bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Analytical Model for Composite Reservoirs Produced at Either Constant Bottomhole Pressure or Constant Rate
Authors: Olarewaju J. S. , Lee W. J. 
Published: December 2007

ABSTRACT
In this paper, we present a model of the complete characteristic transient response from a composite reservoir including the effects of skin, wellbore storage and phase redistribution at the well. We present six flow regimes and the combined effects of wellbore storage and phase redistribution on pressure behavior in composite reservoirs.
Using an automatic history matching approach, we analyzed three buildup tests and a pressure falloff test. This method eliminated the serious uniqueness problem associated with type curve analysis. We demonstrate that incorrect reservoir parameter estimates and incorrect production performance predictions would result from the use of any model that lacks the capabilities of the model we present in this paper. We also demonstrate possible misinterpretations of pressure data that may result from not recognizing the presence of phase redistribution in the buildup test data or not recognizing the composite reservoir behavior.
Applications of Well Logging for Compaction and Subsidence Studies in the Orinoco Oil Belt, Venezuela
Authors: Ramirez M. O. , Zubillaga J. I. 
Published: December 2007

ABSTRACT
A pilot study project is presently carried out in the unconsolidated low gravity oil sands of the Orinoco Oil Belt, in the eastern part of Venezuela, one of the largest heavy oil accumulations in the world. The objective is to evaluate the interactions and environmental impact of Compaction and Subsidence due to fluid withdrawal.
Thirteen injection-production and two observation wells were drilled for this purpose. The optimal location of the latter was determined after detailed log evaluation of the injection-production wells. The logging program for the observation wells was designed for a thorough evaluation of the geological, petrophysical, and geomechanical reservoir characteristics. In addition, a large number of radioactive bullets were placed along the boreholes, in the observation wells, for compaction or deformation monitoring.
This paper presents the results of the extensive logging program carried out including those of the Field Subsidence Monitoring Tool (FSMT). The methodology used in the evaluation of the shaly intercalations on sands is particularly referred.
Development of the Lisburne Reservoir
Authors: Paige K. T. , Dayton J. S. 
Published: December 2007

Abstract
This paper provides an overview of the Lisburne, the most recent producing reservoir on the North Slope of Alaska. It will briefly touch on the geology of the Lisburne Field and then move into the development history and reservoir description. Following this, there will be a discussion on the first phase of development, and the paper will close with a brief look at the future.
The Lisburne is a naturally fractured carbonate reservoir and was the geologic target for drilling of the Prudhoe Bay State No. 1 in 1968, which discovered the shallower Sadlerochit Reservoir. Due to the Sadlerochit's immense size, relative to the Lisburne, development of the Lisburne was delayed until the early 1980's. The Lisburne started-up on December 15, 1986 at a rate of approximately 40,000 barrels of oil per day. This was the first time a fully integrated North Slope major production facility was brought up on a single sealift and started in the same year.
Relative to most domestic reservoirs the Lisburne is a substantial reservoir with three billion barrels of oil in place. From primary recovery supplemented by produced gas re-injection we expect to produce between 250 to 350 million barrels of oil. Ultimate recovery, including both primary and secondary, could range up to 500 million barrels. Primary development includes the drilling of up to 200 wells with initial well rates varying between 1000 to 3000 barrels of oil per day. Development cost at start-up was approximately 850 million dollars; ultimate cost is anticipated at 1.5 billion dollars. The field is being operated by ARCO Alaska, Inc. on behalf of the three owner companies, ARCO Alaska, Inc., Exxon Company, U. S. A., and Standard Alaska Production Company.
Oil Prices: Can We Predict Where They Are Going?
Authors: Dougherty E. L. 
Published: December 2007

Abstract
Earlier explorations of how to predict oil prices led, in 1978, to my being named project director of a contract between USC and the OPEC Secretariat in Vienna to develop a world energy model. OPEC wanted a tool to help devise rational oil production and pricing policies. Late in 1981, we installed the model on OPEC's computers in Vienna. It is unknown how effectively OPEC was able to use the model, but it did foretell the shape of recent events in world oil markets. In Jan, 1981, we gave our sponsors the results of a study of what would happen if OPEC raised its production rate back to 20 million barrels per day, a study they requested after their production rate fell to around 18 million B/D. The model predicted that if OPEC's rate were to be raised as proposed, oil price would fall $20/bbl within a year. Although not spot on, the prediction is certainly indicative of what was to come. (For this study all price elasticities were arbitrarily increased by 10 percent from their base levels, the medians of estimates reported in the literature. In hindsight, this adjustment was conservative. The past decade's price-induced, reduced growth rate in energy consumption, so-called conservation, corresponds to even larger values of price elasticity.) There is no indication that OPEC paid attention to this or other model predictions; they were still whistling their favorite high-price tune when the market forced their first official price cut late in 1982.
This paper presents some rules of thumb that my experience suggests may help to understand the evolution of oil prices. The intent is to identify factors to consider in deciding on the credibility of an oil price forecast (yours or another's), rather than to prophesize future oil price. The presentation is professorial in style; a series of questions penetrating different aspects of the dynamics of oil prices are asked, and answers to these queries are advanced. This interrogatory is targeted to broaden the reader's perspective on what makes the oil market tick. We also examine how individuals have responded in the past to signals from the marketplace. This examination's purpose is to call to attention the impact of emotions on the subjective weightings applied in reaching an economic decision. In the oil patch expectations about highly uncertain outcomes, both economic (mostly prices and taxes) and physical, exert a major influence on investment decisions. Being aware of how emotions can slant these expectations is a key consideration for a decision maker.
Evaluation of Reserves for a Number of Small, Partially Shut-in Gas Fields in Northern Tennessee
Authors: Blasingame T. A. , Poston S. W. , Hedberg W. H. 
Published: December 2007

ABSTRACT
This paper presents analysis techniques for post-transient gas flow at a constant flowing bottomhole pressure. Reservoir parameters can be estimated from production decline curve analysis using analytical solutions which are formulated in terms of real gas pseudopressure analysis.
These techniques were applied to a field study of two small, low productivity gas reservoirs in Northern Tennessee. The production data for this field study was analyzed using decline curve analysis. The types of decline curve analysis used were: rate-time graphical, rate-time and cumulative-time non-linear least squares. Decline curve analysis by the use of type curves was attempted, but data scatter caused significant deviation of results when compared to the other types of decline curve analysis.
The decline curve analysis results were then interpreted using an analytic reservoir model which did include pseudopressure analysis. This analysis was verified by a simulated real gas example which attempted to model producing conditions similar to those encountered in the field.
The overall objective of the field study was to find correlations of reservoir parameters to measured production data. Several rate-reserve, rate-permeability/porosity-агеа ko A, and rate-permeability-thickness (kh) correlations were obtained from the results of the decline curve analysis. The best correlations were based on an average rate, q¯3, calculated from a well's first three months of production.
The Engineering Approach to Sand Production Prediction
Authors: Weissenburger K. W. , Morita N. , Martin A. J. , Whitfill D. L. 
Published: December 2007

ABSTRACT
An engineering system has been developed for sand production prediction. The system synergistically uses geological reservoir characterization, log analysis, and core rock strength testing to forecast perforation cavity stability. Coupling the system with a reservoir simulator permits the modeling of cavity stability at initial conditions and throughout the life of a well. Three examples are given of applications of the engineering system to sand problems in North Sea reservoirs.
Study of the Effects of Fluid Rheology on Minifrac Analysis
Authors: Lee W. S. 
Published: December 2007

ABSTRACT
Incorporation of a energy balance equation into the pressure decline analysis (minifrac) greatly improves the effectiveness of this analysis.
Minifrac analysis currently being employed by most petroleum industry operators does not consider the rheological properties of the fracturing fluid. The most severe consequence of this omission is that the geometry determined by minifrac analysis often differs from that of the fracture design programs based on the same model.
Inclusion of the energy balance equation developed by Biot, Masse, and Medlin enhances the analysis as described below. Rheological properties are considered, therefore geometry determined from pressure decline analysis is in agreement with geometry determined from fracture design programs. Because of the close agreement, one can better predict fracture fluid volume required in a full scale treatment.This method does not require the assumption that created fracture width is proportional to the pressure difference between instantaneous shut-in pressure and formation closure pressure. When this difference is on the order of 1000 psi, calculated widths can be several times as great as the width found by the fracture design program based on the same model.
Subject presents: (1) discussion of theoretical aspects of new analysis method, (2) case histories of jobs performed with this analytical method as a planning tool, and (3) a comparison of calculated parameters with those used for job design.
Determination Of Formation Properties From Long-Term Gas Well Production Affected By Non-Darcy Flow
Authors: Fraim M.L. , Lee W.J. 
Published: December 2007

SPE Members

Abstract
This paper presents new type curves to estimate formation and well properties such as gas in p lace, drainage area, and hydraulic fracture half length for fractured gas wells with finiteconductivity fractures. We model non-Darcy flow in the fractures or in the formation in unfractured wells with our type curves. Application of the curves allows rigorous modeling of gas property variation with pressure even after the boundary-dominated flow regime is reached. For wells with finite-conductivity fractures in bounded reservoirs, we generated a new analytical solution using Green's Functions.

Introduction
The purpose of this paper is to present new constant pressure type curves to analyze short-term and long-term production data for the following two physical situations:Wells with finite-conductivity fractures in bounded reservoirs having conductivity, CfD' varying from 0.1 to 100.Wells in homogeneous formations.
In addition, the paper presents a method to account for gas property variation with pressure, even after the boundary-dominated flow regime is reached. The paper presents methods to use the type curves to model non-Darcy flow in the fractures or in homogeneous formations.
Data required for the type curves include rate vs. time and either surface or bottom-hole pressures which, if not constant, can be treated using superposition.
In this paper, we present (1) back-ground on solutions for fractured wells and for handling variable gas properties; (2) a description of our mathematical model for a well with a finite-conductivity fracture; (3) a discussion of the deliverability equations for a homogeneous reservoir and for a vertically fractured well and of how we created the non-Darcy flow correlations; (4) an explanation of the non-Darcy correlations ; (5) an explanation of normalized time and normalized rate which are needed to use the type curves for gas wells; (6) an explanation of the new type curves that includes a description of the dimensionless variables and the relationship between the cumulative production-time match point and the rate-time match point; (7) a detailed description of the algorithms for history matching and predicting future performance with the type curves; (8) a discussion on superposition with normalized time and rate; (9) a discussion of the cumulative production type curve with an explanation of possible characteristic shapes; (10) a description of the numerical model used to generate data for the correlations and to validate the type curves; (11) a validation of the type curves with other published work; and finally (12) examples of application of the type curves to two field cases and one simulated case.

Background
Gringarten et al. in 1973 and 1974 developed analytical type curves for vertically fractured wells with infinite-conductivity fractures and with uniform flux into the fractures.
The Well Data System (WDS): An Advanced Formation Evaluation Concept in a Microcomputer Environment
Authors: Ball S.M. , Chace D.M. , Fertl W.H. 
Published: December 2007

Abstract
As processing capabilities of microcomputers Continue to increase in today's accelerated development climate, advanced formation evaluation, previously considered unsuitable for smaller processing environments, has now become both technically feasible and economically attractive.
Formation evaluation packages on microcomputers have typically been restricted to simple processing routines, including data entry either by hand or through digitization of a particular zone of interest. With microcomputers now having larger memory capacities, disk storage, and faster processing speeds, advanced log evaluation may often be performed at data rates exceeding the capabilities of minicomputer systems. With appropriate peripherals, a workstation can be established that allows true advanced log interpretation on microcomputer systems.
The Well Data System (WDS), an advanced log evaluation system operational on a microcomputer, increases the productivity of formation evaluation specialists in single and multi-well reservoir descriptions. WDS incorporates software packages for both open and cased hole well log analysis, advanced dip log evaluation (including stratigraphic analysis), statistical analysis in complex reservoir rocks, formation pressure evaluation, and completion flow systems nodal-type analysis.
Performance is oriented toward high volume operation and incorporates batch and interactive processing modes, datailfile portability, tape processing, digitizing, plotting, and data communications.
This paper highlights the multidisciplinary approach of WDS, facilitating cost-effective and comprehensive evaluation of well logging and related petrophysicaI and production data over the entire life of a well.
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Wettability Alteration Induced by Oil-Based Drilling Fluid
Authors: Ballard T. J. , Dawe R. A. 
Published: December 2007

ABSTRACT
Invert emulsion oil based drilling fluids rely on surfactants and emulsifiers to maintain the stability of the invert emulsion. An excess of oil wetting agents in the system is usually necessary in order to oil wet the drilled solids. This excess of surfactants causes wettability alteration in the drilled formation. This is recognised as one of the mechanisms of formation damage.
A study has been carried out to assess the influence of the surfactant concentration in oil based mud filtrates on the wettablility alteration of glass surfaces. Micromodel work has shown that oil based mud filtrate can cause emulsification and migration of connate water, thus reducing the water saturation as well as the alteration of the wettability of the pore walls. Results of contact angle studies suggest the surfactants in oil-based mud filtrates adsorb on to silica surfaces to build up a monolayer, Thus changing the initailly strongly water-wet surface to one of intermediate wetting.
This paper reports in detail the experiments carried out to demonstrate the wettability alteration caused by an oil based mud filtrate. A detailed investigation carried out to discover any correlation between the concentration of oil-wetting agent in the filtrate and the magnitude of the change in wettability produced on glass surfaces.
The studies of contact angle variation as a function of surfactant concencentration show that even very small concentrations of surfactants are potentially damaging to reservoir formations.
Formation Damage During Gravel-Pack Completions
Authors: Houchin L. R. , Dunlap D. D. , Hutchinson J. E. 
Published: December 2007

ABSTRACT
Most gravel packed completions are considered successful if the well produces sand free. However, many successfully gravel packed wells suffer reduced productivity as a result of formation damage induced by current gravel pack completion practices. Gravel packing even a slightly damaged formation can result in long term detrimental effects on production. The most predominate problem is that dehydration of the gravel carrier fluid will be restricted and perforation tunnels will not tightly pack.
The areas of interest in which formation damage can be limited during a gravel pack completion include perforating, filtration, gravel carrier fluid selection, lost circulation control, and workstring hygiene. In addition, fluid leak-off during gravel packing may be optimized by proceeding the gravel pack slurry with low strength acid.
Discussion of Intermediate Casing Design Parameters
Authors: Curry W. E. 
Published: December 2007

Abstract
Design procedures used to establish burst requirements for surface and intermediate casing are extremely different and are nearly as numerous as the companies that design casing. This paper briefly discusses the differences in design philosophies, but primarily examines the historical performance of the entire design spectrum and the explanation of why so many widely varying design procedures have succeeded equally well. From this examination, a list of key design considerations is developed which will hopefully assist designers who may now (or in future) struggle with surface and intermediate casing burst design.
Performance Evaluation of a New Rock Bit Bearing Seal
Authors: Kelly J. L. , Ledgerwood L. W. 
Published: December 2007

Abstract
Reliability functions derived from field performance data are used to measure the effectiveness of a new rock bit bearing seal. The new seal is a metal face seal and its performance is compared to the standard O-ring seal. The results show a significant increase in bit life measured in cone revolutions under typical operating conditions. This increase in cone revolutions may be utilized to increase rotating time, rotary speed or both. An example comparing various alternatives is provided. Data are also provided which show a much improved tolerance to high bottom hole temperatures.
Applications of a Computerized Bit Record Database
Authors: Steinke S. C. , Watson J. A. , Bremner D. C. 
Published: December 2007

Abstract
The Bit Record Database and analysis program discussed in this paper were developed to provide rapid access to and analysis of bit run information. The system was developed in three phases:
Bit Record Database construction Analytical programs that also access Engineering, Manufacturing, and Sales databases Computer-assisted well programming
The Bit Record Database resides on an IBM mainframe and provides rapid on-line access as well as a down load facility to floppy disks for microcomputer applications. The system contains over 100,000 bit records which represent over 700 million feet of drilling hole. Data accuracy and confidentiality are strictly controlled through stringent data validation, access codes, and flagging of tight holes.
Programs have been written to evaluate bit performance data in relation to various engineering and manufacturing parameters. This data enables both product engineers and manufacturing process engineers to set specifications that will result in consistently high bit performance.
The microcomputer is used in various field offices to assist technical personnel in preparing recommended bit programs and rapidly summarizing the drilling history for a selected area. The computer quickly identifies offset wells and then accesses programs which optimize hydraulics, evaluate bit run efficiency, and determine overall cost effectiveness. The result is a well program that allows field technicians to combine their knowledge of an area with the computer's ability to quickly locate wells and then precisely calculate needed values. This helps produce accurate and timely well programs which result in the lowest cost per foot.
Spudding a Vertical Hole in Deep Water Using MWD Surveys
Authors: Belaskie J. P. 
Published: December 2007

ABSTRACT
Spudding a well in deep water can be complicated as the presence of large currents may cause the bottom hole assembly (BHA) to be inclined up to ten degrees at the bit. A desirable hole inclination would be less than 0.5 degrees for setting surface casing. A method of taking Measurements While Drilling (MWD) surveys and repositioning the rig until the drill collars are vertical has been developed and tested on two wells.
The Drilling and Testing of High-Pressure Gas Condensate Wells in the North Sea
Authors: Low E. , Seymour K. P. 
Published: December 2007

ABSTRACT
During the 1980's exploration activity in the North Sea turned towards deep, high pressure, Jurassic gas condensate reservoirs. These reservoirs occur at 16 – 18,000 ft, are abnormally pressured with pore pressures of approximately 15,500 psi, and temperatures approaching 400 deg F. This presented a new challenge to the drilling industry which required the development of new techniques, equipment and philosophies.
By 1985 considerable experience had been gained in the drilling and testing of these wells. In mid 1985 Ranger Oil drilled Well 29/5b-4 to a depth of 17,930 ft using their own semi-submersible drilling unit, the SEDCO 714. Electric logging indicated that the Upper Jurassic objective at 17,080 ft had a pore pressure of 15,800 psi. The presence of H2S and CO2 were detected and calculations showed that the maximum anticipated tubing head pressure was 13,500 psi. By following the concepts developed from past experience that wells of this type cannot safely be tested from a floating drilling unit, the well was suspended. Procedures were established to permit the safe testing of this well using engineering innovation to develop new equipment and techniques. Re-entry and testing took place in August 1986 using the jack-up GLOMAR MORAY FIRTH and produced a total of 54 mmscf/d and 4,500 BOPD. Maximum wellhead pressure was 12,500 psi, surface temperatures reached 300 deg F and reservoir temperatures of 406 deg F were recorded.
By examining the operational procedures, equipment and techniques used to overcome the problems encountered, a drilling and testing philosophy is developed, which provides a field proven basis for the economic exploitation for reservoirs of this type.