bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Logging Method for Enhanced Coal Grading
Authors: Johnston D. J. , Gales R. H. , Ahmed U.
Published: December 2007

The new surge in drilling for coalbed methane gas has increased the need for quantitatively defining the grade of the various coal seams. The most common measurement for grading the coal seams has been through the use of formation bulk density. Empirical algorithms have been developed which use the formation bulk density to rank coal in terms of proximate analysis. Such empirical analysis has also made use of the Litlio-Density (LDT*) with its Photo Electric Factor (PEF), neutron, and resistivity measurements in recent years. New methods need to be developed that do not depend on empirically derived algorithms so that the coal grading analysis can be significantly improved.

The addition of data from the Geochemical Logging Tool (GLT*) to a LDT/CNL (Compensated Neutron Log) and resistivity logging suite offers such an opportunity. The GLT measures natural activation and prompt neutron capture gamma rays from which it produces measurements of the most abundant, and a few trace inorganic elements. This paper illustrates the need for development of a coal ranking and grading model based on the elemental analysis. For proper application of the model, it is necessary for it to be calibrated to core measurements (ie. rank of the coals).
Laboratory Tests To Determine Parameters for Hydraulic Fracturing of Coalbed Methane
Authors: Penny G. S. , Conway M. W. , Klem R. C.
Published: December 2007

A series of laboratory experiments have been conducted with specially designed equipment to aid in quantifying the pressure drop of proppant-laden slurries while flowing between coal, and measuring the conductivity of various proppants once placed in a coal fracture.

The rheology and proppant transport of borate-crosslinked fluids with and without proppant has been evaluated in a slot with walls cast from the surfaces of fractured coal, in an effort to quantify the impact of tortuous coal fractures on the pressure drop down the fracture. A second device has been constructed to view the flow of slurries through cleats of various sizes. Data is presented on the measurement of pressure increases due to bridging vs cleat size, proppant size, concentration and rate.

The long-term conductivity and permeability of various sands have been measured between fractured Fruitland Coal. Predictive equations have been developed to predict permeability between coal vs sand sieve size, and predict loss of permeability due to embedment. Non-Darcy flow factors and constants are presented for calculating non-Darcy flow vs sand type and size between coal.
Damage to Coal Permeability During Hydraulic Fracturing
Authors: Puri R. , King G. E. , Palmer I. D.
Published: December 2007

Coalbed methane wells are routinely fracture stimulated using gelled fluids and proppants. Surprisingly, there is no published report on the compatibility of the coals with fracturing fluids containing polymers, surfactants, biocides, friction reducers, and other chemicals. The objective of the research presented here was to understand and measure the change in coal permeability after it was brought in contact with hydraulic fracturing fluids.

The permeabilities of whole core samples of coals from San Juan and Warrior Basins were severely damaged (5-10 fold reduction) after they were exposed to gelled fracturing fluids that had been broken and filtered repeatedly. Efforts to restore coal permeability by prolonged flushing with water and HC1/HF solutions were unsuccessful. While damage to coal permeability appears to have been caused by sorption-induced swelling of the coal matrix, some plugging of the cleat system by residual gels cannot be ruled out.

Based on limited lab data, it appears that even water containing low concentrations of friction reducing polymers can cause significant damage to coal permeability. These results are alarming since extensive damage to coal permeability by gelled fluids and friction reducing polymers could negate most of the benefits of a large effective wellbore radius created during an expensive fracture stimulation. Field comparison of well productivities suggest that, in general, small low cost propped water fractures are as effective, if not more, as large high cost propped gel fractures. It is anticipated that coal permeability damage would be exacerbated in thin, low cleat porosity, high permeability coal seams.

It is recommended that every effort be made to avoid contacting coals with gelled fluids, polymers, or liquid chemicals. Furthermore, remedial workover treatment should be considered for coal wells that could have been damaged in the past by hydraulic fracture stimulation.
Efficient Algorithms for Computing the Bounded Reservoir Horizontal Well Pressure Response
Authors: Thompson L. G. , Manrique J. L. , Jelmert T. A.
Published: December 2007

In recent years, horizontal wells have assumed an ever increasing role in the production of fluids from hydrocarbon reservoirs. While these wells significantly improve productivity in many cases, they also present difficult interpretation problems to engineers who must analyze and predict their behavior. In particular, analysis of pressure transient well test data and prediction of rate decline behavior are not straightforward. This is due to the complex system geometry; i.e., pressure and rate behavior are affected by reservoir boundaries, anisotropy, well length, well location in the reservoir, etc. Our major purpose is to present simple efficient algorithms for generating horizontal well pressure and rate responses, to facilitate analysis and prediction in these complex systems.

Analytical solutions for the pressure response for a uniform flux horizontal well in a finite anisotropic sealed rectangular box reservoir is well known and documented in several previous publications. The exact (constant rate) solution involves a product of three infinite series, which (if not treated carefully), can require a large computational effort to evaluate. The first objective of this paper is to show how the solution can be accurately evaluated over all time ranges with minimal computational effort. (In test runs on an IBM compatible 20 MHz 386DX, 12 log cycles of pressure data encompassing all flow regimes, were generated in under 9 seconds.)

Using the constant sandface rate pressure response, we show how to efficiently generate the variable sandface rate pressure response in the reservoir for both homogeneous and dual porosity systems. In this case, we work in both real and Laplace space to optimize the computational speed. As examples, we show how the method is applied to generate wellbore pressure response when wellbore storage effects are important, and to generate decline curves for constant wellbore pressure production.

Finally, using the Principle of Superposition in time, the pressure response for production at a sequence of constant rates (with or without wellbore storage effects) is generated. Buildup is included as a special case of multiple step rate production.
Use of the Borehole Television Camera and the Low-Volume Flowmeter to Identify and Measure Gas Flow in Low-Permeability Formations
Authors: Walbe K. , Collart D.
Published: December 2007

Within many of the low permeability gas reservoirs of the world identification and measurement of gas entries is difficult due to the low volume of the flow. Also, in many areas, identification of natural fracturing is important since much of this fracturing is related to better production within the low permeability formations.

During logging operations the Borehole Television Camera (BHTV) is capable of giving a real-time observation of the wellbore by use of a colour television camera mounted on the end of the camera tool assembly. This camera transmits a picture directly to a monitor within the logging truck. Observed oil and gas entries are noted and natural fracturing can be observed. Also, with the BHTV's internal gyroscope the orientation of the observed fracturing can be recorded. Twin VHS videotape recorders record the logging run for a permanent client record.

The Low Volume/High Resolution Flowmeter (HRFM) is used in conjunction with the BHTV in both open and cased hole logging as it is capable of measuring gas flow down to a fraction of an MCF. With the HRFM, flowrate is determined by injecting a tracer gas into the gas flow1. The dilution of the tracer gas is then measured at a downstream detector. Mass flow is therefore determined by this method rather than the velocity of the gas in the wellbore as measured by conventional production spinner surveys.

Both the BHTV and the HRFM are capable of being run in vertical and horizontal open and cased holes.
Horizontal Wells: Concepts in Reservoir Evaluation
Authors: Jacobson S. J. , Fett T. H. , Singer J. M. , Ahmed U.
Published: December 2007

The primary challenge in evaluating a horizontal well is to clearly identify what is needed and what is done with this information. The formation parameters that best define naturally fractured formations are quite different from those associated with matrix permeability reservoirs. The need for logging tools will also be different. And, the difference in the measurement geometry between the vertical and horizontal settings for each type of tool further complicates the evaluation.

This paper is comprised of four parts. The first examines current client needs in horizontal well evaluation for both the naturally fractured and matrix type reservoirs. Next, a basic view of the geometrical considerations in the transition from the vertical to the horizontal depth frame is discussed. This is followed by discussion of the measurement characteristics of the most common openhole tools as they pertain to fractured and matrix reservoirs. The paper concludes with several interpretation case examples.
Modeling the Geochemistry of Scale Formation and Formation Damage in Carbonate and Sulfate-Bearing Clastic Reservoirs
Authors: Dunn T. L. , MacGowan D. B. , Surdam R. C.
Published: December 2007

Chemical divide pathway models have been shown to be useful for delineating the evolution of formation waters and the rock-water interactions of reservoir systems. The physical and chemical processes which formation fluids undergo during production can be modeled by pathway methodology. Since these processes may result in scale formation and formation damage they are of interest to production engineers and geologists. We have developed a pathway of critical divides for the processes involved in the formation of scale minerals accompanying production from sulfate mineral bearing clastic reservoirs.

The critical divides characterizing these processes involve the following: 1) the presence or absence of sulfate bearing minerals within the production fluid contacted volume; 2) the presence of sulfur-rich petroleum; 3) the presence of iron within the formation and production line; 4) the ratio of the concentration of bicarbonate to hydrogen sulfide; 5) the mixing or dilution of the formation waters; 6) the introduction of sulfate-reducing bacteria and 7) the magnitude of pressure and temperature reduction during production. The model qualitatively predicts the liklihood of: sulfate, sulfide and carbonate mineral precipitation and dissolution within the production tubing or the formation. The prediction is based upon the pathway of interactions between production fluids and the reservoir material as well as the insitu geochemical conditions.

This pathway model has been developed from the production histories for Weber sandstone fields and has been applied to anticipated scale problems within the Tensleep and Minnelusa Formations of Wyoming during CO2 treatments. The model indicates that problems of scale formation will potentially be the greatest in the Minnelusa and that scale formation and formation damage due to CO2 injection in the Tensleep will be minimal.
Implications of Recent Laboratory Experimental Results for Hydraulic Fractures
Authors: Johnson Edward , Cleary Michael P.
Published: December 2007

Extensive laboratory experiments on hydraulic fracturing have been performed with a convenient and proven apparatus, developed over the past ten years at MTT. Results of these experiments are presented, for instance: Dimensions of created hydraulic fractures with various injected fluids and flow ratesPressure measurements along the fracture lengthPressure responses to injection of various fluid sequences (e.g. viscosity and flow-rate variation)

These measurements generally confirm a variety of elastic models developed by Cleary in the early 1980s, which have since been widely adopted by the industry. However, we have had to greatly modify such models over the past five years, because the predictions of such purely elastic models do not seem to agree with most field measurements (e.g. with net pressure), suggesting that most existing industry models are inadequate for practical applications. The reason for such discrepancies between lab and field behavior is traced to nonlinear rock response in the near-tip region of the fracture, which we generally call the leading edge.

Other implications of these results for field applications are discussed, in particular with regard to the following primary issues: The role of fracture propagation in shut-in analysisThe role of fluid rheology in fracture openingThe importance of near-wellbore tortuosity in interpretation of pressure responses measured in the fieldThe role of stress barriers in providing only partial containment of height growth

It is suggested that current industry concepts need major revision on these and other issues (see related paper, Ref. [1]).
Characterization of Low-Permeability Dry Gas Reservoirs in the Arkoma Basin
Authors: Chen S. , Robbins R. E.
Published: December 2007

The exploration and development strategy can be strengthened with improved understanding of reservoir characteristics. For this purpose, the characteristics of low-permeability gas reservoirs in the Arkoma basin are examined in this paper by analyzing 75 wells in a seven county area. The study area covers portions of Crawford, Franklin, Logan, and Sebastian Counties in Arkansas, as well as, Latimer, Leflore and Haskell Counties in Oklahoma. The examined reservoir characteristics included a geological background, reservoir fluid and rock properties, formation evaluation, and production performance.

Of the three types of reservoirs classified in this paper, i.e. (I) relatively high porosity/high permeability, (II) relatively low porosity/low permea-bility, and (III) relatively high poro-sity/low permeability, Type III reservoirs are the most difficult to characterize because of a dual porosity system in the sand-stone matrix. The matrix pore system is primarily composed of varying amounts of intergranular and dissolution porosities. How to characterize this type of reservoir is the main effort of this paper.
Geologic Influences on the Location and Production of Antrim Shale Gas, Michigan Basin
Authors: Manger K. C. , Oliver S. J. P. , Curtis J. B. , Scheper R. J.
Published: December 2007

The Michigan basin's Antrim Shale is one of the most actively drilled gas plays in the United States. Last year, Otsego County, the focus of current drilling activity, was among the leaders in gas well completions.

The Antrim is a geologically complex target. Gas producing horizons, located in the black shale facies, are primarily the result of a combination of high kerogen contents and permeability enhancing fracture systems. Preliminary depositional environment and facies work is being incorporated into a depositional model which will assist in the identification of possible areas with greater organic matter preservation. Structural mapping has located subsurface geological variations likely to influence the development of fracture systems. Combined, these geologic factors suggest where gas generation and storage, and permeability are sufficiently enhanced to create economic completion targets.

All Antrim wells require stimulation treatments. Stimulation design and success, in part, is affected by the Antrim stratigraphy. Mineralogie and lithologie differences between the black shales and the gray shales that bound them appear to influence the response of the Antrim to hydraulic fracturing. Correlation of core analyses to geophysical logs will enable better location of target horizons and better control in the design of well completions.

The Antrim appears to be geologically complex in the study area and this complexity has significant influence on gas productivity. This paper presents initial results from a geologic evaluation in a four township area of southeastern Otsego County, the center of present activity. The purpose of this study is to use geologic factors to better define the location and production of gas from the Antrim Shale. Incorporation of these results in designing exploration and exploitation strategies could enhance gas production.
Modeling the Effects of Time, Temperature, and Shear on the Hydration of Natural Guar Gels
Authors: Stromberg J. L. , Brown D. , Curtice R. J.
Published: December 2007

Laboratory work has been performed and a mathematical model formulated to describe the time, temperature, and shear effects on hydrating gels produced from natural guar-based concentrated liquid gelling agents. This same model has been applied to field scale fracturing equipment and allows the prediction of viscosity development at any point in the system. This mathematical model can be a valuable tool to equipment and job designers. The model allows the designer to determine the most feasible means of producing a desired viscosity by predicting the combined effects of time, temperature, and shear on hydrating gel.
Horizontal Well Performance in a Layered Carbonate Reservoir
Authors: Pieters D. A. , Al-Khalifa A. J.
Published: December 2007

A heterogeneous carbonate reservoir displaying a characteristic sequence of high permeability layers above low permeability layers and undergoing peripheral waterflooding, a non-uniform flood front usually develops. Oil in the tight facies is normally trapped or bypassed when water preferentially sweeps the upper clean facies. Recovery of this bypassed oil is often complicated by the presence of overlying water. With the advent of horizontal well technology, the question arises as to whether or not this new technique can improve the recovery from these heterogeneous reservoirs.

This paper examines the use of a horizontal well and compares the result to that of a vertical well in the type of reservoir described above. A 3-0 simulation model was constructed of a localized area within the reservoir. Vertical and horizontal wells were simulated in separate cases of decreasing vertical permeability between the permeable and the tight zones. Model runs were also made with varying layer locations for the horizontal well.

Results indicated that horizontal wells in the tight facies recovered no more oil from the dirty than a vertical well penetrating the entire reservoir thickness. Furthermore, the horizontal well in the tight facies recovered the same percentage of permeable to tight as a horizontal well completed in the clean facies. The only difference being the earlier, higher recovery from the respective layer in which the horizontal well is completed. This behavior is explained by the fact that severe cross flow from permeable to tight existed. This cross flow persisted down to vertical permeability values of .0001 millidarcy.
Effects of Drying on Absolute and Relative Permeabilities of Low-Permeability Gas Sands
Authors: Morrow N. R. , Cather M. E. , Buckley J. S. , Dandge V.
Published: December 2007

Water adsoiption/desorption (sorption) isotherms, surface-area measurements, and electron and optical microscopy all demonstrate the presence of significant microporosity in low permeability gas sands as exemplified by cores taken during the course of the Multiwell Field Experiment (MWX). Pore space in these sandstones occurs primarily as solution pores that are often partially filled by fine-structured clay minerals such as illite and smectite. Quantitative information on pore size and volume of microporosity can be obtained from sorption isotherms. A hygroscopic index for rocks based on desorption behavior is proposed. To delineate changes in pore structure that can arise during drying, water desorption isotherms, absolute permeabilities to brine, and effective permeabilities to gas were compared for preserved (undried) and dried cores. Permeabilities of cores which had been allowed to dry tended to be higher than those of the fresh cores. Changes in effective permeabilities and sorption isotherms were consistent with observed decreases in absolute permeabilities. Low water content in preserved MWX cores demonstrated that the technique used to protect them from drying was sometimes inadequate.
Slimhole Continuous Coring and Drilling in Tertiary Sediments
Authors: Randolph S. B. , Jourdan A. P.
Published: December 2007

A Soft Rock Project was conducted by Amoco Production Company and Elf Aquitaine on the Texas Gulf Coast in June and July 1990. The purpose of the project was to demonstrate and gain experience in slim hole continuous coring and drilling in soft sediment formations. Four wells were completed, which included two planned sidetracks. A total of 1670 ft was continuously cored and 1018 ft was full hole drilled. Both 4-3/8 in. and 3-1/16 in. hole sizes were cored/ drilled.

Slim hole continuous coring and drilling were suc-cessfully conducted in recent age sediments (Tertiary). It was determined that the most, important factor affecting wellbore stability was keeping the flow regime in laminar flow. Lost circulation in unconsolidated sands was controlled by using calcium carbonate and starch for fluid loss control. Modified face-discharge core bits used with a split tube core barrel assembly were the most effective in recovering core. Setting cement plugs and sidetracking were accomplished and open hole logs were successfully run in the slim holes.
Real-Time Formation Analysis Can Help Drilling Decisions
Authors: Allen D. F. , Sheppard M. C. , Rasmus J. C. , Ahmed U.
Published: December 2007

During drilling it is important for the driller to know the properties of the formation being penetrated. Mud weight, the necessity for wiper trips and gas sand detection are some of the routine drilling operations that depend on the type of rock being drilled. To properly perform these operations, an analysis of the formation lithology on a real-time basis can be very important. Recent developments is MWD technology coupled with sophisticated computer processing at the rig site now provide unprecedented real time analysis of the formation being drilled. This formation analysis greatly facilitates decisions about safe mud weights, correlation and marker identification, and safe and efficient drilling. Also, the formation analysis can allow the geologist to perform a preliminary evaluation in order to plan the wireline logging program.

The term "formation analysis" as it is used here includes properties commonly estimated by oilfield geologists and petrophysicists. In addition to distinctions based on rock type (sandstone, shale, anhydrite…) and mineralogical composition, it incorporates porosity and fluid saturations since these properties influence drilling operations and are essential to computations of pore pressure.

In this paper we present the process of formation analysis while drilling. Starting at bit depth the mechanical measurements of downhole weight and torque provide an indica-tion of lithology and early warning of possible pore pressure changes. The interpretation is refined as subsequent measurements of spectral gamma ray, resistivity, neutron porosity, bulk density and Pe become available as drilling proceeds and the various MWD subs pass a particular horizon.

The interpretation of lithology is performed in a number of ways depending on which data are available at a particular depth. At bit depth the mechanical data allow distinction between major lithology types. Once the gamma ray and resistivity measurements are available a volumetric analysis is possible which provides information about sand and clay volumes as well as porosity. This volumetric analysis can subsequently incorporate the full suite of measurements. Combining gamma ray, neutron porosity and density also enables classification of lithology by reference to a prebuilt data base of lithologies. This analysis can be further refined by the inclusion of cuttings data. The analysis of lithology is extended to provide qualitative detection and description of thin beds through the supplemental use of curve shape analysis. Porosity and fluid types axe evaluated using a standard log analysis method. In this way an increasingly refined specification of formation properties becomes available as drilling progresses.

We will describe the identification of different lithologies, including the identification of thin beds, the identification of hazardous gas sands and the estimation of pore pressure in real time, which enables us to substantially reduce the risk of kicks and differential sticking.
Intelligent Control of Drilling Systems
Authors: Rowsell P. J. , Waller M. D.
Published: December 2007

Research in drilling automation, at the University of Nottingham, has the ultimate objective of achieving computerised drill control through the the application of an intelligent based system.

From a laboratory drill rig, various parameters are measured and stored to a database for a variety of rock types and drilling conditions. The database is used by the Inteldrill system to generate a series of Self Learning Prediction Matrices [S.L.M.P.] which allow the determination of the best drilling performance likely to be achieved. The control can be based on either maximum penetration rate or minimum cost drilling.

Minimum cost drilling is based on a cost equation which is configured with constants for the various cost centres. The computer passes drilling conditions from the drilling S.L.P.M. through the cost equation to generate a cost matrix. This matrix is then searched to determine the most economical drilling parameters. The system has a self-learning capability such that the more information in the database, the greater the accuracy of the S.L.P.M.'s.

A prototype system has been developed and is currently undergoing trials, using data generated by laboratory rig, together with simulated data.
Economics of the Delaware-Val Verde Basin Deep Gas Play
Authors: Fish George E.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

This paper was prepared for the 43rd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Sept. 29-Oct. 2, 1968. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

During the past several years the oil industry has developed large gas reserves in the Delaware-Val Verde Basin. This effort required a large investment in men and material.

A minimum of 18,300 billion cubic feet of gas has been found and developed for an expenditure of 775 million dollars in direct costs. The rate of return on this investment should equal 9%, which is less than the average rate of return derived from all investments by domestic producers.

The current discovery rate promises important new reserve additions. However, as the more obvious features are drilled the undiscovered accumulations will become harder and harder to find. This factor plus the current inflationary trend for goods and services is expected to hold the rate of return at its present level.

Introduction

Eighteen years ago the exploration emphasis in the Delaware-Val Verde Basin shifted from the search for shallow (2,500' to 6,000') Delaware Sand stratigraphic oil to the deep gas bearing Devonian and Ellenburger structural traps (12,000' to 25,000'). An early success at Puckett, coupled with the discovery of Brown Bassett a few years later, soured the oil industry into a massive campaign to find more Delaware Basin gas. Cash outlays for geophysical coverage, leases, and exploratory drilling nave been tremendous.

Are gas reserves being found in sufficient quantities to justify this large outpouring of money? If so, will industry obtain an adequate rate of return on its investment? What is the current trend of the exploratory success ratio? To answer these questions has been the primary purpose of this investigation.

A geographic area containing the elongated geosyncline known in the industry as the Delaware-Val Verde Basin was outlined. (Shown by Figure 1.) Beginning in 1950 and continuing through 1967, all investment directed toward finding and producing hydrocarbons in this area from formations of Wolfcamp age and older was accounted for by year.
Quality Improvement of Liner Cementations by Using Bottom and Top Plugs
Authors: Dreikhausen H.
Published: December 2007

An examination of cement samples from the top and bottom of liners and statistical studies of all liner cementations since 1982 clearly indicated that for long liners (approx. 1000 m) the cement was of poor quality and that for longer liners (up to 2200 m) cement contamination was so bad that the cement would probably never set.

As a result, a top and bottom wiper plug system was developed to prevent contamination of the cement inside the string while pumping the slurry. Repeated downhole testing and initial field experience resulted in improvements to the system, and the final design has been in field use since mid-1989. By December 1990, twenty-six 1" liners had been cemented using this system with a significant improvement in the quality of the cementation. The weight percentage of cement in samples taken from above the liner top using the old 2-Plug System was between 177» and 867> and for samples taken from the liner collar/shoe it was between 377» and 877» depending upon the length of liner which was run. The use of the new 4-Plug System resulted in a weight percentage of cement of greater than 90% in samples taken from the liner top and the collar/shoe, irrespective of liner length.

This paper deals with the research, development, and field experience associated with the use of a four plug liner cementation system.
SIPM Practice for Site Specific Structural Fitness for Purpose Assessment of Jackup Rigs
Authors: Sliggers P. G. F.
Published: December 2007

This paper describes the practice adopted by Shell Internationale Petroleum Maatschappij (SIPM) for the site specific assessment of jack-ups in elevated condition. In particular it addresses the structural engineering considerations that lead to a systematic approach for site specific analysis, condition assessment and condition monitoring of the jack-up structure. Experience with the approach has shown that through proper planning and timely execution of the work there needs to be little or no disturbance to the schedule of normal drilling operations.
Re-Entry and Relief Well Drilling To Kill an Underground Blowout in a Subsea Well: A Case History of Well 2/4-14
Authors: Ølberg T. , Gilhuus T. , Leraand F. , Haga J.
Published: December 2007

Well 2/4-14 in the Norwegian Sector encountered well control problems in January 19S9 at a depth of 4734 m. After some days effort to reestablish normal pressure control the well blew out on surface of the floater and had to be closed in using the shear ram. This left the subsea BOP closed and with a shut in wellhead pressure of 10000 psi. In addition a full string of drillpipe with approximately 4500 m of coiled tubing was left in the well. After an attempt to regain control by bullheading heavy mud, in which a flexible kill line bursted, the well was left for a periode. Preparations were made to reenter the well with high pressure snubbing equipment to fish out the drillpipe and coiled tubing, so that the well could be circulated dead. In parallel to this effort a relief well was started immediately.

After the well was reopened it was discovered that the casing had bursted and that the well was blowing out underpound.

On December 12, 1989, 295 days after the shear ram was closed, the well was killed.

Another four months were required to finish cleanup and final abandonment of the blowout well.

The paper presents the case history and indicates some of the tools and technology that was developed to regain control of this well.
Shut-In and Abandonment Decision Economics
Authors: Lohrenz J.
Published: December 2007

When should producing properties in irreversible decline be shutin? When abandoned? These questions are addressed from an economic perspective. The questions are old, but analyses reveal new, currently relevant facets of decisions to shutin and abandon producing properties.
Consolidating and Managing a Mature Portfolio
Authors: Morris R. L. , Lafitte F.
Published: December 2007

With a multitude of oil companies restructuring and consolidating operations and assets, the processes required to effectively manage a portfolio of mature, diverse assets also need reformulation. It is our vision that an Integrated Asset Management approach will enhance the knowledge of the life cycle of producing assets, from exploration through sale or abandonment. Identifying trends to capture value and determining optimal acquisition and divestment timing are essential ingredients in managing mature assets. Also of significant importance are the impact of operational and economic risk, the understanding of interrelationships and interdependence of groups of properties, and the enhancement of the selection process for long term projects and strategic initiatives. Computer visualization of a variety of economic and operational performance parameters, together with exploration and development plans, offers an improved methodology for proactive asset management. By embarking on construction of an Integrated Asset Management System a course is being set for the strategic value enhancement for one's portfolio.
Primary and Secondary Containment of Hazardous Substances in Cold Regions With HDPE Liner
Authors: Richards F. T. , Foster M. L.
Published: December 2007

Manufacturers of products which compete with high density polyethylene (HDPE) liner for use in exposed primary and secondary containment of hazardous substances have criticized the use of HDPE in Arctic environments. The criticism has primarily focused on the point that HDPE should not be used in above ground, exposed installation where there are large annual temperature fluctuations. The main point of contention is that environmental stress cracking (ESC) will be produced in the HDPE liner by expansion and contraction caused by seasonal temperature changes in cold regions.

Dames & Moore has performed preliminary design and feasibility studies to select an impermeable containment media that could be installed in exposed pits and withstand environmental effects without degrading, tearing, cracking, or in any other way allowing contained media to leak. Our research showed that with proper design efforts and good quality control/quality assurance practices during manufacturing and liner installation that HDPE can provide continuous containment without degradation from environmental processes.
Conglomerate Identification and Mapping Leads to Development Success in a Mature Alaskan Field
Authors: O'Sullivan T. P. , Kiloh K. D. , Starzer M. R. , Trevena A. S.
Published: December 2007

Lithology, porosity and water saturation were evaluated as part of a field-wide reinterpretation of log and core data for the Hemlock Reservoir, McArthur River Field, Cook Inlet, Alaska. To identify the conglomerates and sandstones which comprise this reservoir, a new method was developed for estimating the fraction of rock framework which is conglomerate. The method is based on the observation that, in this reservoir, the replacement of sand by nonporous pebbles results in poorer sorting and an overall decrease in porosity. Comparisons between core- and log-derived conglomerate estimates were used to calibrate and test the method.

The reservoir properties of conglomerates and sandstones in the Hemlock Formation differ significantly, and while depositional factors have most likely resulted in a heterogeneous distribution of conglomerates and sandstones, the core data are too sparse to resolve this distribution. A map of the log-derived conglomerate fraction is sufficiently controlled to provide detailed information on reservoir heterogeneities; trends on this map are consistent with depositional models for the Hemlock Formation. The conglomerate map was integrated into the waterflood management of the field; for wells from one platform this resulted in a greater than two fold increase in incremental oil production per dollar spent on reperforations.
Enhanced Oil Recovery of Ugnu Tar Sands of Alaska Using Electromagnetic Heating with Horizontal Wells
Authors: Islam M. R. , Wadadar S. S. , Bansal A.
Published: December 2007

A non conventional enhanced oil recovery technique is proposed for recovering oil from an Alaskan tar sand reservoir. This technique involves the use of electromagnetic heating with horizontal wells along with water injection, gas injection or primary depletion. This technique eliminates one of the bigger technical problems with conventional steam injection in the North Slope area. The existence of a large permafrost region in North Slope reduces the effective heat that can be transmitted to a reservoir, even with insulated tubing. Applying the heat with a downhole device, such as electromagnetic heating is a much more efficient process than conventional thermal recovery techniques. The presence of horizontal well allows one to eliminate the problem of small heating radius and large area may be conducted even when the heating radius is small. Also, a horizontal well, particularly one located at the bottom of a thick sand with vertical permeability, allows gravity drainage of a much larger reservoir volume. This paper presents numerical simulation results of such a process for Alaskan tar sand reservoirs using a horizontal well simulator. Various options, such as gas injection, waterflooding, etc. are investigated along with electromagnetic heating. Numerical simulation results show oil recovery as high as 60% of the oil in place for tar sands. The recovery is even higher for heavy oil of moderate viscosity. Finally, a numerical run using steam-assisted gravity drainage is conducted for comparison. The new scheme presented in this paper showed much higher efficiency than the steam-assisted gravity drainage process.
The Use of Computers in the Undergraduate Petroleum Engineering Curriculum
Authors: Koederitz W. L. , Macon B. , Whitehead W. R.
Published: December 2007

Within less than a generation, dramatic changes in the computing needs of petroleum engineering graduates have occurred. Slide rule techniques gave way to hand calculators, which, in turn, has given way to solving problems using personal computers. The rapid change in technology has caught the academic community off guard, with some asking if the petroleum engineering curriculum prepares students for the advanced computing technology that is In use today. This paper addresses the problem and proposes an approach to computer use in undergraduate petroleum engineering curricula.
Differential Sticking Laboratory Tests Can Improve Mud Design
Authors: Bushnell-Watson Y. M. , Panesar S. S.
Published: December 2007

A laboratory method of freeing differentially stuck pipe with shear has been used to rank different mud types. This highlights the effect of minor changes in mud chemistry and enables speciality additives such as lubricants to be assessed. The influence of mud type, mud circulating conditions and time of filtration on sticking tendency is also discussed.

Tests reported here were carried out at a pressure of 100 psi and ambient temperature. A new apparatus which more accurately simulates downhole conditions has now been constructed.
An Assessment of the Performance of Liner Hanger Bearings
Authors: Archer G. L. , Jacobs M. , Rabia H.
Published: December 2007

Liner movement results in substantial improvements in cementing performance, principally by assisting mud displacement efficiencies. Rotation is more effective and safer than reciprocation. A number of plain (Astro) and taper roller bearings from different manufacturers were tested in a laboratory program. None of the bearings tested satisfied the original performance target of 24 hours life at a bearing load of 112,000 lbs and speed of rotation of 25 RPM. Taper roller bearings were found to give better performance than Astro bearings. One design of taper roller bearing performed sufficiently well to satisfy most cementing jobs and would be selected for future use. It was thought, however, that all the bearings tested could be improved by better sealing and structural design. Documented field applications of liner rotation are discussed and found to be consistent with the test results in general.
Drilling Fluid Formulation for Shallow Offshore Horizontal Well Applications
Authors: Polnaszek S. C. , Fraser L. J.
Published: December 2007

The paper discusses the laboratory evaluation and field application of an unconventional drilling fluid system for drilling horizontally in an unconsolidated shallow gas sand. Laboratory work has suggested a mechanistic model which is consistent with field observations. Detailed formulation work addressed anticipated concerns identified for the project. Two case histories are described. Fluid formulations and operational performance are described in detail.
The Effect of Capillary Forces in Heterogeneous "Flow-Units": A Streamline Approach
Authors: Van Batenburg D. W. , Bruining J. , Bakken H. , Palmgren C. T. S.
Published: December 2007

Up to now much of the work on permeability heterogeneity has focussed on viscous flow ignoring the effect on capillary pressure. Small scale permeability variations, however, may lead to capillary trapping of a considerable amount of oil within for instance the crossbeds of channel sands.

Fractional Brownian motion (fractal) permeability fields have been generated to obtain heterogeneous permeability fields with a varying degree of smoothness. It appears that these are ideal fields to investigate the relation between capillary trapping and local variability. The fractal fields have been used as input in a probabilistic simulator in which capillary forces have been implemented.

From the simulations presented it has been concluded that effect of the capillary and viscous forces on the saturation distribution is related to the Hurst coefficient.
Capillary Imbibition and Gravity Segregation in Low IFT Systems
Authors: Schechter D. S. , Zhou Denqen , Orr F. M.
Published: December 2007

The effect of reduced interfacial tension (IFT) on oil recovery by spontaneous imbibition and gravity segregation is investigated experimentally for a wide range of IFT’s in cores oriented vertically. The experimental results presented indicate that a crossover from capillary to gravity driven imbibition occurs. For cores with low permeability and high IFT between the wetting and nonwetting phases, capillarity initiates coun-tercurrent imbibition and oil is produced from all faces. For moderately low IFT’s and permeabilities above about 100 md, gravity segregation is the controlling mechanism. In this case, the rate of oil recovery may actually be greater for low IFT’s. Gravity induced imbibition is cocurrent (oil produced from the top face only), which helps prevent snap-off and entrapment and allows high total recoveries. In addition, data are presented that indicate that surface tension gradients arising from composition gradients can substantially increase or decrease the rate of imbibition depending on the direction of the surface tension gradient.
Three-Phase Relative Permeability of Intermediate-Wet Berea Sandstone
Authors: Oak M. J.
Published: December 2007

Three-phase relative permeability data are required in reservoir studies of CO2 floods, steam floods or other enhanced gas drives in which three-phase flow occurs. This paper presents a laboratory method developed for direct measurement of three-phase relative permeabilities, which requires only a few extra tests in addition to the two-phase tests commonly performed. It also presents a new set of three-phase relative permeability data for an intermediate-wet Berea sandstone core. In the intermediate-wet rock studied, injection of gas did not reduce oil saturation below the residual oil saturation after waterflooding. This is in contrast with the results previously reported for strongly water-wet cases. The experimental three-phase relative permeabilities are compared with the values calculated from Stone’s correlation methods. The calculated values show significant differences from the experimental ones. It is suggested that three-phase relative permeabilities be verified by laboratory testing.
Making Change Work For Us
Authors: Wycoff Robert E.
Published: December 2007

Society of Petroleum Engineers Annual Technical Conference, Convention Center, Dallas, Texas

Thank you. I'm very happy to join SPE's Technical Conference this afternoon to give my view of your meeting theme which is, of course, "Winds of Change — Impact on Energy."

It's well that we have four speakers here this afternoon because there's certainly no lack of keynoter material in that topic. Just follow your nose these days and you'll run into more change than you bargained for.
Joint Venture Opportunities in the USSR and Eastern Europe
Authors: Matzke Richard H.
Published: December 2007

While attempting to relate the theme of this year’s conference to my presentation - it occurred to me that the metaphor "Winds of Change" unfortunately didn’t come dose to describing the magnitude of the events that have taken place in Eastern Europe and the Soviet Union.

Perhaps use of greater natural phenomena might be more appropriate in this case -- say -- "Hurricanes of Change" or possibly "Earthquakes of Change".

Or -- how about the ultimate? -- the "Mother of All Changes!"
The Emerging Services Directive and Procurement in the Hydrocarbon Sector
Authors: Wells R. E.
Published: December 2007

This paper describes the formulation of the European Community, how it works and the inpact on Procurement and Services in the Hydrocarbon Sector.

Procurenent activities and Contracting in the Upstrean business of companies involved in the exploitation and extraction of Hydrocarbons in the European Arena will be impacted by the introduction of regulatory controls inposed by three Directives entitled the "Utilities": –Supplies and Works.Planning for Projects, Purchasing Policies, Qualification of Bidders, issue of notices and statistics. Increase in Manpower and associated costs.–ServicesIntra Group Services, Partnering Agreements, Standards, Qualification, Central Product Classification, Buying from Third Countries.–RemediesSetting Aside, Dissuasive Payments, Suspension, Conciliation, Attestation.

All the above will determine changes to policies and procedures for evaluating and budgeting for Projects and Operational activities.