bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diagnostic Techniques To Understand Hydraulic Fracturing: What? Why? and How?
Authors: Cipolla C. L. , Wright C. A. 
Published: December 2007

SummaryIn recent years, there have been numerous advances in fracture mapping/diagnostic technologies. This paper details the state of the art technologies in applying both conventional and advanced methods to better understand hydraulic fracturing and improve treatment designs. The initial portion of the paper describes the application and limitations of various diagnostic tools and methods, including well testing, net pressure analysis (fracture modeling), techniques that employ open-and cased-hole logs, surface-and downhole-tilt fracture mapping, microseismic fracture mapping, and production-data analysis. The bulk of the paper is dedicated to case histories that illustrate the application of these fracture-diagnostic technologies. The case histories include examples of how several fracture diagnostics can be used in concert to provide more reliable estimates of fracture dimensions and allow better economic decisions.
Selective Plugging of Waterflood Input Wells Theory, Methods and Results
Authors: Breston Joseph N. 
Published: December 2007

Abstract
Selective plugging is a practical and economical method for preventing the wasteful circulation of water through barren zones and fractures. It is accomplished by injection into the wellhead of finely divided in a suitable liquid carrying agent, either oil or water.
The paper describes several plugging agents now in use and the methods of application for such typical problems as open sand streaks natural and induced fractures, leaky packers or casing settings and thief zones.
Field results are given for several typical selective plugging operational in Pennsylvania, Illinois, Oklahoma and Texas. These show how selective plugging reduced the amount of water injected and increased oil production.

Introduction
In most oil reservoirs the oil saturated formations have strata of varying permeabilities. In the process of water flooding the more permeable strata are depleted of oil first, and thereafter they continue to take large quantities of water even though they produce no more oil. Under such conditions the following will result:Large quantities of water are circulated through depleted formations making unnecessary expense in the way of water costs and pumping.The injection rate (pressure) may have to be reduced resulting in insufficient pressure on the less permeable strata causing the oil in them to be unrecoverable.High back-pressure in the vicinity of the producing well which will interfere with the flow of oil from the less permeable strata.
Formation fractures natural or induced, will also by-pass large quantities of water. In fact, they are often the reason for failure of a flood right from the start. By-passing of water through fractures creates the same conditions as by-passing through highly permeable strata only worse. Loss of useful water will also result from leaky packers or casing settings and thief zones.
These problem conditions were recognized soon after pressure flooding was started over a generation ago. Solutions were hoped for in the haphazard dumping in of nearly every granular solid imaginable along with portland cement, aqua gel and miscellaneous "gumbos." It wasn't until 1942, however, that a scientific approach was made to the problem through research sponsored by the Pennsylvania oil operators at the Pennsylvania State University. By 1944 the theory of selective plugging was well advanced and a practical plugging agent developed for the Bradford Third sand. Since then selective plugging agents and methods have been developed for conditions in most waterflooding areas of the country.
Bank Financing of Secondary Recovery Projects
Authors: Brown C.L. 
Published: December 2007

Abstract
Normally, much of the investment requirements of the average independent oil operator desiring to develop a secondary recovery project will be sought from a lending institution. The criteria by which The Chase Manhattan Bank judges such an application are discussed detail. To satisfy itself that the undertaking is one which it may be proper to finance, the bank considers managerial competence of the operator, the engineering information and program, and an economic analysis of the project and proposed financing.
The application of these principles to the case of a successful water flood in the Mid-Continent area is presented to illustrate the importance of the bank's standards in considering the financing of a secondary recovery project.
Good management and competent, continuing engineering guidance are considered essential to a financeable secondary recovery project. The quality of the properties must be proven by comparison of laboratory data and engineering studies with pilot flood performance. The amount of financing the bank will be willing to undertake is determined by an economic analysis and valuation method described in the paper.

Introduction
During the next 10 years, according to recent predictions, petroleum production in the United States will fail by over 10 billion bbl to meet domestic demand. A recent study forecasts domestic crude oil requirements of 9,155,000 B/D during 1957, rising to 13,375,000 B/D in 1966, which will total approximately 40.63 billion bbl for the decade. Predicted production rates in the United States range from 7,600,000 B/D in 197 to 9,250,000 B/D in 1966, amounting to only 30.44 billion bbl.
That the industry has assigned a major role to secondary recovery in meeting the future deficiency is apparent from recent reports. Several researchers have been working on in situ combustion and at least one field test of this method is now in progress. Bottom-hole heaters have been tested and the use of hot-injection water has been advocated for water flooding. There is current interest expressed in the use of light hydrocarbon fractions for the displacing fluid. The use of carbon dioxide and of wetting agents in injection water has been the subject of many excellent articles on net waterflood techniques. These are only a few examples of the intense interest manifested in secondary recovery.
Measurement of Dynamic Proppant Fall Rates in Fracturing Gels Using a Concentric Cylinder Tester (includes associated paper 9970 )
Authors: Hannah Robert R. , Harrington Larry J. 
Published: December 2007

Summary
This paper describes the measurement of proppant terminal velocity in a simple non-Newtonian gel during shear. The shear was imposed between Lucite™cylinders with the outer cylinder rotating. During rotation, a proppant particle was introduced and the terminal velocity was measured. This measurement then was compared with Stokes law measurement then was compared with Stokes law using the fluid's apparent viscosity at the known shear rate for the Newtonian viscosity. This results in a good correlation between measured and theoretical data.

Introduction
Most of the early work done on sand settling used vertical fracturing models. Kern et al.1 and Babcock et al.2 reported on tests performed in such models which defined equilibrium bank height and equilibrium velocities. Novotny3also used a vertical model in his proppant transport study. Wahl4 studied the transport of proppants in a horizontal model.
A knowledge of particle settling velocity is a necessary input in all design techniques that describe the final location of proppants in the fracture. For Newtonian fluids, the measurement of settling velocity is straightforward since their viscosity remains constant with variations in shear rate. For these fluids, particle settling velocity will follow Stokes law for particle Reynolds numbers less than two. For all but very thin fracturing fluids, particle Reynolds numbers will be in this range. Under these conditions, single particle settling velocity will follow Stokes law:Equation 1
This is the settling velocity for a single particle in an infinite media.
Most fracturing gels, on the other hand, are non-Newtonian in character and are considered to follow the power law:Equation 2
Under these conditions, Stokes law becomesEquation 3
From this equation, settling velocity becomes a function of shear rate. As shown by Novotny,3 shear rate (?) consists of two components: a horizontal component imposed by fluid motion and a vertical component imposed by particle settling. The vertical shear rate can be expressed by V/d, and the combined shear rate becomesEquation 4
This shear rate expression leads to an altered form of Eq. 3. For the fluids used in these tests, the vertical shear rate V/d is very small and can be ignored without significant error.
The experiments conducted were designed to see how closely dynamic particle fall velocity would follow Stokes law for the shear rate range imposed by the test device. If the measured values agreed with Stokes law, only a knowledge of shear rate would be required to predict settling velocity. Novotny3 found a good correlation working with a similar tester. The fluids used in our test were somewhat more viscous than shown by Novotny.3
Effect of Fractional Flow Hysteresis on Recovery of Tertiary Oil
Authors: Gladfelter Robert E. , Gupta Surendra P. 
Published: December 2007

Abstract
This paper deals with the oil/water bank propagation in a tertiary oil recovery process. Oil/water bank propagation was studied in a series of laboratory micellar floods and simultaneous oil/water flow tests using a microwave scanning apparatus for measuring in-situ dynamic oil saturation. It was observed that a high oil saturation region, or hump, developed at the leading edge of the oil/water bank and grew linearly with distance. A lower steady-state oil saturation region was observed behind the hump. As the hump was produced from the core, high initial oil fractions were observed, as often seen in laboratory micellar floods. This is the result of the observed hysteresis in fractional flow behavior.
A graphical method of predicting the occurrence of a hump, its rate of growth, and saturations within an oil/water bank was developed using the observed hysteresis in fractional flow. Using this prediction procedure, it was concluded that in a tertiary oil recovery process, oil breakthrough time or rate of advance of the oil/water bank, oil saturation at the leading edge, and initial produced oil fractions are only functions of the oil-saturation-increasing fractional flow curve and are not necessarily indications of oil recovery efficiency.
Effect of Dispersion on Local Displacement Efficiency for Multicomponent Enriched-Gas Floods Above the Minimum Miscibility Enrichment
Authors: Johns R. T. , Sah P. , Solano R. 
Published: December 2007

SummaryRecent research on four-component 1D displacements has shown that enriching the gas above the minimum miscibility enrichment (MME) can increase oil recovery substantially for certain systems. Research has shown further that the oil-recovery increase can be very sensitive to the level of dispersion at the enrichment chosen.The main focus of this paper is to extend the research on four-component systems to displacements of multicomponent oils and gases in which the recovery is affected by dispersion and enrichment. We consider here a 12-component oil displaced by solvents enriched above the MME. For this case, the increase in recovery (displacement efficiency) above the MME can be as large as 15% original oil in place (OOIP), depending on the level of mixing. The methodology outlined can be used as a screening tool to determine whether a significant benefit may exist and whether further 2D and 3D studies are warranted.A secondary focus of the paper is to examine in detail how dispersion affects recoveries and displacement mechanisms for the 4- and 12-component systems. We show that for the case of the four-component model, the displacement mechanism changes from a combined condensing/vaporizing (CV) displacement to a strictly condensing one as enrichment increases above the MME. We also show how to quantify the percentage of the CV displacement that is vaporizing or condensing by calculating the compositional distances between key tie lines identified from "dispersion-free" theory.
Potential New Sources of Natural Gas
Authors: Schrider Leo A. , Wise Robert L. 
Published: December 2007

The U.S. DOE's gas resource program aims at resolving existing technological barriers to effective recovery of natural gas from Devonian shale and methane from coalbeds. Upon completion of these projects, DOE expects the technology developed jointly with industry to result in wide-scale recovery and use of these new sources of natural gas.

Introduction
Natural gas continues to be one of the major sources of energy produced and used in the U.S. Declining gas reserves and curtailment of supplies have reemphasized the major influence this energy source has on the U.S. economy. The U.S. DOE is investigating several options for increasing the supply, including a program for unconventional gas recovery (UGR). Four UGR projects currently are being assessed: western tight gas sands, geopressured reservoirs, Devonian shales, and methane from coalbeds. Both the Devonian shale and methane from-coalbeds projects are paramount in this assessment, since they underlie a large section of the U.S. The eastern (Devonian) shales contain a vast, essentially unexplored volume of natural gas. This area could represent new gas recovery from approximately 250,000 sq miles throughout the U.S. Studies by the government and industry have been focused on shale characterization to determine the magnitude of potential gas reserves and technology development needed to improve current state-of the-art stimulation techniques. The initial R and D results have shown promise and point out the technology needed for successful development. The goal of the methane-from-coalbeds project is to provide natural gas from coal seams. While coal itself is recognized as a major energy source, it also contains vast quantities of methane gas. This methane source is not new, since coal mine operators have been aware of its presence and release into the atmosphere during mining operations. Technology studies are being conducted to learn the production potential of this methane and to show how this gas potential of this methane and to show how this gas may be put to widespread use.

Devonian Shales
The Devonian shales of the Appalachian, Michigan, and Illinois basins have produced natural gas since the 1800's. These shales in the eastern U.S. (Fig. 1) contain a high volume of gas. Independent estimates of the recoverable gas range from 3 Tcf to several hundred times that amount. To date, the gas produced from these shales has been limited to an produced from these shales has been limited to an estimated 2.5 Tcf because of the unpredictable behavior and economics shown by existing Devonian shale wells. Similarly, these uncertainties have restricted private-sector R and D funding and development of technology needed for Devonian shale gas production.
JPT
P. 703
Casing Drilling: An Emerging Technology
Authors: Shepard S. F. , Reiley R. H. , Warren T. M. 
Published: December 2007

SummaryBP America Production Co. used the Tesco Casing Drilling™* process to drill the surface and production intervals of 15 Wyoming gas wells. These wells range in depth from 8,300 to 9,600 ft. This paper provides a case-history discussion of the critical issues encountered and resolved during the planning and operations phases of this project.Oilfield casing was used as the drillstring, along with a wireline-retrievable bottomhole assembly (BHA), to reduce the overall time required to drill, run casing, and cement the surface holes. Drilling with casing matched the rate of penetration (ROP) for conventional wells, and both the downhole and surface tools proved to be reliable.The production-hole interval turned out to be more challenging. Drillstring vibrations were encountered when drilling with the 4½-in. casing, and difficulty was experienced in maintaining a competitive ROP with the wireline-retrievable drilling assembly. The last 11 production holes were drilled with casing and a nonretrievable bit assembly. Nine of these wells were completed without tripping the casing. Drilling times were competitive with conventional drilling in the Wamsutter area. One of the wells was the third-fastest well ever drilled in the field.The project demonstrated that the casing-drilling process can be used successfully but may not be cost-effective in all situations. It is probably better suited to softer formations and larger casing sizes than those used at Wamsutter. The process seemed to improve wellbore stability, reduce lost circulation, and minimize gas influx, even when drilling with a lower mud weight than is typical for conventional drilling.
Integrated Study of a Fractured Middle East Reservoir With Stratiform Super-K Intervals–Part 2:Upscaling and Dual-Media Simulation
Authors: Cosentino L. , Coury Y. , Daniel J. M. , Manceau E. , Ravenne C. , Lingen P. Van , Cole J. , Sengul M. 
Published: December 2007

SummaryThe paper describes the upscaling and reservoir simulation of a giant Middle East oil field, the geological modeling of which is described in a companion paper.1 The main objective of the study was the simulation of the irregular water advance observed in some parts of the field as a consequence of peripheral water injection.Three scales of heterogeneity were identified in the characterization phase: the matrix, the stratiform Super-K intervals, and the fractures. To accommodate the different hydraulic properties of each heterogeneity system, a dual-media approach (dual porosity and dual permeability) was used.The assignment of the effective properties to the simulation grids (matrix and fracture grids) was performed independently for the three heterogeneity systems. In particular, the geostatistical facies model was upscaled with algebraic methods, while the stratiform Super-K layers and fracture properties were reproduced explicitly at the simulation gridblock scale through an original upscaling procedure.The history match was achieved in a short time by a small variation of the fractal dimension of the fracture distribution and without resorting to any local modification.Simulation results showed that the fracture system was the controlling factor in terms of water advance and breakthrough, while the impact of the stratiform Super-K layers proved to be of second order.In a later stage, the model was used to run production forecasts under different exploitation scenarios.The conclusions of this study indicate that for such porous and fractured reservoirs with stratiform Super-K occurrences, a detailed characterization of all the heterogeneity systems, coupled with a dual-media formulation, is necessary for accurate reservoir simulation and effective reservoir management.
Use of Carbon/Oxygen Logs Run in Open Hole in Wells Drilled With Oil-Based Muds
Authors: Sullivan M. J. , Belanger D. L. , Stewart W. F. 
Published: December 2007

Summary
Carbon/oxygen (C/O) logs have been run in open hole to assess zones that are potentially swept with fresh injection water in several infill wells offshore Cabinda, Angola.
Interpretation of these logs has been challenging because of the invasion of oil-based mud (OBM) filtrate, mixed sand/carbonate lithology, variable water salinity, large boreholes, and lack of clean wet zones in which to normalize. We discuss the impact of these factors and our experiences in managing them. An example is included in which the results of time-lapse logging suggest that the invasion of OBM filtrate in water zones dissipates slowly or not at all. We show comparisons between saturations derived from the resistivity and the C/O ratio (COR) for these various conditions.
Performance of Linear Algebra Codes on the CRAY-1
Authors: Calahan Donald A. 
Published: December 2007

Abstract
As of 1978, the CRAY-1 has potentially the highest floating-point computation rate in both scalar and vector modes of any available general scientific processor. Exploitation of this superior capability is the subject of this paper. In particular, we consider (1) mathematical models, software issues, and performance measures of vector machines, (2) algorithmic and coding procedures related to development of linear algebra codes on the CRAY-1, and (3) performance of direct solution codes commonly encountered in reservoir simulation.
Perforating for Stimulation: An Engineered Solution
Authors: Lestz R. S. , Clarke J. N. , Plattner D. , Byrd A. C. 
Published: December 2007

SummaryPoint-source perforating has reduced fracture-stimulation expenses in the south Texas Lobo trend. Although the producing intervals frequently exceed 100 ft, the operator typically perforates the bottom 5 ft of the interval. Data collected during perforating are used to design optimized fracture-stimulation treatments. The optimized treatments average 55% less proppant than the jobs designed previously with conventional practices that had perforations across the entire pay interval. The new well's initial production and sustained performance has been higher than conventionally stimulated wells of similar potential. In addition, the point-source-perforated wells have produced significantly less proppant than similar wells with perforations across the entire pay interval. Point-source perforating has reduced the cost of perforating, proppant, fluids, equipment rentals, and cleanup.This case-history paper presents the following.Historical account of previous completion practices (limitedentry, multiple-stage fracturing, and full-zone perforating). Discussion of the "perforating for stimulation" fracturingtechnique currently used. Comparison of production results. Formation-evaluation methods (logs and bottomhole gauges). Perforating methods (phasing, charges, and perforating-interval selection). Results from a recompletion confirming that depletionhas occurred.
Evaluation of a pH-Sensitive Polymer for Gravel-Packing Operations
Authors: Al-Anazi Hamoud A. , Sharma Mukul M. 
Published: December 2007

Summary
Rheological data is presented for a type of polyacrylic acid polymer as a function of polymer concentration, pH, shear rate, and temperature. It was found that the viscosity of the polymer is strongly dependent on the pH of the solution. Compatibility tests showed that the polymer was compatible with most brines (NaCl, NH4Cl, and KCl) used for field applications. Core-flow results indicated that the filtration rate was low compared to that of hydroxethylcellusose (HEC). Our evaluation study shows that this anionic polymer would be an excellent nondamaging carrier fluid for gravel packing. It has excellent rheological and suspension properties and is easily broken down with a mild acid wash before flowback.
An Improved Formulation and Solution Method for Single-Phase Flow Problems
Authors: Welty Douglas H. , Meijerink J. A. 
Published: December 2007

Abstract
This paper presents an improved formulation and solution method for use in single-phase finite difference reservoir simulators. The formulation allows easy, implicit inclusion of source and sink terms (wells) in the solution. The equations are expressed in residual form, and a Newton-Raphson scheme is used to update any nonlinearities in both the well model and fluid properties.
The resulting system of linear algebraic equations is solved using the symmetric strongly implicit procedure (SSIP). SSIP is an iterative solution algorithm that is highly efficient with respect to both work and storage requirements. Additionally, SSIP is not very sensitive to high transmissibility ratios in the reservoir description. Our experience indicates that this combination of formulation and solution methods is reliable and efficient.