bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Finite Element Model to Estimate In-Situ Stress and Fracture Toughness From a Step-Rate Test
Authors: Khattab H. A. 
Published: December 2007

ABSTRACT
A numerical model to simulate step rate test (SRT) has been developed using finite element technology. This model accounts for the interaction of the fracture and the formation by coupling the fluid flow in both fracture and reservoir. Unlike the conventional models which utilize assumed values of fluid leak-off rate from the fracture into the formation, this coupled fluid flow model yields a realistic fluid leak-off rate. The model also incorporates the effects of rock mechanics on the fracture opening/closing and fracture extension and consequently, on the pressure behavior during a step rate test. This paper reviews the governing fluid flow and poroelastic equations both in the fracture and in the reservoir and also presents the associated finite element formulations. A procedure to history match the step rate test data, to estimate the horizontal in-situ stress and the fracture toughness of the reservoir rock, is also presented. This has been demonstrated by applying the procedure to actual field data.
The present work should be useful for investigating the fracturing mechanisms (opening/closing and propagation) so that a better understanding of the fracture behavior during a step rate test can be obtained. Proposed procedures also can be used to estimate both the horizontal in-situ stress and the fracture toughness of the reservoir rock.
Reservoir Description of West Sak Sands Using Well Logs
Authors: Panda M. N. , Zhang M. , Ogbe D. O. , Kamath V. A. , Sharma G. D. 
Published: December 2007

ABSTRACT
The West Sak field located on the North Slope of Alaska is estimated to contain 25 billion barrels of heavy oil in place. This heavy oil of 10.5-22.5°API gravity lies at depths ranging from 2500 to 4500 feet. The reservoir temperature due to the overlying permafrost is between 45 and 100°F and therefore, the recovery of this oil will require the application of some enhanced oil recovery (EOR) process. Deployment of an appropriate EOR process for commercial production will require a detailed reservoir description. Delineation of the reservoir system, both at the microscopic and macroscopic scale, should include the depositional environment, the reservoir rock and fluid properties, and the rock-fluid property interactions.
This study presents the reservoir description of the West Sak sands. Salient reservoir properties such as the porosity, water saturation, and pay zone thickness are determined using well logs from the West Sak field. Isopach maps, subsurface correlations, and 3-D surface plots are prepared to determine the spatial variations in porosity and water saturation in the pay zones. The correlations of the Spontaneous Potential (SP), Gamma ray and resistivity traces of wells from the West Sak field are used to determine lateral and vertical gradients of the lithofacies of various horizons. The lithofacies distributions are then used to describe the depositional environment of these sands.
The results of the reservoir description study were used as EOR screening criteria and a number of EOR processes were found to be technically applicable to the West Sak field.
A Mathematical Model of Edgewater and Bottomwater Drives for Water Influx Calculations
Authors: Olarewaju J. S. 
Published: December 2007

ABSTRACT
This paper presents a new water influx model that includes either edgewater drive, bottomwater drive or a combination of both. The solutions are presented graphically in form of dimensionless groups which make the solutions applicable to a wide range of systems. Using the classical superposition technique, an example application of the water influx solution to data from a waterdrive oil reservoir is presented.
Evaluation of Waste Energy Utilization for Downhole Steam Generation: Application to Alaskan Arctic Environment
Authors: Thomas A. H. , Maguire M. , Dehghani K. , Ogbe D. O. 
Published: December 2007

ABSTRACT
Steamflooding and steam stimulation are the most popular methods for the recovery of heavy oil. Usually, the steam for these methods is generated at the surface. However, surface steam generation is not economically feasible in deep reservoirs due to excessive wellbore heat losses and high injection pressures.
Downhole steam generators, although still in the research stage, offer an alternative for steam injection into deep reservoirs. In a direct downhole steam generator (DHSG), air, gas and water are injected into a chamber downhole where upon combustion of the air and gas, steam is formed and forced into the reservoir. To produce the high pressure steam needed for deep reservoirs, powerful gas and air compressors are required on the surface. These air and gas compressors generate an excessive amount of waste heat. One method of utilizing the waste energy is to preheat the feed water prior to injection.
This paper presents a method for modelling the surface and wellbore thermal system of a downhole steam generator. A computer program is developed to model the energy balance in the DHSG system. The program determines the amount of waste energy available at the surface and uses this energy to preheat the injection water. This energy is balanced with energy derived from combustion in the DHSG. Effects of surface temperature, steam quality, injection pressure and wellbore configuration on waste energy and preheated water temperature are studied. The model is applied to arctic and non-arctic reservoirs. The effects of low surface temperature and the presence of permafrost were considered when the model is used in the study of downhole steam generation in arctic reservoirs.
Results from the program indicate that energy consumption can be reduced by using waste energy to preheat injection water. Wellbore configuration and climate were found to strongly influence energy consumption.
The Effect of the Presence of a Third Phase on Capillary Pressure By Centrifuge Method and CT Scanning
Authors: Dehghani K. , Bansal A. , Ogbe D. O. , Ostermann R. D. 
Published: December 2007

ABSTRACT
A series of centrifuge experiments was conducted on Berea core plugs to investigate the equilibrium distribution of two and three phase systems in the drainage process. Computer - assisted - tomography (CT) scanning was used to determine the saturation distributions. In order to preserve the saturation distributions for the scan process the oil and water phases were solidified at the experiment conditions. Polyethylene glycol-1000 and a mixture of paraffin, nonadecane, and iodohexadecane were used as water and oil phase substitutes respectively. The spreading coefficient of oil on water was positive. A set of two phase experiments was conducted and the drainage capillary pressures for air-water, oil-water, and gas-water were calculated by the conventional Hassler and Brunner method. The oil water capillary pressure curve by Hassler and Brunner method was compared to the height saturation plots determined by the CT scanning of drainage process at two different centrifugal speeds. Three phase experiments consisted of drainage of mobile or residual oil by gas in the presence of mobile or connate water. The experimental results show that, the height saturation profiles generated in the two phase experiments agree with the capillary pressure data calculated by the Hassler and Brunner method.
The height-saturation profiles obtained by CT scan method in a three phase system including a spreading oil show that gas breakthrough occurs for the secondary drainage process at lower bond numbers and leakage and the drainage process will cause the production of the residual oil. These results also show that at the same gas saturation, gas-liquid capillary pressure in a three phase system is different from that obtained in two phase system.
Paraffin Chemical Treatment vs. Hot Oiling in Subsurface Hydraulic Wells
Authors: Wagner R. D. 
Published: December 2007

ABSTRACTThe use of a crystal modifier to control paraffin deposition in hydraulically pumped wells in Hartzog Draw has proven successful. There are currently thirty wells, 11,000 BOPD, being treated chemically for paraffin. Before the chemical program was initiated, the wells were being treated by hot oiling. The frequency of hot oiling the wells averaged as high as three times per month. This cost, along with paraffin cleanouts with workover equipment and frequent pump repairs, caused high operating costs. Therefore, a chemical treatment program was implemented.Data were gathered for each well before and after chemical treating. The total cost for hot oiling versus chemically treating the wells showed a savings of 20% per month. The cost of chemical has been reduced which in turn has lowered the treating costs from $.l6/bbl. initially to $.10/bbl. currently.Some of the wells have shown production increases one to two months after chemical treating was initiated. This is due to keeping the entire system cleaner and reducing the plugging of the formation with paraffin, a result of hot oiling.This paper will document the data collected and further impress the fact that chemical treatment of paraffin is far superior to hot oiling.
The Sensitivity of U.S. Gas Supply Outlook to Changes in Price or Demand
Authors: Woods T. J. 
Published: December 2007

ABSTRACT
Strategic planning of Gas Research Institute's R&D program requires an appreciation of the outlook for U.S. energy supply and demand and an estimate of the role that natural gas will play within that outlook. The development of a consistent framework that establishes a likely projection of future energy supply and demand is critical to this planning process. This framework is called the GRI Baseline Projection.
Overall, the 1988 GRI Baseline Projection indicates that U.S. gas production can be held stable over the next 25 years as a result of incremental production of gas in the lower-48 using new technologies and production practices and the introduction of Alaskan gas into lower-48 markets. In the 1988 GRI Baseline Projection, detailed sensitivity analyses were made of the effects on this gas supply outlook arising from significant changes in the outlook for oil prices or the demand for gas, such as might be expected should environmental policy decisions encourage gas consumption.
These sensitivity analyses lead to some interesting observations. The linkage between oil and gas prices may not be as strong as past experience has indicated. That is, while gas prices will follow oil prices down, they will not necessarily follow oil prices up. Return to gas demand levels comparable to the peak level of the early 1970s will require a substantial increase in gas imports. New gas supplies must be viewed from three perspectives: cost, location relative to gas demand, and the incremental unit size at which the new sources are introduced into the U.S. gas supply slate.
Independent Access to Institutional Capital
Authors: Vig P. R. 
Published: December 2007

Abstract
It is my pleasure to be with you. I am going to direct most of my comments today to investment in oil and gas by pension plans, including: the major participants in this market; the type of deal structures involved; and perhaps most important, how to position yourself to access this particular market.
First, I feel it's important to look back for a moment to the independents’ historical access to capital and how this market has changed in the 1980's, and, unfortunately, most of the changes have been to the independents’ disadvantage. The independents’ historical source of capital has essentially been three-fold: internal cash generation,bank borrowings, andindustry partners.
Utilization of the Personal Computer To Map Lineament Densities as a Tool for Fractured Reservoir Exploration
Authors: Walbe K. A. 
Published: December 2007

ABSTRACT
Production of gas and oil from the fine grained, low permeability Upper Devonian rocks of the Appalachian Basin depends on connecting with natural fractures. In an attempt to correlate these productive zones with surface features a correlation has been observed between subsurface fracturing intensity, as observed from Borehole Television Camera surveys, and surface lineament density. The digitizing, calculating and density contouring of these surface lineaments can now be done with reasonably priced commercial software and a personal computer. The utile nature of this system is that it gives exploration departments a quick look at possible fracture-enhanced areas of production without the tedious and time consuming process of generating the statistics and maps by hand.
The Use of a Semianalytical Method for Matching Aquifer Influence Functions
Authors: Wattenbarger R. A. , Ding Sheng , Yang Weiping , Startzman R. A. 
Published: December 2007

ABSTRACT
Aquifer performance can be modelled with an aquifer influence function (AIF). For a heterogeneous aquifer of unknown size and shape, the AIF can be calculated from field production and pressure data. The most successful method for doing this has used linear programming (LP) to compute the AIF. The current research introduces an alternate method to LP in an effort to improve computer storage and speed.
The new technique is based on the analytical solution form of a heterogeneous aquifer of any size and shape. The approximating AIF is a continuous function which is a truncated series of the analytical solution. This "semi-analytical function" is fit to field data by the use of nonlinear least squares fitting, using the Levenberg-Marquardt method. The advantages of this method, over the LP method, are that the new method (1) uses less computer storage, (2) is much faster, (3) does not require evenly spaced production periods, and (4) is more robust in use with actual field data.
The results of the new method are striking. Results show that the new method runs as much as 3,218 times as fast as LP and only uses a fraction of the computer storage. The previous implementation of the LP methods was limited to about 70 months of production history on a microcomputer, whereas the new method is virtually unlimited on the amount of production data it can handle.
Support of Drilling Operations Using a Central Computer and Communications Facility With Real-Time MWD Capability and Networked Personal Computers
Authors: Booth J. E. , Hebert J. W. 
Published: December 2007

ABSTRACT
Mobil's Drilling Data Center system in Dallas gathers real-time data and manually entered reports for high cost drilling operations. The information is made available throughout the Drilling organization by means of a communications network which comprises a satellite earth station and high speed data links between major network nodes in Dallas, Houston, New Orleans and Denver. Some 200 users in these locations are directly connected to the network. Access via high speed modems is available to users not directly connected.
As personal computers have replaced terminals as the primary end-user device, the role of the Data Center and the communications network has changed. Recent upgrades to the network permit high speed data transfer from the minicomputers at the Data Center, to personal computers. Text, numeric, and graphic data (including real-time MWD information) can be transferred to the personal computer, then edited or manipulated using standard software packages. This provides the user with much greater flexibility than was possible when using terminals and host computer software. The Apple Macintosh is the standard computer used within Mobil Drilling and the network has been configured to support Apple's Localtalk/Appletalk protocol. This provides users with Wide Area Network connectivity between Local Area Networks in division offices, while maintaining the graphical user interface with which they are familiar.
A Microcomputer-Aided Experimental Gas Reservoir Simulator for Well Control Operations
Authors: Santos O. L. A. , Bourgoyne A. T. 
Published: December 2007

ABSTRACT
An experimental simulator has been designed and constructed to model a gas reservoir performance during well-control operations. The simulator has been installed in a full-scale well in which a gas kick is simulated by injecting natural gas through a tubing string into the bottom of the well.
Basically, the system consists of a pressure sensor installed at the bottom of the well, a gas flow controller valve placed on the surface injection lines and a microcomputer that stores a gas reservoir inflow performance curve (flowing pressure at producing formation face vs. gas producing rate). A variation of flowing bottomhole pressure is sensed and electrically transmitted to the surface where it enters the microcomputer that processes the corresponding gas flow rate based on the previously defined inflow performance curve. This information is sent to the gas flow controller device that adjusts by itself to deliver the new injection gas flow rate.
Including the data acquisition and the gas meter systems, the simulator employs as many as four microcomputers.
The simulator performance is evaluated through graphical comparison between the gas flow rates calculated from the inflow reservoir performance curve and the actual gas flow rates delivered by the system. These data were obtained during well unloading experiments.
The overall performance of the simulator was satisfactory for the range of gas flow rates used in the experiments. Operational factors have limited the range of gas flow rates to be delivered, however. These limitations are discussed and recommendations are made to widen the range of utilization of the simulator.
Intelligent Interfaces for Reservoir Simulators
Authors: Guerillot D. R. , Blanc G. A. , Madre V. 
Published: December 2007

ABSTRACT
This article describes an interactive software called AIRS ™ (for Artificial Intelligence for Reservoir Simulators). This system helps the user build the input data file for reservoir numerical simulation software.
It uses Artificial Intelligence methods to create some ‘friendly intelligent interfaces’ used to input the large amount of data needed by the simulator1. In these interfaces, the user is guided through a set of screens automatically generated by a screen generator 2 according to his set of data.
Two operational applications were developed: one for a well-testing simulator3,the other for a 3-phase, n-components compositional thermal reservoir model4, 5.
An Expert System for Multiphase Measurement and Regime Identification
Authors: Darwich T. D. , Toral H. , Archer J. S. 
Published: December 2007

ABSTRACT
ESMER is a novel PC based package which can measure individual flowrates of gas and liquid phases in multiphase flow by matching the hydrodynamic turbulence characteristics of the flow, represented by pressure and void fraction waveforms, to a calibration database. The method applies advanced random signal processing algorithms employed in voice recognition and seismic analysis. A "calibration feature vector database" is first constructed on the superficial liqud-gas velocity domain. Pattern recognition techniques can then be applied to match the "feature vector of measured samples" to the "calibration database".
ESMER is available as a turnkey multiphase flowrate measurement system consisting of sensor's of user's choice, an analog to digital converter and a personal computer. Existing absolute or differential pressure electronic transducers or a simple void fraction sensor, such as a capacitance sensor could be used. The software is menu driven and includes facilities for digital filtering of noisy signal, graphical presentation of results and the compilation of the rig dependent feature vector calibration database. Help menus are provided.
ESMER has yielded accuracies of ±5% in laboratory trials. Its principal advantages are ease of installation and maintenance.
ESMER poses no obstruction to the flow line and would not normally require any modification to the flow line.
A Multiple-Process Algorithm for Laboratory Automation Systems
Authors: Nelson H. C. 
Published: December 2007

ABSTRACT
This paper describes a multiple-process algorithm for Hewlett-Packard computers controlling real-time laboratory automation systems. The algorithm, called the Multiplexer, allows the resident control software to automate several independent experiments concurrently on a time-sharing basis. The multiplexing mechanism is an automated context switching cycle that directs the control software sequentially to one laboratory process at a time. The software carries out scheduled data acquisition and control operations for that process, then switches to the next process until all have been serviced. The Multiplexer keeps track of each experiment by managing context tables stored in the computer's volatile memory. The context tables contain the process hardware driver commands, automation instructions, and run status variables that define each experiment. The Multiplexer also supports context switching from the keyboard. This enables the operator to bring one of the experiments into the foreground where it can be monitored and controlled directly from the keyboard.
The Multiplexer is part of a proprietary process control and scheduling software system that automates laboratory displacement experiments such as core floods, slim tubes, permeameters, and capillary tube viscometers. Scheduled operations include data capture from various analog and digital devices, control of pumps and valves, fluid sample collection, automated gas chromatography, and on-line graphics data processing. The software also permits experiments to be monitored and controlled indirectly over telephone lines from a remote computer.
Evolution of a Network System in a Geologic Research Organization
Authors: Duncan K. M. , Orr E. D. 
Published: December 2007

ABSTRACT
The Bureau of Economic Geology has successfully integrated DEC minicomputers, Apple Macintosh and IBM-compatible PC's, IBM and CDC mainframes, and a CRAY supercomputer in a flexible network that allows geologists as well as support staff to use a wide variety of software and output devices.
Petroleum Engineering Studies Educational Model
Authors: Daltaban T. S. , Archer J. S. , Toral H. 
Published: December 2007

ABSTRACT
PRESEM is a computer aided field development training system used in the Petroleum Enginering postgraduate and final year undergraduate courses at Imperial College.
PRESEM provides an integration of many of the activities which go into field development from drilling to the design of surface facilities, economic forecasting of pre performance and application to regulatory authorities.
The core of the PRESEM system consists of a data base which is generated by the system supervisor through a menu driven suite of programs simulating the properties of a given or hypothetical oil field. The data base contains the geological description of the reservoir, rock and fluid properties, presented as mud and electrical logs, RFT and production test data, core and PVT analyses. These vary in accordance with the depth and location of the exploration wells chosen by the user with reference to the formation top surface map.
PRESEM also contains many auxilary programs including Schlumberger type log plotting, log-interpretation, pressure analysis, phase package for separator design, reserves estimates by Monte-Carlo analysis and economic feasibility analysis.
The paper describes the basic features of PRESEM and presents a case study.