bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing Hydraulic Fracture Designs in Formations With Poor Containment
Authors: Ahmed U. , Thompson T. W. , Kelkar S. M. , Strawn J. A. , Veghte R. , Hathaway S. 
Published: December 2007

Abstract
Hydraulic fracturing is a commonly used technique to improve hydrocarbon recovery from low permeability reservoirs. Practical fracturing treatments are designed to maximize the high conductivity propped fracture area in pay while minimizing the formation damage resulting from various fracturing materials within economic constraints. The effectiveness of hydraulic fractures can be greatly improved by controlling the geometry of the created fracture to maximize the fraction of the fracture area in the pay zone.
In situations where vertical fractures tend to migrate due to insufficient fracture containment, the effectiveness of a treatment may be increased by using a number of techniques. These include the proper selection of the perforation placements, controlling pumping rates and the use of various fluid types and other additives. Some of these techniques are currently under investigation in a Gas Research Institute funded project in western tight sands formations.
This paper reviews general considerations regarding hydraulic fracture designs, and presents the development of a perforation placement technique and a field application to verify the technique.
A New Fully Implicit Compositional Simulator
Authors: Chien M. C. H. , Lee S. T. , Chen W. H. 
Published: December 2007

ABSTRACT
A new fully implicit formulation for compositional simulators is presented. Rather than solving for pressure, saturations and phase compositions, the new formulation solves for pressure, overall concentrations and K-values. This change of primary unknowns to be solved improves numerical stability by yielding a more diagonally dominant Jacobian. The use of K-values as primary unknowns also allows the composition constraints to be solved separately from the other equations. The solution of the constraint equations is very efficient because they can be reformulated as monotonic functions*. The primary unknowns are further classified into reduced-unknowns and pivotal-unknowns. The latters are eliminated from the mass conservation equations using the fugacity equalities and constraints. The pivotal-unknowns are selected according to the sensitivity of the equations to the unknowns. This selection conforms to the partial pivoting strategy of Gaussian elimination and enhances numerical stability. Finally, a partial solution method is introduced to eliminate unnecessary calculations of those equations which have met the convergence criteria.
For a simple system, it is shown that the new formulation results in a more diagonally dominant Jacobian matrix. Numerical experiments involving one dimensional multicontact-miscibile (MCM) and immiscible problems, a two dimensional MCM problem and a three dimensional MCM problem are conducted to illustrate the capability and efficiency of the new formulation. Results indicate that the number of iterations per time step required by the new formulation is only about 40% – 60% of an existing fully implicit scheme. It is almost as low as that required by an IMPES scheme.
Air Drilling Operations Improved by Percussion Bit/Hammer Tool Tandem
Authors: Whiteley M. C. , England W. P. 
Published: December 2007

ABSTRACT
Tenneco and other operators air drill whenever possible to improve rate of penetration. This is done with pneumatic hammer tools and various bit types used with standard rotary air rigs. The recent application of a "flatbottom" percussion bit combined with a custom designed hammer tool originally developed for mining operations has significantly improved air drilling operations in the Arkoma Basin. The improvements include a large increase in ROP, improved hole geomotry, reduced drillstring stresses and a substantial reduction in cost/ft. This paper provides:
Discussion of the engineering design and operation of the flatbottom bit/hammer tool tandem Applications and limitations of the tools Guidelines for optimization of performance Documentation of field performance on Tenneco wells in the Arkoma Basin to demonstrate the improvements in air drilling operations provided by the flatbottom bit/hammer tool tandem.
Evaluation of Collapse Strength of Cemented Pipe-in-Pipe Casing Strings
Authors: Marx C. , El-Sayed A. A. H. 
Published: December 2007

ABSTRACT
The first test series has proved the high collapse strength of a combination of 5" casing cemented into 7" casing and the importance of high strength cement /5/. The extent of the tests included twelve pipes of 13-3/8" – 9-5/8" (P 110 -N 80) casing combination, as well as two pieces of 5-5/8" thin wall (0.08 in wall thickness) −7" (P 110) and eight pieces of 7" – 5" (P 110 – C 95) casing combination. The cements used were of API Class G type, blast furnace slug cement, and API Class G type with silica flour. The paper describes the results obtained, discusses possible field applications, and presents equations for calculating the collapse strength of cemented pipe-in-pipe casing strings.
Lost Circulation Treatments for Naturally Fractured, Vugular, or Cavernous Formations
Authors: Canson B. E. 
Published: December 2007

ABSTRACT
This paper presents methodologies to resolve severe lost circulation problems involving naturally fractured, cavernous or vugular formation intervals in which a pressure environment below .432 psi/ft exists. Lost circulation events in these rock conditions are compared to lost circulation events that are caused by induced fracturing or by drilling through permeable zones having intergranular porosity with excessive mud density.
Treatment philosophy and guidelines, methods of problem analysis, treatment materials and special techniques for their emplacement are discussed and evaluated. Procedures for several types of lost circulation treatments are included. Planning considerations are reviewed and the need to evaluate alternatives to drilling with conventional fluid circulating systems when operating in areas where the geological conditions exist to produce these rock anomalies is also discussed.
Low-Heat Input Welding Process for Corrosion-Resistant Cladding of Wellhead Components
Authors: Kovach P. J. , Williams T. D. 
Published: December 2007

ABSTRACT
Welding has historically been used to clad or overlay low alloy steels with corrosion resistant alloys (CRA's), with successful applications in the chemical processing, nuclear power, and oilfield industries. One of the main concerns about weld cladding, however, has been that weld penetration required to assure good bonding results in significant dilution of the CRA and thereby changes its composition.
This paper presents the results of developments to minimize dilution of the CRA composition while maintaining high integrity bonds. Research has yielded in a low heat input welding process which achieves good bonding with minimum dilution. The products of this new welding technology are compared to the properties of cladding as applied by the Hot Isostatic Pressing (HIP) process.
The results show that both the low heat welding process and the HIP process deposit cladding of the specified chemistry and have bond strengths comparable to the low alloy steel base material mechanical properties. However, it is evident that HIP clad deposits are prone to carbide precipitation at the interface resulting in reduced ductility and sensitivity to cracking at the interface when deformed.
Comparison of Laboratory and Field Data for a PDC Bit
Authors: Clark D. A. , Walker B. H. 
Published: December 2007

ABSTRACT
This paper compares penetration rate data for a polycrystalline diamond compact (PDC) bit generated at Drilling Research Laboratory (DRL) with data from an actual well. The bit was lab tested in new condition before being run in the field and in worn condition afterwards. The paper shows the usefulness of doing lab testing along with the field testing of PDC bits.
A Christensen 8 3/4 inch R40LF bit was tested at DRL in Mancos shale and oil base mud. Bit weight and rotary speed were varied from 4,000 to 16,000 lbs and from 90 to 140 rpm, respectively. It then was run in Sussex well #217, Johnson County, Wyoming, drilling over 4,100 feet in oil base mud. During the bit run, penetration rate data at bit weights of 8,000 to 20,000 lbs and rotary speeds of 75 and 105 rpm were taken at 1,000 feet intervals. Finally, it was retested at DRL in Mancos shale and oil base mud. In the second lab test, bit weight and rotary speed were again varied.
Differences between the hardness of the lab shale samples and the shales drilled in the field make direct comparison of the data difficult. However, similarities in the response of the PDC bit to changes in bit weight and rotary speed in the lab and the field are shown. The relative effect of bit wear and shale hardness on the penetration rate of the R40LF are discussed. Data from other R40LF bit runs in the same field are also presented.
Economical Drilling With Rock Bits Equipped With Extended Nozzles; Field Experiences in the North Sea
Authors: Peschel E. , Abdullah H. F. , Walters G. 
Published: December 2007

Abstract
Extended nozzles are features added to soft formation three cone drill bits for improved bottom hole cleaning. Field results from the North Sea indicate increased ROP up to 50%, an average of 16%. Cost calculations prove that more expensive extended nozzle bits are reducing cost/ft by increasing the ROP by more than 4%.
Matrix Body PDC Bits Prove Most Cost Effective in the Powder River Basin
Authors: Gill C. W. , Martin J. L. , Mounder T. E. 
Published: December 2007

ABSTRACT
In the past four years, Polycrystalline Diamond Compact (PDC) bits have gained recognition as a viable tool in the drilling industry, with many spot applications in soft to medium-hard formations. Prior to December 1983, PDC bits had been only marginally successful in the Powder River Basin of Wyoming. With the higher cost of PDC bits and the low rig cost, substantially longer runs were necessary for PDC bits to be economical. This was not being accomplished primarily due to the inability of Steel body bits to maintain gauge when drilling through the harder sandstone sections. Since many of these sandstone sections occur between the depths of 4,000 and 6,500 feet and surface casing is set between 1,000 and 2,500 feet, this left only 1,500 to 2,500 feet of shale to be drilled. Most PDC bits runs were less than 3,000 feet before the bit was worn out. Although some of these bits could be rebuilt, the cost and delays outweighed the advantages. With design changes made to Matrix body PDC bits, it became possible to drill the shales faster and maintain gauge while drilling the sandstones. This has led to more footage per bit and very cost effective savings when drilling with Matrix body PDC bits. The advantages of the Matrix body PDC bit are such that one major manufacturer of both styles stopped running Steel body PDC bits in this area and two other manufacturers have introduced their Matrix body PDC bits to this area.
Effects of Selected Mud Properties on Rate of Penetration in Full-Scale Shale Drilling Simulations
Authors: Cheatham C. A. , Nahm J. J. , Heitkamp N. D. 
Published: December 2007

ABSTRACT
Full-scale drilling simulations were conducted to determine effects of mud weight and static fluid loss on rate of penetration in medium-hard shale with water-base and oil-base muds. Two new 6 1/8 inch(156 mm) bits were tested: a natural diamond and a roller-cone insert type. Test data were analyzed using regression techniques. Results are presented in the form of four equations which predict rate of penetration – one for each combination of mud and bit type. Mud properties affected rate of penetration for the roller bit much more than for the diamond bit. Rate of penetration was usually greater for the roller bit except when high mud weight or overbalance conditions occurred.
Performance Drilling Optimization
Authors: Karlsson H. , Brassfield T. , Krueger V. 
Published: December 2007

ABSTRACT
The use of a newly-designed bottomhole assembly in the Kuparuk River Field on Alaska's North Slope has proven to be a cost-effective improvement over traditional rotary drilling methods.
The bottomhole assembly consists of a polycrystalline diamond compact bit, a positive-displacement downhole motor with specially-designed tilted drive sub (called a navigation sub), and a measurement while drilling system. The use of these tools in combination allows the driller to constantly monitor the well path and either drill straight ahead or make necessary course corrections, while drilling continues uninterrupted.
The savings from such a system have proven to be substantial, with significant reductions in drilling time, increases in rate of penetration, and average savings to the operating company of over $50,000 per well.
Reduction of Nonmagnetic Drill Collar Length Through Magnetic Azimuth Correction Technique
Authors: Russell A. W. , Roesler R. F. 
Published: December 2007

ABSTRACT
Traditional compass-type surveying instruments with their ability to sense only the direction of the local magnetic field vector must be used in conjunction with appropriate lengths of nonmagnetic drill collar to ensure that the local magnetic field vector is uncorrupted by drillstring magnetization. It is now possible to compensate for the effects of drill-string magnetization and, hence, utilize much shorter nonmagnetic drill collars by using solid-state surveying instruments which use gravity and magnetic transducers. Measurements in different bottom hole assemblies show that the required nonmagnetic collar lengths can be reduced in most situations using this compensation technique. This ability to run with shorter collars has significant impact on the use of MWD tools because it allows greater flexibility in the configuration of the bottom hole assembly as well as allowing the directional sensor and other MWD sensors to be positioned closer to the bit.
Directional Drilling Using the Catenary Method
Authors: McClendon R. T. , Anders E. O. 
Published: December 2007

ABSTRACT
The catenary curve method of drilling a directional well is a radical departure from conventional drilling methods. Examples demonstrate the process used to select a catenary curve and its application to a typical directional drilling program. Comparative studies provide supporting evidence of the catenary curve method's advantages over conventional directional methods.
High-Current, Deepwater Drilling Experiences
Authors: Shanks F. E. 
Published: December 2007

ABSTRACT
HIGH CURRENT and DEEPWATER are two topics which each require very special considerations and equipment to allow trouble free drilling throughout the waters of the world. There has been a substantial increase in the interest and activity of drilling in deepwater, high current, and deepwater high current locations. This paper will focus on the planning and equipment required for drilling in those areas where deepwater and high currents exist. The combination of the two requirements requires each have its own stand-alone considerations as well as a special merging of the separate considerations.
Use of Drillstring Models and Data Bases for the Scientific Control of Vertical and Directional Hole Paths
Authors: Amara M. H. 
Published: December 2007

ABSTRACT
From the early fifties, several authors and companies have made significant efforts in the field of bottom hole assemblies modelization.
This work has resulted in considerable improvements in drilling practices such as the use of pendulum and packed-hole assemblies.
Nonetheless, heuristics and empirism remain the rule as far as directional drilling is concerned.
Part one of this paper establishes the necessary link between theory and practice, missing so far, by the use of computer models and data bases together with realtime follow-up of vertical and deviated drilling operations.
The scientific criteria used to optimize the design of rotary drill strings are presented. Their theoretical and practical bases are underlined.
Concepts of BHA's relative rigidity, BHA efficiency related to ROP and hole curvature are developed and quantified.
Part two underlines the practical usefulness of such concepts for the control of vertical and deviated hole paths and ROP optimization. It is illustrated by four examples:
6″ hole drilling in Montmirail field onshore cluster 12 1/4″ phase in ISIS field offshore TUNISA. 17 1/2″ lock-up phase in ABK field offshore drilling. 12 1/4″ motor kick offs offshore INDONESIA.
Detailed Validation of a Liquid and Heat Flow Code Against Field Performance
Authors: Tsang C. F. , Doughty C. 
Published: December 2007

ABSTRACT
The numerical code PT, which calculates liquid and heat flow in a saturated porous or fractured porous medium, has been validated against a series of field experiments involving the injection and subsequent production of hot water into a confined aquifer. The layered structure of the aquifer and strong buoyancy effects, indicating highly coupled liquid and heat flows, provide a stringent test of the code's ability to model the real world.
Multidimensional Flux-Corrected Transport for Reservoir Simulation
Authors: Christie M. A. , Bond D. J. 
Published: December 2007

ABSTRACT
Flux Corrected Transport (FCT) is a method which was developed to reduce numerical diffusion in simulation of compressible flow. This paper describes how to implement FCT in an IMPES simulator. We first review the properties required of a difference scheme for accurate resolution of shocks. We then describe implementation of FCT in an IMPES simulator, and finally show examples for both miscible and immiscible flow.
Front Tracking in Two Dimensions Without a Grid
Authors: Karp A. H. , Greenstadt J. 
Published: December 2007

ABSTRACT
We present a method for handling non-linear partial differential equations having solutions that develop steep fronts. Traditional methods for solving such problems (the finite difference and finite element methods) implicitly assume a simple form for the solution over a limited domain. Instead of using a simple basis set and many small spatial elements, we use a complex basis set and no spatial discretization. The method produces accurate results because we are able to include in the basis set a non-rational function that can represent a step.
We have chosen to use the Buckley-Leverett equations to model the quarter 5-spot problem of oil reservoir modeling in two dimensions. The problem is a coupled system of partial differential equations – the flow equation which is nearly hyperbolic, and the pressure equation which is elliptic. In this paper we discuss the solution of the flow equation; the solution of the elliptic equation is discussed elsewhere.
The test problem is two dimensional and restricted to the unit square. Extensions to three dimensions and more general geometries will be discussed.
An Effective Method To Reduce Grid Orientation Effects in Steamflood Simulations
Authors: Caracotsios M. , Bertiger W. I. , Woo P. T. 
Published: December 2007

ABSTRACT
The velocity interpolation technique of Bertiger and Padmanabhan (1983), was formulated for block lefted cartesian grids and implemented in a fully implicit steamflood simulator. A detailed numerical study shows that the technique essentially eliminates grid orientation effects in uniform grids and greatly reduces them in non-uniform symmetric ones. Furthermore, it was found that for asymmetric diagonal orientations the results agree with those of symmetric ones. However, for parallel asymmetric configurations, grid orientation effects reappear.
Finite Element Methods for Enhanced Oil Recovery Simulation
Authors: Cohen M. F. 
Published: December 2007

ABSTRACT
A general, finite element procedure for reservoir simulation is presented. This effort is directed toward improving the numerical behavior of standard upstream, or upwind, finite difference techniques, without significantly increasing the computational costs. Two methods from previous authors' work are modified and developed: 1) upwind finite elements and 2) the Petrov-Galerkin method. These techniques are applied in a one- and two-dimensional, surfactant/ polymer simulator. The paper sets forth the mathematical formulation and several details concerning the implementation. The results indicate that the Petrov-Galerkin method does significantly reduce numerical-diffusion errors, while it retains the stability of the first-order, upwind methods. It is also relatively simple to implement. Both the upwind, and Petrov-Galerkin, finite element methods demonstrate little sensitivity to grid orientation.
Higher-Order Godunov Methods for Reducing Numerical Dispersion in Reservoir Simulation
Authors: Bell J. B. , Shubin G. R. 
Published: December 2007

Abstract
Standard finite difference methods used in reservoir simulation employ large amounts of numerical dispersion. This inherent numerical dispersion causes sharp fronts to be smeared over many grid blocks, and can cause their shapes to be wildly distorted. In this paper we discuss a new method that substantially reduces the effects of numerical dispersion. The new method significantly improves the resolution of fronts, and is specifically constructed to be essentially free of grid orientation effects.
Infinite Element Modeling of Heat Losses During Thermal Recovery Processes
Authors: Lewis R. W. , Morgan K. , Roberts P. M. 
Published: December 2007

ABSTRACT
This paper reports on preliminary investigations into the application of recently developed ‘infinite elements’ for modelling heat losses from a reservoir during thermal recovery techniques. The infinite elements were chosen for their ease of incorporation into an efficient alternating-direction finite element simulator. The numerical examples presented are based on modelling the simplest non-isothermal displacement process, i.e. hot-waterflooding, but the techniques demonstrated may be extended to the simulation of more sophisticated processes such as (cyclical) steam-flooding and in-situ combustion.
Simulating Steam Additive EOR Processes
Authors: Buchanan W. L. 
Published: December 2007

ABSTRACT
The simulation of EOR processes characterized by the injection of gases, solvents and/or chemicals with steam into a petroleum reservoir requires a fully implicit, thermal, compositional formulation. The simulator must be able to handle robustly and efficiently all the different types of PVT-composition behavior found in these processes. For reliable predictions, it also must accurately account for the complex physical effects that these additives have on oil, gas and aqueous phase properties such as density and mobility. Finally, the formulation must be able to accommodate future developments in steam additives EOR processes with a minimum of change to the simulator.
This paper describes such a multi-phase multi-component thermal model. The use of global mole fractions as primary variables permits all phase equilibrium calculations to be carried out in an interchangeable flash module which is designed specifically for the type of additive being injected. Two examples of these flash modules are presented. The phase equilibrium constraints are coupled to the flow equations using a novel method which optimizes robustness and efficiency. Phase properties are calculated in another interchangeable module which is tailored to reproduce the desired effects of the additive.
Results show that the simulator can handle a wide range of steam injection processes efficiently. Several examples are used to compare this model with another model that employs a more conventional formulation.