bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hilly Terrain Effects on Slug Flow Characteristics
Authors: Zheng Guohua , Brill J. P. , Shoham Ovadia 
Published: December 2007

Abstract
A mathematical model is developed to include the hilly terrain effects on slug flow characteristics. The model is based on a new sink/source concept applied at each pipeline connection, termed an elbow. An elbow accumulates liquid as a sink, releases liquid as a source, and has a characteristic capacity which can be either positive or negative. This concept allows the flow interaction between two pipeline sections to be studied with relative ease, including the generation of additional slugs at a positive-capacity elbow and dissipation of slugs at a negative-capacity elbow. The model shows the persistent existence of slug flow in the downhill section, as observed in the experiments. It also predicts slug length variation with pipeline orientation, which agrees well with the acquired experimental data. This work is applicable to the design and analysis of field pipelines and separation facilities.
Three-Phase Flow-Rate Measurement by Pressure Transducers
Authors: Qiu Jianhang , Toral Haluk 
Published: December 2007

Abstract
A multiphase flowmetering technique based on characterisation, classification and identification of pressure signals has been developed and tested in oil-water-air slug flow. The technique extracts a set of stochastic features from pressure signals and relates these to water-cut and liquid and gas flowrate by training back-propagation neural networks with calibration samples. Laboratory tests in 3 inch and 4 inch horizontal three-phase flow over a wide range of flow conditions have shown a measurement accuracy of +/- 10% for liquid-gas flowrates and +/- 5% for water-cuts.
The Use of Vapor Recovery Units in the Austin Chalk Field
Authors: Liu Dianbin , Meachen J. V. 
Published: December 2007

Abstract
This paper deals with the practical problems and considerations associated with the installation and operation of Vapor Recovery Units (VRUs) in the Austin Chalk field. Other aspects will also be discussed such as oxygen sensing and working together with gas gatherers and oil haulers.
VRUs have been used successfully in Austin Chalk field to recover the gas otherwise vented to the atmosphere. The Austin Chalk horizontal wells usually give high production initially. For high GOR (Gas Oil Ratio) wells, they tend to cause separation problems which result in significant volumes of gas in the stock tanks. PVT analysis, mainly flash calculations, can be used to optimize liquid recovery at separation point and predict the gas volume at the stock tanks.
So far over two dozen VRUs have been installed recovering about $10M daily. More will be installed in the near future. The installation of VRUs is an attractive idea because it is both environmentally conscious and profitable.
The ideas and discussions presented here can also be applied to other oil fields with high GOR and high production.
The results presented in this paper will further one’s understanding of the oil field operations and also help the environment.
Scale Prediction and Control in the Denver Unit CO2 Flood
Authors: Morgenthaler L. N. , Lawson J. B. , Faircloth R. J. , Berkshire D. C. 
Published: December 2007

ABSTRACT
Mineral scale deposition, a costly problem in many oil recovery operations, becomes more severe as producing wells respond to CO2 injection. Carbon dioxide reduces brine pH and enhances mineral dissolution at reservoir conditions, increasing brine scaling tendency in the wellbore. In this work, we report on scaling tendency trends in the Denver Unit (Permian Basin, San Andres) CO2 flood based on both thermodynamic calculations and field water analyses. Results of taking the effect of CO2/brine interactions into account are presented. The impact of reduced pH and temperature on scale inhibitor performance is also described.
The Effect of pH, Calcium, and Temperature on the Adsorption of Phosphonate Inhibitor Onto Consolidated and Crushed Sandstone
Authors: Sorbie K. S. , Jiang Ping , Yuan M. D. , Chen Ping , Jordan M. M. , Todd A. C. 
Published: December 2007

ABSTRACT
In this paper, results are presented from an extensive series of phosphonate inhibitor adsorption experiments using both consolidated and crushed clean (clay free) sandstone core material. A near complete account of phosphonate adsorption in highly quartzitic systems is developed from the results presented. Although some details are known in the literature, we believe that this is the most complete analysis of these effects on phosphonate adsorption that has been assembled to date. The effects on inhibitor adsorption of pH, calcium ion concentration, temperature and inhibitor concentration are investigated in some detail. The appropriate adsorption mechanisms which operate under the various conditions are elucidated from the inhibitor adsorption experiments and from the additional work on the ζ-potential measurement for quartz. In particular, the respective roles of hydrogen bonding at low pH (~2) and calcium binding at higher pH (~6) are clearly demonstrated and explained. At intermediate pH values (~4) at room temperature, the adsorption of inhibitor is found to be lower than at both pH 2 and pH 6 due to a relative weakening of both the hydrogen bonding and calcium binding mechanisms. Mechanistic results from the crushed rock and core adsorption experiments are consistent although the level of adsorption is rather different for each medium. At elevated temperatures, inhibitor adsorption is higher under all conditions and, when Ca2+ is present, the effect of calcium enhanced surface condensation (or surface precipitation) is clearly shown. The importance of this enhanced adsorption mechanism is discussed in the context of field scale inhibitor adsorption/desorption and "precipitation" type squeeze treatments.
This work should be viewed in the context of: (a)previous work on the effect of pH on phosphonate adsorption1 and;(b)forthcoming work on adsorption onto pure clay mineral substrates and in clay-containing reservoir cores.2
Update Case History: Performance of the Twofreds Tertiary CO2 Project
Authors: Flanders W. A. , DePauw R. M. 
Published: December 2007

Abstract
The performance of the first Texas field-scale tertiary CO2 injection project in a sandstone formation is updated. The Twofreds tertiary CO2 injection project was developed in two phases. The east side of the reservoir was initiated in February 1974 and is now essentially completed. Expansion to the west side started in the early 80’s. Detailed evaluation of the actual performance of the east side CO2 flood will be presented along with operations, design, and monitoring considerations.
Integrated Methods for Coal Gas Reservoir Completion Zone Selection
Authors: Pratt T. J. , Close J. C. 
Published: December 2007

Abstract
Successful selection of single and multiple completion zones in heterogeneous, layered coal natural gas reservoir systems is predicated upon vertically partitioning the stratigraphic interval into zones with discrete ranges of geologic and reservoir characteristics. In gassy zones, the estimation and determination of true net pay depths with respect to permeability-thickness product values is accomplished through integrated interpretation of field operation, well test, geophysical log, and core/fluid property data (in order of increasing vertical resolution). Such partitioning of reservoirs enables more accurate and comprehensive estimates of reservoir simulation input parameters required for quantitative reserve assessments to be obtained. Cost effective completion decisions for exploration, development and workover well candidates can consequently be formulated and implemented. The principles and implications of completion zone selection methods are also applicable to most non-coal petroleum reservoir systems, which are inherently heterogeneous and layered.
Application of Extended Equation of State Work To Optimize the Pegasus Devonian Field Unit No. 3 Gas Cycling Operation
Authors: Whitaker C. A. , Kim J. S. 
Published: December 2007

Abstract
Due to the retrograde condensate characteristics of the reservoir fluid, gas cycling operations were initiated in the Pegasus Devonian Field Unit No. 3 during 1963 to maximize condensate recovery. At the initial reservoir conditions of 5,400 PSIA and 203° F, the condensate yield of the reservoir fluid was 189 BBL/MMSCF. Since production began in 1952, the condensate yield has declined steadily to 25 BBL/MMSCF due to changes in fluid composition resulting from pressure depletion and injected lean gas breakthrough. In order to describe the complex mass transfer and composition changes of the mix between reservoir fluid and injected gas, a twelve component fluid characterization model was developed for the Devonian hydrocarbon fluid system using a Peng-Robinson equation of state program. This paper details how this model has been used to determine the degree of gas cycling, monitor the effectiveness of surface production facilities, and establish an efficient field development plan which will maximize the value of this property.
Capillary Effects in Heterogeneous Porous Media: Experiments, Pore Network Simulations, and Continuum Modeling
Authors: Chaouche Mohamed , Rakotomalala Nicole , Salin Dominique , Xu Baomin , Yortsos Y. C. 
Published: December 2007

Abstract
We investigate effects of capillary heterogeneity induced by variations in permeability in the direction of displacement in heterogeneous porous media. The investigation is three-pronged and uses macroscopic simulation, based on the standard continuum equations, experiments with the use of an acoustic technique and pore network numerical models. It is found that heterogeneity affects significantly the saturation profiles, the effect being stronger at lower rates. For drainage, a good agreement is found between continuum model predictions, experimental results and the pore network numerical models based on which it can be concluded that capillary heterogeneity effects in the direction of displacement act much like a body force (e.g. gravity). The results are interpreted with the use of invasion percolation concepts. For secondary imbibition, a poorer agreement exists between continuum model and experimental results at low capillary numbers, which requires the use of a pore network simulator involving film flow. Numerical simulation results are discussed for 2-D geometries.
An Investigation Into the Processes Governing Flow and Recovery in Different Flow Regimes Present in Gas Condensate Reservoirs
Authors: Henderson G. D. , Danesh Ali , Tehrani D. H. , Peden J. M. 
Published: December 2007

ABSTRACT
A series of long core experiments have been conducted at reservoir pressures, where a synthetic gas condensate fluid was used in order to study the flow of gas and condensate in the area of the reservoir close to the wellbore, and the region of the reservoir away from the producing wells. A horizontally orientated core was used in order to investigate flow of gas and condensate in the region around the producing wells, with the flow rates of gas and condensate being increased from capillary dominated to viscous dominated in order to observe the effect of flow rate on flow and recovery. The final flow velocities were comparable to field conditions around the wellbore region. A vertical core was used at similar pressures in order to simulate flow of condensate in a gravity and capillary dominated regime away from the producing wells, where viscous forces are negligible.
The results of the horizontal core tests have highlighted that the mobility of condensate in the area around the wellbore may be greater than previously assumed. In the vertical core tests, the rate of free-fall gravity drainage of condensate at conditions where the interfacial tension between the gas and condensate was low has been measured. It has been shown that the reduction of the condensate saturation by drainage is in this gravity/capillary dominated regime can be considerable.
Experimental methods such as those described in the paper are required in order to obtain suitable relative permeability curves for simulation purposes.
Modeling Commingled Reservoirs With Pressure-Dependent Properties and Unequal Initial Pressure in Different Layers
Authors: Gao Chao , Lee W. J. 
Published: December 2007

ABSTRACT
This paper introduces a new approach to model the performance of commingled reservoirs with pressure dependent fluid properties in each layer. With this approach, reservoir engineers can readily modify an analytical model for slightly compressible liquids to model commingled gas systems. We used a numerical simulator to verify this approach. Based on the analytical model and this approach, we developed an analytical computer simulator which reservoir engineers can use to model the performance of commingled reservoirs with unequal initial pressures in different layers and which allows each layer to be homogeneous or dual porosity, hydraulically fractured or have radial flow (with skin), and to be finite or infinite in extent. This analytical simulator can be used to predict future performance, match past performance, and to assist in the analysis of pressure transient tests. A major advantage of this simulator is that it requires far less computer time than conventional finite-difference simulators to solve the same problem.
Using the new analytical simulator, we can model several important reservoir situations with different inner and outer boundary conditions and reservoir rock types. Most importantly, in this paper we present a new technique to model pressure buildup performance of a commingled reservoir following constant pressure production.
Drilling Close to Salt Diapirs in the North Sea
Authors: Seymour K. P. , Rae Graeme , Peden J. M. , Ormston Keith 
Published: December 2007

ABSTRACT
In the period May 1991 to April 1992 Ranger Oil (U.K.) Ltd., drilled five separate wells close to salt diapir structures in the Central Graben area of the North Sea. Two different salt diapirs were appraised, one in block 23/27 and the other straddling blocks 29/2a and 22/27a.
Without exception all of the wells exceeded their planned dry hole drilling time estimates. In addition to two planned geological sidetracks, there were three further unplanned mechanical sidetracks, all caused by unstable hole conditions. A breakdown of non-productive time associated with the wells is outlined.
This paper emphasises the prerequisite of good seismic and geological data in planning salt diapir wells. The use of high angle and horizontal drilling techniques are outlined for appraisal and development, as a means to satisfy both drilling and reservoir engineering requiements in these often marginal prospects.
The history of the salt diapir drilling in other parts of the world is also reviewed. It is concluded that drilling close to salt diapirs is usually complex and that wells must be designed and managed with a high degree of flexibility.
Hydrate Inhibition Effect of Produced Water: Part 1—Ethane and Propane Simple Gas Hydrates
Authors: Tohidi Bahman , Burgass R. W. , Danesh Ali , Todd A. C. 
Published: December 2007

Abstract
Produced waters, due to the presence of salts, have a hydrate inhibiting effect. However, the data on hydrate formation in the presence of electrolytes is scarce. This paper presents experimental and modelling results on the effect of salts on hydrate equilibria for ethane and propane simple gas hydrates. This is a part of an ongoing research project on the hydrate inhibition effect of electrolytes in relation to subsea transmission lines where the proportion of water could be significant.
The conventional graphical method, backed up with visual observation has been used in hydrate dissociation point determinations. For ethane hydrates, dissociation conditions have been determined in the presence of 20 Wt% NaCl solution, while for propane, aqueous electrolyte solutions of NaCl, KC1, and CaCl2, with concentrations ranging from 3 to 20 Wt% have been used.
Both Valderrama (VPT) EoS with Non Density Dependent (NDD) mixing rules and Peng-Robinson (PR) EoS have been used for the fluid phases. The effect of salts in the water phase has been modelled by adding an electrostatic contribution to each EoS, with parameters from vapour pressure depression in electrolyte solutions. For the hydrate phases the model is coupled with the ideal solid solution theory.
The predictions of the model are compared with experimental and literature data and good agreement is demonstrated.
Slim-Hole and Coiled-Tubing Window Cutting Systems
Authors: Faure Alban , van Elst Herman , Jürgens Rainer , Krehl Dietmar 
Published: December 2007

Abstract
Slimhole re-entry horizontal drilling offers operators an opportunity to improve field recovery by infill drilling, and revitalize wells suffering from gas or water coning. Re-entry drilling systems are available for hole sizes down to 3-7/8". The potential for coiled tubing drilling has created significant industry interest over the last 18 months. In offshore applications where there is no derrick in place, use of a coiled tubing drilling system makes it possible to redrill old wells and perform horizontal re-entries.
Coiled tubing re-entry wells completed so far have used a conventional rig to cut the window. This adds unnecessary costs and time to the program. A coiled tubing conveyed window cutting system will dramatically reduce the overall wells costs, and thereby expand the market for coiled tubing re-entries.
The problems of slimhole window cutting include controlling weight on bit while starting the window, and reducing torque while milling to prevent drillpipe failure.
In the coiled tubing application, rotation is supplied by a downhole motor which presents additional problems with respect to controlling weight on bit.
A milling system using downhole motors with hydraulic thrusters to supply constant weight on bit has been bench-tested and field proven. The prototype system required three milling runs after setting and orienting the packer. Subsequent systems will be tested to reduce the number of milling runs to one.
A description of the applications and requirements of the window cutting system is provided, along with bench test and field test results.
Results of Feasibility Study of Running Coiled Tubing to Depths of 30,000 ft in Deviated Wells
Authors: van Adrichem W. P. , Spruill R. L. 
Published: December 2007

Abstract
When planning a workover, Coiled Tubing has become more indispensable due to its ability to accomplish a wide range of tasks yet remain economical affordable.
As wells are drilled deeper and the radial displacement of deviated wells increases, the question arises whether CT can still be utilized. Coiled Tubing is commonly run to 18000 ft in several places around the world. However, wells are now planned with measured depths of 30000 ft, and radial displacements of up to 25000 ft.
There are multiple reasons for drilling wells to such depths: *By drilling wells offshore with a larger radial displacement, more wells can be completed from a single platform, and less platforms may be required. In deep water, this provides a substantial cost saving.*Similarly, onshore applications include minimizing environmental liabilities by directional drilling multiple wells from one location.
The Optimal Design of Thermosiphon Reboilers
Authors: Kerr Clayton P. 
Published: December 2007

This paper was prepared for the 44th Annual Fall Meeting of the of the Society of Petroleum Engineers of AIME, to be held in Denver, Colo., Sept. 28-Oct. 1, 1969. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal, provided agreement to give proper credit is made.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Introduction
Vertical thermosiphon reboilers are widely used because of their high heat transfer rates and because they do not foul easily. However, in spite of their widespread use they are not easily designed because of the complex nature of two-phase fluid flow and heat transfer. Current design procedures rely heavily on empirical correlations. Obtaining an optimal design of a vertical thermosiphon reboiler in general consists of varying the tube number, length, diameter, tube material, tube wall thickness, and heating medium pressure, then selecting the design that gives the lowest cost or other desired criteria.
This article develops a procedure for obtaining the optimal design of a particular class of vertical thermosiphon reboilers. This procedure will be limited to situations where procedure will be limited to situations where the tube side pressure is high enough so that the sensible heating zone in the tubes may be ignored and isothermal boiling occurs in the tubes. The effect of acceleration losses on the liquid circulation rate will be ignored and is reasonable for isothermal boiling in short tubes. The reboiler liquid will be treated as a one-component material. The heating medium cost will be taken as being directly proportional to its temperature and the tubing cost proportional to its temperature and the tubing cost directly proportional to area. All other costs will be assumed constant. The design problem then is to select the heat transfer area and heating medium temperature to minimize the total annual cost.

DESIGN PROCEDURE
The vapor to be supplied by the reboiler and the tube side isothermal boiling temperature are specified. The heating medium enters as a saturated vapor and leaves as a saturated liquid. With this information, the total cost may be written as
[1]
The total variable cost may be written as
[2] where c1 = c1 (1)Q.
The inside tube area Ai may be written as
[3]
where
[4]
The New Business Challenge for Major Contractors in the Offshore Oil and Gas Industry
Authors: Mourn I. O. , Laskemoen Inge 
Published: December 2007

ABSTRACT
We are expecting that in future developments the smaller and marginal oil and gas fields will dominate the offshore oil and gas business.
Engineering contractors will be more heavily involved at the early stages of such development, and in particular conctractors will be expected to provide innovative technical and commercial solutions that can make more of the fields commercial.
We believe that those contractors that have a wide technological foundation, and a significant engagement in providing new technical concepts, are best prepared for the future challenges.
We also see new contract and cooperation models emerging between client and contractor, and the development of incentive schemes that secures the commitment of the main contractors to the overall economy of each project.