FROZEN HEAT | Volume 2

2.3 GAS HYDRATE EXPLORATION

As with traditional oil and gas resource development, gas hydrate development will occur through two linked phases: exploration and production. In the exploration phase, vari- ous geological and geophysical tools and concepts are ap- plied (Riedel et al. 2010c) to search for the most promising deposits and to evaluate the resource potential of the fields. These interpretations are then tested through exploration drilling, with extensive data collection that includes complex geophysical well logging and collection and analysis of core samples (Text Box 2.2). If initial drilling results are positive, delineation wells might be drilled to refine the extent and na- ture of the accumulation. Numerical reservoir simulation is then used to assess the potential recovery and the nature and potential economics of the full development plan (Moridis et al. , 2009; Kurihara et al. 2010). Only when it is deemed cost-effective to develop the resources in accordance with re- quired environmental standards will industry move into the

production phase. (Promising production technologies are discussed in Volume 2 Chapter 3 of this report.)

Although gas hydrate exploration is still in the research phase, initial results are positive. Progress toward viable ex- ploration approaches has been confirmed in both Arctic (Lee et al. 2011) and deep-water (Shelander et al. 2010) settings, where pre-drill, geophysics-based predictions were con- firmed by later drilling. This approach tailors the petroleum systems concepts that guide traditional hydrocarbon explo- ration to the issue of gas hydrates (Fig. 2.3; Text Box 2.2). Future gas hydrate exploration will search for locations that combine evidence from seismic surveys and other remote- sensing data with interpretations of the geologic develop- ment of the region that suggest the confluence of supplies of gas, reservoir-quality sediments, and gas hydrate stability conditions (Collett et al. 2009).

Figure 2.3: Gas hydrate exploration. The method shown here is a tailored variant of the “petroleum systems” approach that guides conventional oil and gas exploration. In this example, a cross-section and map view (insert) from the deep-water setting, geological and geophysical data from previous drilling and remote sensing are used to reduce the uncertainty associated with geophysically-defined prospects (B) by confirming the presence of gas hydrate stability conditions (A), the occurrence of gas sources and pathways (C), and the occurrence of potential reservoirs (D).

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