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Raymond J.,Dow Microbial Control | Parnell E.,Baker Hughes Inc. | Fichter J.,Encana Oil and Gas United States Inc.
NACE - International Corrosion Conference Series | Year: 2014

Conventional antimicrobial treatments for hydraulic fracturing fluids, flow-back water, and produced water include chemistries such as glutaraldehyde, tetrakis-(hydroxymethyl)-phosphonium sulfate (THPS), and quaternary ammonium compounds (quats). While the rapid microbial kill efficacy of these biocides in top-side water sources are effectively demonstrated by traditional microbial enumeration methodologies, such as "bug-bottles", the long-term potential for protection of the oil and gas reservoirs from microbial-induced damage has received limited attention. A stringent two-stage laboratory method has been developed to assess rapid and long-term biocide efficacy, ranging from the mild, top-side conditions of water sources in drilling and fracturing operations to the harsh conditions of downhole environments. Specifically, water sources used in stimulation and fracturing operations were treated with various concentrations of biocide combinations and incubated at elevated temperatures during the course of the laboratory experimental procedure. At predetermined time points during the two-month test, the heat-aged samples were challenged with oil and gas field microbial contaminants (acidproducing and sulfate-reducing bacteria) to evaluate extended biocide performance in water chemistries and temperatures that mimicked downhole environments. This paper discusses a summary of effective biocide treatments for the holistic protection of hydraulic fracturing operations from microbial contamination. © 2014 by NACE International.


Williams-Stroud S.C.,MicroSeismic Inc. | Barker W.B.,MicroSeismic Inc. | Smith K.L.,Encana Oil and Gas United States Inc.
73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 | Year: 2011

Microseismic activity was monitored during stimulation of a horizontal well in a tight gas shale using a wide-aperture array of geophones deployed on the surface above the well location. The lateral was drilled perpendicular to the presumed maximum horizontal stress direction, but long, linear, well-constrained microseismic event trends developed at an angle to the wellbore. Source mechanisms of the events show the failure planes of the events were parallel to the microseismicity trends. However, in-situ stress analysis from a crossed-dipole shear log acquired in the well showed the event trends are not parallel to the maximum horizontal stress direction. This result has important implications for stress interpreted from source mechanism analysis and for the impact of natural fractures on the stimulation treatment. Prior knowledge of existing fractures in the reservoir may be critically important for deciding the deviation of horizontal wellbores in order to optimize the stimulation treatment and placement of subsequent wells for field development.


Kulmann J.,Encana Oil and Gas United States Inc. | Herbert C.K.,Encana Oil and Gas United States Inc.
GPA Annual Convention Proceedings | Year: 2011

As the oil and gas industry works more and more with electrical components and with equipment that requires electricity, attention has become more focused on how to train personnel and how to keep workers safe from electrical hazards. A discussion covers some of the hazards of electricity specific to the oil and gas industry; some electrical safety best practices; awareness of arc flash; ways to prevent or mitigate the risk associated with arc flash; and basic requirements of an electrical safety program to be in compliance with industry accepted practices. This is an abstract of a paper presented at the 90th Annual Convention of the GPA (San Antonio, TX 4/3-6/2011).


Mitchell R.F.,Halliburton Co. | Sweatman R.,Encana Oil and Gas United States Inc. | Young G.,Encana Oil and Gas United States Inc.
SPE/IADC Drilling Conference, Proceedings | Year: 2013

This paper describes thermal modeling and its combination with drilling fluid analysis to reveal concealed changes in well conditions during various drilling and completion operations. These hidden conditions represent significant changes in the well's drilling and completion fluid temperature, pressure, and density (FTPD) that may help explain wellbore stability and integrity issues. For example, the model results may allow operators to look for FTPD-related wellbore stability issues where the hole is not circulated and is static for many hours. Deeper wells and those with greater differences between induced and natural temperature and pressure conditions may have dangerous conversions of pressure over-balances into under-balances that can cause pore fluid influx, cross-flow, collapse, and other severe wellbore failures. Long, deep holes that are being circulated may also be modeled to look for FTPD-related issues not revealed by other means. Conditions such as over-balanced pressure and stable rock conditions may actually change to under-balanced pressure and unstable rock conditions with consequences including kicks, solids beds from formation breakouts, flow after cementing, stuck pipe by hole collapse, salt creep acceleration, etc. A case history is discussed where the prototype model correctly predicted that no formation gas influx would occur during a long static period. A nearby well with similar open-hole conditions experienced a blowout during the same static time period. A comparison of the well's annular pressure measurements to the model's predictions indicated that the pressure changes were thermally induced and were not from a formation pore-pressure source. When the annular pressures subsided as predicted, no gas was found in the annulus. Studies will continue to test the FTPD model in different types of wells, well conditions, and applications for drilling and completion operations, and the prototype model may be modified accordingly. Copyright 2013, SPE/IADC Drilling Conference and Exhibition.


Gale B.R.,Encana Oil and Gas United States Inc. | Trostel M.V.,Encana Oil and Gas United States Inc. | Armitage D.L.,Cartasite | Mason M.A.,Cartasite | Bautista L.S.,Cartasite
Proceedings - SPE Annual Technical Conference and Exhibition | Year: 2011

Over 40% of all injuries and fatalities in the oil and gas industry are attributed to vehicular operations. Additionally, nearly one third of all fatalities were due to highway motor vehicle crashes as reported in a study of deaths in the industry between 2003-2008 (Retzer, et. al, NIOSH, 2011). For years the industry has tried a myriad of strategies to influence behavior, yet the risk of motor vehicle incidents (MVI's) remains a challenge for the industry and remains at the top of the list of hazards. The proliferation of inexpensive sensors and wireless networks presented an opportunity to measure subtle patterns of human behavior that might be leading indicators of a driver's crash risk. Several years ago, Encana Oil & Gas (USA) Inc. (Encana) and a Denver based technology firm, Cartasite, teamed up to study driver behavior. The goals of this research were twofold: ⊙ profile the patterns of individuals against a large population of drivers, and ⊙ attempt to influence those patterns to reduce risk, fuel consumption, and emissions. The yearlong study program produced encouraging results and after analyzing the data, the decision was made to move forward with commercial product development. Encana has now deployed this technology on its entire fleet for over a year. A new Driving Safety Program has been put in place at Encana to effectively leverage the insights and data being collected. The impact of Encana's Driving Safety Program, presented herein, are encouraging and suggest that corporations may well be able to significantly reduce motor vehicle incidents and increase safety for field workers. Copyright 2011, Society of Petroleum Engineers.

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