Figures

The following figures are in two formats: PDF and JPG for your convenience.

JPG PDF Details
figure 1 figure01.pdf Flow chart depicting the evolution of gas hydrate understanding from a non-producible unconventional gas resource to a producible energy resource.
figure 2 figure02.pdf Graphs showing the depth-temperature zone in which methane hydrates are stable in (a) a permafrost region and (b) an outer continental margin marine setting (modified from Collett, 1995).
fiigure 3 figure03.pdf Two gas hydrate crystal structures:  (a) Structure I; and (b) Structure II (modified from Sloan, 1998).
figure 4 figure04.pdf Location of known and inferred gas hydrate occurrences (modified from Kvenvolden, 1993).
figure 5 figure05.pdf Physiographic map of the southeastern continental margin of North America.  Location of ODP Leg 164 drill sites are indicated.  Also shown is the area (pink shaded area) where gas hydrate occurrence has been mapped on the basis of bottom simulating reflectors (BSRs).  Contours are in meters.
figure 6 figure06.pdf Seismic profile along which Sites 994, 995, and 997 are located.  Note that Site 994 is not associated with a distinct BSR although a very strong BSR occurs at Sites 995 and 997.
figure 7 figure07.pdf Chloride concentration profiles for interstitial waters collected from cores at Sites 994, 995, and 997.  Downhole electrical resistivity log data from Sites 994, 995, and 997.  Also shown is the chloride concentration and electrical resistivity inferred gas hydrate distribution (modified from Shipboard Scientific Party, 1996).
figure 8 figure08.pdf Physiographic map of the Cascadia continental margin of North America.  Location of ODP Leg 146 drill sites are indicated.  Also shown is the area (pink shaded area) where gas hydrate occurrence has been mapped on the basis of bottom simulating reflectors (modified from Hyndman et al., 1996).
figure 9 figure09.pdf Downhole log data from Site 889.  Data shown include the natural gamma ray log, bulk-density data, neutron porosities, compressional-wave acoustic velocities, and deep-reading electrical resistivities.
figure 10 figure10.pdf Cross section showing the lateral and vertical extent of gas hydrates and underlying free-gas occurrences in the Prudhoe Bay-Kuparuk River area in northern Alaska.  See Figure 11 for location of cross section.  The gas-hydrate-bearing units are identified with the reference letters A through F (modified from Collett, 1993).
figure 11 figure11.pdf Composite map of all six gas-hydrate/free-gas units (Units A-F) from the Prudhoe Bay-Kuparuk River area in northern Alaska.  Also shown is the location of the cross section in Figure 10 (modified from Collett, 1993).
figure 12 figure12.pdf Map of part of the Mackenzie Delta region showing the calculated depth to the base of the methane hydrate stability zone (modified from Judge and Majorowicz, 1992).  Exploration wells with well log inferred gas hydrate occurrences are shown. Contours are in meters.
figure 13 figure13.pdf Well log display for the Mallik 2L-38 well showing gas hydrate occurrences (highlighted with gray shading) and interpreted geology.  Data shown includes the caliper log (CAL), natural gamma ray log (GR), neutron porosity (NEU), bulk-density (DEN), compressional-wave acoustic velocity (VEL), deep-reading electrical resistivity (RES), and total gas from the mud log (GAS).
figure 14 figure14.pdf Enlarged portion of Figure 13 showing downhole log data from the Mallik 2L-38 well.  Data shown includes the natural gamma ray log, neutron porosity, bulk-density, deep-reading electrical resistivity, compressional- and shear-wave acoustic velocities, and compressional-shear-wave acoustic velocity ratios (Vp/Vs).  Also shown is the depth of the downhole log inferred gas-hydrate-bearing stratigraphic interval.
figure 15 figure15.pdf Various morphological forms of natural gas hydrate occurrence (modified from Sloan, 1998).
figure 16 figure16.pdf Figure 16a: Permafrost associated gas-hydrate reservoir model for conditions below the base of ice-bearing permafrost (Model A).
Figure 16b: Permafrost associated gas-hydrate reservoir model for conditions above the base of ice-bearing permafrost (Model B).
Figure 16c: Marine (clay-rich) gas-hydrate reservoir model (Model C).
Figure 16d: Free-gas- and gas-hydrate-bearing reservoir model (Model D).
figure 17 figure17.pdf Graph showing the depth-temperature zone in which gas hydrates are stable in a permafrost region [assuming a 9.795 kPa/m pore-pressure gradient] (modified from Holder et al., 1987).
figure 18 figure18.pdf Schematic of proposed gas hydrate production methods.
Tables

The following tables are in two formats: PDF and Microsoft Word .DOC for your convenience.

Microsoft Word Document PDF Description
table01.doc table01.pdf

Volume of gas within the downhole log inferred gas hydrate occurrences at ODP Sites 994, 995, 997, and 889, and in the Northwest Eileen State-2 and Mallik 2L-38 wells

table02.doc table02.pdf

World estimates of the amount of gas within hydrates

table03.doc table03.pdf Economic study of gas hydrate production

Natural Gas Hydrates: Resource of the 21st Century?