bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Type-Curve Techniques to Decline Analysis and Forecasting of Gas Wells
Authors: Harrington A. G. , Lee B. Y. Q. , Taylor P. S. 
Published: December 2007

ABSTRACT
This paper presents a computer method for forecasting gas well performance and back calculating reserves using flow equations currently employed in well test/type curve analysis. Recent advances in well testing have allowed a greater understanding of reservoir properties and configuration early in the production life of a well. This knowledge can be used to directly estimate the future productivity through analytic procedures. The same techniques can also be employed to match production data and determine the original gas-in-place and reservoir configuration. The components of the empirical decline curve equations are thereby identified directly.
The usual limitations to type curve predictions caused by constant pressure, and constant rate assumptions or periods of shut-in are surmounted through use of superposition suggested by Carter and Tracy13. This enables the correct application to actual field cases where both pressure and rate decline throughout the production life. Flexibility exists to include linear reservoirs with eccentric well locations, low permeability, dual porosity, non Darcy flow and various wellbore conditions.
A Systematic Deliverability Analysis for the Hoadley Gas Condensate Field
Authors: Newbert J. D. , Trick M. D. 
Published: December 2007

ABSTRACT
To maximize return on long term and short-term excess gas sales contracts and to minimize investment in field equipment, a producer must be able to quickly and accurately assess the deliverability of a gas field throughout its entire economic life. This paper outlines a systematic approach for predicting the deliverability of the Hoadley gas-condensate field. This paper illustrates procedures, applicable to any gas or gas-condensate field, for tuning the tank-type model to match historic data, and for performing deliverability forecasts.
Production Forecasting for Gas Wells Under Variable Conditions
Authors: Aminian K. , Ameri S. , Beg N. , Yost A. B. 
Published: December 2007

ABSTRACT
Forecasting production rates from gas wells has always been of considerable importance to the natural gas industry. The conventional method to predict the performance of gas reservoirs requires data which are often unavailable. This is especially true for low permeability reservoirs. In the absence of complete reservoir data, production decline type curves are employed to predict future production rates utilizing past production data. The general assumption behind this technique is that the reservoir parameters such as drainage area, skin factor, etc., and operating conditions (back pressure) affecting gas production in the past will remain unchanged. There are, however, many occasions where it is necessary to forecast production rates under conditions which are not similar to those of the past.
This paper introduces a series of production decline type curves which can be utilized to forecast gas production rates under conditions which are different from those affecting well performance in the past. A gas reservoir model has been utilized to generate the type curves through changing the operating conditions and reservoir parameters. The model takes into account many factors which are usually ignored. These include the non-Darcy flow effects, skin factor, and pressure dependent gas properties.
Flow Imaging in Porous Media Using Neutron Radiography
Authors: Jasti J. K. , Lindsay J. T. , Fogler H. S. 
Published: December 2007

ABSTRACT
A new technique is introduced to visualize flow through consolidated porous media. A neutron based computer tomography system is used to inspect a series of laboratory core flood displacements. Two-dimensional advancement of miscible and immiscible fronts were monitored in real time using radial Berea sandstone cores. The effect of the heterogeneity of the core, miscible viscous fingering and immiscible water flooding in sandstone cores have been observed and are discussed. These experiments reveal that neutron radiography has a great potential to study laboratory scale EOR processes. The coupling between flow instability and heterogeneity has been observed for miscible and immiscible flooding. In addition to flow visualization, this technique can also be used to obtain quantitative information such as in-situ oil saturation distribution.
An Approach for the Determination of Economically Optimum Injection and Production Rates in a Large Multi-Pattern Waterflood
Authors: Anthony J. L. , Meggs A. J. M. 
Published: December 2007

ABSTRACT
In a large multi-pattern waterflood, significant improvements in the efficiency of the waterflooding process can be achieved through careful management of the flood rates in each waterflood pattern. Balancing injection and production rates within and between patterns can substantially reduce produced water handling requirements, improve long-term production rates and enhance ultimate recovery. This paper quantifies the impacts of this balancing process and presents a methodology for determining the economically optimum injection and production rates for each well in the waterflood.
Previous work, employing physical models, has investigated areal sweepout behavior as a function of corner to side well producing ratios in a nine-spot injection pattern1, allowing for the determination of ideal producing rates within a single, isolated pattern of homogeneously distributed pore volume. This paper extends the concept of ideal injection and production rates to account for heterogeneously distributed pore volume in a large multi-pattern waterflood.
The deviation of injection and production well rates from ideal values will result from well damage and areal variations in injectivity and productivity. A parameter for measuring the degree to which actual rates vary from ideal rates is developed and correction factors for areal sweepout behavior as a function of this parameter are presented. These correction factors may be used to alter predictions of project-wide performance in order to determine the impact of non-ideal well rates. Examples are included for the determination of the economic incentive for improving production and injection well rates through infill drilling and workovers.
Relative Permeability for Intermediate Wettability Reservoirs
Authors: Heaviside J. , Brown C. E. , Gamble I. J. A. 
Published: December 2007

ABSTRACT
The measurement of relative permeability, essential for the predictive simulation of reservoir response, poses particular problems for rocks of intermediate wettability. This situation is found in many reservoirs for which the well established scaling criteria for cores of well defined wettability no longer hold.
This paper presents results of waterflooding tests on sandstone cores which maintain the intermediate wettability of the reservoirs from which they were sampled. A particular concern was how to characterise displacement for the actual field rates (with the appropriate balance between capillary and viscous forces) whilst avoiding core scale effects which can occur at such low flow rates. Therefore the tests were carried out over a range of flow rates (frontal advance rates from 1 to 100 feet per day) and used both pressure taps and saturation monitoring (1) to obtain distributed data along the cores. Numerical simulation was used to aid interpretation.
The results confirm that displacement in these intermediate wettability cores differs from that in strongly oil or water wet systems in several important regards (a) core scale artefacts ("end effects") are not present even at the low flow rates (b) rate dependencies of relative permeability occur which are due to the microscopic fluid distribution (c) the waterflood displacing shock front is less dispersed at low flow rates, giving increased recovery at breakthrough. Based on these results recommendations are made for relative permeability data for use as input in reservoir performance calculations.
Percolation Theory of Steam/Water Relative Permeability
Authors: Parlar M. , Yortsos Y. C. 
Published: December 2007

ABSTRACT
Thermal recovery and geothermal processes typically involve regimes where the simultaneous flow of water liquid and vapor takes place. Vapor condensation and liquid evaporation are phenomena commonly accompanying such flows. Traditionally, the flow description relies on relative permeability and capillary pressure functions. In contrast to immiscible fluids, however, relative permeability and capillary pressure characteristics of condensing phases are not well understood at present. Instead, the vapor is commonly treated as a non-condensible phase and assigned corresponding flow properties.
In this work, a systematic investigation is undertaken to derive relative permeability and capillary pressure functions for condensible phases, specifically pertaining to a steam-water system. The metnod used is an extension of the approach proposed by Heiba et al1 for immiscible fluids. The novel element is the use concepts from percolation theory for the description of capillary condensation and evaporation processes in porous media obtained elsewhere2. Based on derived analytical expressions saturations and capillary pressure curves are evaluated. Relative permeabilities are next calculated from approximate expressions for Bethe lattices3. The results obtained are compared against those presently used. Implications and extensions to related processes are also discussed.
Cation Exchange Studies on Fractionated Clays
Authors: Fertl Walter , Jessen F.W. 
Published: December 2007

Abstract
Clay containing mono-and divalent exchangeable cations indicate a significantly greater amount of divalent cations on the coarser fractions while monovalent cations are concentrated in the finer ones.
The sequence of replaceability of cations present on the clay sites followed the rule Na &gt;K &gt;Mg &gt;Ca.
A Tektite electrode shows a specific sensitivity to divalent cations and measures the sum of both calcium and magnesium present.
A graphical solution has been presented for determining either the Cation Exchange Capacity [CEC] of calcium or magnesium alone. The chart is valid only if the calcium-to-magnesium ratio in the investigated natural system. is known.
Introduction
The concept of cationic exchange reactions on bentonitic clays [sodium or calcium montmorillonite) is fundamental in many aspects related to drilling muds, well logging and formation properties. Drilling fluid technology has been largely influenced by the chemical reactions of montmorillonite clays. These clays may retain adsorbed cations in an exchangeable state; i.e., a calcium montmorillonite can be converted into a sodium clay, or conversely the sodium, may be replaced by calcium. The basic significance of exchange reactions of montmorillonite in drilling fluids is recognized as an important factor in the rigid requirement of mud properties for drilling deeper and deeper wells. The purpose of this investigation was to develop a method whereby the cation exchange capacity of certain clay fractions, obtained through a fractionation procedure using a supercentrifuge, could be determined through direct titration. Primarily, the study was undertaken to determine the degree of variation, if any, which might exist in the exchange monovalent and divalent cations and clay particle size.
Development of an electrode sensitive to divalent cations was recognized as a vital part of the investigation and the scope of the work was broadened the determine the utility of tektite glass [thin slices of tektite material] as a divalent sensitive electrode. The preparation and use of the tektite electrodes, for the purpose stated, was a distinct objective.
Three different clays were investigated. They represented [1] predominantly Ca++ clays, as in the case of clay No. 4; [2] heterogeneous clays, with Na+ content dominating Ca++ - Mg++ as in clay No. 11 and No. 14; and [3] heterogeneous clays with Ca++ - Mg++ content in excess of Na+ as in the case of clay No. 1. Source of the materials was clay fractions obtained in previous work by Mungan.
Localities and Descriptions
No. 1- Bentonita Blanca Vetessa. Locality:Mexico. Color: beige. Impurities:mostly talc and cristobalite.
No. 4- Bentonita Comisa. Locality: Mexico Color: greyish-white. Impurities:quartz and calcite
No. 11-Bentonita de Durango. Locality: Mexico Color: red-brown. Impurities: large quantity of feldspar and some quartz.
No. 14-Wyoming Bentonite. Locality: Wyoming Color: beige. Impurities: quartz and feldspar.
P. 33^
Drill Fluid and Return Permeability Tests of South Texas Wilcox Cores
Authors: Droddy M. J. , Jones T. A. , Shaw D. B. 
Published: December 2007

ABSTRACTCore plugs of argillaceous sandstone from the Wilcox Formation of South Texas were examined by petrographic methods and tested for oil permeabilities before and after exposure to a variety of drilling fluids and filtrates. This was done to determine why some drilling fluids are more damaging to permeabilities than others. The clay minerals in these sandstones, which are mostly diagenetic, include chlorite, kaolinite, and pore-bridging mixed-layer illite-smectite. The greatest permeability damage was caused by gelligno-sulfonate-based fluids, which caused pore throat blockage by dispersion and migration of the mixed-layer clays. Much less damage wascaused by the PHPA polymer/KCl-based fluids, which apparently stabilized the fibrous illite-smectite.
Batching Setting of Deviated 30-in. Conductors
Authors: Oag A. W. 
Published: December 2007

Abstract
Britoil plc operates the Clyde field in the U.K. Continental Shelf (UKCS) on behalf of its coventurers Shell and Esso. The field was discovered in 1978 and a single production platform was installed in 1986.
During the Clyde project design phase, drilling personnel co-ordinated the requirements of conductor setting with the jacket structure, drilling rig and wellhead systems design. It was necessary to set the conductors at a depth of 550 ft below the mudline to obtain sufficient formation strength to allow mud returns to surface and safe diversion of potential shallow gas. During the planning phase conductor running and cementing procedures were broken down into a detailed operations sequence. The necessary procedures and specialist tools required for the job were developed to minimise conductor handling times.
Drilling techniques involved using a top drive unit in combination with a turbine to directionally drill a 17.1/2″ pilot hole to 550 ft below seabed up to inclinations of 4 to 5 degrees. This resulted in the earliest possible separation of wells being achieved. The pilot hole was subsequently opened to 36″ in a single underreaming operation.
The cementing procedure for open-ended conductor was developed especially for Clyde from a technique used on another operated field. The slurry was pumped through a stinger and electric logs were adapted to monitor the tops of cement inside the conductor and in the open hole annulus while cementing. Minimal time was spent waiting on cement to set before it was possible to leave the conductor free standing and move on to the next one.
Britoil has so far set 16 conductors in this way. And through detailed pre-planning and implementing changes when required, has achieved conductor installation to 550 ft penetration in under two days.
Mechanistic Approach in Designing BHA's and Forecasting Wellbore Position
Authors: Rafie S. 
Published: December 2007

Abstract
BHA bending analysis and drilling ahead prediction are important topics because they can improve drilling efficiency and help prevent unplanned borehole deviation. Without them, there is extra risk of undesirable deviation which can cause severe drilling problems and greatly increase the cost of drilling. This paper presents the analytical basis and field applications of an integrated computer method in directional drilling. The method includes two-dimensional BHA bending analysis for designing BHAs and predicting their deviation tendencies, and a heuristic formation-bit interaction model for forecasting the future wellbore position while drilling. Using this computer method, parametric studies are performed on several single and multi-stabilizer bottom hole assemblies to demonstrate the effects of stabilizer placement and wear, WOB (weight on bit), hole angle, and borehole current curvature on the deviation tendency of these assemblies. Predicted wellbore positions from the drilling ahead model are compared with actual field data for two directional wells.
The Characterization of a Drilling Fluid Additive
Authors: England A. A. , Davis N. 
Published: December 2007

Abstract
The guidelines for selection of a drilling fluid additive have changed during the past few years. No longer is performance the only criterion to characterize an additive. Demands on the drilling mud specialist to select the correct additive comes not only from drilling personnel, but also from explorationists, production personnel, purchasing agents, and governmental agencies.
Recent advances in analytical instrumentation and techniques utilizing gas chromatography and pyrolysis have provided geological personnel insight into the masking effects of mud additives in evaluation of exploration prospects. Government regulations on both offshore and land operations have restricted or precluded certain additives which normally would be used in this environment. Concerns about the damaging effects of mud additives in hydrocarbon production zones have increased in our present efforts to maximize production. The mud specialist faces a dilemma in selecting an additive which can satisfy and/or minimize these concerns.
This paper lists seven parameters which one company uses to characterize and rank drilling fluid additives. These include cost, performance, quality, environmental effects, production and exploration evaluation compatibility, drilling utilization, and logistics. In addition, the paper discusses the methods this company uses in evaluating additives under these established parameters and how the information is disseminated to operating units for utilization.
Appropriate Design of Drillpipe Internal Upset Geometry Focusing on Fatigue Property
Authors: Tsukano Y. , Nishi S. , Miyoshi H. , Sogo Y. 
Published: December 2007

Abstract
Drill pipe fatigue failure initiated at the transition area of internal upset is one of the most serious problems. A method to prevent this type of failure is described focusing on an improvement in the internal upset design. Firstly, a design was conceived in which the stress in the transition area of internal upset never exceeds that at the external surface of pipe body under bending moment. Secondly, finite element analysis was employed to obtain the appropriate internal upset geometry based on the design concept. Finally, the validity of the criterion given by the finite element analysis was evaluated by full-size fatigue tests and excellent agreement was obtained.
A Field Comparison of the Directional Accuracy of MWD in Comparison With Six Other Survey Tools
Authors: Gabris P. M. , Hansen R. R. , Bartrina J. 
Published: December 2007

Abstract
A recent high angle well in the Mediterranean Sea offered a unique opportunity to compare survey tools. Seven different survey tools from six different companies were used over the same hole section, enabling their performance to be compared under the same conditions. Only the MWD tool gave consistently accurate survey data throughout the entire well.
Development of the Gullfaks Field
Authors: Grinrod M. , Justad T. , Tomren P. H. 
Published: December 2007

Abstract
The development of the Gullfaks field includes three giant gravity based platforms and subsea wells.
This paper describes the field, the drilling program and the drilling equipment installed on the platforms.
Shallow gas and abnormal pore pressure are among the challenges the operator faces. The block was awarded to a group comprising Statoil, the operator (85%), Norsk Hydro (9%) and Saga Petroleum (6%) in 1978. Exploration drilling commenced the same year.
The Application of Robotics to the Drilling Process
Authors: Boyadjieff G. I. 
Published: December 2007

Abstract
Robotics, a recently popularized phrase, has captured the interest of the general public as well as the drilling industry. This paper reviews the history of robotic applications in drilling and their outcome for the purpose of determining future trends. An analysis of the obstacles and limitations common to all industries is used to adjust the trend projection, and a survey of current efforts and programs is presented to complete the presentation.
Applications analyzed include the automatic drilling rig, various pipe-racking systems, and recent offerings in pipe-handling machines.
Innovative Approaches to Drilling High-Angle Wells in Bass Strait
Authors: Shaw M. N. , Sutherland W. G. 
Published: December 2007

Abstract
Esso/BHP has used innovative approaches to drilling high angle wells up to 72° average angle on its Snapper platform in Bass Strait. Drillstring designs, bit selection, hole conditioning, fishing, cementing and completion techniques have been reevaluated for innovation and cost-effectiveness. These techniques were used to make a comprehensive redrill program technically and economically viable.
Use of Borehole Stability Analysis for Successful Drilling of High-Angle Hole
Authors: Fun G. F. , Whitfill D. L. , Schuh P. R. 
Published: December 2007

Abstract
The removal of rock during the drilling operation disturbs the natural rock formation that is being subjected to a state of compressive in situ stresses at depth. The redistribution of the stresses around the hole thus produces stress concentrations at or near the borehole wall. Having no effective control to counter the high stress buildup around the wellbore may lead to a number of hole problems that include stuck pipe, borehole collapse, sloughing shale, and excessive fill. Using the theory of elasticity in rock mechanics, a numerical model has been designed to practically evaluate the stability of hole conditions both before and during drilling operations. This paper addresses the control of mechanical instability due to stressed conditions other than the interaction of mud chemistry on the rock formations. Case analyses are presented for offshore drilling in the Gulf of Mexico. The results have shown that the rock mechanics modeling of borehole stresses can help achieve the successful drilling of high-angle holes using optimum mud weights determined in advance for controlling hole stability.