bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultra-Lightweight Proppant Development Yields Exciting New Opportunities in Hydraulic Fracturing Design
Authors: Wood William D. , Brannon Harold D. , Rickards Allan R. , Stephenson Chris 
Published: December 2007

Abstract
Recent research involving the modification of the mechanical properties of particles has resulted in the development of new materials which have particle strengths suitable for application as fracturing proppant yet, possess much lower apparent specific gravity than today's commercial proppant products. For example, whereas the apparent specific gravity of commonly used Ottawa sand is 2.65 g/cc, various embodiments of the new proppant materials range from 1.25 to 2.0 g/cc.
Options for proppant selection have previously been limited to identifying the product of median particle diameter to avoid bridging and, sufficient particle strength to withstand the fracture closure stress, thus providing high proppant pack permeability. Fracturing fluids have been selected primarily based upon in-situ rheological properties in an effort to insure proppant placement by providing sufficient viscosity to minimize proppant settling.
Treatment pumping rates are limited by the wellbore configuration, the cumulative cross-sectional perforation area and, the desire to keep the fracture ‘in zone’. As the reservoir properties are fixed and the proppant variables dictated by the wellbore and reservoir stress environment, the fracturing practitioner was left with only limited control of two input variables, significantly limiting creative optimization of the stimulation treatment design.
Many potential benefits of application of the new ultra-lightweight proppant in hydraulic fracturing treatments are readily apparent. These include substantially reduced proppant settling, allowing the potential for much increased effective propped length, for fluids of lower viscosity and/or, for reduction of pumping rates. The development of the ultra-lightweight proppants is perhaps most exciting from the perspective of the stimulation design engineer, owing to the enhanced options afforded him or her to improve well stimulation. The design engineer is provided not only a new parameter to influence design, but given freedom from the previous limitations imposed on the fluid and treating rates by the high density proppants previously employed.
The objective of this paper is to identify those new opportunities afforded the stimulation design engineer, due to availability of these new ultra-lightweight proppants. Numerous fracture modeling runs have been conducted varying fluid density and rheological properties, treating rates (Reynold's Number), proppant density and size.
The results of these efforts are provided, and compared in terms of created fracture geometry, propped fracture length, propped fracture surface area, settled proppant height, and fracture conductivity. The data clearly illustrate that the use of ultra-lightweight proppant allows for optimization of fracturing treatments with greatly improved effective fracture length and more importantly, well producibility.
A New Treatment Increases the Fracture Gradient to Cure Lost Circulation and Control a Flowing HPHT Well in the East Mediterranean Sea
Authors: Sanad Medhat , Butler Carl , Waheed Arshad , Sweatman Ron 
Published: December 2007

Abstract
This paper addresses a well-control issue in a challenging high pressure/high temperature (HPHT) exploration well where a possible underground crossflow was in progress and the well was losing oil-based mud before reaching the final target depth below 15,000 ft (4572 m). Several days were spent trying to control the well using various formation-sealing treatment systems (some conventional and others new), but with no success. Eventually a new wellbore pressure containment improvement system (WPCIS) was implemented, and it controlled the losses effectively. Full circulation was then re-established to overbalance the HP zone and kill the well. The well had been losing at an equivalent circulating density (ECD) of 16.4 lb/gal. Application of the WPCIS process improved the wellbore pressure containment (WPC) side of the mud weight window, also called the fracture gradient (FG), to sustain an equivalent of 17.0 lb/gal mud as measured by a formation integrity test (FIT). This remarkable WPC and apparent FG improvement was achieved along with several other cost-saving factors.
Upon re-entry of the well seven months after the successful WPCIS treatment, the seal in the exit zone(s) was still holding against pressure of more than 12,000 psi and temperatures of 300°F. This sustained WPC seal by the WPCIS saved even more cost and enabled a liner to be set without losses for a successful completion of the well.
As a followup to previous discussions,1 this paper further describes the WPCIS process and its applicability and then demonstrates how the system can help optimize well plans, leading to lower costs for drilling fluids, casing design, cementing, and completion equipment. A post-treatment study is also included to help explain how the WPCIS sealing mechanism shut off the HPHT flow into the exit zone and increased the near-wellbore FG.
Brunei Field Trial of a Fibre Optic Distributed Temperature Sensor (DTS) System in a 1,000m Open Hole Horizontal Oil Producer
Authors: Lanier G. H. , Brown G. , Adams L. 
Published: December 2007

Abstract
A fibre optic DTS system was installed on Brunei Shell's South West Ampa (SWA) 293 well to allow real-time measurement of the temperature profile along well bore and open hole producing section. The object was to infer the inflow production profile of the well. Although fibre optic distributed temperature systems are now commonly used in different types of well applications, this particular application posed a significant challenge requiring the system to be installed in a horizontal well bore and monitor data located within a 2 degree Celsius geothermal temperature range.
Thermal simulations suggested that the inflow profiles could be used to determine whether flow was being produced from the heel, toe or distributed along the open hole section - despite the expected small degree of temperature change. In addition, the simulations suggested qualitative changes in time related to production changes associated with gas and/or water breakthrough could be identified along the horizontal producing section. This information was used to impact future development well designs, location of horizontal sections within the reservoir and planned length of horizontal.
SWA 293 well design and installation considerations will be presented along with findings and interpretations of the temperature survey results from the distributed temperature system installation.
Application of Flow-Thru Composite Frac Plugs in Tight-Gas Sand Completions
Authors: Eberhard Mike , Meijs Raymund , Johnson Jeff 
Published: December 2007

AbstractSeveral major developmental programs in the Rocky Mountain region of the United States are in fields where zones of several hundred to several thousand feet of stacked, tight (&lt;0.05 md) lenticular gas sands exist. In order to be productive, these wells require multiple fracture treatments over the pay interval. Since field development has been ongoing, the drilling programs are extending into more marginal production areas. Infill programs are downsizing spacing, and also, successful refracturing programs are being conducted in some fields. Before 1998, traditional methods were being used to isolate fracture treatments. These methods usually required killing the well between fracture treatments or during cleanout operations. Unfortunately, field studies have determined that the traditional isolation methods have negatively impacted well productivity.In view of the costs involved and the lower productivity experienced with the new drilling programs, it became apparent that either well costs had to be reduced or well productivity had to be improved!This paper will discuss the application of flow-thru composite frac plugs (FTCFP) and how they were capable of addressing the current needs to reduce operational costs and improve productivity. These plugs can be used as an alternative to traditional isolation methods, or induced stress diversion. Through June 2002, there have been over 3,200 FTCFPs run in the Rocky Mountain region. The benefits gained from FTCFP usage are derived from the following: Well drill-out costs are reducedPositive isolation is allowedAll zones can be produced during completion.Their use has now become a "best practice" in stacked-pay completions.
Monitoring and Managing Business Performance from a Portfolio Perspective
Authors: Howell John I. , DuBois James R. 
Published: December 2007

AbstractCorporations often begin each year with a corporate strategy, a business plan and high expectations of success from their pending business operations. As they execute the business plan they meet with successes and failures, all the time wondering if they should reassess future business plans. Are they better off drilling the remainder of the proposed opportunities, or should they reconsider other opportunities? These decisions are frequently impacted by emotion and intuition as much as by technical analysis.Throughout the year, corporate executives routinely share information with analysts and stakeholders about their results to date. The information reflects their reactions to the results received to date as tempered by their expectations for the remainder of the year. This system of information collection, analysis, decisions and communication frequently lacks consistency and can be quite time consuming.This paper will illustrate how companies can use portfolio management techniques to improve the efficiency of their business plan monitoring and the quality of the information available to the decision process. We will show how portfolio management can be used to track corporate performance and continually reassess the remaining business plans throughout the year. As results are derived, the company can use portfolio processes to monitor the expected business results and the probability of meeting their goals. We will illustrate how portfolio management can help decision makers determine when to change plans and when to stay on the planned course.
Capillary Pressure and Wettability Behavior of Coal - Water - Carbon Dioxide System
Authors: Mazumder Saikat , Plug Willem-Jan , Bruining Hans 
Published: December 2007

Abstract
Enhanced Coal Bed Methane (ECBM) recovery techniques, based on carbon dioxide injection, have been proposed for the recovery of larger fraction of methane in place. Laboratory studies and recent pilot field tests demonstrate that CO2 injection has the potential to enhance coal bed methane recovery through displacement desorption mechanism with an added advantage that this technology can be employed to sequester large volumes of CO2 in deep coal seem reservoirs, thereby reducing emissions of industrial CO2 as a greenhouse gas.
It can be expected that carbon dioxide enhanced ECBM is detrimentally slow unless operated at high enough pressures such that the coal becomes carbon dioxide wet. Indeed in water wet coal the small fracture system remains almost entirely filled with water and kinetics of CO2 adsorption and CH4 desorption is determined by the slow diffusion in the relatively large aggregates of water filled fractures and coal. Capillary diffusion is of the order of hundred times faster and fills the small fractures with carbon dioxide proportionally faster provided that conditions are such that the coal is CO2 wet.
For this reason we undertook to measure the capillary pressure of grounded coal between water and carbon dioxide. The grounded coal precisely exposes the coal surface of relevance here. A computer code is written, which simulates the capillary pressure experiment. The code makes it possible to get useful results before complete capillary pressure equilibrium in our laboratory cell have been attained.
Compositional and Non-Isothermal Simulation of CO2 Sequestration in Naturally Fractured Reservoirs/Coalbeds: Development and Verification of the Model
Authors: Cicek O. 
Published: December 2007

Abstract
This study presents development and verification of a field scale compositional and non-isothermal numerical simulator for CO2 sequestration in naturally fractured systems/coalbeds. The main body of the model is three-dimensional, and four-phase mass and energy flow equations are based on compositional balances. Dual-permeability approach is used for the mathematical formulation of the problem. Single-porosity and dual-porosity approaches, subsets of the dual-permeability formulation, are considered as the second and the third approaches in the mathematical formulation of the problem. The model accounts for fluid displacement due to capillary, viscous, gravitational forces and diffusion. The field-scale simulator is developed using a fully implicit numerical solution considering the highly non-linear nature of the problem. The proposed formulation assumes (potential) nonlinearity for all the reservoir and operational parameters with respect to all primary variables identified. (2nhc+10) primary variables for each grid block are solved simultaneously, where nhc denotes the number of hydrocarbon components permissible. A direct solver is used for the resulting system of linear equations.
The present model is verified and benchmarked against two SPE Comparative Solution Projects; the Sixth SPE Comparative Solution Project: A Comparison of Dual-Porosity Simulators1, and the compositional problem of the Fourth SPE Comparative Solution Project: Comparison of Steam Injection Simulators2. In addition to these two benchmark problems, the model is tested and verified against a coal seam degasification problem from the literature3.
The present study is capable of handling the ever-changing relative effects of the various dominant forces on the establishment of fluid displacement mechanisms. The model formulation also accounts for complex fluid flow problems involving thermal effects, injection and production of fluids of different compositions as well as various composite fluid systems encountered in a given system. Having formulated sorption phenomena as a function of composition, pressure and temperature, various sorption mechanisms in coal seams would be studied by the present model.
The developed model is very flexible and capable of enveloping a number of different reservoir domains and different types of problems. As a result the present study should enable us test various hypothesis leading to improved conceptualization and modeling of fluid flow in naturally fractured geological systems.
Adding the Human Factor to Rig Anti-Collision Systems: A New Technology Explored
Authors: Whyte Jason A. 
Published: December 2007

Abstract
Advances in drilling rig automation have dramatically increased overall safety and efficiency by mechanizing activities traditionally accomplished by personnel working on the drill floor. However, these laborsaving machines also pose new challenges for maintaining a safe operating environment where man and machine must share the same workspace. This paper will explore a new system designed to reduce the likelihood of injuries caused by man-machine interference while also improving efficiency. The paper will discuss the methodology behind this personnel monitoring system and its potential to further improve rig safety.
Laser Drilling: Effects of Beam Application Methods on Improving Rock Removal
Authors: Parker Richard A. , Gahan Brian C. , Graves Ramona M. , Samih Batarseh , Zhiyue Xu , Reed Claude B. 
Published: December 2007

Abstract
Since 1997, Gas Technology Institute (GTI) has been investigating the interaction of high power lasers with different rock lithologies to determine possible applications in drilling and completing oil and gas wells. As part of an initial effort to determine the energy required to remove rock with laser beams, GTI performed a series of experiments under a US Department of Energy contract together with Argonne National Laboratory and the Colorado School of Mines. As part of this investigation, GTI identified the specific energy requirements (kJ/cc) required to remove rock from test samples of sandstone, shale and limestone using a 1.6 kW pulsed Nd:YAG laser beam. Each sample was subjected to a single exposure of the beam, and the resulting specific energy calculation was made. Results were presented in a previous SPE paper.
Additional experiments since then were performed with the same Nd:YAG laser to determine how repetitive beam applications on the same sample influence rock properties, rock removal efficiency and penetration rates. Key considerations in determining the series of tests performed included geometric pattern applications, beam overlap and spacing, focal distance changes while lasing, beam intercept angles, purging systems and thermal relaxation time between successive shots. By providing multiple overlapping beam shots, several advantages were observed that allowed faster and deeper penetration of the beam into the rock sample with no evidence of melted minerals present. This paper will describe the experimental procedures as well as pre- and post-laser data analysis to determine changes in rock properties (i.e., permeability, porosity) and effects on observed specific energy measurements for sandstone, limestone and shale samples.
Advanced Cutting Structure Improves PDC Bit Performance in Hard Rock Drilling Environments
Authors: Mensa-Wilmot Graham , Soza Robert , Hudson Kyle 
Published: December 2007

Abstract
Hard rock applications continue to pose serious challenges for PDC bits. Although improvements1,2,3 have been achieved in these environments, PDC bit performance is highly inconsistent and leaves much to be desired. Operational costs in such environments, due to reduced footage and/or low penetration rates (ROP), are enormously high.
This paper will evaluate the challenges of hard rock drilling. It will discuss the effects formation hardness has on drilling efficiency, and the energy level requirements associated with the different rock failure mechanisms. The definition and relationships between WOB requirements, drilling efficiency, ROP, wear flat generation and on-bottom drilling time will also be discussed.
An advanced cutting structure (ACS), which improves PDC bit effectiveness and consistency in hard rock drilling environments, will be presented. ACS improves drilling performance by re-defining and optimizing the relationships between ROP, durability and stabilization. It maximizes bit life, by slowing the PDC cutter deterioration process, without compromising ROP. This paper will describe ACS's functionality, and show the positive effects it is having on operational costs. Laboratory and field data, supporting ACS's effectiveness will also be presented.
Simulation Of Sour Gas Injection Into Low Permeability Oil Reservoirs
Authors: Thibeau Sylvain , Barker John W. , Morel Danielle 
Published: December 2007

Abstract
Sour gas injection into an oil reservoir is an attractive process. It provides a solution to unlock sour gas and oil reserves in other near-by reservoirs and it is an efficient EOR process, due to the high miscibility nature of the H&lt;sub&gt;2&lt;/sub&gt;S and CO&lt;sub&gt;2&lt;/sub&gt; molecules.
Field evaluation of this process is classically obtained by local evaluation on a well pattern; the upscaling of the pattern; and the use of the upscaled model at the field scale.
Injectivity is a crucial issue for sour gas injection projects, since projects are due to inject sour gas volumes produced elsewhere. This is even more critical in low permeability reservoirs, where high pressure losses can be located in the near well region, leading to reaching compression and/or pumping limits.
The aim of this paper is to present the upscaling step, focusing on the sour gas injectors behaviour; to underline the limitations of single phase upscaling in a miscible environment; and to propose a consistent upscaling strategy in this context.
Multiscale Numerical Modeling of Three-Phase Flow
Authors: Ruben Juanes , Patzek Tad W. 
Published: December 2007

Abstract
In this paper we present a stabilized finite element method for the numerical solution of three-phase flow in porous media. The key idea of the proposed methodology is a multiscale decomposition into resolved (or grid) scales and unresolved (or subgrid) scales. In the context of subsurface flow and transport, the term multiscale usually refers to subgrid heterogeneity and upscaling. In contrast, this paper deals with unresolved physics: multiple scales are present in the solution even if the medium is homogeneous.
We use the fractional flow approach for the mathematical description of the three-phase flow equations, which leads to a global pressure equation of elliptic type, and a system of conservation laws (the saturation equations). Numerical di culties in solving these equations include: high nonlinearity, advection-dominated flow, degenerate diffusion, sharpening near-shock solutions, boundary lay- ers, and convergence to nonphysical solutions.
The multiscale formalism allows one to split the original mathematical problem into a grid-scale problem and a subscale problem. The effect of the subgrid scales is then incorporated - in integral form - into the grid-scale equations. Accounting for the subgrid effects results in a finite element method that has enhanced stability properties and is not overly diffusive. Specific original contributions of the methodology proposed herein are: (1) the formulation is applied for the first time to the three-phase flow equations; (2) the fully nonlinear equations in conservation form are used, which is essential for correctly predicting the location of shocks; and (3) a novel expression of a discontinuity-capturing technique is proposed and compared with existing formulations.
The methodology is applied to the simulation of two problems of great practical interest: oil filtration in the vadose zone, and water-gas injection in a hydrocarbon reservoir. These numerical simulations clearly show the potential and applicability of the formulation for solving the highly nonlinear, nearly hyperbolic system of three-phase porous media flow on very coarse grids.