bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maximum Differential Pressure Perforating
Authors: Walker Terry , Brown Jack E. , Briggs George E. 
Published: December 2007

Abstract
Laboratory data and field results have shown that casing perforations are plugged when there is a pressure differential toward the formation at the time of perforating. As a result, there has been a trend toward thru-tubing completions so that the wells can be perforated with a pressure differential toward the wellbore. However, there has been an accompanying sacrifice in depth of penetration because of the smaller charge size, especially in the thru-tubing hollow carrier guns. Also, when the encapsulated charges are used, the casing has to absorb the shock when the gun is fired.
Recently, a perforating system has been developed whereby the deep penetration of the larger charges in casing guns can be combined with the efficient clean-out of the negative differential perforating. In this system each perforation is sealed perforating. In this system each perforation is sealed off from hydrostatic pressure as the gun is fired. The volume inside the gun at atmospheric pressure is sufficient to contain the products of combustion and still give essentially full formation pressure as a differential into the gun. The resulting implosion into the gun insures that each perforation will have maximum capacity for flow or injection. Laboratory and field data are presented showing the benefits of this new perforator. Full allowable wells are being obtained through natural production in many cases. In others lower breakdown pressures, higher injection rates, and more efficient well treatments and sand consolidation jobs are the result.
Introduction
The effectiveness of perforations in oil and gas well casing has been the subject of a number of papers since the introduction of bullet guns in 1932 and of jet guns in 1948. In 1956 Allen and Worzell and Krueger reported the results of perforating Berea sandstone targets with various perforating Berea sandstone targets with various wellbore fluids and pressure differentials. Their data indicated that serious perforating plugging occurred whenever there was a differential pressure to the formation at the time of perforating, especially with mud in the well bore. These plugs consisted of crushed formation, liner particles, jet charge particles and mud. Pressure differentials as high particles and mud. Pressure differentials as high as 430 psi were required to initiate backflow on some of these tests.
Petrophysical Properties of Ferron Sandstone During Two-Phase Flow: Implications for Heterogeneity in Tertiary Deltaic Reservoirs
Authors: Miller M. A. , Yang Huade , Holder J. T. , Jounus M. J. , Gray K. E. , Fisher R. S. 
Published: December 2007

Abstract
This study was part of a comprehensive program of quantitative characterization of heterogeneity in fluvial-deltaic reservoirs, using the Ferron, Utah outcrop as an analog reservoir. A suite of petrophysical properties were measured simultaneously in the laboratory for over sixty specimens, representing different geologic facies, flow units, and barriers. Properties included porosity, permeability, electrical conductivity, shear and compressional wave velocities, and quasi-static moduli, measured under simulated reservoir conditions during two-phase steady-state flow of gas and brine, in both drainage and imbibition. Petrographic data on each sample were also gathered, including quantification of detrital and authigenic phases, thin-section porosity, textural and grain-size distribution analyses. Centrifuge capillary pressures on plugs from the laboratory test specimens were also measured. Minipermeameter determinations of test specimen air permeabilities were conducted in companion studies. Statistical studies were conducted to relate petrophysical data to petrographic information in an attempt to examine the correlation of petrophysical data with geologic genesis and diagenesis. Reasonable correlations were obtained for most of the data, that may be of use in other similar fluvial-deltaic environments. These types of correlations may also be of use in discerning expected statistical distributions of petrophysical data other than permeability.
Fight Sand With Sand - A Realistic Approach To Gravel Packing
Authors: Sparlin Derry 
Published: December 2007

Abstract
Gravel packing is one of the oldest and most useful methods for controlling loose sand in wells. This art has advanced considerably with the studies of proper gravel sizes, improvements in the manufacture and design of screens and the multitude of tools to help get the gravel in place.
A significant improvement was the pressure packing technique. By placing pressure packing technique. By placing gravel outside the casing a higher flow capacity can be expected. Radial flow equations show that productivity increases as much as 50% can be obtained. However, seldom are such good results achieved and it is rare when good productivity is maintained.
Existing gravel packing techniques and literature are aimed at trying to use the largest possible gravel size. Much thought has gone into retaining a high flow capacity but controlling the sand has been secondary. In fact, many experts claim that it is necessary that formation fines be continuously produced through a gravel pack in order to produce fluids. To do that a relatively large gravel size must be used.
We have looked at gravel packing with the idea of using the smallest possible gravel size that will not decrease the productivity of a well. It can be proven that productivity of a well. It can be proven that the use of gravel only slightly larger than the formation sand if properly placed in the well will actually increase productivity.
A new gravel placement technique has been developed and field tested using small gravel. This technique uses no special tools or equipment and can be done in a fraction of the time that many gravel packs presently use. It results in an almost presently use. It results in an almost ideal pack which gives perfect control of the formation and high production rates are retained. A unique slurry is used which departs dramatically from all known gravel packing procedures. packing procedures.
Multifacies Modelling of Fluvial Reservoirs
Authors: Egeland Thore , Georgsen Frode , Knarud Ragnar , Omre Henning 
Published: December 2007

Abstract
A stochastic model for the for the facies architecture of fluvial reservoirs is presented as well as a computer program called SISA designated to simulate from the model. While previous papers (Georgsen and Omre [7] and Georgsen et al. [6]) have offered complete mathematical presentations, the one at hand emphasizes the geological setting and intuitive descriptions of the model. The model includes totally -1 different types of facies; background, channel sand, sheetsplay sand and barriers. The translation of geological information into input to SISA is explained. Two kinds of examples are shown: One synthetic with a few number of facies-bodics and one real from a fluvial north sea. field. The aim of these examples is to emphasize the following features; location and behaviour of facies-bodies; relation between different types of facies and conditioning on well-observations. SISA produces realizations of the models honoring well observations
Analysis of Slack-Off Force Transmitted Downhole in Coiled-Tubing Operations
Authors: Gu Hongren , Newman K. R. , Hauglund L. F. 
Published: December 2007

ABSTRACT
This paper presents an analysis of the relation between the slack-off force and the force transmitted downhole when coiled tubing is slacked off or set down at the surface. It is generally believed that the force transmitted downhole cannot be larger than the slack-off force at surface. An analysis for coiled tubing in deviated wellbores shows that the force transmitted downhole can be smaller or larger than the surface slack-off force, depending on the well deviation profile and buckling conditions. Analytical solutions of the forces for constant-curvature well profiles are presented to explain the relation. The reason is that when coiled tubing contacts the wall of a curved well, the belt friction also plays a role in supporting the tubing weight and hence, affects the force transmitted downhole. The use of a computer tubing-forces model to calculated the forces for general well conditions is described. The results are compared with published solutions for vertical wells and explained for a field case of deviated well.
Overbalance Perforating and Stimulation Method for Wells
Authors: Handren P. J. , Jupp T. B. , Dees J. M. 
Published: December 2007

ABSTRACT
Underbalanced perforating is generally accepted as the petroleum industry standard for perforating. This paper presents the concept, the mechanics, the procedures, potential applications, and the results of perforating by a "new" convention of perforating that incorporates the use of overpressured wellbores. This procedure can also be used in wells with existing perforations if an overpressured surge is used. Oryx has successfully used overbalanced perforating and overbalanced surging procedures in more than 50 wells. This paper will highlight some of the case histories that have used these techniques.
A Method to Select Resin-Coated Proppants
Authors: Dewprashad Brahmadeo , Abass H. H. , Meadows D. L. , Weaver J. D. , Bennett B. J. 
Published: December 2007

Abstract
This paper describes a procedure that can be used to select the resin-coated proppant to be used for a particular hydraulic fracturing application. Using this procedure, samples of proppant were cured in a carrier fluid under simulated downhole conditions and the elastic properties, thermal displacement, and time-dependent characteristics (creep) of these samples were determined at different temperatures. Testing involved measuring the time-dependent axial strains for a given load and temperature. Another phase of testing involved loading a cylindrical sample to a predetermined axial load, then increasing temperature slowly until failure occurred. The physical and mechanical properties of these consolidated resin-coated proppant samples were measured to establish a guideline for application of rock mechanics in selecting resin formulations for optimum well performance after a hydraulic fracturing treatment.
Development of Composite Coiled Tubing for Oilfield Services
Authors: Sas-Jaworsky Alexander , Williams J. G. 
Published: December 2007

Abstract
As coiled tubing services expand to meet the challenges of the oil and gas industry, limitations of steel tubulars continue to temper the potential impact of this workover service. Presently, coiled tubing used in well servicing operations is milled from modified A-606 High Strength Low Alloy (HSLA) steel, with yield strengths ranging from 70 ksi to 100 ksi. Although current coiled tubing services can performed safely and reliably with conventional steel coiled tubing, the behavior of the isotropic metal limits the yield pressure and tensile load capability of the tube.
Composite Coiled Tubing (CCT) offers the potential to exceed the performance limitations of isotropic metals, thereby increasing the service life of the pipe and extending operational parameters. CCT is constructed as a continuous tube fabricated from non-metallic materials to provide high body strength and wear resistance. CCT can be tailored to exhibit unique anisotropic characteristics which optimally address burst and collapse pressures, tensile and compression loads, as well as high strains imposed by bending. This enabling capability expands the performance parameters beyond the physical limitations of steel or alternative isotropic material tubulars. In addition, the fibers and resins used in CCT construction make the tube impervious to corrosion and resistant to chemicals used in treatment of oil and gas wells.
Based on the performance of prototype specimens constructed and tested to date, the service life potential of CCT is substantially longer than that of conventional HSLA steel pipe when subjected to multiple plastic deformation bending cycles with high internal pressure. In addition, CCT is expected to provide the ability to extend the vertical and horizontal reach of existing concentric workover services. This paper reviews the limitations of conventional HSLA steel coiled tubing, explores the design criteria requirements for CCT, and discusses the results of tests performed on numerous CCT prototype specimens.
Single-Phase or Multiphase Blowdown of Vessels or Pipelines
Authors: Norris H. L. , Puls R. C. 
Published: December 2007

Abstract
In order to predict the consequences of a leak or rupture of a pipeline or vessel, or to design a controlled pressure release system, a method of predicting the mass efflux is required. Although a large body of literature exists on blowdown simulation for vessels or short pipes, relatively little analysis and experimentation has been performed for the depressurization behavior of pipelines. In addition, the impact of the thermodynamics of multicomponent hydrocarbon fluids has been relatively unexplored. A mechanistic homogeneous equilibrium model applicable to both vessels and pipelines has been written. Since fluid thermodynamics are evaluated external to the model, single or multicomponent fluids can be simulated as well as single or multiphase flows. In addition, a series of small scale blowdown experiments has been made using both gas bottles and coiled tubing. The coiled tubing has a length to diameter ratio of 60,000, comparable to that encountered in field piping. Air, carbon dioxide, and carbonated water have been used in the experiments. Excellent agreement between the model and experiments has been obtained, along with excellent agreement with at least one field data set.
Acid-Resistant Microfine Squeeze Cement: From Conception to Viable Technology
Authors: Heathman J. F. , Carpenter R. B. , Sanders G. S. , Wedman M. L. 
Published: December 2007

Abstract
This paper focuses on the development and field application of an acid resistant, microfine portland cement composition. This specialized cementing system has been developed for remedial water and/or gas shut-off squeeze operations in the Prudhoe Bay Field of Alaska.
Because of the unique properties of microfine cements and the requirements of this application, new laboratory and field test procedures have been introduced. A full-scale mixing and pumping test was conducted prior to field application of the new Portland cement system. This testing was performed to ensure proper performance of the cement in a field environment. Slurry properties after mixing and pumping through 17,300 ft. of coiled tubing are presented. To better illustrate the sequence of lessons learned, several case histories and prior microfine cement designs are discussed.
Thickening Time Test Apparatus Provides Method of Simulating Actual Shear History of Oilwell Cements
Authors: Purvis D. L. , Mueller D. T. , Dawson J. C. , Bray W. S. 
Published: December 2007

Abstract
A reliable prediction of cement thickening time is central to the success of oilwell cementing operations. The amount of time that a cement remains "pumpable" is dependent on several factors, including shear rate history. Current industry testing methods, however, allow for only a single rotational speed of the consistometer slurry cup during a thickening time simulation. This, in turn, relegates the range of shear rates found within the cup to those due only to the changes in the Theological properties of the cement. Yet, oilwell cements encounter a much wider range of shear rate conditions during placement due to changing surface pump rates and variable wellbore geometries. The physical attributes of oilwell cements, including thickening time, are influenced by this shear rate history.
A conventional pressurized consistometer, fitted with a variable speed motor, is combined with a standard slurry cup containing a helical screw paddle (HSP). This device provides the basis for comparative thickening time testing. Computer modeling allows for an actual depiction of the shear rate history to be integrated into a thickening time evaluation. This information was used to program a modified consistometer to replicate the shear rate, temperature, and pressure conditions found during placement.
Presented are the comparisons of standard API thickening times, thickening times with the HSP rotating at 150 revolutions per minute (RPM), and thickening times with the HSP in actual shear rate history simulations. The results indicate that thickening times are shortened in a low shear rate environment. At higher shear rates, the differences in thickening time among the three testing methodologies are minimal. Knowledge of the actual shear rate encountered during a cementing operation and a slurry’s susceptibility to changes in thickening time due to shear rate history, is vital to predicting the true thickening time of the slurry under downhole conditions.
New Well Completion and Stimulation Techniques Using Liquid Jet Cutting Technology
Authors: Peters A. D. , Henson S. W. 
Published: December 2007

Abstract
Liquid jet cutting technology has made rapid advancement in industries for manufacturing, industrial cleaning and mining. Commonly, pressures from 5000 psi to 60,000 psi are used. In recent years, a number of downhole assemblies have been developed to utilize this technology for use in the oil industry. This paper will cover the development of two such techniques that are capable of creating tunnels in the formation rock up to ten feet in length by one inch in diameter in cased hole or open hole wells. The original design of the downhole assemblies will be discussed. New data on the lab and field testing of the effectiveness of creating tunnels in a variety of formation rocks, jetting with aqueous and acidic fluids will be mentioned. The results will show substantially improved penetration rate when jetting with HCl in carbonate rocks and improved penetration rate when pumping with polymer additives. These techniques provide new options in completing and stimulating zones in a variety of applications. The techniques discussed will provide completion engineers with selective, controlled options for initial completion, stimulation or workover. The resulting tunnels are superior to perforations in length, and diameter and leave no compaction. This paper will also serve to inform the industry of the significance of liquid jet cutting for a variety of downhole applications.
Hydraulic Fracture Modeling in Formations Exhibiting Stress-Dependent Mechanical Properties
Authors: Poulsen D. K. , Abass H. H. 
Published: December 2007

Abstract
Although most fracturing treatment design models assume that the behavior of the formation being fractured can be approximated by linear elastic theory, many formations, particularly unconventional ones such as coalbeds and poorly consolidated sandstones, exhibit sufficiently nonlinear behavior to invalidate this assumption. Methods are developed and presented for generalizing fracture design models and net fracturing pressure analysis to consider nonlinear stress-strain behavior.
Realistic Fracture Conductivities of Propped Hydraulic Fractures
Authors: Milton-Tayler David 
Published: December 2007

ABSTRACT
Preliminary results of an experimental programme to determine the significance of dual phase flow in propped fractures are presented. Gas-water flows are considered. The results demonstrate that, even in cases of minimal water production, effective permeabilities may typically be reduced by a factor of 2, or more. In severe cases of water production, permeabilities may be less than 20% of their single phase values.
Influence of the Permeability Anisotropy Ratio on Large-Scale Properties of Heterogeneous Reservoirs
Authors: Duquerroix J- P. L. , Lemouzy Pierre , Noetinger Benoit , Romeu R. K. 
Published: December 2007

Abstract
When performing fluid-flow simulations, up-scaling techniques must be used because of the required coarse grids. For this purpose, algebraic formula, combining arithmetic and harmonic averagings, extension of Cardwell and Parsons’s results, derived from perturbation techniques are proposed taking into account the anistotropy, either natural or due to the reservoir geometry. These formula are valid for 2D or 3D problems and are very little computational time consuming compared to direct numerical methods. Moreover they integrate rigorous mimima and maxima thus showing the global uncertainty on equivalent permeability determination. They proved to work well for large permeability contrasts and anisotropy ratios either for simple log-normal or geostatiscally generated media.
In the first application case numerical calculations were carried out for the upscaling of isolated cells. In the other case well test simulations were performed either with the original fine grid or further coarser grids.
Noniterative Phase Equilibrium Calculation in Compositional Reservoir Simulation
Authors: Stenby E. H. , Wang Peng 
Published: December 2007

Abstract
An efficient, non-iterative flash calculation algorithm has been developed for equation of state (EOS) compositional reservoir simulation problems. In this algorithm, the flash calculation is carried out by solving two sets of linear equations. The solution of these equations is the mole number of each component in each phase. The phase saturation can thus be obtained without solving the Rachford-Rice equation1. Tests against many PVT data sets show that the new approach gives the same results as those computed by the fugacity iteration based on the EOS. However, the computation time is reduced significantly.
A series of reservoir simulations has been conducted by an EOS compositional reservoir simulator, UTCOMP, with this new flash approach. Comparisons are made with those performed by UTCOMP with a rigorous fugacity iteration of the Peng-Robinson5 EOS. The results obtained by these two methods are in very good agreement. However, a considerable reduction of the CPU time is generally accompanied by using the new approach. For the runs in which an immiscible displacement process takes place in the reservoir, the computational burden in the phase behavior calculations is reduced by around 90%. Correspondingly, the reduction of the total simulation time is as much as 65%. Besides, it is found that the number of components used affects on the CPU time of the simulations much less with the new approach. These observations may lead to the time used for an EOS compositional reservoir simulations with the new approach being comparable to a black-oil simulation without sacrificing computational accuracy.
Also in this work an attempt is made to employ the non-iterative approach as a tool for providing the initial guess for the rigorous EOS iteration. A considerable reduction of the CPU time is still observed.
Predicting Capillary Crossflow in Layered Reservoirs
Authors: Haq S. , Reis J. C. 
Published: December 2007

Abstract
A model that predicts capillary crossflow into the layers adjacent to a high-permeability layer during waterflooding is presented. A material balance on the injected water that includes the water loss to the adjacent layers by capillary imbibition is solved by Laplace Transforms to obtain equations for the areal extent of the watered zone and the fraction of displaced oil coming from the adjacent layers.