bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-Stage Fracturing of Horizontal Wells Using Ninety-Five Quality Foam Provides Improved Shale Gas Production
Authors: Brannon Harold D. , Kendrick Daniel E. , Luckey Eric , Stipetich Abby 
Published: December 2009

AbstractThe increasingly active exploitation of tight gas shale resources has resulted in new and improved processes to more effectively recover the vast reserves. Horizontal well construction, multi-stage interval isolation, and fracturing techniques are among the more prominent. However, for such otherwise leading-edge engineering and operational processes, ‘minimalistic’ fracturing system technologies such as high rate, large fluid volume, low sand concentration slickwater treatments have been the norm.The Big Sandy is a productive field of more than 25,000 wells, located in the eastern USA. Production is dominated by ultra-low permeability Berea tight gas sands and Devonian Ohio shales such as the Huron formation. Post-frac commingled production from area wells typically ranges from 20 to 500 Mcf/D. Due to the low reservoir pressures exhibited by the Lower and Upper Huron, they are considered to be fluid sensitive, and consequently, have historically been stimulated with high-velocity nitrogen or nitrogen foam fracturing treatments. Previous studies indicated the long-term production was better in the stimulations including proppant than in those treated with nitrogen alone. Additional studies concluded that clean-up effectiveness was critical to maximizing net present value. Therefore, it was believed that treatments providing proper proppant placement with a minimized amount of liquid loading would be the best route to improving well performance.Recently, two vertical wells were fractured using a new process incorporating a pre-slurried proppant concentrate foamed to 93-99 quality with nitrogen, and pumped to place ultra-lightweight in partial monolayer concentrations. Cumulative production after the first 30 days was observed to be approximately 200% greater than offsets. Less equipment, tank storage, and water volume are required for the process, providing for a much smaller location footprint, minimal water-hauling expenses, and significantly lower recovered fluid disposal costs.Following the successes of the process in the vertical wells, several horizontal wells having 8 to 9 intervals each were treated using the new process in the Big Sandy. This paper provides case histories of those horizontal well stimulations, along with comparison to offset wells treated with nitrogen fracs and conventional foam fracs.
Prospectivity on the Erris Ridge (Licence 7/97)—High Risk/High Reward Frontier Exploration on the Irish Atlantic Margin
Authors: Howard A. , Beswetherick S. , Miglio G. 
Published: December 2009

Abstract
Frontier Exploration Licence 7/97 is located 115km offshore north-west Ireland and directly overlies the Erris Ridge. The ridge is an enigmatic, narrow, segmented, NE-SW orientated structural high which lies between the Erris Basin to the east and the Irish Rockall Trough to the west and which, to date, remains un-drilled.
Seismic data quality across the Erris Ridge is typically poor and correlation with the sparse offset well database is challenging. Zones of poor seismic imaging are associated with combinations of complex shallow volcaniclastics, possible intrusive features and large-scale Tertiary channels/entry points which overlie older strike-slip zones and segment the ridge along its length. Displaying considerable complexity and structural variation along strike, seismic based interpretations provide models ranging from a shallow basement horst to preservation of significant thicknesses of Paleozoic and Mesozoic sediments.
Recent work by Eni identifies the potential for prospective section to be preserved on the Erris Ridge resulting in two large prospects, Fiachra and Conn, and a number of leads being identified. The Fiachra Prospect is a large fault assisted four-way dip closure situated within a crestal location on the Erris Ridge and forms the focus of an exploration well planned for 2010. An early Triassic sandstone play (Sherwood Sandstone Group equivalent) is prognosed as the primary reservoir target interval, although several secondary targets also exist.
After an intensive evaluation programme the critical geological risk remains modelling the presence of sedimentary section with reservoir potential in areas where the quality of seismic data is very poor. However, it is concluded that Licence 7/97 possesses good potential for deepwater frontier exploration; the Corrib gas field to the south of the licence area and the Dooish gas discovery to the north indicate the potential for a favourable location within an effective petroleum system.
Siting and Permitting of Class II Brine Disposal Wells Associated With Development of the Marcellus Shale
Authors: Arthur J. Daniel , Dutnell Stephen L. , Cornue David 
Published: December 2009

Abstract
Recent estimates place technical recoverable reserves of natural gas from the Marcellus Shale at approximately 500 tcf. Development is anticipated to consist primarily of long-reach horizontal wells drilled from multi-well pads with each well stimulated using multi-stage slickwater hydraulic fracturing. Currently, it appears likely that disposal via Class II brine water disposal wells will be an important option for managing water produced from Marcellus Shale wells over the long-term. This paper is structured toward brine disposal issues in Appalachia and associated Marcellus Shale development issues. Many issues come into play with both the siting and the permitting of Class II disposal wells in the Appalachians. Currently, the limited number of existing disposal wells in the region along with geologic challenges makes developing new disposal wells a complex process. Well siting of injection wells must address a variety of environmental and access considerations, especially where water will be trucked to the well. Permitting must consider issues such as calculation of the ‘zone of endangering influence", which becomes more complicated in tight or fractured receiving zones. Gaining approval for well testing and other well drilling and completion activities can be different from western or mid-continent states, so upfront planning is critical. This paper will include a review of the regulatory environment in the region, permitting timeframes, regulatory and permitting requirements, formations being considered for brine water disposal and the associated challenges.
Continuous Multistage Fracture Stimulation Completion Process in a Cemented Wellbore
Authors: Stegent Neil , Howell Matt 
Published: December 2009

Abstract
Multiple-stage fracturing is a very common practice, especially in reservoirs with microDarcy permeability. The process of perforating, fracturing, and setting plugs has been performed for many years and has both advantages and disadvantages. Coiled tubing (CT) completion methods have increased completion efficiencies but can have limitations as well. Though multistage tools placed in the casing string have become a standard completion practice in horizontal completions, little has been done in vertical, cemented wellbores. As multiple wells drilled on single pads become more common, increased economic completion efficiencies are necessary.
To address the increasing need for completion efficiency, an alternate method of multiple completions was tested in several vertical wellbores. The casing strings were conventionally cemented in place and ball-activated sliding sleeves were placed across target completion intervals. Failures in similar techniques can have catastrophic effects if the initial tool does not open. To address this issue, a new hydraulic-actuated sleeve was developed. It was successfully tested in multiple wellbores and performed as designed. Multiple fractures were completed in a continuous operation with excellent production results.
This completion process can provide an efficient method for multistage fracturing in conventional and unconventional reservoirs in either vertical or horizontal wellbores. It can be used on single-well completions or on multiwellpads.
This process provides an efficient, low-cost alternative to conventional multistage fracturing for vertical and horizontal wells.
Successful Strategies for Dewatering Wells Using ESP's
Authors: Bassett Lonnie 
Published: December 2009

Abstract
Pumping water from a well is a straight forward effort that has been done for centuries. Pumping fluid from relatively shallow wells should be an easy task. Normally a pump is installed in a well, started and then forgotten. This premise does not hold true in CBM wells. In CBM wells, this pumping process can be complicated by many issues unless precautions are taken. This paper is designed to address the basic precautions that can be taken to improve de-watering of CBM wells and will focus on real experiences in producing CBM wells and the steps required to make them economical.
Even though every well is different, this paper will focus on the common areas that are key to getting acceptable performance using an ESP as the primary artificial lift method. As in most pumping situations, success is planned for and not just an accident.Electric Submersible Pumps (ESP’s) best practices for a vertical well: This paper will address the key areas of importance for optimizing operations in a vertical well. The paper will address issues like proper motor cooling, successful operation in turbulent conditions and gas lock avoidance and solids control.This paper will concentrate on these three items and show through real case histories how CBM can be successfully produced through proven dewatering techniques.Electric Submersible Pumps (ESP’s) best practices for a horizontal well: A horizontal well is a place an ESP flexibility can really shine. This paper will identify the key areas that drastically improve the chances of success. The paper will identify the operational differences and the different options in running in a horizontal well compared to a vertical well. It will cover the preplanning required to avoid negative operational issues including gas locking, solids intrusion and optimized drawdown.
This paper will concentrate on these two items and highlight techniques that will increase the effectiveness of utilizing ESP equipment for dewatering.
UV Light Reduces the Amount of Biocide Required to Disinfect Water for Fracturing Fluids
Authors: Gloe Lindsey , Neal Greg 
Published: December 2009

Abstract
Water used to make fracturing fluids usually requires treatment to reduce aerobic acid-producing bacteria and, more importantly, to eliminate anaerobic sulfate-reducing bacteria that can cause a well to go sour. Typically, this treatment is performed with the use of chemical biocides. To reduce the amount of chemical biocides used, a new technology, ultra-violet (UV) light, was tested. The equipment used to generate sufficient UV light to disinfect the large volumes of water needed for fracturing was mounted on a trailer for road mobility (Fig 1). This required modifying the UV light equipment and the way it was installed to withstand oilfield conditions. The effectiveness of UV light in disinfecting water for a fracturing treatment was tested in both a controlled laboratory environment and also on a fracturing location. Serial-dilution tests were performed to examine the effectiveness of UV light in controlling both aerobic- and sulfate-reducing bacteria. The serial-dilution method was chosen because it measures both active bacteria and dormant spores that can become active when placed in ideal conditions.
Bacteria control has recently become an important topic for discussion among the oil and gas industry, although it is still misunderstood by the industry. A bacteria problem can oftentimes be subtle and difficult to detect. Bacteria detection in the field is difficult because many tests take a long period of time or are simply not accurate. New regulations on flowback and produced water have led to investigating ways to reduce the amount of residual chemicals in flowback fluids. Environmental concerns associated with chemical disinfection have led to the move from traditional chemical disinfection to mechanical procedures (Cho 2002). Using UV light to disinfect water on-the-fly for stimulation treatments will greatly reduce the amount of chemical biocides that are necessary. A low concentration of biocide is still recommended to provide a more long-term protection from bacteria as the fluid is pumped through the blender and then downhole. Although the use of some biocide is still recommended, these small concentrations are more likely to be at undetectable levels in flowback waters.
Optimal Use of Vogel's Dimensionless IPR Curve to Predict Current and Future Inflow Performance of Oil Wells
Authors: Chase Robert W. , Shaver Carter A. 
Published: December 2009

Abstract
Vogel’s dimensionless IPR curve is frequently utilized to predict the inflow performance of oil wells. While Vogel’s curve was developed for wells having a flow efficiency of one, i.e. a skin factor of zero, this fact is often ignored even when a well has a flow efficiency not equal to one. It has been widely documented that this usually results in serious over or under-prediction of a well’s inflow performance. This paper points out additional errors that may occur when using Vogel's dimensionless IPR curve to predict the inflow performance of an oil well. It demonstrates how the careful selection of the flowing bottom-hole pressure and resultant single stabilized flow rate will result in more accurate IPR curve prediction. A new, simple approach for predicting future IPR curves is also presented.
Marcellus Shale Post-Frac Flowback Waters – Where is All the Salt Coming From and What are the Implications?
Authors: Blauch M. E. , Myers R. R. , Moore T. R. , Lipinski B. A. , Houston N. A. 
Published: December 2009

Abstract
One of the most prominent unexplained phenomena observed in the Marcellus and some other shale plays is the concentration of dissolved salts in produced waters after hydraulic stimulation. In this paper, we present both geochemical and lithologic laboratory and field data to address the salt question. Is salt being dissolved from the shale, or are deep saline aquifers being breached during hydraulic fracturing? What evidence do we have to support or refute either theory?
To address these questions, over 100 flowback analyses were collected over 18 months from both the southwestern and northeastern regions of the Marcellus Shale play. These data incorporate both cation and anion water analyses in either a full or partial determination of the cation and anion balance. Detailed inorganic geochemical and mineralogical analyses of shale samples were integrated to help determine the presence or absence of physical evidence of minerals that may be the root cause for high salinity. If present in the shale, is halite dissolution desirable from a formation stimulation perspective? If so, is this gain a worthwhile trade when balanced against the costs of returned load water handling and reuse or disposal? This paper provides interpretations at both the regional and local scales to try to explain basinal variations observed in the data. It discusses implications of the phenomenon of high saline frac flowback fluids, along with methods being used to mitigate environmental problems associated with the post-frac flowback water geochemistry.
Reliable Method of Achieving Annular Isolatoin for a Multi-Stage Frachtrue Treatment in an Air-Drilled Hole
Authors: Hamilton Russell , Williams Shannon , Martin James , Stalnaker Chad , Davis Tim 
Published: December 2009

Abstract
With conventional reserves in the United States in a decline, more and more operators are turning to unconventional reservoirs such as shale gas to meet the energy needs of the country. Unconventional reservoirs provide additional economic reserves in the United States through advancements in technologies and new applications for existing technologies. There are a number of shales in the Appalachian Basin that contain trillions of cubic feet of recoverable gas reserves. The Huron Shale, a Devonian aged formation, has been developed since the early 20th century. The Huron Shale is a very low pressure formation and wells are drilled with air to minimize formation damage from drilling fluid. To achieve optimum gas flow, the wells must be stimulated. The most common methods used are hydraulic fracturing with N2 gas only or N2 foam with proppant. There are many studies in the literature with no clear indication of which method is best. The benefits of N2 only are presented in this paper.
Areas of the Huron shale that once showed to be non-productive with vertical wellbores are now being developed through advancements in horizontal drilling and cement-less multi-stage fracture treatments. One of the critical components of a successful multi-stage fracture treatment in a horizontal wellbore is effective annular isolation. Effective annular isolation ensures that fracture placement is known and that the entire length of the lateral is treated. This paper will describe one approach in completing and performing multi-stage fracture stimulations in an air drilled hole using inflatable casing annulus packers and ball activated frac sleeves.
Economic Impact of Reservoir Properties and Horizontal Well Length and Orientation on Production from Shale Formations: Application to New Albany Shale
Authors: Dahaghi A. Kalantari , Mohaghegh S. D. 
Published: December 2009

Abstract
This paper presents a study on the impact of reservoir characteristics such as matrix porosity, matrix permeability, initial reservoir pressure and pay thickness as well as the length and the orientation of horizontal wells on gas production in New Albany Shale.
The study was conducted using a publicly available numerical model, specifically developed to simulate gas production from naturally fractured reservoirs. Reasons for selecting a non-commercial simulator for this study were two folds. First, we wanted to make sure that our results, discussions, and conclusions are accessible and repeatable by all interested operators and individuals that are currently producing or plan to produce from New Albany Shale since the simulator we used is readily available. Secondly, we wanted to demonstrate the utility and ease of use of this publicly available simulation software.
The study focuses on several New Albany Shale wells in Western Kentucky. Production from these wells is analyzed and history matched. During the history matching process, natural fracture length, density and orientations as well as fracture bedding of the New Albany Shale are modeled using information found in the literature and outcrops and by performing sensitivity analysis on key reservoir and fracture parameters.
Sensitivity analyses are performed to identify the impact of reservoir characteristics and natural fracture aperture, density and length on gas production. Economic analyses are performed to identify and rank the impact of the above parameters on the Net Present Value of investing on gas wells producing from New Albany Shale.
Montney Unconventional Gas - Next Generation, An Integrated Approach to Optimizing Wellbore Completions Technology
Authors: Schnell Rodney , Tapper Nicole , Genyk Ryan , Deliu Dalis , Tavakol Habib 
Published: December 2009

Abstract
In this paper we will present the evolution of well construction in the Montney play, technical and economical challenges, and the new synergy developed between drilling and completions.
The financial driver that all operators are facing today is to lower well construction costs. The drilling and completions processes should not be looked at as separate entities but rather as an integrated team. This will allow for the achievement of an optimal solution for overall well construction, a solution that can not be achieved by either discipline in isolation. This paper demonstrates the evolution of a unique completion system that lowers costs in a technically challenging area.
Case histories of two completion methods, swellable packers and cemented sliding sleeve technologies are discussed in detail. The cemented sliding sleeve systems were deployed at a field scale for the first time in North America in the Pouce Coupe area of Alberta, Canada in December 2008.
The Impact of Stimulation Treatment on EUR of Upper Devonian Formations in the Appalachian Basin
Authors: Krcek R. , Aminian K. , Ameri S. 
Published: December 2009

Abstract
This study focuses on how the fracturing treatment design parameters such as the volumes of liquid injected, size and amount of proppant influence the Estimated Ultimate Recovery (EUR), in Upper Devonian formations in the Appalachian Basin. An extensive database containing completion, stimulation, and production data from the Benson formation was utilized in this study. The selection criteria for wells which were ultimately used in the study included wells with single zone completion and long production history with adequate completion data. These criteria eliminated the major uncertainty caused by multiple zone completions or inconsistent production data. The total proppant placed during stimulation treatments was found to be the major variable that influenced EUR. Increasing the total proppant not only increases EUR but also to decreases the number of wells required to effectively drain the reservoir. Subsequent economic analysis provided the basic guidelines to achieve economic recovery from the Upper Devonian formations in the Appalachian Basin.
Fracture-Stimulation in the Marcellus Shale—Lessons Learned in Fluid Selection and Execution
Authors: Houston Nathan , Blauch Matt , Weaver Dalton , Miller David S. , O'Hara Dave 
Published: December 2009

Abstract
This paper provides a look-back review of lessons learned from early exploration to the full-scale development phase of the Marcellus shale in Pennsylvania. Fracture stimulation of over 100 wells has resulted in an in-depth understanding of details needed to achieve optimal frac performance. Much of the necessary learning curve is derived from the empirical testing of theory and what many refer to as "trial and error." The ability to evaluate and capture the best practices and develop them into a standing operating procedure (SOP) is one of the most important aspects in development of a new unconventional play. Lessons learned involving fracturing strategies and technologies to date have greatly narrowed the learning curve enabling more rapid advancement toward full-scale development.