bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of Japanese Energy Policy
Authors: Matsuzawa Akira , Tsumura Akinobu 
Published: December 2007

To limit oil imports, Japan has established goals for 1985 and 1990 in terms of energy conservation, production of nuclear power plants, importation of LNG and coal, and development of new energy sources. In addition, the government and private concerns are making efforts for strengthening the exploration and development of oil resources and for diversifying the sources of imported oil.

Introduction
Two decades before the oil crisis in 1973, Japan had enjoyed unprecedented rapid growth of its economy. The gross national product (GNP) had increased 10% per year in 20 years, resulting in a rapid growth of energy consumption. Total energy consumption in 1973 was equivalent to 7 MMB/D (407 × 106 m3/a) compared with 1 MMB/D (58 × 106 m3/a) in 1953. Oil consumption represented 87% of this increase. As a result, in 1973 Japan was consuming 5.5 MMB/D (319 × 106 m3/a) of oil, which represented 75% of primary energy consumption, and 99.8% of the oil was imported. In fact, Japan's rapid economic growth for two decades had relied on the plentiful and stable supplies of oil that had been achieved in the world, particularly in the Middle East.This crisis, first experienced as oil shortages and sharp price increases, had an especially profound impact on oil-dependent Japan. Trends in economic growth changed fundamentally after the oil shock and the unprecedented recession that followed. In the postcrisis period, there has been little expectation that the future economic growth rate will equal that of the pre-1973 period.As a result of observations over the past few years on the global development of oil and other energy sources, and through continued discussions concerning the future status of these sources, the great majority of Japanese have become aware that a stable energy supply will be the decisive factor for economic growth in the future.

Guidelines of the Ministerial Task Force for Energy Policy
The oil shock made the Japanese government and people aware of the importance of stable supplies of energy for future economic performance. The government set up the Natural Resources and Energy Agency (attached to the Ministry of International Trade and Industry) and the Ministerial Task Force for Energy Policy, headed by the prime minister.In 1975, upon request by the Natural Resources and Energy Agency, the Advisory Committee for Energy worked out a recommendation for a new energy policy, including interim projections of energy supply and demand. The Ministerial Task Force reviewed the report submitted by the committee and set up guidelines for an energy policy.The result of the study by the committee suggested that there is no simple and easy way to ensure a stable energy supply for a country like Japan, which lacks the indigenous energy resources and is dependent on large amounts of energy.
JPT
P. 1691＾
Mixing Rules and Correlations of NMR Relaxation Time With Viscosity, Diffusivity, and Gas/Oil Ratio of Methane/Hydrocarbon Mixtures
Authors: Lo Sho-Wei , Hirasaki George J. , House Waylon V. , Kobayashi Riki 
Published: December 2007

Summary
Viscosity, diffusivity, relaxation time, and gas/oil ratio are important properties in the characterization of reservoirs by nuclear magnetic resonance (NMR) well logging and in prediction of production performance. For the past few years, NMR well logging has been used to estimate formation properties and hydrocarbon liquid/ vapor characterization. Previous work has shown that pure al-kanes, alkane mixtures, viscosity standards, and stock tank crude oils have NMR relaxation times that vary linearly with viscosity/ temperature and diffusivity on a log-log scale. However, pure methane at some temperatures and pressures does not follow the same trend. Thus, the linear correlation may not be valid for live crude oils that contain a significant amount of methane. Therefore, the study of methane-hydrocarbon mixtures is of interest.
An NMR spectrometer equipped with a high-pressure probe was used to study the relationship between NMR T1 relaxation time and viscosity/temperature, diffusivity, and gas/oil ratio of methane-hydrocarbon mixtures. Relaxation time and diffusivity measurements of three mixtures were made: methane-n-hexane, methane-n-decane, and methane-n-hexadecane. It was found that unlike stock tank oil, relaxation times do not depend linearly on viscosity/temperature on a log-log scale. Each of the mixtures forms a different curve.
Generalized correlations between viscosity, diffusivity, gas/oil ratio, and NMR relaxation times were developed. First, the relaxation time mixing rule was developed by studying the theory of NMR relaxation mechanism. From the mixing rule, it was found that departure of relaxation times of methane-n-alkane mixtures from linear correlations on a log-log scale can be correlated with the proton fraction of methane, expressed as gas/oil ratio. Thus, correlations between relaxation time, viscosity/temperature, and gas/oil ratio were developed. Correlations between relaxation time, diffusivity, and gas/oil ratio were also developed. There is a linear relation between diffusivity and viscosity/temperature that is independent of composition. From these correlations, viscosity and gas/oil ratio can be estimated from NMR T1 relaxation time and diffusivity.
The Role of Sequential Well Testing in Improving Oil Recovery From a Closed Sand Lens in the Bahrain Field
Authors: Zubari H.K. , Abdulwahab A.E. 
Published: December 2007

Summary
The Ac zone refers to the sandstone facies of the Wara formation, which belongs to the Wasia group of the Middle Cretaceous age.* Owing to variable shale to sand ratios, the Ac zone is realized as different isolated sand lenses scattered all over the field. Owing to the complexity of the geology and the flow mechanism, well testing was used to manage the reservoir. The concept of a sequence of well tests on the same well was found to be essential in improving the oil recovery. Conducted on a specific well situated within a closed sand lens, sequential well testing yielded valuable information that assisted in understanding the drive mechanism and the deteriorating reservoir parameters, permeability, and skin. Such a method was crucial in improving the recovery from the sand lens as well as from the single-well-treatment perspective. This paper presents an example of how such a technique aided in improving the oil recovery from a small sand lens.
Relative Permeability Correlation for Mixed-Wet Reservoirs
Authors: Kjosavik A. , Ringen J. K. , Skjaeveland S. M. 
Published: December 2007

SummaryA two-phase relative permeability correlation for mixed-wet rock is presented and validated. It includes provisions for bounding drainage and imbibition processes and scanning hysteresis loops, and is inferred from a capillary pressure correlation.The well-known Corey-Burdine relative permeabilities were developed for water-wet rock from a Brooks-Corey power-law capillary pressure correlation and a bundle-of-tubes network model. We have extended this correlation to mixed-wet rock and now propose the ensuing relative permeability correlation for mixed-wet reservoirs. The functional form is symmetric with respect to fluid-dependent properties, because neither fluid has precedence in a mixed-wet environment. It reverts to the standard Corey-Burdine correlation for the completely water- or oil-wet cases, and exhibits the following characteristics in agreement with reported experiments: first, water-wet behavior at low water saturations and oil-wet behavior at low oil saturations; second, an inverted S-shape oil relative permeability curve with an inflection point; and, third, closed hysteresis scanning loops.
Alternate Producing and Gas Repressuring for Greater Oil Recovery
Authors: Cook Alton B. 
Published: December 2007

Abstract
Considerations are presented to support a theory that alternately producing and repressuring a reservoir with gas will flush oil out of zones of low permeability in a reservoir under conditions in which conventional gas cycling would be relatively ineffective.
Gas repressuring and batch gas cycling (alternately producing and repressuring) in semidepleted oil reservoirs may be a practical secondary recovery practice in many fields. Although this practice may not be as successful as water flooding in most shallow oil reservoirs, it holds considerable promise as a means of increasing recovery from deep reservoirs where water flooding would not be economically practicable.
Batch-type gas cycling will sweep a greater part of a non-homogeneous reservoir than conventional gas cycling and therefore should result in a greater oil recovery. It can be used successfully where two or more reservoirs can be operated as a unit. Also, it can be used in a single reservoir if the reservoir is also used for gas-storage operations. This cycling procedure can be used successfully in reservoirs whose states of depletion range from newly developed oil fields to fields depleted by primary production.

Introduction
From a study of methods of predicting the performance of semidepleted oil reservoirs used for gas storage made recently by Bureau of Mines engineers, it was concluded that the amount of oil recoverable by repressuring and cycling a reservoir may be as great as that produced during primary recovery operations. It appeared also that the normal operations of a gas-storage project would generally gas-sweep a larger part of a reservoir than gas cycling at essentially constant pressure, especially in unfractured reservoirs with large variations in permeability.
The flow of fluids in a reservoir used for gas storage differs from that in reservoirs subjected to gas cycling. In normal gas-cycling operations in non-homogeneous reservoirs the reservoir pressure is essentially constant, and the major flow of gas is through the more permeable zones. When a reservoir is used for gas storage, the oil-recovery operation may be in effect an alternate repressuring and partial depletion process.
A Study of Relevant Parameters To Predict Sand Production in Gas Wells
Authors: Ghalambor Ali , Asadi Mahmoud 
Published: December 2007

SummaryA sensitivity analysis was carried out during a course of study to develop a model for predicting sand production from Gulf Coast gas wells that produce free water. A multiple linear-regression analysis was used to incorporate data from producing gas wells and log-derived properties of reservoir rock in a useable model. This model fits the field data of water-producing gas wells. It will be a risky proposition to analyze each individual parameter related to sand production when designing sand-control measures. This study shows that the combined effects of these parameters are making a significant contribution in the process. The results indicate that the volume of water is not relatable, but the presence of free water (uncondensed from the gas phase) increases the sanding tendencies of most gas wells. As a reservoir depletes, its tendency to produce sand increases; efforts to reduce sanding should be directed toward reducing the drawdown across the completion; and many of the log-derived parameters that show merit in correlating the sanding tendencies of dry gas wells have no value in waterproducing gas wells.
Quantitative Risk Assessment as a Design Tool—Recent FPSO Experience
Authors: Overfield R. E. , Collins J. F. 
Published: December 2007

Summary
Quantitative risk assessment was used as a tool for the conceptual and detailed design of two floating production, storage, and off-loading (FPSO) installations. Results from the risk-assessment study were used to identify significant risk contributors that influence the design and operation of the facilities and to demonstrate that the risk-acceptance criteria adopted by the company were met. The results were also used to identify opportunities to further reduce the risk to a level that is as low as reasonably practical (ALARP).
Traditional risk, reliability, and consequence analysis methods were used to evaluate impacts from process and marine facilities and to determine the design of accidental loads during the conceptual engineering and design phases. Results were used as data for a detailed fault-tree analysis of accident scenarios and used to set the design criteria for significant structures and facilities.
In addition, analyses of subsea facility interfaces and field operations were performed to incorporate the full development scope. Particular attention was given to subsea pipelines and flexible risers as well as tanker operations and their effects on FPSO operation and design.
Event frequencies were determined from industry data and conditioned for the special design and operating features of the chosen FPSO concept. Risk sources, impacting fatal accidents, impairment of safety functions, and loss of asset value, were quantified for use in demonstrating an acceptable level of risk and to test opportunities to further reduce operating risks.
Results from the analyses show that process fires and explosions dominate the risks to personnel and safety functions, followed by cargo tank explosions. Tanker collisions, subsea pipeline and riser leaks, and turret operations were found to represent significant asset risks. Design development and operations planning efforts focused on these areas to reduce risk and improve reliability.
A Numerical Method for Computing the Dynamical Behavior of Fluid-Fluid Interfaces in Permeable Media
Authors: Sheldon J.W. , Dougherty E.W. 
Published: December 2007

Abstract
A numerical method for computing the dynamical behavior of fluid-fluid interface is described. Results of studies made to assess the accuracy and economy of the method on a computer are reported. If is concluded that it is practical to obtain digital computer solutions for a fluid-fluid interface problems with two space dimensions.
PROBLEM DEFINITION
We consider two-dimensional flow in a rectangle as shown in Fig. 1, where a fluid-fluid interface divides the rectangle into two regions. The pressure is specified along the lower boundary (the injection boundary) and upper boundary (the withdrawal boundary). There is to be no flow of fluid across the side boundaries, which are walls of symmetry for the flow, and px = 0 along these boundaries. The fluids are incompressible, the absolute permeability and porosity is constant, and each fluid has its own constant mobility. Thus the pressure satisfies Laplace's equation in each region. Across the interface, pressure is continuous and the normal component of fluid flux is 1. These conditions are shown in Fig. 1. The velocity of a point on the interface in the direction of the normal from Fluid 1 into Fluid 2 is, where is thenormal component of volumetric flux at the point on the interface, i.e.,
For brevity, we call the problem defined above "Problem A". Problem A is a simple example of a dynamical fluid-fluid interface problem. However, the same numerical methods which we use to solve Problem A can be extended to the solution of a large number of fluid-fluid interface problems which are mathematical models for various oil recovery processes, hence our interest in Problem A.
OUTLINE OF METHOD OF SOLUTION
We define the interface by prescribing the x, y coordinates of a finite set of points. These points are called "interface meshpoints" and are illustrated by triangles or asterisks in the figures. Fig. 2 is a procedural (flow) chart displaying the main steps in the solution. We comment briefly on some of these steps in this section and then give further details in subsequent sections.
SPEJ
P. 158ˆ
Laboratory Results of Cleaning Produced Water by Gas Flotation
Authors: Strickland W. T. 
Published: December 2007

AbstractLaboratory studies were conducted to determine the factors governing flotation-cell performance. It was learned that oil removal is increased by increasing collision and attachment efficiencies and gas/liquid contact time. Collision efficiency is increased by increasing oil-drop size and gas concentration and by decreasing gas-bubble size. Several factors (crude type, pH, temperature, etc.) were found to change attachment efficiency. No correlation between basic system properties and attachment efficiency was found.Some of these important parameters are determined by the cell design, whereas others are characteristics of the feed. Thus, the same type (design) cell will produce different effluent oil concentrations for different feeds. Also, the effluent from a given cell will change when the feed characteristics change.
Thermal Simulation With Multisegment Wells
Authors: Stone T. W. , Bennett J. , Law D. H. -S. , Holmes J. A. 
Published: December 2007

SummaryThe extension of a previously reported well model to compositional and thermal applications is discussed. This multisegment, multibranching wellbore model has been fully coupled to a commercial reservoir simulator that can operate in black-oil, compositional, or thermal modes. In this paper, the discussion will focus on thermal, heavy-oil applications in which simulation requires a better representation of the wellbore geometry and the physics of fluid flow and heat transfer.
Fracture Pressure-Slope Analysis for TSOs in High-Permeability Formations
Authors: Smith Jeffrey E. , Meyer Bruce R. , Jacot R. Henry 
Published: December 2007

Summary
The relative popularity and success of the frac-pack technique in hydraulic fracturing has resulted in some misconceptions regarding the objective, procedure, and pressure analysis after a screenout. This paper addresses frac-pack procedures and the pressure response after a tip screenout (TSO).
An analytical method has been developed for analyzing pressure-slope behavior after a TSO in high-permeability formations. These equations incorporate the first order parameters affecting the fracture pressure, rate of pressure change (derivative), and pressure-slope behaviors after a screenout.
The fundamental equations for pressure-slope analysis are similar to those originally developed by Nolte for pressure-decline analysis. The major difference is that after the fracture stops propagating (i.e., after a TSO), the injection rate is not zero. Consequently, if the injection rate is greater than the leakoff rate, the fracture volume and net pressure (constant compliance) must increase. If the injection rate falls below the leakoff rate, the fracture net pressure must decrease.
Although analytical equations will not replace 3D fracturing simulators normally used for design and real-time history matching, they do provide insight into the major parameters affecting pressure behavior after a TSO without running a numerical simulator. The analytical equations presented in this paper demonstrate why pressure slopes after a screenout are typically much greater than unity for low-efficiency fractures.
A generalized set of equations is presented for analyzing the pressure-slope behavior after a screenout. Numerous graphs are provided that illustrate the parametric effects of fracture efficiency, spurt loss, and fracture net pressure at the time of a screenout on the pressure, derivative, and slope behaviors after a TSO. Comparisons of the analytical pressure-slope equations with a 3D fracturing simulator are presented to show the analysis’ application.
A new methodology of frac-pack post-analysis is presented using the pressure slope technique. This methodology uses the pressure slope during a screenout as a check on the minifracture and fracture efficiency. Two frac-pack cases with bottomhole data are analyzed with a 3D hydraulic fracturing simulator to illustrate the pressure-slope analysis for low efficiency fractures.
Relationships Between the Mud Resistivity, Mud Filtrate Resistivity, and the Mud Cake Resistivity of Oil Emulsion Mud Systems
Authors: Lamont Norman 
Published: December 2007

Introduction
The evaluation of certain reservoir properties, such as porosity and fluid saturation, from electrical well surveys has been widely accepted in petroleum engineering. Various investigators have established relationships between these properties and certain parameters which affect the response of the electrical log. Among these are the resistivities of the mud, its filtrate, and its filter cake. In 1949, Patnode established a relationship between the resistivities of the mud and filtrate. The well logging service companies have contributed relationships for the mud-mud cake resistivities. These have been valuable since it was the practice to measure only resistivity of mud at the well site.
During the mid–1940's the industry began drilling wells with oil-emulsion drilling fluids. These were conventional aqueous muds with a dispersed oil phase. Since 1950, oil-emulsion muds have been used on an increasing number of wells each year. However, the practice of measuring only the resistivity of the mud at the well site has continued, and the mud filtrate and mud cake resistivities have been determined by the above-mentioned relationships. Service companies are now equipped to measure all three resistivities at the well site.
An investigation was conducted on the resistivities of oil-emulsion muds, mud filtrates, and mud cakes to determine if these values conformed to the relationships for aqueous muds.

Types of Muds
Fifty-one oil-emulsion mud samples were prepared in the laboratory following a standard manual published by a leading mud company. The diesel oil in the samples varied from 5 to 50 per cent, the majority of the samples being in the 10 per cent region. The basic aqueous mud types which were converted to oil-emulsion muds were commercial clay and bentonite muds, low pH and high pH, caustic-quebracho treated muds, and lime treated muds. The emulsions were stabilized by dispersed solids, lignins, lignosulfonates, sodium carboxymethyl cellulose, or sulfonated petrolatum. It is worthy of note that after a quiescent period of two weeks at room temperature all samples, regardless of emulsifying agent, remained stable.
The make-up water for the muds was from the laboratory tap. Resistivities were varied by the addition of table salt to the water. A range of mud resistivities from 0.44 to 3.9 ohm-m was obtained in this way.
On Near-Wellbore Modeling and Real-Time Reservoir Management
Authors: Bøe Ø. , Flynn J. , Reiso E. 
Published: December 2007

Summary
This paper is concerned with the problems of real-time reservoir management, simulation while drilling (SIWD), and near-wellbore modeling. These problems are discussed in terms of work process, feasibility, and numerical- and simulation-related aspects. A software tool developed to perform high-precision local simulation while accounting for global field behavior is described. Field examples are presented to illustrate the potential and use for SIWD exercises.
Development and Testing of Insulated Drillpipe
Authors: Finger J. T. , Jacobson R. D. , Champness A. T. 
Published: December 2007

SummaryThe Geothermal Research Dept. at Sandia Natl. Laboratories, in collaboration with Drill Cool Systems Inc., has worked to develop and test insulated drillpipe (IDP). IDP will allow much cooler drilling fluid to reach the bottom of the hole, making possible the use of downhole motors, electronics, and steering tools that are now useless in high-temperature formations. Other advantages of cooler fluid include reduced degradation of drilling fluid, longer bit life, and reduced corrosion rates.This article describes the theoretical background, laboratory testing, and field testing of IDP, including structural and thermal laboratory testing procedures and results. We also give results for a field test in a geothermal well in which circulating temperatures in IDP are compared with those in conventional drillpipe (CDP) at different flow rates. A brief description of the software used to model wellbore temperature and to calculate sensitivity in IDP design differences is included, along with a comparison of calculated and measured wellbore temperatures in the field test. There is also analysis of mixed (IDP and CDP) drillstrings and discussion of where IDP should be placed in a mixed string.