bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring Gas Storage Reservoirs
Authors: Katz Donald L.
Published: December 2007

Monitoring procedures used in underground gas storage operations are reviewed. Besides bringing together the many techniques now used, methods are presented for systematizing the monitoring process.

Introduction

The underground storage of natural gas is a relatively young industry. In some 20 years of major growth, storage facilities deliver to market annually some 1.5 trillion cubic feet of natural gas. Major gas systems deliver from storage as much as one-third to one-half of their total send-out on a cold winter day. Further indication of the industry's maturity is the effort to improve safety of operation and control of gas reservoirs. This paper reviews the monitoring procedures of gas storage reservoirs and suggests ways of systematizing the alerting process so that appropriate action can be taken, should any imperfection in the system appear.

The storage operator is expected to know where his inventory of stored gas resides. He is charged with sending to market large quantities of gas in a short period at planned rates of delivery. Monitoring is the taking of observations which will insure the satisfactory operation of the storage facility. The primary concern is that no unknown gas migration underground is taking place. Early detection of unexpected gas movement — penetration of caprock—movement behind the production pipe — or loss from surface equipment — pipe — or loss from surface equipment — can initiate remedies to minimize any effects on the environment.

Monitoring is interpreted as not only sensing the basic information but also transmitting it to the proper decision center for action. People are a vital part of any monitoring system and must be included in its consideration.
LNG and the Midwest
Authors: Horn John , Bates Bruce L.
Published: December 2007

Introduction

We need first to examine the importance of natural gas as a source of energy both in the United States and the Midwest. Total United States consumption of natural gas in 1969 rose to 20.9 trillion cubic feet. Since 1964, when total consumption was 15.5 trillion cubic feet, consumption has increased nearly 35% on a volumetric basis. These figures are for total gas distributed through utility mains and direct industrial sales but since natural gas now accounts for 99% of the total gas used by the ultimate customer in the U.S., they represent natural gas consumption accurately. The rapid growth of natural gas consumption and its place in the energy market compared to other forms of energy is shown on Figure 1. In 1968, natural gas provided just over 31% of the total energy consumed in the United States. The present shortage of natural gas and the increasing demand for energy points up the need for additional supplies of points up the need for additional supplies of all sources of energy gas, LNG, coal, nuclear power, and fuel oil. We propose to outline how power, and fuel oil. We propose to outline how LNG will serve as an important supplemental supply of energy to help meet spiraling U.S. demands. The growth of population is an important factor in the present energy picture; however, the consumption of natural gas-has increased almost six times faster on a per capita basis. The northeastern megalopolis (from Washington, D.C. to Boston, Mass.) is sometimes thought to have the greatest demands for U.S. natural gas. Consumption of natural gas in 1969 in the six-state area of New Jersey, New York, Pennsylvania, Delaware, Massachusetts, and Maryland Pennsylvania, Delaware, Massachusetts, and Maryland plus the District of Columbia amounted to 2.1 plus the District of Columbia amounted to 2.1 trillion cubic feet. But the 12-state Midwest area of South Dakota, Nebraska, Iowa, Missouri, Illinois, Michigan, Indiana, Kentucky, Tennessee, Ohio, Minnesota, and Wisconsin in 1969 consumed over 5.5 trillion cubic feet or 26% of the total U.S. consumption. This is equivalent to about one billion barrels of oil. Since 1964, natural gas consumption in the Midwest market has grown 41% compared to the U.S. average of 35%. With the shortage of domestic natural gas it is obvious that the Midwest will require major supplies of energy from other sources. LNG will provide some of this energy through the importation of gas from remote regions of prolific gas production to the areas of heavy prolific gas production to the areas of heavy consumption.

THE STATUS OF LNG TODAY

The use of liquefied natural gas (LNG) as an energy source is of great commercial interest today. The problem of equating supply and demand of natural gas has increased during recent years because of the increasing differentials between winter and summer requirements that have resulted from increased gas consumption for space heating.
Engineering A Management Career
Authors: Hawkins Roger E.
Published: December 2007

A PROFESSIONAL DILEMMA

The engineering-management career dilemma came to my attention while serving as director of a management development center at a small private liberal arts college. The professional life of an engineer is limited, and during his late 20's or early 30's he must acknowledge his impending professional obsolescence. He must decide whether to embark on a new career in another profession; namely, management, or to enhance or update his professional training. professional training. Many of our students were engineers who were writhing in the pygmalian agony of determining whether to commit themselves wholeheartedly to the practice of management. This loomed particularly problematic for them because the role of problematic for them because the role of a fledgling or beginner threatened their established image of themselves as highly qualified professionals.

This paper will review several dimensions of this topic. Briefly, these are the changes in attitudes, skills, and career planning necessary to parlay engineering temperament and ability into a successful management career.

MANAGEMENT PRACTICE VS. SCIENCE

Certainly not all professional engineers experience difficulty in adapting to a management career. Those that do, however, find that the very temperaments, skills, and training which served them well in applying their professional knowhow become impediments professional knowhow become impediments which handicap their ability to master supervisory-management duties. Although we have a number of scientific tools which apply to the solution of management problems, there is still a considerable margin of error between the formula's illumination of a problem and actual decision-making.
Canadian Oil and Gas - Reliable Energy Supplies for the Midwest
Authors: Stabback John G.
Published: December 2007

This paper analyzes a special relationship between the United States Midwest and Canada in oil and gas trade.

Increasing interest in Canadian oil supply to the Midwest is reviewed against the widening oil production-demand "gap" in the "lower 48" and studies leading to the looping via Chicago of the Interprovincial-Lakehead pipe line. Recent export pipe line. Recent export levels are discussed in relation to United States-Canadian understandings and the import control system of March, 1970.

Economic, supply and political factors affecting future growth are reviewed. These include relative crude oil prices, exchange rates and Alaskan oil, the present Canadian reserves and deliverability situation and the potential of "frontier areas" and of the tar sands; Government policies in the two countries are, however, regarded as of overriding importance.

Concerning gas, while Canadian potential is great, near-term potential is great, near-term prospects are bleak due to lack of prospects are bleak due to lack of a "surplus". Accelerated reserves development - partly contingent on access to oil export markets - could, however, make possible increasing Canadian gas exports.

Introduction

Oil is the largest commodity in international trade and natural gas is becoming increasingly important in this respect. The major oil concerns are the original "multinational companies". There is growing international interdependence between markets on the one hand and supply sources on the other.

It is against this broad background that I would like to isolate the Midwest area of the United States and examine what I think is a special relationship between it and Canada.
The Nature Of The Ecology Problem Facing Alaska Oil Operators
Authors: Kelly Thomas E.
Published: December 2007

ROBERT SERVICE, POET OF THE NORTH, WROTE:

"IT'S THE GREAT, BIG, BROAD LAND WAY UP YONDER, IT'S THE FORESTS WHERE SILENCE HAS LEASE, IT'S THE BEAUTY THAT THRILLS ME WITH WONDER, IT'S THE STILLNESS THAT FILLS ME WITH PEACE."

ALTHOUGH RECALLING HIS FONDNESS FOR THE YUKON, HIS DESCRIPTION IS ALASKA TO ALASKANS AND WAS PARTICULARLY SO UNTIL A FEW YEARS AGO. ALASKA, THE SLUMBERING GIANT TO WHOM VERY FEW OUTSIDERS PAID MUCH ATTENTION, HAS BECOME THE FOCAL POINT FOR CONFLICT PAID MUCH ATTENTION, HAS BECOME THE FOCAL POINT FOR CONFLICT BETWEEN DEVELOPMENT AND CONSERVATION — MORE APPROPRIATELY LABELED PRESERVATION. AND THE PEACE THAT WENT WITH THE BEAUTY HAS FADED. PRESERVATION. AND THE PEACE THAT WENT WITH THE BEAUTY HAS FADED. AT THE CENTER OF THE CONTROVERSY IS - OIL. PRIOR TO THE DISCOVERY OF PRUDHOE BAY, THE OIL INDUSTRY IN ALASKA, AS WELL AS THROUGHOUT THE COUNTRY, BELIEVED THAT PETROLEUM EXPLORATION AND DEVELOPMENT, AND PROTECTION OF THE ENVIRONMENT-WERE COMPATIBLE. WITH HONESTY AND GOOD CONSCIENCE, THE INDUSTRY ATTEMPTED TO TELL THE STORY TO THE GENERAL PUBLIC AND OCCASIONALLY WAS ABLE TO CITE SPECIFIC EXAMPLES OF HARMONY BETWEEN DEVELOPMENT AND PROTECTION OR EVEN ENHANCEMENT OF OTHER RESOURCE VALUES. THE DEVELOPMENT OF SWANSON RIVER FIELD ON THE KENAI PENINSULA WAS PRIMA FACIE EVIDENCE THAT OIL AND GAS COULD BE PRODUCED IN QUANTITY WITHOUT SURFACE DEGRADATION AND WITHOUT DISRUPTION OF THE FISH AND WILDLIFE HABITAT. CREDIT FOR THIS, OF COURSE, RESTS PRIMARILY WITH THE BUREAU OF SPORTS FISH AND WILDLIFE, WHO MANAGE PRIMARILY WITH THE BUREAU OF SPORTS FISH AND WILDLIFE, WHO MANAGE THE KENAI NATIONAL MOOSE RANGE UNDER CAREFUL AND SOMETIMES STRINGENT REGULATIONS.
Application of Parametric Pulsing to the Operation of Producing and Storage Reservoirs
Authors: Tek M.R. , Gould T.L.
Published: December 2007

The concept of "Parametric Pulsing", first introduced during 1970 by authors and shown to increase gas deliverability over a limited number of producing days in production or injection, has been extended to the operation of entire producing fields and storage reservoirs. producing fields and storage reservoirs. The maintenance of continuing unsteady state conditions whether producing or while shut-in on some reservoirs with well established transmissibility, porosity x thickness, pressure distributions porosity x thickness, pressure distributions (as of zero time) permits much enhanced deliverability when the field is operated on a "pulsed" rather than "continuous" mode. The judicious choice of the optimum number of producing and shut-in days as well as the exact determination of the reservoir conditions during the succession of unsteady-states are obtained from models and specially developed computer algorithms described. Pressure-flow gradients and rate Pressure-flow gradients and rate functions which develop as a result of pulsed operation are discussed. pulsed operation are discussed. When an entire producing or storage field is operated on a parametrically optimized pulsed mode, cumulative deliveries are shown to be enhanced by as much as 95 percent over the continuous mode of operation.

Introduction

The concept of "Parametric Pulsing" was first introduced during 1970 by Tek, Hedges, and Gould as a …"New Approach for Increased Gas Deliverability". The basic idea stemmed from the observation that many systems when operated under steady-state conditions, yield higher transfer rates during short time intervals.

Examples of many such unsteady-state processes, described by parabolic processes, described by parabolic partial differential equations, may be partial differential equations, may be cited in the areas of heat transfer, mass and momentum transfer, reaction kinetics and hydraulics.

Anyone involved in testing or operating gas wells must have observed at some time that when the well is first turned on to flow, starting with equalized pressure distribution, it will produce at high rates for short times before gradually settling down toward a steady-state rate. This of course suggests that a cyclic operation, consisting of several flow periods interspaced with "shut-in" periods interspaced with "shut-in" periods, sufficiently long to nearly periods, sufficiently long to nearly restore the initial uniform pressure distribution around the well bore, would perhaps yield more cumulative flow perhaps yield more cumulative flow over a given time period than that which results from uninterrupted continuous flow.
Water Drive Performance of the Fractured Kirkuk Field of Northern Iraq
Authors: Al-Naqib F.M. , Al-Debouni R.M. , Al-Irhayim T.A. , Morris D.M.
Published: December 2007

The Kirkuk Main Limestone reservoir in Northern Iraq has produced a total of 5,210 million barrels since the field went an production in 1934, of which 3,250 million barrels production in 1934, of which 3,250 million barrels have been recovered since 1961 under pressure maintenance by water drive. Currently the production rate which is balanced by water production rate which is balanced by water injection is 1.1 million barrels a day. Oil is contained in an extensive, highly permeable system of fractures, and in a less permeable matrix comprising several different limestone types with a total thickness of 1,200 feet.

The matrix oil has been estimated from log and core analysis, but fracture dimensions cannot be measured directly. The report describes in detail the method of estimating fracture volumes and matrix oil recovery from the reservoir performance under water injection.

The recovery process under water drive consists of two components:-

the immediate flushing of oil by water from the fractures; and 2. a slower recovery of oil from the matrix by imbibition and gravity drainage.

The second process is quasi exponential with time and in the present analysis it was assumed to be represented by a simple exponential, characterised by a half life and a value of the ultimate oil recovery.

Unusually complete data on oil/water contact movement during the water injection period are available from a number of original observation wells and wells which went wet during the flood history. Rock volume and matrix oil volume submerged during successive six month time steps of the flood have been estimated and matched against volumes of oil recovered during the same time period. The analytical procedure described in period. The analytical procedure described in the report then establishes the parameters:-

Ultimate recovery of matrix oil. The time scale of matrix oil recovery. The fracture volumes of two rock groups with generalized porosity/fracture characteristics.

These data are used to estimate remaining recoverable reserves and provide the basis for forward planning and prediction of future production performance. production performance.
Silica-Lime Systems for High Temperature Cementing Applications
Authors: Hook F.E. , Rosene R.B.
Published: December 2007

In order to provide a reliable cementing composition and reduce variations noted with Portland type cement, silica-lime cements have Portland type cement, silica-lime cements have been developed to provide a new deep well cementing composition. Although Portland type cement has been used successfully for several decades as a well completion material, the complicated manufacturing process produces a cement that varies within limits from batch to batch. These variations are tolerable when cementing the shallow well, but the deep wells, with temperatures from 300 degrees F to 500 degrees F, present a different situation. At these temperatures, normal variations will be magnified to an extent that different batches often perform much the same as different cements.

The silica-lime system consists of a simple mixture of ground quartz sand and hydrated lime. At temperatures above 200 degrees F, lime will react with freshly broken faces of sand and with water to form calcium silicate hydrate. There are only two factors to be considered with this system. Since a surface reaction is involved, the surface area of the ground quartz will control the quantity of calcium silicate hydrate formed. The temperature at which the reaction takes place will dictate the ratio of calcium to silica and water to calcium silicate. This chemistry has been well documented by publications from the autoclaved calcium silicate building products industry in Europe and the United Kingdom. The utility of this system is demonstrated by the growth of the autoclaved calcium silicate products industry over the past few decades. products industry over the past few decades. This composition has been thoroughly tested for thickening time, permeability, compressive strength, shear bond, rheology, and compatibility with some drilling muds. Data are presented to show the concentration of retarder to give adequate thickening time and compressive strength throughout the temperature range of 260 degrees F to 400 degrees F. Strength retrogression data have been gathered up to 28 days. Shear bond and permeability is similar to that of Portland type permeability is similar to that of Portland type cement. This system can be mixed with 60 to 90 percent water as well as with a weighting agent to percent water as well as with a weighting agent to give any slurry density from 12 to 20 pounds per gallon. Because of the surface chemistry, this system can be used at any slurry weight without materially affecting the thickening time. This is a very simple but flexible system that offers more reliability for cementing deep hot wells.
Exploitation Of Minerals In Disposal Brines
Authors: Collins A. Gene , Crocker Michael E.
Published: December 2007

The practice of pooling disposal brines in gaining momentum in be petroleum industry, and large quantities of brines are processed by single disposal facilities. Through a survey of these facilities, the economic value of the minerals in some of these brines was determined. The results indicate that 6 of the 40 sampled brines contain concentrations of minerals and values comparable with those of a commercial brine, 29 brines contain concentrations of minerals more valuable than those found in seawater. One sample was near potable and one was usable for irrigation.

Introduction

The purpose of this study was to determine the composition of the salt water that is disposed of by some of the larger petroleum production facilities in the United States. According to Bleakley, Shell Oil Company disposes of 70,000 barrels per day (B/D) of salt water from the West Lake Verret field in Louisiana by subsurface injection. By subsurface injection, surface disposal, and evaporation pit, Shell Oil's Onshore Division, southern region disposes of about 375,000 B/D. If appreciable concentrations of valuable minerals are present in these waters, their recovery may be warranted. We were unable to obtain samples from these systems for this study.

For the study, samples of the salt waters were obtained from 40 disposal facilities. The samples were analyzed, and the maximum worth, brine value, and brine worth of each sample were determined. These values were compared with values for sea water and a brine that is used for mineral recovery as shown in table 6.

Minerals Recovered from Brines

Ever since someone inadvertently or premeditatively precipitated a compound from a salt solution the precipitated a compound from a salt solution the recovery of minerals from saline waters has been practiced. Salt water was produced from wells solely practiced. Salt water was produced from wells solely for the production of salt as early as 1800. Currently minerals other than sodium chloride that are recovered from saline waters include compounds of the following elements: Lithium, sodium, potassium, magnesium, calcium, chlorine, bromine, and iodine.

Lithium can be recovered by precipitation as lithium carbonate after removal of excess magnesium from a brine.
Multiple Use and Problems of Saline Aquifers in North Dakota
Authors: Noble E.A.
Published: December 2007

INTRODUCTION AND SUMMARY

"A large proportion of the available water supply of North Dakota is saline," is a statement made in a recent U.S. Geological Survey Water Supply Paper assessing the saline water resources of this landlocked state at the geographic center of the North American continent. That federal agency report defines saline water as water containing more than 1,000 ppm dissolved solids; I shall use the same arbitrary definition in this paper. A quick inspection of a list of analyses of municipal water sources indicates that well over half of these sources are saline. Total dissolved solids in these town supplies are almost entirely within the 1,000–3,000 ppm range. Major anions are sulfate and bicarbonate; locally, chloride content is high. Sodium is a conspicuous cation; analyses showing several hundred parts per million are common.

Emphasis in this short paper will be on the "Dakota Aquifer," the most extensive and prolific bedrock aquifer in North Dakota. This aquifer is saline by the above definition and is only locally used as a source of water in North Dakota, although it is more widely utilized in South Dakota. It is the aquifer most commonly used for brine disposal in North Dakota oil fields. Water from the Dakota Aguifer is also injected in secondary recovery programs in some fields. In the agricultural field, natural discharge of saline Dakota water in a several-hundred square-mile area in the state's richest agricultural valley sharply reduces a productive potential that the world may productive potential that the world may someday need. Aquifers are locally present in the unconsolidated glacial deposits that mantle more than half the state, but both quantity and quality in many places are not suited for intensive development or wide application.

It is inevitable that North Dakotans must use saline water extensively, and must therefore look at saline water as a resource to be understood and managed to the best advantage. Feasibility of upgrading the quality of saline water for town supplies is now being investigated, and river diversion projects will introduce other possibilities. projects will introduce other possibilities. Background geologic studies of the nature and patterns of both bedrock and unconsolidated aquifers are furnishing information needed to interpret groundwater flow and chemistry, and to relate the two. Continuing studies are needed, not only for benefication and utilization of water, but also to furnish background knowledge for storage and waste disposal projects.
Sensitivity Studies in Profitability Analysis
Authors: Vogel Lawrence W. , Brons Folkert
Published: December 2007

In this paper a profitability model is developed for an exploratory drilling venture. Probability distributions are outlined for the Probability distributions are outlined for the model parameters and Monte Carlo simulation techniques are used to obtain estimates of venture profit, venture risk and a probability distribution of the profit.

Reported in the paper are the results of several sensitivity studies utilizing the data obtained in the profitability simulation. The sensitivity studies are designed to assist the decision maker in assessing the uncertainties inherent in an exploratory venture.

One sensitivity study analyzes the effects of changes in parameter values on venture profit and risk. This is done through the use of a Sensitivity Ratio which facilitates the measurement of the relative importance of changes in various model parameters on the value being observed.

In another study, two aspects of the convergence of the expected profit with model executions were analyzed. The first investigated a possible relationship between model executions and an accuracy range of profitability. No such relationship was found to exist. The second aspect investigated the differences in profitability simulated after 1000 and 10,000 model executions. No significant differences between profitability values was found.

A third study analyzed the relationships between return, risk and the number of wells drilled in the venture. Mathematical relationships were found which could relate these factors.

Introduction

Freedom from uncertainty is a luxury rarely enjoyed by the contemporary decision maker. In a society characterized by change, uncertainty is an established and accepted fact of life. This is especially true in the Petroleum Industry. Notwithstanding the Petroleum Industry. Notwithstanding the difficulties, the decision maker desires an evaluation which in some way measures the effects of these uncertainties.

In the face of uncertainties related to an exploratory venture, the most recurring questions are of the form, "What if. . . ?" What if the posted price of oil increases by 30%? What if we drill 30 exploratory wells rather than 20? How about 10 wells? What if the cost of a dry hole doubles?
Present Value of Hyperbolic Decline Production
Authors: Dietz D.N.
Published: December 2007

A new method for calculating present value of hyperbolic describe for all hyperbolic constants and all interest rates is presented that uses incomplete gamma functions. When the hyperbolic constant is an integer, the gamma function cannot be used and a new function is introduced to replace it.

Introduction

Brons and McCarry calculated present values of hyperbolic decline production for the cases in which the hyperbolic constant is either one (harmonic decline) or two. These are by far the most important practical cases, but it is still intriguing to find a universal solution to the problem. problem.

Derivation of Formula

Production is fully defined if the rate is Production is fully defined if the rate is given as a function of time. In many cases one uses the cumulative production and the rate of production decline. Thus there are four variables and there are six possible combinations of two variables. The relation between any two may serve as a definition. This study is based on the choice of production rate and time as the two basic variables.

(1)

Different wells may have production graphs of the same form, but do not necessarily have the same starting time on their common graph. in other words, there is no magic in taking the moment of initial production as zero on the time scale. A universal and mathematically more significant zero point for the time scale can be found where point for the time scale can be found where formula (1) tends to infinity.

(2)

The defining formula is thus simplified to

(3)a where (q t) is a single proportionality constant, i i though its components may differ for wells with different starting times on the same mathematical production curve. production curve. The production curve is fully characterised by the parameter a; the proportionality constant and the boundary conditions (time of start and stop) should not cause any difficulties.
PCP - A Computerized Data System for Manually Operated Oil Fields
Authors: Milton L. Harold
Published: December 2007

"Pumper Controlled Production" (PCP) is a system for gathering, storing, and recalling information on the status and producing capability of oil wells. This producing capability of oil wells. This system has been operational within Humble Oil and Refining Company's South Texas Division since the spring of 1968. Adapted to the IBM Model 1130 computer, the PCP system provides storage on disk files for data reported by field personnel regarding oil well status (Producing or shut-in? If shut-in, why?) and tested capability (bbls/day, gas-oil ratio, water cut, etc.). Available subroutines sort and manipulate the data into output formats useful for solving a variety of problems routinely encountered in the surveillance of oil producing properties. At present the operations of properties. At present the operations of 60 oil fields are being monitored with the PCP system.

Introduction

Some four years ago a need was recognized within Humble Oil and Refining Company's South Texas Division for a better tool to aid in maintaining a desirable level of surveillance over oil production. Rapid changes in well production. Rapid changes in well producing characteristics necessitate prompt producing characteristics necessitate prompt reaction by field and office personnel to sustain production volumes. In addition, permanent adoption of the Texas lease allowable assignment system in May 1968 (temporarily authorized during the 1967 Mid-East emergency) granted additional flexibility in scheduling production which had not been possible with the old "well allowable" system. This new allowable system permitted operators to transfer allowable" among wells within the same reservoir and/or field in order to optimize casinghead gas and gas-lift volumes and minimize water production. To maintain control of the rapidly changing field conditions and also benefit from the operating efficiencies offered by the new regulations called for collecting, transmitting, and storing large amounts of information on the status and producing capability of the wells.
Pressure Buildup in a Linear Gas-Condensate System
Authors: Pascal H. , Dranchuk P.M.
Published: December 2007

This paper examines the pressure buildup phenomenon for a gas condensate in a linear phenomenon for a gas condensate in a linear porous medium. The study considers the porous medium. The study considers the situation where the liquid-phase saturation is below the critical value (the liquid is immobile) and nondarcy flow of vapor occurs.

The results obtained indicate that the pressure buildup test may be used for the pressure buildup test may be used for the insitu determination of permeability, inertial resistance coefficient and liquid-phase saturation at the outflow face.

Introduction

Fluid flow through porous media depends upon the properties of the medium and the fluid, the physical laws that govern such flow and the initial and boundary conditions imposed. Consequently, if the laws governing flow are known and may be expressed mathematically, flow behavior can be predicted for any system for which the medium and fluid properties are known and the initial and boundary conditions are specified, by conducting the necessary mathematical experiments. On the other hand, given a mathematical statement of the laws governing flow and the fluid properties and initial and boundary conditions, observations taken while fluid flow occurs may be used to determine the properties of the medium. properties of the medium. In the exploitation of petroleum reservoirs, it is important that one be able to predict how a given reservoir will behave under various production schemes. It is equally important production schemes. It is equally important that well and field behavior be employed in the evaluation of reservoir properties.

In the particular case of gas condensate reservoirs, differential equations describing flow are available and numerical solutions have been developed so that the prediction of behavior is possible where reservoir properties are known. However, the development of closed form solutions for these equations appears to have been neglected so that the interpretation of field, well and laboratory tests results is at best uncertain.

It was, therefore, the object of this work to develop approximate analytical solutions to the differential equations describing gas-condensate flow through a simple porous medium and to show how these solutions might be used to interpret experimental observations.
High Pressure Miscible Gas Displacement Project, Bridger Lake Unit, Summit County
Authors: Burt R.A.
Published: December 2007

The Bridger Lake Unit is a 15,600 feet Dakota sand reservoir. The field was discovered by the Fork A No. 1 in December 1965. Since then, nine producing wells and two dry holes have been drilled to develop this near shore marine strat trap. laboratory tests indicated gas-crude miscibility at 5300 psi and 225 degrees F reservoir temperature. Gas injection was initiated in April 1970 and response to re-pressuring was observed in December 1970. Miscible pressure is expected in late 1971, and miscible recovery should be 80 percent of the swept reservoir volume.

Introduction

The Bridger Lake Unit is located about 81 miles east of Salt lake City, Utah, and twenty-five miles south of Lyman, Wyoming in Summit County, Utah and Uinta County, Wyoming, as shown on the attached index Trap, Figure 1. Township 3 North and Ranges 13, 14, and 15 West are in Utah and portions of 12 North, Ranges 114 and 115 West are in Wyoming. The field was discovered on December 17, 1965, with the Fork A No. 1 in Section 25, T3N, R14W. This Dakota sandstone stratigraphic trap has an average depth of 15,600 feet. Average ground level elevation is 9000 feet above sea level. The Unit was produced by reservoir oil expansion until April 4, 1970, when gas injection started. All produced gas less lease fuel and approximately 13 MMCFD of purchased gas are being injected. purchased gas are being injected.

Development

Since discovery, nine producing wells and two dry holes have been drilled. One producing well has been converted to gas injection, and one dry hole has been converted to water disposal. Table 1 summarizes the completion data for these wells. In general, 13-3/8 inch conductor pipe is set at 400–500 feet, and 9-5/8 pipe is set at 400–500 feet, and 9-5/8 inch intermediate is set at about 9000 feet. A full string of seven inch is run for production casing. A permanent packer is set above the perforations and 3-1/2" tubing is set into the packer. The first two wells were drilled with 2000 and 3000 feet of intermediate casing.
Deepwater Development Santa Barbara Channel
Authors: Rigg A.M.
Published: December 2007

In the 1968 Sarita Barbara Channel Lease Sale Humble acquired an interest in 47 offshore tracts. Of the Humble-operated properties, 80 percent are in water depths properties, 80 percent are in water depths exceeding 600 feet and 30 percent are in depths exceeding 1200 feet. Activities during the past 3-1/2 years include deepwater exploratory drilling and the development of deepwater producing technology.

About 30 wells have been successfully drilled in the Channel in water depths to 1500 feet. Two of the floating rigs have been equipped with special deepwater drilling systems. These systems are basically an evolutionary extension of proven floating drilling technology. proven floating drilling technology. Development plans include the use of deepwater platforms supplemented by submerged production systems. Design studies indicate the feasibility of extending platforms to 1000 foot water depths in the Channel. These structures are designed to resist the dynamic forces caused by earthquakes and storm waves, and are extensions of proven platform design and construction techniques.

The submerged production system developed by Humble includes clustered underwater wells drilled from a floating rig, manifolded together on a submerged structure, and produced to a nearby platform. Well control, monitoring, and servicing are performed remotely from the platform. The SPS is maintained using a remotely controlled manipulator. A 3-well SPS is now being land tested.

This paper discusses Humble's deepwater floating drilling activities and the development of technology for producing deepwater acreage in the producing deepwater acreage in the Santa Barbara Channel.
Applying Quantitative Risk Assessment to Casing Design
Authors: Keilty I. D. , Rabia H.
Published: December 2007

"There are three kinds of lies: lies, damned lies and statistics" - Mark Twain, ca. 1890

In 1993 British Gas decided that it would be advantageous to explore the possibility of developing a new casing design methodology, based on probabilistic concepts and historical data. This became necessary in order to align drilling design practice with that of other disciplines within the E&P group. For example, it was considered uneconomic to design a well to last for ever when platform life-spans were of the order of twenty years.. To date, British Gas has been encouraged by its findings, and the potential benefit from such an approach, demonstrated through initial studies into current casing designs.
Innovative Technology for a Cost Effective Land Rig
Authors: Mehra Sachin , Bryce Tom
Published: December 2007

Sedco Forex are currently building a new land drilling rig based upon the SIMPLER* concept. This SIMPLER* concept reviewed a wide range of issues associated with the well construction process and developed an innovative approach to drilling operations resulting in significant cost savings. The basis of this novel approach is to re-engineer and integrate the well construction activities with regards to personnel and equipment, and make extensive use of cost-effective technology from oilfield an<J non-oilfield applications.

The use of multi-skilling and integration of personnel implies a smaller rig crew which results in direct and indirect cost savings. However, smaller crew also implies mechanisation of labour intensive tasks which not only reduces personnel exposure to hazardous activities, thus increasing safety, but also increases efficiency, thus reducing well costs. Smaller crew also implies improvements in rig design and material selection for minimum maintenance, ease of cleaning, etc.

This paper will briefly describe the methodology used for the rig design, which takes into consideration not only operator's priorities and needs, but also, local conditions and constraints. These issues combined with a simplified client/contractor relationship leads to a "fit for purpose" rig design.

In detail the paper describes the application of various cost effective technologies used on this land rig to achieve objectives of well cost reduction, improvements in HSE performance and rig mobility. Finally, it is explained; how these initiatives have influenced the overall rig design, showing that the use of innovative technology can have a marked positive effect on the economics of our future energy exploitation.
A Predictable and Efficient Short Radius Drilling System
Authors: Hill David , Askew Warren , Tracy Pat , Koval Vernon
Published: December 2007

A short radius drilling system has been designed and used commercially in reentry-sidetrack horizontal wells. The system consists of a unique articulated mud motor and a retrievable MWD tool. The articulated motor has a design that allows it to be used in both the build and lateral sections of the hole, reducing the number of motors required on location. The motor can be rotated in the lateral section for faster drilling rates, angle holding, less friction, and longer reaches. The build rate of the motor is smooth, predictable, and easily changed on-site. It has been used with both PDC and rock bits, giving the operator and the directional driller greater flexibility and better efficiency.

A set of case studies highlights the benefits of the system. Four wells, with curve radii between 75 and 260 feet (build rates between 75°/100' and 22°/100’) demonstrate the flexibility and robustness of the system. The drilling parameters, hardware and tubulars used are examined.
Balanced Risk Management of Drilling Process Accelerates Field Development at Reducing Horizontal Well Duration and Cost
Authors: Ogidan Biodun , Akinmoladun Toba
Published: December 2007

This paper addresses CHANGE and the process for managing associated challenges in well construction. It is based on 2 years of continuous drilling of horizontal wells in a desert environment, using a trailer mounted land rig.

Adopting a balanced risk management approach in introducing CHANGE to various critical operations, activities and contracting relationships, a carbonate reservoir in the Saih Rawl field in the Sultanate of Oman is being successfully developed with continuous cost reduction using a slim casing design.

Cost effective development of the Saih Rawl field is so successful that an initial plan of 6 medium radius horizontal wells has been revised to an actual plan of 30 wells. This medium depth (3000m) wells have been drilled back-to-back and at more than a 20% reduction in time and cost.
IFP's Computerized Optimization System for Turbodrilling
Authors: Gosselin J.C.
Published: December 2007

During the drilling process the down-the-hole drilling rate may be quite different from the surface feeding speed due to drill pipe elasticity. In turbodrilling, for example, the turbodrill may stick in the hole bottom while pipes are still being fed at the surface with no other result than an increase in the weight on the bit. Conversely, when the pipe feed is arrested at the surface the bit may "drill off."

An accurate measurement of the down-the-hole drilling rate has been developed and success fully tested by the IFP. The system includes a real time computer which calculates the mean value of the drilling rate for each cycle of the mud pump. This computerized drilling rate is thus valuable in both continuous and transient movement.

Knowledge of the down-the-hole drilling rate makes possible an automatic real time optimization of the turbodrilling process. This optimization is based on the fact that the drilling speed passes through a maximum for a certain value of the weight on the bit.

In the automatism developed by the IFP the weight on the bit is slightly increased and decreased in alternation so that its mean approximates an optimum value. This turbo-drilling optimization was conceived, developed and tested with the help of the IFP's experimental "flexodrilling" rig. Results obtained in December 1970 seem very encouraging and indicate future adaptability to more conventional turbodrilling with rigid pipes.

Optimisation of the drilling rate may not, however, be enough to ensure optimization of the drilling cost which obviously should be the ultimate goal. When turbodrilling with diamond bits whose footage is very high, optimization of drilling rate would of necessity result in optimization of drilling cost. On the contrary, when drilling with tricone rock bits, the rate of bit wear and tripping costs must be taken into account in order to ensure a minimal drilling cost. This involves continuous measurement of the degree of bit wear—easily accomplished in flexodrilling but very difficult in the case of conventional turbo-drilling.
Remote Drilling Operations Offshore Sakhalin Island, Russia
Authors: O’Meara J. E. , Yarwood D. J. , Mandel A. Y.
Published: December 2007

This paper reviews an operator's experience in drilling two offshore wells in Russia in 1992. The wells were drilled using a Russian rig and services with the exception of electric logging, cementing chemicals, drilling fluids, and testing. Some unique inroads were made in contracting and logistics. This paper identifies the Russian and western services and materials used to drill these wells, the problems encountered in conducting the operations, and the cooperative effort established between the operator and the Russian contractor.
Chad: Remote Drilling Operations
Authors: Eads R. W.
Published: December 2007

Chad is a central African country stretching over 1450 kms long and 450 kms wide and is remotely situated in regard to proximity to any significant industrial / commercial centers. The country is landlocked and bordered by six other African countries. It is a sparsely populated country with approximately 6 million people. The economy is agricultural based and has limited infrastructure to support heavy industries. The remoteness of the area has created special challenges for hydrocarbon exploration since this work began in the 1970's. The country is split into essentially two climatic zones, desert climate of the barren Sahara in the north and a sub-Saharan savannah in the south with dry and rainy seasons. In the south the rainy season stretches from June through October and, due to the veiy heavy monsoon rains, is a significant factor in executing drilling operations.

Esso Exploration and Production Chad, Inc. has been active in exploration and appraisal activities in Chad since 1984, shooting 12,500 kms of seismic and drilling 24 wells. This paper will discuss the performance of several drilling campaigns in Chad and highlight the various other challenges such as logistics, security, work force safety, and medical/health aspects of the operation that consume as much, and sometimes more, effort than the drilling itself.
Using a Temporary Semi-Submersible MODU, the Ocean Voyager, on a Pre-Laid Floating Production Facility Mooring
Authors: Ettle R. E. , Bamber P. J. , Dove P. G. S. , Wilson H.
Published: December 2007

A large, independent Operator drilled three discovery wells and installed a 24 well template at Garden Banks 388. Two 12 inch pipelines were laid to the location. The Operator also designed a Floating Production Facility (FPF) which consisted of an Ocean Victory class senli-submersible moored to a permanent* 12 leg, catenary mooring system. The FPF conversion, due for completion in January, 1995, fell behind schedule. The Operator desired to stay as close to schedule as possible by temporarily substituting a semi-submersible drilling unit to complete the discovery Wells and tieing them back to the 24 well template.

Each pre-laid mooring leg consisted of a 25 metric ton anchor, a spiral-strand ground wire, a dip-zone chain, a spiral-strand catenary wire, and a submersible buoy assembly. First, laying additional mooring legs between the twelve pre-laid legs was considered. This was ruled out because of the danger of tangling mooring legs and damaging the relatively fragile spiral-strand construction wire ropes in the pre-laid mooring legs. Second, mooring a semi-submersible MODU to the existing pre-laid mooring legs was evaluated and selected. The MODU Ocean Voyager, similar to the FPF prior to conversion, was used. One advantage of using the pre-laid moOrings and a similar unit was that the hook-up and disconnect procedures could be tested prior to the arrival of the FPF. These procedures were refined considerably.

The initial hook-up was completed in December, 1994. Two similar 6140 BHP anchor-handling, towing, supply (AHTS) vessels were rigged with an additional two drum winch and a shallow-depth, diving spread to connect the legs. Four of the pre-laid mooring legs were left idle. Despite some difficulties, the hook-up was completed in nine and one-half days which included four days of weather delay. Disconnecting the moorings was completed in May, 1995. A single AHTS vessel was rigged with an additional two drum winch and a large A-frame over the stern* Because Of the revised procedures, considerably less diving was required. Using only one AHTS vessel further reduced costs and required only seven days, including two days of weather delay, to disconnect the moorings.

Using the temporary semi-submersible MODU allowed the Operator to complete and test two wells and connect the wells to the template with jumpers. Thus, although the FPF arrived five months late, getting production on stream should be only two months behind schedule.