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