bluuebunny/crossref_metadata_2025 huggingface dataset:
Critical Points Regarding Internal Corrosion and Corrosion Control of Offshore Process Facilities
Authors: Eliassen S. , Edie G. H. , Brattas L.
Published: December 2007

Application of adequate corrosion control techniques to achieve the necessary safety and desired life of offshore process facilities are considered primary tasks of operators and authorities. The paper will describe different types of corrosion hazards and consequences of a corrosion failure for the different components of a process system. The following aspects will be considered: –accessibility of components–consequences of a corrosion failure–corrosion types such as CO2-corrosion, H2S-corrosion, erosion corrosion etc.–corrosion control techniques such as inhibitors, coating, corrosion resistant steels, etc.–corrosion monitoring with special emphasis to procedures for thickness measurements

The work is primarily based on experiences from design evaluation and inspection of equipment which have been in service, but it is also supplemented by laboratory testing of corrosion rates and inhibitors. The so-called "sweet" corrosion which is caused by corrosive gases such as C02 and chlorides dissolved in the produced water is influenced by a number of parameters which are discussed. The "sour" corrosion type materialized by hydrogen induced stress corrosion is caused by H2S and water when unsuitable materials are used. Requirements on selection of materials and fabrication procedures and testing methods for application under sour conditions are reviewed. The application of corrosion control techniques to achieve the necessary safety and desired life of the equipment are considered primary tasks of both the operators and the authorities and different approaches may be used to achieve this goal.
Zonal Control With Single Selective Completions Udang Field — Natuna Sea — Indonesia
Authors: Rodriguez Fernando H.
Published: December 2007

Discovery and delineation wells which proved the Udang Field did not yield sufficient data to indicate the complexity of the reservoir. Development drilling showed the Udang pay section to be a series of interbedded shales and sands having individuals gas caps and water/oil contacts. The initial plan, to complete the wells by perforating a 40-foot section and installing a screen with slurry pack, was quickly changed in favour of multi-zone single selective completions.

This paper describes the various types of completions and equipment used, and the success achieved by utilizing single selective completions to control excessive gas and water production.

The field commenced production in January 1979. Since then to the present, about 100 trips nave been made with wireline tools to open or close sliding sleeves with only one failure. In 3 wells the same sliding sleeve was successfully actuated six times. This has been achieved even though some wells have 65 degree inclinations and most all wells produce measurable amounts of sand. It is concluded that these type completions have substantially increased present and projected oil recovery from the Udang Field.
The occurrence, Causes and Detection of Abnormal Pressure in the Malay Basin
Authors: Singh Indarjit , Ford C. H.
Published: December 2007

Abnormal pressure strata are believed to exist throughout the Malay Basin with the exception of the southwest and northeast margins. The onset of abnormal pressure is abrupt in the northeastern portion of the basin but is generally more gradual in the southeastern area.

The abnormal pressure is a complex origin and is attributed to a combination of rapid burial of certain stratigraphic units, uplift of initially normally pressure strata, faulting and hydrocarbon column effects.

Predrill abnormal pressure predictive techniques used by EPMI in the Malay Basin are interpretation of seismic interval velocities and electric log correlation. With accurate seismic velocity information, an interval transit time profile, called a Pennebaker plot has aided in predicting top of abnormal pressure in 80% of the wells drilled to date. Log correlation is most applicable within the confines of a particular structure.

Detection of abnormal pressure in the Malay Basin while drilling is difficult at standard pressure indicators while drilling and use of industry generated overlays to derive quantitative estimations of pore pressure from drilling exponent plots do not provide satisfactory results. As a result, EPMI developed a "Malay Basin" overlay which provides more accurate quantitative estimation of pore pressure from drilling exponents. In addition, EPMI employs a technique for monitoring gas feed-in, called an extended connection, or 10-10-10 to detect geopressure while drilled.
Development of Pabelokan Island
Authors: Powell D R
Published: December 2007

PERTAMINA-IIAPCO has an expanding complex of offshore production platforms in the Southeast Sumatra Contract Area of the Java Sea. One of the requirements for this complex is a treatment facility for water to be used in secondary recovery operations. Because of the water quality required, the water treatment system is substantially larger than that normally used offshore. Instead of constructing one or more platforms for the treatment system, a small coral Island named Pabelokan Island has been utilized for this purpose. Although the water treatment system is the primary reason for the base, other facilities were co-located to centralize: electrical power generation, living quarters and recreation facilities, and facilities for storage and maintenance of offshore equipment. Future plans for the Island include a gal-liquids recovery system.

This paper describes the Island facilities, and provides a case study in responsible planning and construction techniques in the development of a coral Island for use as an offshore base. The experience gained should be useful in the planning of other coral Islands for similar purpose.
Financial Evaluation of An Offshore Drilling Rig Venture
Authors: Slaughter Lou S.
Published: December 2007

The paper is a financial evaluation of an offshore drilling rig venture. It pertains to other ventures world wide involving substantial investments in offshore marine equipment. The scope of the paper ranges from a discussion of the drilling industry to the financial proformas covering the operation of the equipment.

The points that the presentation covers are as follows: The structure, economics, marketing and financing of the drilling industry.The strategic matching of the opportunity with the operating environment, resources and management disposition of the company.A financial analysis of the venture, including: "Back of the envelope analysis."Construction period projection.Proformas as at commencement of operations.Operating projection.Net present value analysis.

Additionally the paper draws attention to issues that are important to the above evaluation.

The paper should enlighten and be well received by those participants to the conference who are mainly orientated towards the technical side and not the financial aspects associated with marine ventures.
An Implementation of a Fully Implicit Reservoir Simulator on an ICL Distributed Array Processor
Authors: Scott A. J. , Sutton B. R. , Dunn J. , Minto P. W. , Thomas C. L. , Habib S. , Oakley C. A. , Krzeczkowski A. J.
Published: December 2007

An oil/water, 3-D fully implicit Reservoir Simulator has been implemented on the ICL Distributed Array Processor (DAP), by a joint BNOC/ICL project team. The DAP is a single instruction, multiple data stream machine with 4096 processors in parallel.

The major computational areas of code have been implemented on the DAP, leaving I/O and well calculations as serial code on the host 2976 machine. Matrix assembly is inherently parallel and can be implemented easily and efficiently on the DAP with compact code. Table look-up, though not obviously parallel, has been coded using a very efficient parallel algorithm.

The Linear Solver, of Line Gauss-Seidel type, has been chosen for its efficiency on the DAP, with odd and even reduction used for solution of the resulting tri-diagonal equations. Further research will be undertaken to increase the robustness of this solver.

The initial implementation has a 1-1 mapping of active grid blocks to processors, thus allowing up to 4096 active grid blocks. It is planned to extend to much larger models, and to 3 phase.
Modelling the Piper Field Using Layer Cross Flow at Faults
Authors: Dunlop K. N. B. , De Boer E. T. , Waldren D.
Published: December 2007

A special finite difference simulator was coded and used to model the Piper Field, which is a large faulted reservoir consisting of layers of contrasting but high permeability. The formulation allows any number of connections between grid blocks providing the flexibility to include fault throw as a variable during three-dimensional history matching. Because correspondence between geological and model layers is preserved, model cost and complexity are reduced.
Acrylamide/Acrylic Acid Copolymers for Cement Fluid Loss Control
Authors: McKenzie Lee Frederick , McElfresh Paul Michael
Published: December 2007

Acrylamide/acrylic acid copolymers are effective fluid loss control additives in a wide range of oil well cements. Unlike HEC based fluid loss additives, these copolymers can be used with calcium chloride accelerator without significantly influencing fluid loss control. Another advantage of the copolymers is that the amount of fluid loss for a given concentration of polymer remains relatively constant over a wide range of temperatures. The use of acrylamide/acrylic acid copolymers has generally been restricted to wells below 60°C BHCT. Above that temperature chemical changes in the copolymer often lead to retardation of the cement.

This paper presents data related to the use of acrylamide/acrylic acid copolymers as fluid loss control agents in oil well cementing. A comparison of these polymers with HEC based fluid loss control additives is made. In addition, data related to the cause of acrylamide/acrylic acid copolymer retarding effects is presented.
Easy Brine Flash Estimates
Authors: Kouzel Bernard
Published: December 2007

The author shows that the enthalpy of sodium chloride solution expressed on a unit weight of water basis is essentially equal to the enthalpy of pure water at the same temperature.

The use of this concept is illustrated for rapid and accurate adiabatic flash calculations involving geothermal brines.

A steam table is used instead of a brine enthalpy table and the simplifying assumption of pure water as the geothermal fluid is not necessary.
Comparison of Conventional and Type Curve Analysis of Pressure Falloff Tests for a West Texas Carbonate Reservoir
Authors: Crawford Duane A. , Waller Herschel N. , Sanders L. J.
Published: December 2007

Pressure falloff data collected in moderately fractured water injectors in a West Texas carbonate reservoir are analyzed using both conventional and type curve techniques, and results of these analyses are compared. The theory and application of the two methods are also discussed. The technique of Hadinoto and Raghavan is used to calculate corrected water permeability capacities and fracture lengths by conventional techniques and to determine the same parameters by type curve analysis. Included are example calculations showing the agreement between water permeability capacity and fracture length using the two approaches and between these parameters calculated for several pressure falloff tests on the same well.
An Improved Method for the Rapid Detection of Microbiological Contamination in Stimulation Fluids
Authors: Penny Glenn S.
Published: December 2007

This study introduces a method that makes possible the direct monitoring of stimulation fluids for microbial contamination. The procedure is based on the assay of adenosine triphosphate (ATP) with luciferin-luciferase. The accuracy of this method is compared to conventional plate counting and nutrient vial dilution techniques. The effects of stimulation fluid additives such as KCl, biocides, buffers, and gelling agents are assessed, and a procedure for the differentiation of bacterial vs. nonbacterial ATP is examined. Data showing the utility of the assay in monitoring biocide effectiveness and predicting batch mixed gel degradation are presented.
Performance Evaluation of Acid Treatments in Seawater Injectors With Reference to Acid Volume Impact
Authors: Beheiri Faisal I. , Nasr-El-Din Hisham A.
Published: December 2007

Acid matrix treatments in carbonate reservoirs create a network of passages in the near-wellbore zone. The acid volume is a key variable that determines the effectiveness of acid treatment. For matrix treatments, the acid volume ranges from 20 to 100 gal/ft. Acid concentration ranges from 15 to 20 wt%. Selection of acid volume and concentration varies based on engineering experience and judgment.

This paper presents an analytical model for calculating time-lapsed injectivity index (II) in order to verify the impact of acid volume with all other contributing variables being fixed. The model integrated matrix acid treatments; injection profile surveys, injection data, completion configurations, and reservoir parameters. The model has been applied on six stimulation treatments where all contributing variables varied, except the acid volume. A normalized performance indicator was characterized based on the II's initial improvement, decline rate, and cumulative improvement.

The calculated IIs by the model successfully matched the measured IIs by the fall-off tests. The model evaluated the treatments contributing variables and established clear correlations between acid volume and the post stimulation performance.
A Study of Getty Oil Co.'s Successful In-Situ Combustion Project in the Bellevue Field
Authors: Long Ralph E. , Nuar Mark F.
Published: December 2007

The in situ combustion project operated by Getty Oil Company in the Bellevue Field, Bossier Parish, Louisiana, has expanded from a single pilot pattern in 1963 to a full-scale operation with more than one hundred patterns in 1981.

Originally discovered in 1921, the field produced for about ten years under primary production methods. The field remained relatively dormant until Getty Oil Company conducted a successful in situ combustion pilot which commenced in 1963. The project is now producing about 2900 barrels daily of 19.5° API gravity crude from 350 producing wells.

Pattern sizes and configurations have varied during the eighteen year project. Wet and dry combustion methods have been used in the field and a combination of the two methods is used today depending on the stage of burn the pattern is experiencing. Several water-air injection ratios have been tried with varying degrees of success.

In this paper, Getty's Bellevue project is traced from its inception to the present. Response to various methods used in the field as well as operational problems are discussed. Ultimate production forecasts are also presented for the field.
Knowledge Management for Shared Earth Modelling
Authors: Mastella Laura , Perrin Michel , Abel Mara , Rainaud Jean-François , Touar Walid
Published: December 2007

Shared Earth Modelling (SEM) describes the process of integrating static (geological structures) and dynamic data (hydrocarbon production) issued from several disciplines to construct a model of a subsurface resource. We claim, however, that SEM should allow sharing and integrating not only data but also the knowledge related to data interpretation. As a consequence, actors from different disciplines, who have different technical skills, should be able to provide a "Shared Earth Model" with specific technical knowledge concerning how to evolve a hydrocarbon prospect at the various stages of its life cycle.

The integration of various levels of scientific and technical knowledge into the modelling process requires an overall view of the knowledge and data workflow. In order to enhance a knowledge management approach, we first examine which types of information (data, interpretation, abstract model, symbolic or spatial representations) should be considered at each step of the reservoir modelling chain. Moreover, in order to allow each expert to bring his/her own contribution in an explicit way, we propose the use of a formal vocabulary related to the different disciplines and define it through ontologies. It is thus possible to picture how the various types of knowledge should interact for producing consistent "Shared Earth Models".

In order to illustrate the above approach, the paper presents a prototype of "Geological Knowledge Editor" (GKE). This module allows representing the knowledge acquired at the beginning of the SEM process and providing services to enhance this knowledge and checking its consistency, guaranteeing thus the quality of service (QoS) attached to the reservoir modelling process. By means of the GKE, the geologist can display geological representations such as fault networks or stratigraphic columns. He/she can also edit the chronological interpretation attached to the model and use it for building structural models in an automatic way.
Analyzing an Oilfield Gas Handling System
Authors: Earhart James W. , Mathur Anil , Haire William M.
Published: December 2007

Reconciling "as designed," "as built," and "as operated" for a complex field gas handling system is crucial to planning system modifications. Field measurements of one such system show extreme scatter, making a consistent prediction of system capacity extremely difficult. Statistical methods make it possible to develop a model of system behavior which is valid over a wide range of operating conditions.
Steam Injection Theories — A Unified Approach
Authors: Farouq Ali S. M.
Published: December 2007

Formation heating and oil displacement by steam injection is a multi-faceted process, which can take several forms. A number of theories have been proposed over the years to explain the mechanics of steam advance in an oil-bearing formation. These range from steam frontal advance to frontal-vertical advance to vertical advance. The premises of these theories vary considerably, but they often give the same ultimate recovery – as shown in this paper. The reasons for this apparent insensitivity are examined. The situation becomes more complicated when bottom water or formation parting is involved, inducing preferential movement of steam in still other directions than those mentioned above.

The paper provides a comparative examination of the above theories, in the light of field experience, numerical simulation and physical model results. The objective is to develop criteria for judging the applicability of one or the other -or, even more than one - theory. A simplified steamflood calculation method is also suggested.

The paper also discusses the principal mechanism of oil displacement by steam, both for light and viscous oils. It seems that the temperature dependence of relative permeabilities is an important factor in the gas drive effect of steam, and should be included to represent the oil recovery process properly.

Application of the above theories to cyclic steam stimulation is problematic, partly because resaturation of the depleted zone may occur.
The Use of Foam in Stimulating Fractured California Reservoirs
Authors: Norton Mike G. , Hoffman Steve J.
Published: December 2007

The majority of oil reservoirs in the Ventura Basin consist of massive sand sections inter-bedded with shales and clays resulting in low to extremely low matrix permeabilities. The geologic tectonic activity surrounding this basin has produced a number of fractured sandstone reservoirs. A well completion in these reservoirs must include hydraulic fracturing to obtain a commercial well.

The Sespe Field located in central Ventura County (T4N,R19-20W;T5N,R19-20W) and the Holser Canyon Field located in eastern Ventura County (T4N,R20W) are characterized by tight, thick (50-300 ft) sands with moderate to extensive natural fracture systems. Hydraulic fracturing stimulation treatments have been performed on wells in these fields as an initial completion practice. A great number and variety of fracturing treatments have been performed, with lease oil fracs proving to be the most successful. Other fluids used have ranged from emulsified lease crudes to nitrified crosslinked gels.

Foams have characteristically exhibited superior leak-off control and rapid clean-up, as well as an ability to carry proppant effectively. These factors are necessary to achieve a mechanically efficient fracture treatment. The use of oil based foam fracturing fluids was initially accomplished in the Rocky Mountains region to overcome fluid compatibility problems. These same problems exist in California sands and have been overcome to a large extent by the use of the oil-based systems. The use of foams as fracturing fluids has resulted in a number of successful stimulation treatments, with initial production rates as high as 80 BOPD- In the author's opinion, the foam based fracturing technique is an economical and technically viable method of stimulating the aforementioned fractured reservoirs.

This paper will describe the geology, completion practices, and fracturing techniques used to stimulate the Sespe and Holser Canyon Fields.
Steam Surfactant Systems at Reservoir Conditions
Authors: Al-Khafaji Ali Habib , Wang Pin-Ton Fred , Castanier Louis M. , Brigham William E.
Published: December 2007

Mobility control is one of the main problems in steam flooding. Channeling of steam through highly permeable zones and gravity override lead to early steam breakthrough at the production wells. Accordingly, volumetric sweep efficiency and oil recovery are reduced. Foam has been proposed as a permeability blocking agent in steam flooding to improve oil recovery.

This paper describes two experiments. One is on static properties such as thermal stability, adsorption and partitioning; the other is on dynamic displacement by steam in the presence of surfactants. The aim of this study is to investigate some commercially available and experimental foaming chemicals (surfactants) for their longevity under simulated steam injection conditions, namely at 400°F (205°C) and 300-500 psia (20-34 bars). The steam injection experiments have been conducted in a linear flow model to study flow, heat transfer and mobility.
A Detailed Geologic Study of Three Fractured Devonian Shale Gas Fields in the Appalachian Basin
Authors: Shumaker Robert C.
Published: December 2007

Analysis of three shale gas fields illustrates the importance of basement structure in developing fracture permeability within the thick Devonian shales of the Appalachian basin. A porous fracture facies within the organic rich lower Huron shale member of the Ohio Shale relates to a regional stress field created by differential shortening of overlying sedimentary section across the lower Huron detachment zone during the Alleghanian deformation. Greater permeability (commercial) occurs near the outer margin of tectonic shortening. Linear trends of wells with abnormally high final open flows relate to linear trends of highly fractured shale. These trends were probably caused by unique stress fields created along flexures in the shale above basement fault zones.
Synthesis of Organic Geochemical Data From the Eastern Gas Shales
Authors: Zielinski Ronald E. , McIver Richard D.
Published: December 2007

Over 2400 core and cuttings samples of Upper Devonian shales from wells in the Appalachian, Illinois, and Michigan Basins have been characterized by organic geochemical methods to provide a basis for accelerating the exploitation of this unconventional, gas-rich resource. This work, sponsored by the United State's Department of Energy's Morgantown Energy Technology Center, was part of a program initiated to provide industry with criteria for locating the best areas for future drilling and for the development of stimulation methods that will make recovery of the resource economically attractive.

The geochemical assessment shows that the shale, in much of the Appalachian, Illinois, and Michican Basins is source rock that is capable of generating enormous quantities of gas. In some areas the shales are also capable of generating large quantities of oil as well. The limiting factors preventing these sources from realizing most of their potential are their very low permeabilities and the paucity of potential reservoir rocks.

Low permeability has prevented migration of most of the free hydrocarbons from their site of origin in the shale matrix into nearby reservoirs. This retention of generated hydrocarbons has retarded the further generation of hydrocarbons within the shale, particularly the liquid (oil) ones, over much of the basin. Where there is fracturing, the shales themselves provide both source rock and the reservoir, and allow generation to proceed. In some cases, contiguous or interbedded siltstones provide small reservoirs, and the fractures provide migration channels through which the hydrocarbons move for relatively short distances.

This geochemical data synthesis gives direction to future selection of sites for stimulation research projects in the Appalachian Basin by pinpointing those areas where the greatest volumes of gas are contained in the shale matrix.

Another accomplishment of the geochemical data synthesis is a new estimate of the total resource of the Appalachian Basin. The new estimate of 2,500 TCF is 25 percent greater than the highest previous estimates. This gives greater incentive to government and industry to continue the search for improved stimulation methods, as well as for improved methods for locating the sites where those improved stimulation methods can be most effectively applied.
Quantitative Log Evaluation in the Devonian Shales of the Northeast United States
Authors: Hashmy Kahled Husain , Hefter Todd , Chicko Robert
Published: December 2007

The organic-rich Devonian shales underlying the Appalachian, Illinois and Michigan basins are potentially the most productive underdeveloped source of natural gas in the northeast United States. Though considerable quantities of natural gas are produced from these unconventional shale "reservoirs", standard well log evaluation techniques developed for sandstones and limestones are not suitable for the Devonian shales.

This work represents an attempt to quantify well log evaluation techniques in these shale reservoirs. The response equations for the Density and Neutron logs are used to establish the density and neutron log porosities appropriate for shale matrix. The Simandaux equation has been modified and adapted for the shale reservoir. With these modifications, the total porosity (intrinsic plus fractured), hydrocarbon density and the water saturation can be computed in these Devonian shales. Results have been consistent in four air drilled wells located in Ohio and West Virginia. Intervals in the shales which are characterized by development of porosity and where a gas saturation has been computed correspond invariably to "hot" zones on the Gamma-ray log. The organic content of these zones is also high when analyzed by the method proposed by Schmoker1. A pattern of high organic content corresponding to the development of porosity and the presence of increasing amounts of gas is discernable. Production tests indicate that large quantities of gas have been produced from intervals identified as porous and gas bearing according to the proposed technique.

Computed logs and listings of results from several wells are presented. Although this technique has been developed for the Devonian shales of the northeast United States, it could extend to other fractured shale reservoirs.
Volumes, Types, and Distribution of Clay Minerals in Reservoir Rocks Based on Well Logs
Authors: Ruhovets N. , Fertl Walter H.
Published: December 2007

Reliable evaluation of hydrocarbon resources encountered in shaly clastic reservoirs of low porosity and low permeability is an important although difficult task.

Log-derived estimates of the volume, type and distribution modes of various clay minerals, determination of cation exchange capacity (CEC) and Qv (CEC per unit of total pore volume), and properly selected water saturation calculation models assist formation evaluation.

Since shaly clastic reservoir rocks require extensive core sampling for CEC and Qv analysis, which is tedious, time consuming, and expensive, attempts have been made to correlate such CEC and Qv data with one specific or a combination of several well logging measurements. The latter include the spontaneous potential, gamma ray, natural gamma ray spectral data, dielectric constant and acoustic-, density-and/or neutron-derived porosity, etc. Constraints associated with these concepts will be reviewed. Discussed in this paper, is an innovative digital shaly sand evaluation approach (CLASS), which provides information on total and effective reservoir porosity, total and effective fluid distribution based on the Waxman-Smits equation, reservoir productivity, silt volume, and volumes, types and distribution modes of clay minerals present in subsurface formations.
Influence of the San Juan Mountain Geothermal Anomaly and Other Tertiary Igneous Events on the Coalbed Methane Potential in the Piceance, San Juan, and Raton Basins, Colorado and New Mexico
Authors: Choate Raoul , Rightmire Craig T.
Published: December 2007

The San Juan Mountain igneous extrusive complex in southwestern Colorado is approximately equidistant from the southeastern Piceance, northern San Juan, and western Raton Basins. These areas are known to contain high-rank coals and to have high methane contents in those coals. Recent studies have shown that this area is the center of an anomalously high geothermal gradient, which may strongly influence the increased coal rank and therefore the gas content in those areas. Other, less extensive Tertiary igneous events locally influencing coal rank and methane content include the intrusives along the margin of southeastern Piceance Basin, northeastern San Juan Basin, and the volcanic extrusives associated with the Spanish Peaks of the Raton Mesa.

Coal samples collected in the Piceance Basin increase in gas content from west to east from approximately 200 cubic feet per ton (cf/t) (6.3 cubic centimeters per gram--cc/g) along the Colorado River in the vicinity of Cameo to greater than 1,000 cf/t (31.3 cc/g) in the vicinity of Coal Basin in the southeastern part of the basin near the Elk Mountain intrusives. Coal samples from the Fruitland Coal in northern New Mexico and southern Colorado in the San Juan Basin have been shown to contain in excess of 500 cf/t (15.6 cc/g). Samples collected by the USGS in the Raton Basin from the Vermejo Formation contain in excess of 500 cf/t (15.6 cc/g).

It is suggested here that the anomalously high geothermal gradients induced by the intrusion of the San Juan Mountain complex and aided locally by other Tertiary events is substantially responsible for the high-rank coals observed in these areas, and therefore is principally responsible for the anomalously high methane content and the high potential for coalbed methane production from these areas.
Methane Drainage: Identification and Evaluation of the Parameters Controlling Induced Fracture Geometry
Authors: Trevits Michael A. , Hanson Merle E. , Ward Victor L.
Published: December 2007

During the conduct of the Bureau of Mines vertical borehole methane drainage research program, questions have been raised pertaining to the containment of fractures induced or extended during hydraulic stimulation operations. As a result of these inquiries, a project was initiated in September 1980, to identify the basic parameters controlling induced fracture geometry. Under this effort, 12 vertical boreholes will be completed and subsequently intercepted by mining operations. The boreholes are located at four separate mine sites, with three boreholes planned per mine site. Prior to hydraulic stimulation operations, the in situ stresses will be measured for the coalbed and the rock units immediately above and below it. This information, along with the results of mechanical and frictional properties tests, will be incorporated into the stimulation treatment design. The treatments scheduled for each borehole will allow for variability of injection rate and sand proppant concentration while strictly controlling fluid quality and treatment pressure. Current project plans call for 113m3 (30,000 gal) nitrogen-generated foam treatments and a maximum of 9,000 kg (20,000 lb) of 20-to 40-mesh-size sand proppant. Upon completion of the stimulation treatments, the boreholes will be produced or abandoned depending upon the needs of the mine operators. As borehole interception takes place, underground studies will be performed to delineate the magnitude and orientation of all induced fractures, effects on mining operations, and structural or depositional anomalies in the coalbed and adjacent rock units. These data will be correlated with the treatment design so that adjustments in the design parameters can be made for future treatments. This paper identifies project plans and provides a summary of the activities performed to date.
The GRI/lndustry Eastern Gas Shale Data Base
Authors: Zielinski Ronald E. , Sharer John C. , Ciramella Anthony F.
Published: December 2007

The Gas Research Institute (GRI) has established, as part of its research program, the Gas Resource Information System (GRIS). GRIS is a computerized data base that contains historical data on eastern gas shale wells. GRIS was established at the request of industry and contains all those elements which industry feels are important for the evaluation of drilling, completion, stimulation and production techniques for eastern gas shale wells. While GRI will be researching the data on the base to optimize production from the eastern gas shales, it will make GRIS available to industry as a mutually beneficial tool. GRI intends to cooperate with industry in updating and maintaining the data base.

Through industry's cooperation in providing input into the data base, it is felt that sufficient data will be available so that the data base can be effectively utilized to optimize techniques for attacking the eastern gas shales as a vaiable production tarqet and as a consequence both the producer and rate payer can benefit from the availability of more gas into the pipeline.

While the data base will not answer all problems, its use as demonstrated in the study case can be of prime importance in sorting out those factors that can be used to develop optimum techniques to maximize gas production from the eastern gas shales.
Foam Fracturing of Upper Devonian Benson Formation in Central West Virginia
Authors: Shea Christopher , Bucher Dean Herbert
Published: December 2007

Stimulation of the Upper Devonian Benson Formation of Central West Virginia has lead to the use of various types of treatments. The following is an investigation of one of the more recent techniques, Foam/Nitrogen Fracturing, as it compares to the conventional Water Frac methods.

The Benson is a shallow water turbodite deposit with thicknesses variable up to 30 feet. It is a brown siltstone which characteristically becomes commercially productive only after stimulation. Over the past three years stimulation of Union Drilling Benson wells in Upshur and Barbour Counties has been exclusively Foam Frac or Water Frac, with few exceptions. Foam Fracs were used initially for three reasons: (1) to keep large volumes of water out of the formation in order to prevent clay swelling, (2) to aid in well clean-up, (3) to allow better sand placement through increased carrying quality of foamed Nitrogen. The ultimate goal of the Foam treatment is to increase gas flow from the wells.

Methods of investigation include records kept of (1) volumes of water used for treatments, (2) cleanup and service rig time and efficiency (3) open flows from foam frac and water frac treated wells, an indication of the sand placement abilities. Conclusions based on open flow results indicate that lower volumes of water, quicker well clean-up, and improved sand placement are desirable for the Benson Formation.
Selection of a Fracture Proppant in a Tight Gas Field, Bauxite vs. Sand, Wamsutter Area, Wyoming
Authors: Seccombe James C. , Anderson Gary E.
Published: December 2007

This paper discusses the results of a study made to evaluate the effectiveness of sintered bauxite as a propping agent for Mesaverde fracture stimulations in Wyoming's Wamsutter Tight Formation Gas Area. It is generally accepted that bauxite should be used when closure pressure exceeds 8000 psi (55 MPa). Above this pressure, sand undergoes significant crushing resulting in very large reductions in permeability. However, in areas similar to Wamsutter, where the closure pressure ranges from 6000 to 8000 psi (41 to 55 MPa), it is not clear whether sand or bauxite should be used.

A reservoir simulator and an economic model were used to optimize fracture length and to determine if bauxite should be used in Wamsutter. It was found that well performance can be accurately predicted with the simulator when a 0.1 in situ fracture flow capacity correction is made to laboratory measured fracture flow capacities.

Over the range of permeabilities studied, (0.01 to 0.4 md) it was determined that bauxite should be used as the propping agent rather than sand. The economic benefits of using bauxite are greatest at the higher reservoir permeabilities. At a reservoir permeability of 0.4 md the optimum fracture length is 2000 feet (610 m) when using bauxite, while at a reservoir permeability of 0.01 md the optimum fracture length is 5000 feet (1,524 m).
Multiple Fracturing Experiments — Propellant and Borehole Considerations
Authors: Cuderman Jerry F.
Published: December 2007

The technology for multiple fracturing of a wellbore, using progressively burning propellants, is being developed to enhance natural gas recovery. Multiple fracturing appears especially attractive for stimulating naturally fractured reservoirs such as Devonian shales where it is expected to effectively intersect existing fractures and connect them to a wellbore.

Previous experiments and modeling efforts1–5 defined pressure risetimes required for multiple fracturing as a function of borehole diameter, but identified only a weak dependence on peak pressure attained. Typically, from four to eight equally spaced major fractures occur as a function of pressure risetime and in situ stress orientation.

The present experiments address propellant and rock response considerations required to achieve the desired pressure risetimes for reliable multiple fracturing.
Comparative Economics of Gas Production From Conventional, Tight, and Deep Reservoirs
Authors: Morra Frank , Brashear J. P. , Haas Mark R.
Published: December 2007

In the near future, the majority of America's natural gas supply will be produced from three principal resources: conventional, deep (more than 15,000 feet), and tight (less than 0.1 md) gas reservoirs. These differ from one another in terms of: Exploration costs due to finding rates and field sizes;Extraction costs — especially drilling and stimulation;Risks -- especially in technologies for diagnosing and stimulating deep and tight reservoirs; andGas prices -- under NGPA, deep gas is deregulated and tight gas receives an incentive price, but is not deregulated.

This paper compares the overall present value economics of the three resources in light of these above factors. The analysis shows that, while extraction costs are lower for conventional gas, larger new field discoveries for "frontier" deep and tight gas may make them competitive when full-field economics is considered. This conclusion is even stronger if either differential incentive prices are continued or the technological risks affecting the deep and tight resources are reduced. To the extent this competition between conventional, deep, and tight gas can be fostered, the productivity of exploration (reserves added per foot) and overall gas reserves will be improved.
Foamed Cement — A New Technique to Solve Old Problems
Authors: Root R. L. , Barrett N. D. , Spangle L. B.
Published: December 2007

The process of foaming cement to make lightweight slurries is well known and documented in the literature. However, the technology for applying this process to oil and gas-well cementing has been lacking. New techniques and treatment designs have now been developed which show that the use of lightweight foamed cements in oil field operations can solve many problems. Treatments can be performed with the current equipment and personnel operating in the field. When compared to other processes for making ultra-lightweight slurries, foamed cements are very economical.

There are many reasons for using lightweight slurries in oil-well cementing. Probably, the foremost of these are problems of lost circulation or where long lifts of cement are required. The use of lightweight foamed cement slurries for these problems offers several advantages over the more common lightweight slurries. Some of the advantages are given below. Lower density slurries, which will develop adequate strengths for filler-type cements, can be obtained. A density as low as eight pounds per gallon can be achieved with foamed cement while approximately 10.5 lb/gal is the lowest which can be achieved when using materials such as bentonite, perlite or sodium silicates.Hollow spheres have been used to achieve slurry densities in the eight pounds per gallon range. Foamed cements are considerably more economical and are not subject to the pressure limitations of ceramic spheres.

A series of field trials using foamed cement has been performed in the Rocky Mountain area. Descriptions of these field trials, including the techniques being used, are presented along with supporting laboratory data showing typical compressive strengths and permeabilities for foamed cement systems.
Predicting Possibility of Oil Production from Tar Sand Deposits Based on Geologic, Logging, and Chemical Composition
Authors: Vogel Albert W. , Amirijafari Bahram
Published: December 2007

In this paper, the question, "What are tar sands?" is addressed. In an effort to categorize the tar sand deposit at Raven Ridge near Vernal, Utah, the coordinated and combined activities with corresponding disciplines such as the following were considered: recognizing the potential of the heavy oil impregnated rock,characterizing the deposit based on the composition of the oil,developing reserves,characterizing the material,establishing possible reservoir characteristics,defining conventional oil production potential.

Some fourteen shallow holes were drilled and cored. Tar sand samples were taken from the lean, medium, and rich bitumen content rock. These samples were analyzed chemically.

The results of the coring, logging and chemical analysis are as follows: There is a definite correlation between the results that were computed from electric logs and with those obtained from chemical analysis of some 268 tar sand samples.Asphaltene, polar molecule and hydrocarbon content of the bitumen from Raven Ridge was compared to similar analyses of other tar sand deposits of the world using SARA (Saturates, Aromatics, Resins, and Asphal-tenes) analyses. The results indicate that the petroleum (oil sand) deposit is a thermally mature oil.A reservoir engineering analysis was carried out to determine the potential rate of oil production, from a well drilled at a suitable location downdip based on the available geologic data from the near outcrop core data. The results indicate a good possibility of conventional oil production.

Conclusions are that chemical analysis (SARA) of tar sand samples obtained from various depths, near surface up to 50 feet deep, could provide a positive indication of oil production from a well drilled down-dip from the outcrop.
Analysis of Pressure Buildups Taken From Fluid Level Data — Tyler Sands, Central Montana
Authors: Bishop David F.
Published: December 2007

Pressure buildups taken by fluid level recording prove to be quite usable for formation evaluation in the "Tyler" sands of Central Montana. This method provides low cost information with surprising accuracy. The procedures followed in obtaining the data, and the precautions taken in assuring the validity of the data are discussed in the paper. The data proved sufficiently accurate to perform engineering calculations in two separate "Tyler" fields. The calculations aided in determination of reservoir parameters, and in one field provided justification for additional development drilling. In another field, the data substantiated the limited reservoir, and development drilling plans were cancelled. The buildup curves illustrated well bore damage in some of the wells and subsequent stimulation of two wells resulted in sustained six-fold and nine-fold increases in producing rates of these wells.

This paper illustrates the value of the engineering calculations when applied to carefully gathered field data. The method should have application in other areas with similar producing properties to the "Tyler" sands in Central Montana.
Planning a Bit Selection for a Deep Overthrust Well
Authors: Lyon Richard C.
Published: December 2007

Bit selection planning for a deep Overthrust well in the tri-state area of Idaho, Wyoming and Utah presents a unique challenge to the drilling engineer. Most bit selection techniques were mainly done by the trial and error method with varying degrees of success. Analysis of bit records from this area, in conjunction with electric log interpretation to locate geological formation tops, has resulted in a technique to correlate bit types to specific formations. This technique has been used with some success in bit selection planning. One particular well using this method is compared with actual performance.
Mergers And Acquisitions Of Oil And Gas Producing Companies
Authors: Collins William E.
Published: December 2007

Introduction

In most aspects the problems arising in connection with acquisition of oil and gas producing companies, by whatever method, are essentially the same as those arising in connection with mergers and other acquisitions or other types of commercial organizations. The differences result primarily from the nature of the assets, particularly the depletable assets of oil and gas companies.

The primary difference is that the form of the transaction is usually dictated by the substantial advantages, both to buyer and seller, from the ABC transaction. It is almost universally true that from both points of view, production to the buyer is obvious. From the stand-point of the seller, even if the tax basis is almost nil, the price obtainable in a production payment transaction quite often is greater after taxes than the value obtainable in a tax free transaction.

The second difference is that in a transaction involving producing oil and gas properties the legal work involved in conveyancing and title examination is usually substantially greater than is involved in most other commercial transactions.

Basically, there are two types of corporate acquisitions - tax free reorganizations and taxable transactions.