The Research Path to Determining the Resource Potential of Marine Gas Hydrates

Abstract

Abstract A primary goal of the U.S. National Interagency Gas Hydrates R&D program is to determine the natural gas production potential of marine gas hydrates. In pursuing this goal, four primary areas of effort are being conducted in parallel. First, are wide-ranging basic scientific investigations in both the laboratory and in the field designed to advance the understanding of the nature and behavior of gas hydrate bearing sediments (GHBS). This multi-disciplinary work has wide-ranging direct applications to resource recovery, including assisting the development of exploration and production technologies through better rock physics models for GHBS and also in providing key data for numerical simulations of productivity, reservoir geomechanical response, and other phenomena. In addition, fundamental science efforts are essential to developing a fuller understanding of the role gas hydrates play in the natural environment and the potential environmental implications of gas hydrate production, a critical precursor to commercial extraction. A second area of effort is the confirmation of resource presence and viability via a series of multi-well marine drilling expeditions. The collection of data in the field is essential to further clarifying what proportion of the likely immense in-place marine gas hydrate resource exists in accumulations of sufficient quality to represent potential commercial production prospects. A third research focus area is the integration of geologic, geophysical, and geochemical field data into an effective suite of exploration tools that can support the delineation and characterization commercial gas hydrate prospects prior to drilling. The fourth primary research focus is the development and testing of well-based extraction technologies (including drilling, completion, stimulation and production) that can safely deliver commercial gas production rates from gas hydrate reservoirs in a variety of settings. Initial efforts will take advantage of the relatively favorable economics of conducting production tests in Arctic gas-hydrate bearing sandstones with the intent of translating the knowledge gained to later testing in marine sandstone reservoirs. The full and concurrent pusuit of each of these research topics is essential to the determining the future production potential of naturally-occuring gas hydrates. Introduction Gas hydrates are a naturally occurring substance that can be found in nature wherever water exists in combination with sufficient volumes of appropriately-sized gas molecules under specific high-pressure, low-temperature conditions (Sloan and Koh, 2007). These conditions are restricted primarily to arctic regions, deep lakes, and marine continental shelves in water depth of ~500 m or more. Additional factors that influence the occurrence and nature of gas hydrates include the mineralogy and petrophysical characteristics of the host lithology, and the chemistry of both the gases and the water.