<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV style="text-align: auto;"><FONT class="Apple-style-span" color="#000000">Please join us Thursday, April 26 at 4:00 pm for a seminar by John Grace of Earth Science Associates on marine methane hydrates. These hydrates represent a potential future energy resource and modulator of climate change. </FONT><FONT class="Apple-style-span" color="#000000"></FONT></DIV><DIV style="text-align: center;"><B><BR class="khtml-block-placeholder"></B></DIV><DIV style="text-align: center;"><B>John D. Grace</B><O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;"><B>Earth Science Associates</B><O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;">April 26, 2007<O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;">4:00 - 5:30 pm<O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;">E40-496<O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;"> <O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;"><B>Methodology for High-Resolution Assessment of</B><O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;"><B>Marine Methane Hydrates in the Gulf of Mexico</B><O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;"> <O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;">
John D. Grace,[1] William Shedd,[2] John H Schuenemeyer,[3]<O:P style=""></O:P></DIV><DIV class="MsoNormal" style="text-align: center;">Jesse L. Hunt, Jr.[2] and Gordon M. Kaufman[4]<O:P style=""></O:P></DIV><DIV class="MsoNormal"> <O:P></O:P></DIV><DIV class="MsoNormal">The concentration of marine methane hydrates (hydrates) in deep water along continental margins is a function of three general factors: thickness of the net hydrate stability zone (HSZ), the fraction of bulk HSZ volume that can be occupied by hydrates and the volume of methane charge to the HSZ. Theory and available empirical evidence provide ranges of values of variables that determine each of these three factors and, in turn, a range of possible volumes of hydrates in place.
</DIV><DIV class="MsoNormal"><BR class="khtml-block-placeholder"></DIV><DIV class="MsoNormal">
In order to generate a probabilistic projection of the volume of in-place hydrates in the Gulf of Mexico our team built a probabilistic model for each general factor and combined them into an omnibus probabilistic model of GOM hydrates. With suitable modifications the model is applicable to the US Atlantic, Pacific and Alaskan margins.<O:P></O:P></DIV><DIV class="MsoNormal"><BR class="khtml-block-placeholder"></DIV><DIV class="MsoNormal">Net HSZ thickness responds to water depth, geothermal gradient, water bottom temperature, proximity to salt and the thickness of the sulfate reduction zone below the water bottom, which is a function of methane flux through the section. Saturation depends on porosity and the ability of hydrates to occupy pore space, both differentiated by lithology.<O:P></O:P></DIV><DIV class="MsoNormal"><BR class="khtml-block-placeholder"></DIV><DIV class="MsoNormal">Although both biogenic and thermogenic methane contribute to known hydrate exposures on the seafloor of the Gulf of Mexico, biogenic methane is assumed to dominate in the shallow subsurface in this phase of our work. Due to the complexity of using both thermogenic and biogenic charge and due to time constraints, only biogenic charge is considered at this time. Biogenic methane production is modeled as a function of a modified version of Arrhenius’ Law, scaled to data on the productivity of methanogenic archea in the subsurface and the influence of water flux (using permeability as a proxy) on productivity as it declines with burial. Charge is modeled by dividing migration of generated volumes between vertical and dip-driven, using the horizontal second derivative of the shape of the basement surface to approximate the latter.
</DIV><DIV class="MsoNormal"><BR class="khtml-block-placeholder"></DIV><DIV class="MsoNormal">Approximately 200,000 2.32 km2 cells cover the area of the Gulf of Mexico where water depths are great enough to support hydrate formation. The omnibus model produces a probability distribution of the total quantity of hydrates in place for each cell. Cell by cell probability distributions can be aggregated to larger regions in the Gulf or Gulf-wide. An important feature of our approach is that it supports high resolution mapping of intermediate and final results.
A probabilistic projection of the fraction of in place hydrates that are technically recoverable is supported by our model’s ability to provide high-resolution, probabilistic projections of in-place volumes. These projections are, in this first phase of the study, limited to hydrates in sand and recovery only through pressure depletion. <O:P></O:P></DIV><DIV class="MsoNormal"> <O:P></O:P></DIV><DIV class="MsoNormal">[1] Earth Science Associates, Long Beach, CA.<O:P></O:P></DIV><DIV class="MsoNormal">[2] US Minerals Management Service, New Orleans, LA<O:P></O:P></DIV><DIV class="MsoNormal">[3] Southwest Statistical Consulting, Cortez, CO<O:P></O:P></DIV><DIV class="MsoNormal">[4] Massachusetts Institute of Technology, Cambridge, MA<O:P></O:P></DIV><DIV class="MsoNormal"> <O:P></O:P></DIV><DIV class="MsoNormal"><BR class="khtml-block-placeholder"></DIV><DIV class="MsoNormal">John D. Grace, Ph.D., a geologist and economist, has specialized over a 20-year petroleum industry career on geologic assessment of hydrocarbon resources, prospect evaluation and modeling regional oil and gas supply. He joined the MMS-academic-industry team assessing marine methane hydrates in 2005.<O:P></O:P></DIV><DIV class="MsoNormal"> <O:P></O:P></DIV><DIV class="MsoNormal"><BR class="khtml-block-placeholder"></DIV><DIV class="MsoNormal"><I>Light refreshment will be provided. </I><O:P style=""></O:P></DIV><DIV class="MsoNormal"><I>Sponsored by the MIT Laboratory for Energy and the Environment</I><O:P style=""></O:P></DIV><DIV class="MsoNormal"><I> </I><O:P></O:P></DIV><DIV class="MsoNormal"> <O:P></O:P></DIV><DIV class="MsoNormal"> <O:P></O:P></DIV><DIV class="MsoNormal"> <O:P></O:P></DIV><DIV class="MsoNormal">Karen L. Gibson<O:P></O:P></DIV><DIV class="MsoNormal">MIT Laboratory For Energy and the Environment<O:P></O:P></DIV><DIV class="MsoNormal">77 Massachusetts Avenue, E40-469<O:P></O:P></DIV><DIV class="MsoNormal">Cambridge, MA 02139 USA<O:P></O:P></DIV><DIV class="MsoNormal">(1 Amherst St., E40-469, Cambridge MA 02142 - for DHL and FedEx)<O:P></O:P></DIV><DIV class="MsoNormal">Tel: +1 617 258-6368; Fax: +1 617 258-6590<O:P></O:P></DIV><DIV class="MsoNormal"> </DIV></BODY></HTML>