bluuebunny/crossref_metadata_2025_split huggingface dataset:
Getting Smarter and Hotter With ESPs for SAGD
Authors: Noonan S. G. , Dowling M. , D'Ambrosio L. , Klaczek W. 
Published: February 2011

Abstract
This paper summarizes the results from a high-temperature test program completed in late 2009 and discusses a new electric submersible pumping (ESP) configuration that was validated by ConocoPhillips for operations at 250°C and planned for 2010 field trials. This new prototype ESP system was jointly tested by ConocoPhillips and Schlumberger for 42 days in the C-FER Technologies high-temperature flow loop at fluid temperatures ranging from 150°C to 260°C, and at 250°C and above for approximately 40% of the total time.
While the primary objective of this test program was to validate this ESP system for use in 250°C fluid temperatures, the additional instrumentation at the test facility also offered an opportunity to investigate the temperature dynamics of the fluid flowing past the motor, and the pressure and temperature behavior of the motor. The test data was also compared to data from a similar test completed in 2008 and the evaluation provided some interesting observations, which will be discussed.
The information in this paper will be of value to any operator that has ESPs installed in high-temperature applications. In addition, the lessons learned from this test program may also be used to increase ESP reliability in conventional applications.
Using Burst Collars in a Liner String for Multi-zone Completions in Horizontal Wellbores: Case Study
Authors: Schoenfeld Jason , Kostenuk Natasha , Jorgensen Max , Sherman Scott 
Published: February 2011

Abstract
This paper introduces a new multi-zone completion technology (MZCT) to stimulate multiple stages in a horizontal wellbore that is either cased using external packers or cemented into place. In both scenarios, a liner assembly containing specialized collars with predrilled ports that are covered by burst disks is run into the horizontal section of a wellbore. There are no restrictions on the number of collars that can be run, nor the spacing between them. After the assembly is set, coiled tubing is used to complete each interval using a cup/cup assembly that straddles each specialized collar, and then pressures up to open the burst ports. The fracture is then initiated through the coil string into the reservoir, with the coiled tubing moving along the horizontal wellbore from the toe to the heel, the process being repeating against each specialized collar.
Advantages of this new system include no limits to the number of stages that can be completed, full bore diameter available following the stimulations without the cost of milling out mechanical ports, and the ability to do re-completions on the same intervals at a later date. The liner with the burst collars can be used with packers or cemented in, additional collars can be run and stimulated at a later date, and the completion is more cost effective than current alternatives.
This paper discusses the application of the cemented burst collars on the Viking formation in the Redwater field of Alberta and Plato field of SW Saskatchewan. Comparisons are made between the burst collar system and previous completion systems used in the Viking. Recognized benefits include reduced downtime during operations after a screen-out and tighter spacing between fracs in a cemented liner application as opposed to perforating.
Practical use of well test deconvolution
Authors: Gringarten A. C. 
Published: February 2011

Abstract
Deconvolution transforms variable rate pressure data into a constant rate initial drawdown with a duration equal to the total duration of the test. It yields directly the corresponding pressure derivative, normalized to a unit rate. It is not a new interpretation method, but a new tool to process pressure and rate data in order to obtain more pressure data to interpret with conventional techniques.
Although deconvolution has received much attention since 2001 following the publication of a stable algorithm by von Schroeter, Hollaender, and Gringarten, its use by practicing engineers is still limited. One reason is limited access to the algorithm, which had only recently become available in commercial well test analysis software products. The other is concerns on how deconvolution should be used and how reliable it is. As a result, few examples of practical applications of well test deconvolution are available in the literature.
This paper illustrates various uses of deconvolution in tests of short and long durations. Examples include DST's with erroneous rates, which deconvolution is able to correct; and data from permanent downhole pressure gauges in vertical and horizontal wells, where deconvolution shows compartmentalization and recharge from other layers, which could not be seen in the original data.
Recommendations on how to perform deconvolution and how to verify deconvolution results are also provided. It is hoped that this paper will encourage well test interpreters to use deconvolution confidently as part of the well test analysis process.
Conditioning Multilayered Geologic Models to Well-Test and Production-Logging Data Using the Ensemble Kalman Filter
Authors: Coutinho Emilio J. , Emerick Alexandre A. , Li Gaoming , Reynolds A. C. 
Published: February 2011

Abstract
Reservoir models utilize highly heterogenous permeability and porosity fields embedded in a structural model derived from geophysical and geological data. It is not uncommon for permeabilities in the initial model derived from static data to differ significantly from values obtained from the interpretation of well-test data. This paper presents the application of the ensemble Kalman Filter (EnKF) to assimilate pressure transient and production-logging data to update permeabilities, estimate layer skin factors and "effective" well skin factor in multilayered reservoir models. The methodology is applied to two synthetic cases and a field case. For the field case application, we consider two approaches. In the first approach we simply use multipliers to adjust the heterogeneous permeability field in each layer. In the second approach, we adjust the prior mean of each layer log-permeability field together with individual gridblock log-permeabilities.
An Innovative Approach to Optimizing Design of HP/HT Well Tubular Strings
Authors: Deng Guijun , Shyu Goang-Ding 
Published: February 2011

Abstract
In traditional well completion design, the size and geometric configuration of various structural tubular components are determined by a set of stress limits based on the material properties and type of loading under the worst conditions expected during the projected service life. Uncertainties associated with design variables are presumably compensated by introducing safety factors derived primarily from past experience. It is intuitively obvious that a lower safety factor leads to a design with higher risk. However, those safety factors give no quantitative indication of risk assessment of an intended design, and no insight into the degree of risk. Moreover, this approach often leads to over-conservative design and therefore excessive cost, or over-risk design, which can cause failure in tubular components.
This paper introduces an innovative approach to fill this gap. This approach integrates design of experiments (DOE) and stochastic study into the design process. It explicitly considers the variability and uncertainty of each design variable in probabilistic terms, and allows the assessment of probability of failure of the design; thus it is able to help achieve better designs and higher-reliability completion tools. Design of experiments provides an efficient methodology to study the effects of design changes and identify the most influential design variables, and, therefore, provides clear design performance improvement direction for complicated designs. Stochastic study addresses sensitivity of stress or strain limits, which are tied to the life cycle of the tools, under the influence of variability of design parameters, and provides quantitative estimation of probability of success of the optimized design. A deepwater high-pressure/high temperature (HP/HT) tubular string design example will illustrate this new approach. The analysis results indicate this approach leads to a more robust design.
Real-Time Monitoring of Sand Control Completions
Authors: Earles Denise M. , Stoesz Carl W. , Amaral Anderson S. , Pearce Jeremy G. , DeJongh Hans A. , Rambow Frederick H. 
Published: February 2011

Abstract
Subsurface geomechanical stresses can cause formation faults, slippage, and compaction. These movements result in well failures, impacting production and resulting in significant expense and lost revenue. Traditional means for detecting such failures are limited and usually require interrupting production to re-enter the well, resulting in late detection of the problem and limited counteractive options.
A fiber optic support device has been developed to permanently monitor strain and temperature on sand screen products for gravel-pack and frac-pack applications. This technology, especially when paired with an optical wet connect, provides for long-term reservoir monitoring at the sand face, resulting in early detection of subsurface movements at a high resolution. With this information, operators can plan early mitigative actions, and monitor the results of these actions in real time.
This fiber support device provides a means of holding a helically wrapped optic fiber rigidly in place at the sand face, with no negative impact on the sand control functionality of the sand screens. New techniques were developed to manufacture this technology, as well as a new method to install the fiber. Dry connects have also been developed to allow connections between individual sand screens and enable longer monitored intervals.
The paper will describe this new technology, review test results to date, and discuss potential applications.
3D Visualization and Classification of Pore Structure and Pore Filling in Gas Shales
Authors: Sisk Carl , Diaz Elizabeth , Walls Joel , Grader Avrami , Suhrer Michael 
Published: February 2011

Abstract
Shale gas is a growing resource worldwide as many basins are being explored and produced. However, little is still known and understood about two key parameters in gas shales: the gas-filled porosity and permeability. Digital rock physics technique, presented in this paper, contains three basic steps: (a) 3D CT imaging at 200 nanometer resolution, and/or FIB-SEM (focused ion beam combined with SEM) imaging at 3-15 nanometer resolution (b) segmentation of the digital volume to quantitatively identify the components, including the mineral phases, organic-filled pores, and free-gas inclusions; and (c) computations of TOC (Total Organic Content), porosity, pore connectivity, and permeability in three axis.
A number of gas shale samples have been used, to specifically analyze the pore systems. The characteristics including dual porosity, organics distribution, gas-filled porosity distribution, and how these properties relate to the maturity of the organic material. Pore geometries (pores filled either with organics or free gas) of these samples fall into the following categories: (a) relatively large (up to 4 micron) with poorly disconnected pores; (b) pores connected by very thin (down to 15 nanometers) conduits; (c) dual porosity system where the large pores are interconnected by large conduits and very thin conduits are interconnected and also connected to the large pores. Within each of these three categories, the pore space may be (a) completely filled with organics or (b) partially or completely filled with gas.
The latter is of most interest as it is a gas source. In such systems we observe various geometries of pore space, including (a) disconnected pores floating in the organics and (b) connected pores within the organics. TOC, open pore volumes, as well as pore-space connectivity are not just qualitatively estimated from the images but quantitatively computed for a given sample. Our ongoing effort is to relate the quantitative patterns thus computed to the maturity of shale.
Carbon Dioxide Storage Capacity of Organic-rich Shales
Authors: Kang S. M. , Fathi E. , Ambrose R. J. , Akkutlu I. Y. , Sigal R. F. 
Published: February 2011

Abstract
This paper presents an experimental study on the ability of Barnett shale core samples to store carbon dioxide. An apparatus has been built for psrecise measurements of gas pressure and volumes at constant temperature. A new analytical methodology is developed allowing interpretation of the pressure-volume data in terms of measurements in total porosity and Langmuir parameters of core plugs. The method considers pore volume compressibility and sorption effects and allows small gas leakage adjustments at high pressures. Total gas storage capacity for pure carbon dioxide is measured at supercritical conditions as a function of pore pressure under constant reservoir confining pressure. It is shown that, although widely-known as an impermeable sedimentary rock with low porosity, organic shale has the ability to store significant amounts of gas permanently due to trapping of the gas in adsorbed state within its finely-dispersed organic matter, i.e., kerogen. The latter is a nanoporous material with micropores (&lt; 2 nm) and mesopores (2-50 nm). Storage in organic shale has the added advantages because the organic matter acts as molecular sieve allowing carbon dioxide —with linear molecular geometry— to reside in small pores that the other naturally-occurring gases cannot access. In addition, the molecular interaction energy between the organics and carbon dioxide molecules is different which leads to its enhanced adsorption. Hence, affinity of shale to carbon dioxide is due to partly steric and thermodynamic effects similar to those of coals that are being considered for enhanced coalbed methane recovery.
Mass transport paths and the mechanisms of gas uptake are unlike coals, however. Once at the fracture-matrix interface, the injected gas faces a geomechanically strong porous medium with dual (organic/inorganic) pore system, therefore, has choices of path for its flow and transport into the matrix: the gas molecules (i) dissolve into the organic material and diffuse through a nanopore-network, and (ii) enter the inorganic material and flow through a network of irregularly shaped voids. Although the gas could reach the organic pores deep in the shale formation following both paths, the application of the continua approximation to the percolation threshold is not known. Here, using gas permeation experiments and history-matching pressure pulse decay, we show that a large portion of the injected gas reaches the organic pores through the inorganic matrix. This is consistent with SEM images that do not show connectivity of the organic material on scales larger than tens of microns. It indicates an in-series coupling of the dual continua in shale. The inorganic matrix permeability is therefore predicted less, typically in the order of 10 nD. More importantly, transport in the organic pores is not due to flow but mainly pore and surface diffusion mechanisms.
Casing Drilling Application with Rotary Steerable and Triple Combo in New Deviated Wells in Cira Infantas Field
Authors: Lopez Edwin , Bonilla Pablo , Castilla Alfredo , Rincón Javier 
Published: February 2011

Abstract
La Cira Infantas (LCI) is the oldest Colombian field in production since the beginning of the twentieth century. Hundreds of wells are scattered throughout the field which is divided in two principal areas, La Cira and Infantas. This field is crossed by faults and is characterized by depleted and shallow gas bearing formations, challenging drilling activity with both loss circulation and well control issues.
Casing while drilling (CWD) has moved from being a new technology to one that is now recognized as a practical method of solving particular drilling problems, optimizing conventional drilling processes and consequently reducing drilling costs. This paper describes the process from the engineering and operational point of view of deploying CWD technology coupled with rotary steerable (RSS) and logging while drilling (LWD) tools, transmitting in real-time with electromagnetic (EM) telemetry in this mature field to improve drilling performance while taking advantage of the automated drilling rig already equipped to deal with casing and currently under contract in this field drilling wells conventionally.
Five injector wells were drilled. The wells ranged in depth from 3,400 to 4,600 ft MD. The project was completed successfully with all wells reaching the geological targets, setting the production casing at the desired depths and acquiring the data required by the Reservoir Team.
Lessons learned were applied from well to well which allowed the reduction of execution time from 7.06 drilling days on the first well to 3.54 drilling days on the last one, reducing the total well cost 28.1% from the first well to the last.
Diffusion in Naturally Fractured Reservoirs - A Review
Authors: Chordia Mudit , Japan J. Trivedi 
Published: February 2011

Abstract
The impetus for this work stemmed from the growing demand in the industry for Carbon Dioxide sequestration during incremental oil recovery and gas or solvent injection for heavy oil recovery from naturally fractured reservoirs. A thorough research and assimilation of available field data led us to believe that a better understanding of the diffusion coefficients and their impact on the overall recovery will go a long way in providing viable techniques in the Improved Oil Recovery sector. This knowledge will further enhance the understanding of the mass transfer process and mechanisms at a molecular scale in the reservoirs.
Remarkable amount of experimental and computational work has been carried out to study the effect of diffusion and dispersion mechanisms in naturally fractured reservoirs. However, what's missing is an extensive and critical review of the efforts in this direction. The synchronization of similar efforts and recognition of all the independent studies in a common direction would not only highlight the deficiencies and limitations of present scenario in the field, it will also give meaningful insight into further developments.
We have investigated methods employed by various authors to arrive at concurrent values for diffusion and dispersion coefficients. The main focus during our work was to, i) evaluate the role of diffusion and the factors that critically affect diffusion and oil recovery, ii) investigate current methods for calculation of the coefficients and iii) various methods/models to incorporate diffusion. Our work includes significant technological contributions and findings of experimental and simulation studies in the field to this day.
It is our understanding that our research will bridge the gap between the fundamental understanding and application of related processes and serve as a useful reference for engineers and researchers for present applications as well as the future.
Improved Production and Profitability Achieved with Superior Completions in Horizontal Wells: A Bakken/Three Forks Case History
Authors: Rankin R. , Thibodeau M. , Vincent M. C. , Palisch T. T. 
Published: February 2011

Abstract
The Bakken/Three Forks oil play is extremely active, with more than 2,500 horizontal wells drilled in Montana, North Dakota, and Saskatchewan during the past nine years. Typical well costs range between $4 -$8 million per well, suggesting the industry has invested more than $15 billion in this resource, in addition to lease, infrastructure, and operation expenses. Despite this enormous investment, the industry has struggled to identify best practices and many operators currently pursue significantly different strategies throughout the play.
This paper will summarize the development philosophy and key learnings of one operator in completing this low permeability reservoir with hydraulically fractured horizontal wells. Significant production gains have been achieved through advancements in completion methods, improving the overall economics of the Bakken/Three Forks oil play.
This paper describes the evolution of completion strategy, including:
– Lateral length and number of stages – Method of isolation – Completion and fracturing techniques – Proppant type and concentration
Through careful investigation and continual improvement, the authors have been able to significantly increase well production compared to their previous wells. Wells with improved completions have also experienced notably higher production rates than offset wells completed by operators with differing strategies. It is clear that lateral length and number of stages, coupled with proppant type and concentration, are key variables that have significantly improved well productivity and profitability. Included economic and financial analyses demonstrate that Bakken/Three Forks profitability can be dramatically improved by altering completion designs. Although specific treatment parameters should be adapted as formation characteristics vary across the play, it is believed this discussion of current design strategy will be useful to the SPE audience and accelerate optimization of Bakken/Three Forks completions. Future innovation will occur, and it is hoped that the publication of these learnings will encourage additional experimentation and optimization.
Safety Valve for Ultradeepwater Lower Tertiary Applications
Authors: Sloan Jim , Bane Darren 
Published: February 2011

Abstract
In recent years, offshore oil and gas exploration has continued to push into deeper and deeper waters, such as those in the Lower Tertiary fields of the Gulf of Mexico. As these field discoveries are being completed, the application requirements for safety valve installations are moving toward valves that can be set extremely deep, yet still require a relatively low operating pressure to control the valve. In traditional safety valve applications, operating pressures are sensitive to the wellbore pressure and are typically above those pressures to hold the valve in the open position. As the setting depth of these valves goes deeper, the operating pressures can increase to a significant level such that the design and performance of the umbilical and wellhead is detrimentally affected.
As a result of these constraints that occur in deep, offshore fields, a safety valve solution is desired to provide an ability to minimize opening pressures by balancing tubing pressure in HP/HT conditions, yet allow extreme valve setting depth capability without compromising operational characteristics such as high opening pressures or pressure- balanced pistons using long-term valve gas charge storage.
This paper discusses a new surface-controlled, subsurface safety valve (SCSSV) that employs the low opening pressures of a tubing-pressure-insensitive safety valve, without gas-charged assisted closure or dual control lines for balanced line applications. This system enhances valve reliability by eliminating the need for pressure reversals across the valve's critical actuating piston seals while maintaining tubing pressure insensitivity. This system provides for much deeper valve depth capabilities compared to the methods previously discussed and also allows the safety valve to account for annulus pressure buildup scenarios not possible in current SCSSV applications.
This paper presents design and development considerations for a new SCSSV solution allowing ultradeep setting depths without closed volume gas charged spring techniques utilized in current deep-set SCSSV technology. Test results will demonstrate the features, benefits, and reliability of this new safety valve in reference to previously unattainable valve operating depths in aggressive subsea well designs or annulus pressure buildup scenarios.