bluuebunny/crossref_metadata_2025_split huggingface dataset:
Annulus Packoff System Provides Economy in Recompletion of Permian Basin Wells
Authors: Giroux R. L. , Brandell J. T. , Scott T. A. 
Published: December 2007

ABSTRACT
Permian Basin operators are using a cup-type tool system to economically recomplete old wells that have deteriorated casing. The system employs high pressure cups, similar to those used on retrievable bridge plugs, to pack off the annulus below the damaged portion of the old casing. New casing installed inside the old casing is limited by the collar OD the old casing will permit.
This tool system was developed in response to the recent oil price downturn, which prompted many operators to plug and abandon water injection wells rather than repair casing leaks with squeeze cementing processes. The technique of recompletion with smaller diameter casing inside the old casing evolved, requiring installation of a barrier at the bottom of the new casing to prevent cementing off the injection formation. Barriers of many forms were developed. Cast iron bridge plug set below new casing, inside old casing. Expensive and difficult to drill out through new casing.Mechanically set packer system to pack off annulus. Economical but capable of holding only about 1000 psi differential pressure.Inflatable packer system. More costly than mechanical, but rated for high differential pressure.
Both 2 and 3 above require use of small ID inner casing due to the packer configuration.
Cup-type packoff systems offer the following advantages. Size is limited only by casing collar OD.Well can be put back on production without drilling out.A slotted liner can be run below packoff tool.Tool can be passed through damaged casing without affecting its capability.
Subject paper presents (1) discussion of barrier systems in use in the Permian Basin, (2) design variations of the new system, (3) job design considerations, and (4) case histories of Permian Basin wells in which the system was used to recomplete wells having damaged casing.
The Well-Site Real-Time Formation Pressure Transient Analysis System
Authors: Smart C. R. , Fertl Walter H. 
Published: December 2007

ABSTRACT
Formation pressure transient analysis techniques are generally applied some time period after data acquisition. However, post test transient analysis, such as pressure buildup, is counter-productive in non-flowing wells. The well may be shut-in for either too long or too short a period to meet the objectives of such a test. Under these circumstances, production could be sacrificed needlessly.
Such constraints can be virtually eliminated with the use of a well-site analysis system described here. The system uses commercial microprocessors to readily record and process all the available logging information. With this downhole information accessible during well test data acquisition, it is no longer necessary to limit the scope of real-time pressure transient analysis to only time and pressure parameters.
The Real-Time Pressure Transient Analysis (REALITY) system utilizes principally analytical techniques, such as Ramey and Agarwal type curves; linear, spherical, and radial flow models; and a p2 gas model. Fast, user-friendly, and flexible plotting routines allow for quick analysis of massive amounts of data. The use of interactive full-color CRT graphics for both parameter input and plot output increases the accuracy of the analysis and the quality of the data presentation.
The basic philosophy and conceptual considerations for the complete hardware and software system are reviewed. Processing flow charts and pertinent mathematical algorithms are presented as well as a field case example.
Gels for CO2 Profile Modification
Authors: Martin F. D. , Kovarik F. S. , Chang P-W. , Goldman I. M. , Philips J. C. 
Published: December 2007

ABSTRACT
A recent study (SPE paper 16728) described a preliminary investigation of the effects of some commercial gelants on reduction in CO2 permeability. That paper presented a method for examining gelant systems by vial tests, core tests, and two-dimensional, flow visualization studies in high-pressure, glass micromodels. For the preliminary study, tests were conducted with CO2, San Andres crude oil, and brine at 1500 psi and 105°F to simulate west Texas/southeast New Mexico conditions. The micromodel studies were coupled with the core tests to assess the pore-level mechanisms responsible for permeability reduction. Each of these commercial gelant systems demonstrated some deficiency in the desired performance in the brine/CO2 systems under investigation.
This paper presents follow-up lab-scale studies with newer gelant systems that are shown to be more stable under the same brine/CO2 conditions. Gelation kinetics are discussed, and results of core tests with a phenolic gel and a vinyl gel are described. These gels are more rigid than the gels first investigated, and the micromodel studies indicate that they are much more effective in remaining stationary in channels or high-permeability flow paths.
Detailed Simulations of the Effects of Process Parameters on Adverse Mobility Ratio Displacements
Authors: Crump J. G. 
Published: December 2007

ABSTRACT
This paper describes research in modeling unstable displacement processes (especially related to the application of CO2 flooding) with the ultimate goal of predicting recoveries in unstable field scale displacements. The research has focused on understanding and quantifying the effects of process parameters, such as reservoir heterogeneity, phase behavior, fluid properties, and solvent/water injection ratio, on the stability of displacements. Numerical simulation using very fine grids was used to obtain these results. These fine grid simulations were compared to simulations using the more standard models based on the mixing parameter concept of Todd and Longstaff and the theory of Koval.
This work produced the following observations: In secondary miscible displacements in heterogeneous reservoirs, the value of the mixing parameter can be strongly dependent on mobility ratio.In displacements which are not first contact miscible, the shockfront mobility ratio is generally less than the fluid viscosity ratio. This effect tends to stabilize the displacement front. The mixing parameter model can, in some cases, be used to model such processes, and the value of the mixing parameter can be estimated from knowledge of the mobility ratio across the displacement front.In general, for displacements which are not first contact miscible, the mixing parameter model is inadequate due to its inability to account for thermodynamic nonequilibrium between zones of oil contacted and uncontacted by solvent.In tertiary displacements the frontal mobility ratios, as computed from a one-dimensional solution, are in general not sufficient to compute the stability of the displacement.
Enhanced Oil Recovery by Inert Gas Injection
Authors: Kantzas A. , Chatzis I. , Dullien F. A. L 
Published: December 2007

ABSTRACT
Downward displacement of oil by inert gas injected at the top of the formation using horizontal wells, has the potential of becoming an efficient method of oil recovery for reservoirs either at initial oil conditions or for reservoirs depleted by waterflooding. Advances in horizontal well drilling technology can make this method of oil recovery feasible for a wide variety of oil reservoirs. This | paper presents experimental results of nitrogen or air injection into strongly water-wet unconsolidated and consolidated samples. Production characteristics are discussed, displacement mechanisms are formulated and the applicability of this method on the field scale is examined.
Evaluation of Steam-Surfactant-Fuel Gas Co-Current Injection Into Two Patterns of a Mature Steamflood
Authors: Yannimaras D. V. , Kobbe R. K. 
Published: December 2007

ABSTRACT
This is a comprehensive evaluation of the background, operations and results of applying the emerging steam-foam technology to two patterns of a mature steamflood suffering excessive steam breakthrough.
Care was taken: (a) to establish a valid baseline for injection and production before the treatments, (b) to hold injection in the surrounding patterns at or below pretreatment levels, in order to isolate the causes of any oil rate increase, and (c) to monitor in detail the two pilots over an extended period of time.
Aspects of the project discussed include its design and implementation, the inferred reservoir mechanisms, the associated production operations and field performance, as well as the economics of the project.
Fosterton Northwest: An In-Situ Combustion Case History
Authors: Mikkelsen P. L. , Cook W. C. , Ostapovich G. 
Published: December 2007

ABSTRACT
Fosterton Northwest Unit has undergone 18 years of in-situ air combustion under both dry and wet combustion modes. Oil recovery by tertiary wet combustion has been more successful than dry combustion, and a portion of the Unit's oil production is considered to be incremental. Evaluation of the combustion process is currently being hampered by operational problems such as pumping and corrosion.
Evaluation of Low-Concentration Surfactant Flooding in the Absence of Mobility Control Agents
Authors: Raterman K. T. , Kremesec V. J. , Suffridge F. E. 
Published: December 2007

ABSTRACT
In some micellar/polymer flooding pilots, severe problems associated with polymer stability and/or polymer injectivity have been experienced. These problems have contributed to less than optimal pilot performances. As a result, process strategies which do not employ polymer have been actively considered.
The strategy evaluated in this paper consists of a low concentration (&lt;2 wt% active) micellar fluid which is injected as a large bank (&gt;20% PV) and which forms a lower phase microemulsion under prevailing reservoir conditions. This micellar bank is in turn displaced by a water drive with no provisions for mobility control. Such a process was deemed to be simplified in application and to be potentially of low economic risk in that a large bank, lower phase displacement was assumed to be less susceptible to the deleterious effects of reservoir heterogeneity in the absence of mobility control agents.
Performance predictions were based first upon the successful simulation of laboratory field core tests for which fluid physical properties, phase behavior, chemical retention, and oil recovery were well-quantified for a commercially available surfactant system. Simulation matches were obtained with a nonproprietary chemical flooding simulator. Once suitably calibrated, the simulator was then applied in a predictive mode to a field scale displacement in a typical 21-acre, four-layered five spot in the target reservoir.
The sensitivity of the process to slug size, chemical concentration, capillary desaturation characteristics, injection rate, microemulsion viscosity, and other design strategies was determined.
The results suggest that the current laboratory system is unacceptable for field testing because the system fails to produce sufficiently low interfacial tensions to significantly desaturate waterflood residual oil in the lower phase environment. The study does, however, point out useful goals, guidelines, and evaluation strategies by which the economic potential of future process designs can be assessed.
Caustic Consumption by Kaolinite and Quartz and Their Mixtures at Temperatures up to 120°C
Authors: Johnson J. R. , Dehghani K. , Hawkins D. B. 
Published: December 2007

ABSTRACT
Hot caustic waterflooding has been shown to improve oil recovery by a number of different mechanisms. To design properly a hot caustic waterflood the consumption of caustic by reservoir minerals at high temperatures must be considered. This study presents the results of a series of batch experiments in which the interaction of quartz, kaolinite and caustic was examined at temperatures expected during hot alkaline waterfloods.
The reaction of quartz, kaolinite, and a mixture of the two minerals with 0.1 N NaOH at 120°C was examined. Also, the dissolution of kaolinite at 70°C and 100°C was studied.
The results show that at 120°C a mixture of 80% quartz/20% kaolinite by weight appears to consume as much or more caustic than either of those minerals alone. The major difference between pure quartz dissolution and that of the mixture was the mechanism of caustic consumption. In quartz dissolution, the hydroxide ion was consumed by silica speciation reactions. When pure kaolinite or a mixture of quartz and kaolinite was reacted, the bulk of the caustic was irreversibly consumed through the formation of new aluminosilicate minerals. The new mineral was identified as the synthetic zeolite Na-Pc, a structural relative of the zeolite phillipsite.
In the case of kaolinite dissolution, increasing temperature from 100°C to 120°C caused a five-fold increase in the rate of caustic consumption. The initial rates of Si and Al dissolution from kaolinite was found assuming first-order kinetics. An Arrhenius plot of the data gave psuedo-activation energies of 8.5 and 1.1 Kcal/mole for the dissolution of Si and Al from kaolinite.
Simulation of Thermally Induced Waterflood Fracturing in Prudhoe Bay
Authors: Garon A. M. , Lin C. Y. , Dunayevsky V. A. 
Published: December 2007

ABSTRACT
Waterflooding operations in the Prudhoe Bay field result in temperature reductions of up to 130 °F within the flooded region. As a result, the fracture gradient is significantly reduced, and the injection pressures may have to be reduced to avoid formation parting. The phenomena of fracturing resulting from thermally induced stress reduction was investigated to provide guidance for decisions on waterflood operating strategy.
Thermal reservoir simulation was performed to determine the in-si tu temperature and pressure distributions following various periods of water injection. A finite-element stress-analysis model was developed to calculate the changes in in-si tu stress field. A three-dimensional fracture simulator was used to predict fracture growth and shape based on the calculated stress distribution. A thermal reservoir simulator was modified to include a simplified fracture mechanism and calibrated against step-rate test data. Fracture areas were then predicted with the modified reservoir simulator and correlated with the fracture shapes obtained with the fracture model.
The fracture predictions confirmed field data which indicated that fractures created during well testing were short and confined to within the perforation interval. In addition, fractures created with clean water injection at pressures above the reduced fracture gradient were predicted to reach equilibrium lengths of less than about 200 ft.
Waterflood Potential of Diatomite: New Laboratory Methods
Authors: Wendel D. J. , Kunkel L. A. , Swanson G. S. 
Published: December 2007

ABSTRACT
Diatomite reservoirs in the San Joaquin Valley contain vast reserves in high porosity, thick pay zones. Waterflooding could substantially increase recovery if implemented successfully. Unfortunately, the presence of fractures in a low permeability matrix makes waterflooding difficult to evaluate by conventional methods. Presented here are unique laboratory methods and results of laboratory tests designed to provide operators with data to better evaluate the secondary recovery potential of diatomite.
Subsidence-oriented compressibility tests revealed extreme sensitivity to standard core cleaning and drying procedures. All subsequent tests, including brine sensitivity, relative permeability, and spontaneous imbibition were performed following miscible solvent cleaning with no drying step. Spontaneous water imbibition was investigated in detail, showing promise for oil movement from the tight matrix into adjacent fractures during a waterflood.
Kern River Field Test of a Steam Quality Measurement Technique
Authors: Redus C. L. , Schoen D. M. , Chien S. F. , Hall D. 
Published: December 2007

ABSTRACT
In large steamflood operations, there is a need to measure accurately the steam quality and mass flow rate at the injection wellhead. At Texaco's steamflood operation at the Kern River Field in Bakersfield, California, a novel technique which incorporates an orifice plate in series with a critical flow choke has been developed and tested in the field.
Results from field testing proved the technique to be a potentially viable, low-cost and reasonably accurate method with an accuracy of +/- 5 quality points for steam quality and +/- 32 BSPD-CWE [5.09 m3/day - CWE] for flow rate. The method was tested at steam qualities ranging from 15 to 88% and at mass flow rates ranging from 200 to 800 BSPD-CWE [32 to 121 m3/day - CWE]. Upstream pressures ranged from 300 to 700 psia [2068 to 4826 kPa].
Effect of Wellbore Steam Quality Variation on Steamflooding Thick Formations
Authors: Kasraie M. , Farouq Ali S. M. 
Published: December 2007

ABSTRACT
In designing steamfloods for thick formations, usually steam quality is assumed to be uniform over the formation face, even if multiple offtake points are present. This can lead to errors in steamflood oil recovery predictions. This paper addresses this question, and examines, first, the effect of multiple offtakes on steam quality and pressure, and second, the effect of variable vs. uniform steam pressure and quality on steamflood recovery predictions.
A wellbore model was developed, which accounts for steam pressure, quality, and flow regime variation, and the added feature of multiple offtake of the steam stream. The model was used to examine a variety of steam injection situations, with steam offtake at a halfway point. Effects of steam splitting on steam quality and pressure was examined for various wellhead pressures and injection rates. The wellbore simulator thus developed was then coupled with a three-dimensional steamflood simulator, to study steam injection performance in formations of various thicknesses, when steam is divided into two streams.
The results show that if the wellbore steam quality variation is not allowed significant errors in the predicted steamflood recovery can result. A number of examples are presented, showing discrepancies as large as 50%.
The Potential of Natural Gas in the Alaskan Arctic
Authors: Sharma G. D. , Kamath V. A. , Godbole S. P. , Patil S. L. 
Published: December 2007

ABSTRACT
The natural gas in the Alaskan arctic represents a truly significant resource; a resource which should be exploited in the most appropriate manner. Currently, the proven reserves of natural gas in Alaska are estimated to be 19.7% (36.7 TSCF) of the total U.S. reserves (186.7 TSCF). In addition, the undiscovered recoverable natural gas resources of Alaska are about 89 TSCF compared to 610 TSCF in the lower 48 states. Furthermore, the Alaskan unconventional gas resources are more than 500 TCF.
The purpose of this paper is to review the potential of natural gas resources in Alaska and to address various important issues related to utilization of natural gas. The paper provides a brief summary of various gas fields and their geologic settings. The different options for utilization of natural gas in the Alaskan arctic such as; transportation of gas to lower 48 states via gas pipeline, conversion to liquified natural gas and transport, conversion to fuel grade methanol and/or gasoline, natural gas for enhanced oil recovery, gas based petrochemical complex, gas utilization in the form of utilities are critically reviewed with respect to merits and demerits addressing engineering, economic, environmental, supply/demand, market and political aspects.
The use of North Slope gas for the enhanced oil recovery on the North Slope fields is considered as the most attractive option. Furthermore, it may be worthwhile to convert part of the natural gas into methanol and transport it through the existing TAPS pipeline; The unavailability of market place does also present opportunities for gas utilization in novel processes.
Optimum Plan of Depletion
Authors: Eden A. L. , Fox M. J. 
Published: December 2007

ABSTRACT
Through the use of reservoir simulation, consideration of operational conditions and constraints, and application of economic analysis, an Optimum Plan of Depletion for a geologically complex reservoir located in a high operating cost environment has been formulated. This paper describes the approach used to formulate the depletion plan. Additionally, the reservoir model lends itself to extensive future use in evaluating operational changes and providing the necessary data to determine the economic viability of any potential changes. The model is and will continue to be a valuable reservoir management tool.
Applicability of Expert Systems To Diagnose Formation Damage Problems: A Progress Report
Authors: Alegre L. , Dougherty E. L. 
Published: December 2007

ABSTRACT
Because of the diversity of problems which can and do arise, diagnosis of formation damage is a complex task requiring considerable practical experience and technical knowhow. To qualify as an expert in this field an individual must read, understand and remember findings reported in a myriad of technical publications and be able to apply this knowledge in a logical and systematic way. Recently programs, called Expert or Artificial Intelligence (AI) Systems, have been developed which perform the activities of a qualified expert in a specialized area. To use these programs the "knowledge base" must first be codified and introduced into the computer's memory, after which the Expert System can (approximately) simulate the expert's analyses. This paper presents a progress report on an Expert System developed to analyze formation damage problems. The goal of the development is to demonstrate the practicality of making available to an average engineer an automated formation damage consultant. We conclude that diagnosis of formation damage is a fruitful application of AI.
A Model for Development, Sensitivity Analysis, and Optimization of Gas Reservoirs with and without Aquifer: Part II-The Sensitivity Analysis
Authors: Alcocer C. F. , Ghalambor A. , Hayatdavoudi A. , Tussaneyakul S. 
Published: December 2007

ABSTRACT
A computational model for development and optimization of the gas reservoirs with or without water inflow was presented in Part I of this series of two papers. In this Part II, a sensitivity analysis will be presented. The most important variables involved in the development of a Gas Reservoir with or without aquifer will be studied. Furthermore, the effect due to neglecting the rock and water compressibility terms for volumetric, steady state, and steady state system on the development of a gas reservoir will be studied. The model used for the sensitivity analysis was written in Fortran 77 and run by using the Multics System. The main purpose of the model is to determine the number of wells to be produced, and reservoir pressure at each period of time that depends upon the production schedule. The conclusions from the sensitivity analysis performed are as follows: Permeability and water viscosity do not have a great effect on finite aquifer but create high affect on infinite aquifer, especially low permeability and high water viscosity; rock and water compressibility affect finite aquifer more than infinite aquifer; each value of porosity will limit the minimum value of reservoir pressure for an infinite aquifer; and the rock and water compressibility term in material balance equation must be considered in the case of problems involving economic decisions.