Browsing by Subject "Marcellus Shale"

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    A Technical and Economic Study of Completion Techniques In Five Emerging U.S. Gas Shale Plays
    (2010-07-14) Agrawal, Archna
    methane and other higher order hydrocarbons, through C4, with interest in further developing reactions important to methane- and ethane-related chemistry. With the increased demand for energy and the declining conventional hydrocarbons worldwide, energy companies, both majors and independents, are turning to unconventional resources to produce the hydrocarbons required to meet market demand. From coalbed methane to low permeability (tight) gas reservoirs and gas shales, energy companies are making substantial progress in developing the technologies required to bring these unconventional reserves to the market. A common misconception is that there are not enough domestic oil and gas reserves to fuel our economy. The United States imports most of the oil used for transportation fuel and several TCF of natural gas annually. However, there is a very large resource of natural gas in unconventional reservoirs, with over 2,200 TCF of gas in place in just the gas shale formations that have been identified in the energy arena (Navigant Study 2008). There are still major gas shale plays and basins that have not been explored and are waiting to be evaluated and developed. The natural gas in shales and other unconventional reservoirs can be used to generate electricity, or it can be turned into liquids and used by the transportation industry. It is also misconstrued that gas shales are relatively new in our industry and something of the future. The first commercially viable gas shale well was drilled in the early 1920s in Pennsylvania, before the famous oil well drilled by Colonel Drake. The objectives of this study are to (1) complete literature review to establish which geologic parameters affect completion techniques in five emerging gas shales: the Antrium, the Barnett, the Haynesville, the Marcellus, and the Woodford; (2) identify the different completion methods; (3) create an economic model for the completion techniques discussed; (4) develop a sensitivity analysis on various economic parameters to determine optimal completion strategy; and (5) create completion flowcharts. Based on the literature review I have done for several gas shale basins, I have identified seven pertinent geologic parameters that influence completion practices. These are depositional environment, total organic content (TOC), average gas content, shale mineralogy, shale thickness, and reservoir pressure. Next, I identified different completion and simulation trends in the industry for the different shale plays. The results from this study show that although there are some stark differences between depths (i.e. the Antrim Shale and the Haynesville Shale), shale plays are very similar in all other geologic properties. Interestingly, even with a large range for the different geological parameters, the completion methods did not drastically differ indicating that even if the properties do not fall within the range presented in this paper does not automatically rule them out for further evaluation in other plays. In addition to the evaluation of geologic properties, this study looked at drilling cost and the production profile for each play. Due to the volatility of the energy industry, economic sensitivity was completed on the price, capital, and operating cost to see what affect it would have on the play. From the analysis done, it is concluded that horizontal drilling in almost any economic environment is economic except for one scenario for the Woodford Shale. Therefore, gas shales plays should still be invested in even in lower price environments and companies should try to take advantage of the lower cost environments that occur during these times. With continual development of new drilling and completion techniques, these plays will become more competitive and can light the path for exploration of new shale plays worldwide.
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    The drill down
    (2012-12) Friel, Katherine Dailey; Dahlby, Tracy
    The town of Millerton, Pa., has always been a small, rural farming community. Settled atop of the famed Marcellus Shale in the foothills of the Appalachians, there have always been rumors of natural gas in the hills around town. In 2008, natural gas companies arrived and began drilling. For a select few lucky enough to have property around the gas wells, their arrival means big money. But not all residents will get so lucky. For many folks in Millerton, the arrival of the gas companies means more traffic, more pollution, more crime and more inconvenience without a monthly royalty check to buffer the pain. The sheer amount of natural gas scientists predict is in the Marcellus Shale will forever change how the U.S. and the rest of the world use energy. Politicians tout it as liberation from foreign oil. Scientists see it as an alternative to “dirty” coal. For this small town, natural gas means change. The money the natural gas companies are pumping into this local economy will change the lives of the townsfolk- and the town itself- forever.
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    Seismic sensitivity to variations of rock properties in the productive zone of the Marcellus Shale, WV
    (2013-12) Morshed, Sharif Munjur; Tatham, R. H. (Robert H.), 1943-
    The Marcellus Shale is an important resource play prevalent in several states in the eastern United States. The productive zone of the Marcellus Shale has variations in rock properties such as clay content, kerogen content and pore aspect ratio, and these variations may strongly effect elastic anisotropy. The objective of this study is to characterize surface seismic sensitivity for variations in anisotropic parameters relating to kerogen content and aspect ratio of kerogen saturated pores. The recognized sensitivity may aid to characterize these reservoir from surface seismic observations for exploration and production of hydrocarbon. In this study, I performed VTI anisotropic modeling based on geophysical wireline log data from Harrison County, WV. The wireline log data includes spectral gamma, density, resistivity, neutron porosity, monopole and dipole sonic logs. Borehole log data were analyzed to characterize the Marcellus Shale interval, and quantify petrophysical properties such as clay content, kerogen content and porosity. A rock physics model was employed to build link between petrophysical properties and elastic constants. The rock physics model utilized differential effective medium (DEM) theory, bounds and mixing laws and fluid substitution equations in a model scheme to compute elastic constants for known variations in matrix composition, kerogen content and pore shape distribution. The seismic simulations were conducted applying a vertical impulse source and three component receivers. The anisotropic effect to angular amplitude variations for PP, PS and SS reflections were found to be dominantly controlled by the Thomsen Ɛ parameter, characterizing seismic velocity variations with propagation direction. These anisotropic effect to PP data can be seen at large offset (>15o incidence angle). The most sensitive portion of PS reflections was observed at mid offset (15o-30o). I also analyzed seismic sensitivity for variations in kerogen content and aspect ratio of structural kerogen. Elastic constants were computed for 5%, 10%, 20% and 30% kerogen content from rock physics model and provided to the seismic model. For both kerogen content and aspect ratio model, PP amplitudes varies significantly at zero to near offset while PS amplitude varied at mid offsets (12 to 30 degree angle of incidences).