bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fiscal Risk and the Stability of Contractural Arrangements for Petroleum Exploration and Development
Authors: Cavoulacos P. E. , Blitzer C. R. , Laughton D. G. 
Published: December 2007

ABSTRACT
The objective of this paper is to develop a methodology to assess the impact of fiscal risk, the risk of contractual non-performance by a host government, on the value and stability of contracts for petroleum investment. In the proposed fiscal risk model, the host government may appropriate a share of excess profits (resulting from perceived price or discovery windfalls) higher than that specified in stated contract terms. A valuation framework similar to that used to price options and futures in financial markets is used. Various components of the project are valued as contingent claims on the revenue stream of the developed field. Four fiscal regimes -- royalty, production sharing, service and resource rent tax -- were designed to give the same asset value to the foreign oil company under stated contract terms; however, when fiscal risk is taken into account, this value can be substantially lower. The royalty and production-sharing contracts are quite unstable because a large fraction of the initial value accruing to oil companies under stated contract terms comes from the possibility of large discoveries, where fiscal risk is most severe. The resource rent tax and the service contract are more stable because both fiscal regimes generate the bulk of oil company value from the possibility of small and medium discoveries. The stability of the production-sharing contract can be enhanced substantially if the host government share of profit oil is set by a progressive sliding-scale schedule. In general, contract stability is enhanced if the government explicitly bears much of the oil price and discovery risk.
Quantitative Analysis of Performance of Polymer Slug Injection
Authors: Lutchmansingh P. M. , Marietta C. , Ertekin T. , Abou-Kassem J. H. 
Published: December 2007

ABSTRACT
The literature reveals a number of criteria used to screen oil reservoirs for polymer injection. The qualitative response of polymer injection process for a given field parameter is also implied. This paper presents a quantitative analysis of the performance of an oil reservoir undergoing polymer slug injection due to variations of parameters used for screening. The reservoir performance is represented by the behavior of oil recovery, WOR and oil production rate. These performance parameters are usually used to determine the economics and economic limit of an enhanced oil recovery project. The field parameters considered for analysis in this study include reservoir permeability (230 – 2300 md), oil viscosity (25 – 100 cp), polymer viscosity (1.45 – 4.8 cp), rock adsorption characteristics (0 – 0.0001 lb/lb rock), polymer slug size of constant concentration (0.1 – 0.4 PV), combination of polymer slug size and concentration such that the injected polymer is constant, and polymer slug program.
In this study a number of numerical exercises were conducted using the reservoir rock and fluid data for the Lower Huntington Beach Garfield zone in two dimensions. A field parameter is varied within the limits of the screening criteria and the response of the reservoir is analyzed.
It is found that the reservoir permeability is of paramount importance to the success or failure of polymer injection as an enhanced oil recovery method. The analysis of the behavior of sandface pressure for low permeability reservoirs provides interpretation of the plugging effects observed in the field. The performance of polymer injection is improved when a polymer slug program aiming at protecting the initial slug by graded buffers is implemented. Finally, our numerical experimentation confirms the widely held view of using 0.70 pore volume injected as a criterion to terminate a polymer injection project.
Fluid Flow Considerations in Hydraulic Fracturing
Authors: Nolte Kenneth G. 
Published: December 2007

ABSTRACT
Significant progress has been made over the past decade in the understanding and modeling of rock failure and deformation during hydraulic fracturing. This progress resulted from a large investment in theoretical, laboratory, and field research programs conducted by private, government and university groups. By comparison, relatively small investments or progress has been made in the companion area of fluid flow in the fracture. To bring the level of understanding for fluid flow to that of rock mechanics, and provide the basis for another major advance in fracturing technology, significant and focused investigations of fluid flow are required.
The purpose of this paper is to review the various aspects of fluid flow within the fracture, provide several relevant pieces of new information, and to identify areas for additional research. The areas considered are the effects of slip flow; proppant on viscosity; width variations on the velocity profile and the pressure gradient; proppant transport and fall after shut-in; particle migration for viscoelastic fluids; and fluid loss.
An Improved Technique for the Evaluation of Performance Characteristics and Optimum Selection of Sucker-Rod Pumping Well Systems
Authors: Lekia S. D. L. , Day J. J. 
Published: December 2007

ABSTRACT
An improved method is presented for the evaluation of performance characteristics and optimum selection of sucker-rod pumping well systems. The procedure is conceptually general for all class I lever (conventional) systems and for the Mark II type of the class III lever systems. The procedure can easily be modified for any kind of special surface pumping unit.
This study uses basic sucker-rod theory already presented in the literature. The new approach, however, groups the most important variables affecting the operation of a total sucker rod pumping well system (from the prime mover to the downhole pump) into eleven dimensionless numbers which are used to aid the simulation of performance characteristics and design parameters. The final results consist of design parameters for various rod size-pump depth-production rate combinations from which an optimum pumping mode is selected. The selection of the optimum pumping mode is based on an optimization criterion proposed in this paper.
Based on limited specified information on a well being considered for the installation of a rod pumping system, the method presented can be used to select a total sucker rod pumping system that will optimize both production and longevity of all parts of the system. The procedure minimizes the design of incompatible parts that very frequently leads to system failures. For already existing installations, the method furnishes information on pumping speed, counter-balance weight, polished rod stroke, etc., for setting a new optimum operation.
An Overview of GRI's Comprehensive Study Well Program in the Devonian Shales of the Appalachian Basin
Authors: Lancaster D. E. 
Published: December 2007

ABSTRACT
This paper presents an overview of the Gas Research Institute's (GRI's) Comprehensive Study Well (CSW) program in the Devonian Shales of the Appalachian Basin. Initiated in mid-1987, the CSW program is a planned series of highly instrumented study wells drilled in cooperation with industry partners. Extensive data are being collected and special experiments are being conducted on each CSW with the objectives of identifying geologic production controls, refining formation evaluation tools, and improving stimulation practices in the Devonian Shales. The focus of stimulation research in the CSW program is on pumping larger treatments carrying more sand at higher concentrations, developing an optimal fluid system for the Devonian Shales, and improving quality control.
This paper reviews the progress of the CSW program thus far and focuses particularly on the CSW No. 2 in Calhoun County, WV, which is the well studied most completely to date. The fracture treatment pumped on the CSW No. 2 demonstrates that large, high sand concentration treatments can be pumped successfully in the Devonian Shales; however, optimizing the fracturing fluid system and improving liquid cleanup remain important unsolved problems requiring additional study.
Downhole Motors Increase ROP and Reduce Cost Per Foot in the Austin Chalk Trend
Authors: Bayoud B. B. , Staiger L. W. 
Published: December 2007

ABSTRACT
With currently depressed oil prices it is more important than ever for operating companies and drilling contractors to find ways of reducing drilling costs. By using some relatively new techniques, including computer-assisted planning aids and downhole motors with polycrystalline diamond compact (PDC) bits, one drilling contractor reduced cost-per-foot by 20% in the Austin Chalk Trend.
Technological advances in downhole motor designs have expanded their use as effective alternatives to rotary drilling in straight-hole and long-interval drilling applications in the Midway Shale and Austin Chalk Formations. The full potential of these motors, which for years have been used successfully in a variety of directional applications, can be tapped only through proper system design, planning and operating techniques.
The key to optimizing downhole motor performance is a systems approach that encompasses motor/PDC bit selection, hydraulics, operations, breakeven cost analysis and projected results. Results of this type of planning can be seen in the following case history data that show the use of downhole motors offers straighter holes, increased penetration rates, fewer washouts, longer on-bottom time and reduced casing/drill pipe wear when compared to conventional rotary drilling operations.
This paper describes the results of a series of wells drilled by a drilling contractor and how downhole motors reduced cost-per-foot by increasing the rate of penetration 50% to 100% in the Midway Shale and Austin Chalk Formations.
Curved Cutters Extend Range of Formations Drilled with PDC Bits
Authors: Knowlton R. H. , Kester R. 
Published: December 2007

ABSTRACT
For the past few years the industry has been trying to extend the operating range of polycrystalline diamond compact (PDC) bits in terms of formations that can be drilled. Initially, the direction was uphole to the softer formations where the high standoff blade bits and large diameter PDC bits have proven economic. The next step is to extend downhole where the formations are harder and generate more heat. Typically, either tungsten carbide insert (TCI) bits or natural diamond bits are used in these harder formations because the heat degrades the polycrystalline diamond compact cutters. However, insert bits tend to be short-lived and require tripping more often than is satisfactory and diamond bits have penetration rates that are slower than desirable.
Bits using PDC cutters with enhanced thermal stability and a radius of curvature on the diamond table have demonstrated a significant economic impact in many harder formations. The diamond wafer is shaped like a dome and set in the bit in place of the conventional, flat PDC cutters. The dome shape dissipates heat better, facilitates more efficient mechanical cuttings removal and drills with a constant rate of penetration throughout the life of the cutter due to the variable rake angle.
In addition to extensive laboratory testing, a rigorous field-test program was undertaken to determine the significance of this new development. Field-test results are presented from Northern Europe and the lower Wilcox Frio sands and other formations of South Texas.
Incentive Approach to Drill Fluids Management: An Experience in Central North Sea
Authors: Geehan T. , Dudleson W. J. , Boyington W. H. , Gilmour A. , McKee J. D. A. 
Published: December 2007

ABSTRACT
The paper describes a modern approach to the operation of drilling fluid at the rig site in which the drilling contractor furnished a total fluids management package inclusive of engineering services, computerised reporting techniques plus all required solids control equipment. The fluids engineering included both drilling fluid engineering and solids control optimisation with the required monitoring of oil based fluid usage and oil discharge to the marine environment.
Applications of a Real Time Wellbore Friction Analysis
Authors: Falconer I. G. , Belaskie J. P. , Variava F. 
Published: December 2007

ABSTRACT
An interpretation technique to determine the friction losses in the drillstring, on a foot-by-foot basis at the wellsite, was proposed at the 1987 SPE/IADC drilling conference (SPE/IADC 16114). Since then the technique has been used commercially on over 40 wells throughout the world. The interpretation uses realtime measurement while drilling (MWD) and surface measurements of weight-on-bit and torque to compute a rotating friction factor and a sliding friction factor while drilling.
This paper describes commercial applications and limitations of the technique. Case histories are drawn from wells drilled in the Gulf Coast, East Canada, South America and Africa. The results illustrate how the technique can be used to: –detect the onset of sticking problems and avoid stuck pipe–optimize bit performance and avoid unnecessary trips–optimize various hole conditioning techniques
Case History of Horizontal Wells Drilled With Navigation Technology in European Operations
Authors: Ehlers R. , Kracht L. , Witte J. 
Published: December 2007

ABSTRACT
This paper describes case histories of four horizontal wells in Europe in which directional and economic objectives were achieved using steerable Navigation Drilling Systems (NDS).
These four wells, part of a multi-well program, featured build-up rates (BURs) of 2-16 degrees/100 ft. (30m), with lateral sections ranging from 440 ft. to 2650 ft. (734-807m). Existing Navigation Drilling System technology was used to achieve BURs of 2-6 degrees/100 ft. (30m), while newly developed Navigation motors were used for BURs of 8-16 degrees/100 ft. (30m).
Case histories #1 and #2 examine two new wells in which existing NDS technology was used from kickoff to closely follow the planned trajectory while reducing torque and drag — the limiting factors for achieving horizontal reach.
In case histories #3 and #4, fixed-angle and steerable medium-radius angle-build motors were used to achieve the higher BURs in two redrills of existing wellbores. To maintain wellbore trajectory, the steerable system can be oriented or rotated in high build-up sections to adjust inclination angle and direction without tripping.
In the multi-well program referenced for this paper, the NDS drilled a combined total of 32,677 ft. (9963m) of wellbore, including 16,926 ft. (5153m) of horizontal footage, and achieved all directional requirements. Following the case histories of the four representative wells, the paper summarizes key factors in wellpath design, engineering planning and equipment selection that contributed to the success of the wells.
MODU Drilling Rig Downtime: An Objective Analytical Approach
Authors: Dew L. L. , Childers M. A. 
Published: December 2007

ABSTRACT
For the past 2 1/2 years and over 250,000 MODU operating hours, which included up to 8 floating drilling rigs and 17 bottom sitting drilling rigs, downtime data was inputted into a defined matrix for analysis. By use of 6 categories (drilling, subsea, mechanical/electrical, etc.) and 5 causes (operation, manufacturer/warranty, maintenance, etc.) of downtime a 6 by 5 matrix was developed to pinpoint fleet wide as well as individual rig problem areas. Downtime data was inputted into the computer weekly as well as accidents, lost time accidents, rig status and "flags" of interest that include up to 100 different printout options. Each downtime incident has a succinct description with corresponding corrective action. The system has proven objective, useful in spotting problem areas, and with its strict definitions very repeatable. With the aid of the downtime system and reinforcement by the companies Preventative Maintenance Program, downtime LTA's and accident rates have all decreased.
Pin-up Drillstring Technology: Design, Application, and Case Histories
Authors: Dudman R. A. , Stull T. , Keane T. 
Published: December 2007

ABSTRACT
Conventional drillstrings frequently pose problems when used to drill relatively small size holes. Pin Up, a new, simple technology, affords economical solutions to problematic hole sizes and conditions. The improvement realized by using Pin Up drillstrings is helping the industry drill higher quality wells, while lowering drilling cost.
Incentive Drilling Operations in Remote Locations
Authors: Marshall D. W. 
Published: December 2007

ABSTRACT
The drilling of wells on incentive contracts has become increasingly common during the past several years. The motives for this trendaway from conventional day rate contracts differ for both the operator and the contractor but for a mutually beneficial result - the operator drills a cheaper well and the contractor has a chance to increase his revenue, or at least reduce his losses.
This paper examines the incentive drilling concept in general andspecifically considers the mutual benefits to be gained by both the operator and the contractor in an incentive contract in remote locations. At the same time the problems and risks of such operations arediscussed and compared with the more conventional incentive operations in the U.S. using, as an example, a recently completed turnkey well drilled by SedcoForex in Senegal.
Lightened Fluid Hydraulics and Inclined Boreholes
Authors: Rankin M. D. , Friesenhahn T. J. , Price W. R. 
Published: December 2007

Abstract
This paper discusses the use of fluids with densities less than that of water as a circulating medium in horizontal wells. The significance of inclined geometry as a determinant of pressure loss and hole cleaning efficiency is discussed as are the results of laboratory simulations.
Optimizing Operator/Contractor Relationships
Authors: Burris K. B. , Welter C. M. 
Published: December 2007

Abstract
The paper that we wish to present concerns operator/contractor relationships. Specifically it will define the proper attitudes of both parties towards communications, bidding procedures, pre-spud conferences, contract per-formance, billing procedures and contract eval-uation.
Information on the above will be derived from actual experience. This, paper will possibly differ from any presented in the past since it deals more in management philosophy rather than technical engineering data.
The results to be shown in this paper will be that optimized operator/contractor relation-ships lead to greater efficiency and lower costs for the operator plus a more profitable operation for the contractor.
EPA Offshore Effluent Guidelines for Mud and Cuttings Discharges: A Regulatory Impact Model
Authors: Randolph T. M. , Simpson J. P. 
Published: December 2007

ABSTRACT
Effluent guidelines for discharges of muds and cuttings offshore are under development. The impact of the proposed guidelines is predicted by a model developed as part of the API comments on the 1988 EPA proposal. A preliminary run of this model shows that 25 percent of the drilling wastes will be hauled for onshore disposal, rather than discharged.
Land Treatment of Oil-Based Drill Cuttings
Authors: Bleckmann C. A. , Gawel L. J. , Whitfill D. L. , Swindoll C. M. 
Published: December 2007

ABSTRACT
Land treatment was successfully tested for treatment and disposal of low toxicity oil-based drill cuttings and reserve pit mud. Oil content of the soil/waste mixture was reduced 84 to 97% over one year. Metals of environmental concern did not migrate vertically or horizontally, even after record rainfall events that occurred shortly after waste application.
During the pilot scale test, cuttings, cuttings plus metals and oil spikes, and reserve pit wastes, were applied to 10' x 10' plots. Plow zone (0-6"), subplow zone (6-12", 12-18") and downslope (5', 50', and 100') samples were taken periodically during the year-long study. Waste applications were based on Oklahoma State regulations governing treatment of such wastes.
Drilling Efficiency Study Reduces Drilling Cost in Colombia
Authors: Hogan S. K. 
Published: December 2007

ABSTRACT
In August. 1986, Tenneco Oil Company's subsidiary, Hocol, conducted a drilling efficiency study of the 32 wells drilled in its San Francisco field near Neiva, Colombia.1 The objective set forth in the study was to reduce the average precompleted well cost from $294,000 per well to $173,150 per well (41% reduction). Since the study was published, the average well cost of six wells was reduced to $239,300 (19% reduction), and the best well cost (SF 48) was reduced to $201,400 (32% reduction). (FIGURE 1)
Effect of Flow Properties on Drillpipe Neutral Point
Authors: Blick E. F. , Shams Q. 
Published: December 2007

ABSTRACT
For the past half century drilling engineers have been computing the required length of drill collars based upon a formula which assumes that the bouyed weight below the neutral point is equal to the weight-on-the-bit (WOB). However, a theory developed in 1950 indicates that the neutral point changes in tubulars when the pressure on the inside wall is different from the outside pressure. Using this theory, this paper proves that the neutral point in drill pipe always moves up the drill string when the mud pump is turned on and it can even move up into the drill pipe. The worst conditions occur in shallow wells, with low WOB, high pump pressure using max jet impact force hydraulics.
Mechanization Replaces the Casing Crew: Experience With the Casing Roughneck System on Polar Pioneer
Authors: Price M. J. 
Published: December 2007

ABSTRACT
This paper contains a description and evaluation of a mechanized system which gives the drilicrew the means to run a casing string without the assistance of a specialist, casing crew. Two years' field experience offshore Norway with a prototype on the semisubmersible drilling rig "Polar Pioneer", has been studied to analyse the consequences the new equipment and procedures has had for safety, costs, efficiency and the working environment.
Relative Permeability of Naturally Fractured Reservoirs from Field Performance Data
Authors: Owusu L. A. , Ershaghi I. 
Published: December 2007

Abstract
The estimation of relative permeabilities from field performance of naturally fractured reservoirs using the x-plot technique is considered for water-oil flow systems. A robust multi-porosity and multi-permeability numerical simulator was developed and used to perform parametric studies. Effect of interporosity flow on the composite relative permeability behavior of a naturally fractured reservoir is examined. A method is presented to estimate the degree of interporosity flow from field derived relative permeability data.