Evaluation of the Gas Production Potential of Some Particularly Challenging Types of Oceanic Hydrate Deposits

Abstract

We use the TOUGH+HYDRATE code to assess the production potential of some particularly challenging hydrate deposits, i.e., deposits that are characterized by any combination of the following factors: absence of confining boundaries, high thermodynamic stability, low temperatures, low formation permeability. Using high-resolution grids, we show that a new horizontal well design using thermal stimulation coupled with mild depressurization yields production rates that appear modest and insufficient for commercially viable production levels. The use of parallel horizontal wells (with the lower one providing thermal stimulation through heat addition, direct injection or circulation of warm water, and the upper one producing under a mild depressurization regime) offers tantalizing possibilities, and has the potential of allowing commercial production from a very large number of hydrate deposits that are not currently considered as production candidates if the problem of the corresponding large water production can be solved.

Assessment of Gas Production Potential from Hydrate Reservoir in Qilian Mountain Permafrost Using Five-Spot Horizontal Well System

“…Moridis et al [12] simulated the gas production from the Mount Elbert gas hydrate deposit by depressurization using both vertical and horizontal wells, and the results showed that the horizontal wells could increase the production rates by almost two orders of magnitude when comparing with the vertical wells. After that, Moridis et al [23] further compared the production behaviors of a single horizontal well design and a two-well design, and found that the gas production rate of the two-well configuration was much higher than that of the single-well design. Combining depressurization and warm brine stimulation methods, Feng et al [24] investigated the hydrate dissociation performance in the South China Sea in two horizontal wells.…”

Numerical Investigation of Hydrate Dissociation Performance in the South China Sea with Different Horizontal Well Configurations

“…For a well spacing of 90 m, and a well length of 1000 m, the average gas production rate is 1.80 × 10 6 ST· m 3 /day. Comparing with the commercially viable production rate (2.8 × 10 5 ST· m 3 /day) in the Gulf of Mexico [33], gas production in this work is favorable. Figure 9.…”

Evolution of Hydrate Dissociation by Warm Brine Stimulation Combined Depressurization in the South China Sea

“…Similarly, the Class 2 hydrate deposit consists of a HBL and an underlying zone of mobile water. The hydrate accumulation in the SCS is similar to the Class 3 deposit which involves only a HBL without underlying mobile fluid zones, and this kind of hydrate reservoir is regarded as "challenging" for gas production [24].…”

“…Subsequently, Li et al [10] further indicated that the hydrate dissociation rate increased with the increase of salinity. Recently, Moridis et al [11] showed that the dual horizontal well system is better than the single horizontal well layout because of preferable heat transference. Much research in recent…”