Production Strategies for Marine Hydrate Reservoirs

Authors: J. Phirani. & K. K. Mohanty

Venue: 6th International Conference on Gas Hydrates (ICGH 2008), Vancouver, British Columbia, CANADA, July 6-10, 2008. http://www.ichg.org/showcontent.aspx?MenuID=287 [external site].

Abstract: Large quantities of natural gas hydrate are present in marine sediments. This research is aimed at assessing production of natural gas from these deposits. We had developed a multiphase, multicomponent, thermal, 3D simulator in the past, which can simulate production of hydrates both in equilibrium and kinetic modes. Four components (hydrate, methane, water and salt) and five phases (hydrate, gas, aqueous-phase, ice and salt precipitate) are considered in the simulator. The intrinsic kinetics of hydrate formation or dissociation is considered using the Kim–Bishnoi model. Water freezing and ice melting are tracked with primary variable switch method (PVSM) by assuming equilibrium phase transition. In this work, we simulate depressurization and warm water flooding for hydrate production in a hydrate reservoir underlain by a water layer. Water flooding has been studied as a function of well spacing, well orientation, and injection temperature. Results show that depressurization is limited by the supply of heat of hydrate formation. Warm water flooding can supply this heat of formation. Gas production rate is higher for the water flooding than depressurization. Optimum configuration for wells and water temperature are identified.

Related NETL Project
This presentation is related to the NETL project DE-FC26-06NT42960, “Detection and Production of Methane Hydrate”. The objective of this effort is to better understand regional differences in gas hydrate systems from the perspective of an energy resource, geo-hazard, and long-term climate influence. Specifically, the effort will: (1) collect data and conceptual models that target causes of gas hydrate variance, (2) construct numerical models that explain and predict regional-scale gas hydrate differences in 2- and 3-dimensions with minimal "free parameters", (3) simulate hydrocarbon production from various gas hydrate systems to establish promising resource characteristics, (4) perturb different gas hydrate systems to assess potential impacts of hot fluids on seafloor stability and well stability, and (5) develop geophysical approaches that enable remote quantification of gas hydrate heterogeneities so that they can be characterized with minimal costly drilling.

NETL Project Contacts
NETL – Rick Baker (richard.baker@netl.doe.gov or 304-285-4714)
Rice University – George Hirasaki (gjh@rice.edu or 713-348-5416)