bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tunnels In Oil Sand
Authors: Harris M.C. , Poppen S. , Morgenstern N.R. 
Published: March 2010

Abstract
Deep oil sand deposits may require shafts and tunnels either as access for in-situ oil methods or for direct mining, Only one tunnel, Saline Creek tunnel, has been constructed in oil sand to date (1978). Recent research has made significant contributions to the understanding of oil sand behaviour, but empirical design methods may still have to be used until more experience is gained. Mathematical relationships show some promise in providing a framework for assessing stand-up time and the effects that in-situ recovery processes, such as steam drive, may have.

Introduction
There are several projects which are being considered for the feasibility or mining oil sand where the depth of overburden exceeds economical mining by open-pit methods (EMR 1977). In these methods shafts, tunnels and underground mining are proposed either to provide access for in-situ processes or for direct mining of oil sand as an ore, However, to date only one Jarge diameter tunnel has been constructed in the oil sands of Alberta and hence the underground behaviour of oil sand poses some uncertainties. The purpose of this paper is to assess tunnel construction in oil sand based on the experience gained from the Saline Creek tunnel (Smith et al. 1978), from observations of the behaviour of oil sand both in natural exposures and man-made excavations and from a review of information available in the literature.
The characteristics of oil sand arc discussed, first within the framework of its geological selling and second as a material with unique engineering properties. Consideration is given to the effects of weak clay layers, water-bearing sands and other geological features such as cemented stringers, gas pockets and sink holes as they might affect tunnel construction.

Background
The construction of shafts and tunnels in Alberta's Athabasca and Cold Lake oil sand deposits has recently assumed practical significance because they may be necessary for access to oil sand under overburden depths too great for economical open-pit mining. A recent study (EMR, 1977) indicates that mining of oil sand as an ore may not be practical until world oil prices are higher than they are at present, but it seems likely that in-situ mining, using shafts and tunnels for access only is feasible. At-least one scheme the Rabbitt Kinetic In-Situ Method (Oilweek, 1978), requires shafts through the oil sand to the underlying Devonian limestone.
Conventional design and the construction of shafts and tunnels in soil and in weak or strong rock is a skill largely based on practical experience obtained from previous work. Although oil sand is an oil-impregnated sandstone, observations from present open-pit mine operations have shown that the oil sand does not behave like most sandstones. The oil sand swells and experiences a significant loss of strength as it is exposed by excavation. Recent research at the University of Alberta has provided an understanding of the physical behaviour of oil sand under stress change, and has provided a framework for predicting behaviour.
Solution of a Non-linear Gas Flow Equation By the Perturbation Technique
Authors: Kale Dilip , Mattar Louis 
Published: March 2010

Abstract
The flow of gas in porous media is represented by a non-linear differential equation, even when the pseudo-pressure concept is used. Analytical solutions, in the past, involved linearization of the coefficient by assuming µc constant at initial conditions. This paper solves the non-linear equation by the method of Perturbation, and demonstrates that the effect of linearization is, for all practical purposes, equivalent to having a small negative skin. The validity of the pseudo-pressure approach using µici instead of µu is thus confirmed.

Introduction
The flow of gas through porous media is represented by the well-known diffusivity equation. In the past (Aronofsky and Jenkins, 1953), assumptions of ideal gas behaviour led to the use of "pressure squared" as the variable for analysis of gas flow rate. The standard approach was to use the same fluid flow equations for gas or oil flow, but in terms of p for oil flow and in terms of p2 for gas flow. Later it was shown that the use of p instead of p2 was appropriate under certain conditions for gas flow relationships (Mathews and Russel, 1967). Al-Hussainy and Ramey (1966) introduced yet a third variable, ψ, known as the pseudo-pressure or real gas potential, which allowed for variations in µ and Z2 the viscosity and compressibility factor of natural gas. The relationship of p and p2 to ψ is explained in Aziz et al. (1976).
Because the diffusivity equation for gas flow in terms of the pseudo-pressure involves the least number of assumptions, it is considered to be the most rigorous of the three treatments (p, p2, ψ). However, even though ψ accounts for variations in µ z (viscosity x compressibility factor), the resulting differential equation, Equation 1 (ERCB 1975), still contains a non-linear term, µ c (viscosity x compressibility).
(Equation Available In Full Paper)
where ΔPD is a dimensionless pressure drop, and is defined in the nomenclature along with the other symbols. Because µc is a function of ψ, this equation is non-linear and cannot be solved analytically. AI-Hussainy and Ramey (1966) assumed µc to be constant at initial conditions, uici, and solved the resulting ice linear partial differential equation. The solution is the familiar exponential integral. Ei, solution.
The dependence of µc on p, p2 or ψ was investigated in a paper by Mattar (1979) and it was found that, under certain circumstances, the change in µc can be substantial Therefore, the assumption of a constant µC to obtain a solvable differential equation may be questionable.
It is the intent of this paper to solve the non-linear Equation 1 by the method of perturbation without assuming µc to be a constant. Because it is the variable that introduces the least number of assumptions, it will be used in preference to p or p2.

Extent of Non-linearity-Variation of µc with ψ
The variation of µc with ψ for natural gas is discussed in detail by Mattar (1979). However, a typical relationship is shown in Figure 2.
Economic Modelling a Game of Chance
Authors: Reath Peter F. 
Published: March 2010

Abstract
The requirements for project evaluation and acquisition analysis grow more complex daily, and demand the use of sophisticated computer assistance. What farm do the systems and models take? Can they really predict the future?
The author sets "out a scenario for the use of computer models in this field and, while recognizing their value, cautions that such systems are only extensions of their human creators. As such, they contain not only the rigidity of machines, but also the fallibility of homo sapiens.

INTRODUCTION

The Rules of the Game
In 1866, William Gladstone addressed Parliament with the words, "You cannot fight against the future. Time is on our side." Just over a century later, the future is certainly no more amenable to control, but there is a considerable question as to whether time is on our side. We are in an era of energy mega-projects the lifespans of which can exceed the working lives of those mortals who initiate them. The destinies of many corporations are entwined with these ventures into the uncharted future, and the risks are copious enough to test the most resilient captains of industry.
This situation has in turn created a sharp increase in the importance of economic evaluations using advanced computer systems: a development which may" have far-reaching consequences for the traditional engineering role in projects. To see what is happening, consider some of the following points: The construction of an oil sands plant later in this decade may require average disbursements of around, eight million dollars per day during peak construction years. It may take six years from first production until the capital expenditure has been recovered (eleven years after detailed engineering design is completed), and this is against a background of reasonably proven technology and experience from two working oil sands plants. Estimates of Beaufort Sea and East Coast developments provide similarly mind-numbing statistics.
Even these projections are made within a "comfort zone" which excludes such assumptions as wars or major catastrophes, wide divergences in price versus cost inflation or social revolution which might damage the fabric of free enterprise beyond repair. Thus, the worst ravages of the future are instantly negated by the elementary assumption that economic variables must be constrained within boundaries established by our current experience. Proponents of "Murphy"s Law" are silenced by the wisdom that major diversions from economically reasonable assumptions will either be offset by man"s infinite capacity to survive or we all go down the tube together (a convenient but hardly comforting, point to begin).
Having defined the boundaries for our projections of future possibilities, we have to face up to reality number two: the rules of this game are complex and never static. As a starting point, we have a fundamental equation:
Profit = Revenue - Costs - Taxation
However, a glimpse at Figure I will show that this particular game is run by the state, and the house advantages are several.
The Elimination of the Constraint Equation And Modelling of Problems With a Non-condensable Gas In Steam Simulation
Authors: Forsyth P. , Rubin B. , Vinsome P.K.W. 
Published: March 2010

Abstract
The numerical formulation previously used in CMG's (Computer Modelling Group) steam simulator used an equation set consisting of flow equations and a constraint equation. The effect of analytically eliminating this constraint equation from the basic equation set, thereby reducing the number of primary variables by one, is investigated. It is found that an alternating use of the two equation sets according to certain switching criteria yields the best results.
A problem of convergence to non-physical answers, which arises in the simulation of steam displacement with a non-condensable gas, is described, and a method for circumventing this problem is proposed. The results of various test runs are included.

INTRODUCTION
The equations used to describe the steam or in-situ combustion processes can be divided into two groups. The "flow" equations (energy and mass balance) contain inter-block flow terms; the "constraint" equations (saturations and mole fraction constraint) depend only on variables in a single block(1). It is possible to eliminate the constraint equations analytically from the equation set, and thereby reduce the number of equations per grid block. However, previous in-situ combustion and steam simulators have retained the constraint equations in the basic equation set(2–4). These authors have reported that the addition of constraint equations to the basic equation set results in better stability and convergence rate, and permits larger time steps. As the amount of computation per time step is increased for a larger equation set, it is not clear that the addition of constraint equations will result in a net saving in computing cost.
This 4-equation formalism has been discussed because it is a natural subset of CMG"s in-situ combustion model ISCOM(5), which is a fully implicit simulator. When ISCOM is run on combustion problems, the constraint equations are eliminated analytically. No difficulties have been observed with this procedure(5–6). Consequently, it was decided to investigate the effect of eliminating the constraint equation (1) from the steam model.

Description of the Model
If equation (1) is eliminated from the set (1–4), there are only three "basic" equations left, which express the conservation of oil, water and energy. In order to reduce the equation set, it is necessary to perform variable substitution on the appearance or disappearance of steam, while the equation set remains the same. This is in constrast to the previous method(5), where the independent variables remain the same, but the equation set is switched.
For the situation in which there is no steam in a given grid block, the primary variables associated with each equation are:
(Equation in full paper)
The disappearance of the water phase is avoided using the pseudo k value method(4). The only other fully implicit steam simulator reported in the literature is that developed by Coats(l) as a subset of an in-situ combustion simulator.
Harsh New Rules For Employee And Shareholder Loans
Authors: Parsons Robert B. 
Published: March 2010

Abstract
This month, "Tax Topics" examines the changes proposed in the November 12, 1981 federal budget relating to the taxation of stock purchase and housing loans. The changes, if enacted, will come into effect in 1982 to tax the benefits derived from low-interest and interest-free loans. As a result of public pressure, some transitional rules have been announced since the budget date to phase-in the new rules.

Introduction
Since November 12, 1981, whim Finance Minister Allan MacEachen introduced his proposed sweeping tax changes, there has been a public outcry at the breadth of tax changes and the lack of public discussions preceding the budget. In addition, the original budget was notable in its lack of transitional rules regarding the implementation of many important changes.
The proposed taxation of stock purchase loans and honsing loans is one of the few areas that, due to the furor created, has seen some substantive changes since November 12, 1981. However, the draft legislation is not expected until April or May of this year. so it is quite conceivable that the rules may change yet.
Many taxpayers associated with the oil and gas industry will be particularly hard hit by these proposals, because of the relatively widespread use of interest-free loans in the industry. For junior oil com panies needing maximum amounts of cash resources to finance exploration and development, the use of interest-free loans to enable employees to acquire company shares has been an attractive compensation device.
As the accompanying examples illustrate, although Mr. MacEachen has lowered the top personal income tax rates, the additional amounts that will be included in taxable income can create a greater tax liability.

The New Rules
According to the budget proposals beginning in 1982, employees and shareholders will be fully taxed on benefits derived from certain loans and other forms of indebtedness. The benefits will be determined by deducting actual interest paid, if any, in the year and within 30 days of the end of the year from imputed interest to be calculated at prescribed rates.
The prescribed rate, in future, will be adjusted every three months in relation to the average interest rate on 90-day treasury bills during the first month of the preceding quarter.
Although it was orginally announced that the prescribed rate for the first quarter of 1982 would be set at 19%, because of a decline in interest rates since the budget, the prescribed rate was subsequently reduced to 16% for this quarter. Although a loan bearing interest at a rate below the prescribed rate will usually give rise to a taxable benefit, there will be no income inclusion unless the rate charged is also below the prevailing rate available in financial markets at the time the loan was made.
The proposed new rules will generally apply to all loans and indebtedness regardless of whether issued before or after the November budget date.
Heavy Oil Production By Carbon Dioxide Injection
Authors: Klins Mark A. , Ali S.M. Farouq 
Published: March 2010

Abstract
Currently, there is a great deal of interest in carbon dioxide for the recovery of both heavy and light oils. This paper deals with an investigation of the efficiency of gaseous carbon dioxide as a recovery agent for moderately viscous oils. The paper gives numerical model results, and compares and contrasts the findings with laboratory and field test observations, pointing out the range of conditions over which carbon dioxide is likely to be effective.
The carbon dioxide injection simulator used simulates three- phase flow, and was checked out for numerical dispersion grid effects, material balance, etc. It was then employed for a variety of carbon dioxide injection simulations. The base cases were in qualitative agreement with the reported experimental data.
It was found that over the viscosity range of J 10 1000 mPa.s, carbon dioxide was superior to natural depletion, inert gas injection or water flooding, jar oil viscosities above 70 mPa. s. The gain over water flooding was as much as 9 per cell· tiles in oil recovery, being greater for the more viscous crudes. Oil saturation was an important variable, as oil recovery decreased rapidly with a decrease in saturation. Another significant factor affecting ultimate oil recovery was the critical gas saturation. Viscous oils showed a 27% increase in recovery as the critical gas saturation varied from 0 to 10%. The blow down recovery on curtailment 0/ carbon dioxide injection was about 1 percentile; field values are as high as 4 percentiles. Reasons for this discrepancy are outlined. The amount of carbon dioxide left in the reservoir was used as a measure of the efficiency of the process; it was high for low oil saturations, especially for the more viscous oils.
An economic analysis of the carbon dioxide injection process showed that the economics are tenuous; a variety of factors in addition to the oil price would determine the economic viability of the process.

Introduction
Although there is little debate that a significant amount of oil remains held in the ground by current technical and economic constraints, opinion is widespread as to the proper recovery technique or techniques to unlock these reserves. (Infill drilling and a handful of alternative recovery methods, such as thermal, miscible and improved mobility floods, compete for the over 52 billion cubic metres of United States and Canadian oil (&lt;980 Kg/m3) that remains in place.
Carbon dioxide injection, as one of these processes, has long been thought of as a miscible process best applied in light oils with densities less than 930 Kg/m3. However, immiscible carbon dioxide flooding as part of the suite of enhanced oil recovery methods being tested may be promising in the case of heavy, moderately viscous oils where carbon dioxide injection improves recovery by lowering oil viscosity and promoting swelling.
Deposits of heavy oil total over one-half trillion metres3 in the U.S., Venezuela and Canada. In the U.S. alone, there are over 2,000 heavy oil reservoirs occurring in 1500 fields in 26 states.
Coping With Change'' Customs Issues Upstream
Authors: Parsons Robert B. 
Published: March 2010

Abstract
The complications of the National Energy Program have satisfied even the most gregarious appetites: now customs duty issues related to exploration, development and production of Canada's non-renewable energy resources are promising to excite the palate. The menu offers a wide selection: legislative amendments for the conventional; exotic constitutional issues ifyou delight in the offshore. But watch out. it's not always a free meal!
This month, Tax Topics reviews some of the emerging issues in the customs area on matters related to resource exploration, development or production. We focus on what's ahead: traps and pitfalls opportunities and savings.

Introduction
In recent years coping with tax changes has become a daily preoccupation at companies operating in Canada's oil and gas industry. Life as the tax administrator has not been easy or dull. If recent developments in the customs area hold true, the tax administrator will soon have to buy a "customs" hat and, in some cases, he may want to put it on retroactively. This article intends to describe in non-technical terms, a few of the emerging customs issues as they might affect the oil and gas industry, especially the players upstream. Furthermore, for easy reference, a few guidelines to the administration of customs duties are set out in the Appendix.

Tariff rates-oil & gas industry
Until recently, customs duties have not been of significant concern to companies engaged in conventional drilling programs. As a rule, a series of specific end use tariff items providing low or free rates of duty has governed the importation of a broad range of goods intended for use in the chain of exploration development- production of Canada's oil and gas reserves. The majority of these end use items are found in the 49XXX series of the Customs Tariff.
Except where specifically named elsewhere, goods imported for a qualifying end use are dutiable at the rate set out for these end-use classes. Depending on the use, duty is assessed either at rates that range from 8.4% to 12.1% or, as often the case, no duty is assessed. In some cases, the' end use class names the goods (e.g., blow-out preventors, derricks for drilling rigs, draw works); other end use classes refer to a basket clause (e.g., all other machinery and apparatus for use in...). Rates of duty also vary depending on whether or not the named goods or a good falling within a basket clause, "is of a class or kind made/not made in Canada." Finally, so as not to discourage the manufacture in Canada of goods qualifying for low or duty-free end use rates, materials imported for use in their manufacture are allowed duty-free entry.
As a result, duty-free status has been gained by companies engaged in conventional drilling programs (or their suppliers) on the purchase or importation of a large portion of their capital acquisitions, including:masts or derricks for drilling, servicing or work-over rigs;drilling, servicing or work-over rigs;well logging equipment;