Obtain information that can be utilized to develop gas hydrate computer production models.
Geological Survey of Canada – manager of consortium
Ottawa, ON K1A -0E8
The Mallik Gas Hydrate Research Well Project began in 1998, with the first research well to core over 100 meters of hydrate bearing sediments. The well was located at the original L-38 site that was reported, in the late 1970’s, as having gas hydrate in its well tests. The well is located on the northeast side of Richards Island and is part of the expansive Mackenzie River Delta where it enters the Beaufort Sea in Canada’s Northwest Territory. The success of the first well, sponsored by the Geological Survey of Canada, JAPEX, The Japanese National Oil Company (JNOC), USGS and NETL, led to a proposal to form another international consortium to drill three more wells and accomplish a production test of the hydrate bearing reservoirs identified at this location.
The reservoir characterization data acquired during this multi-faceted project will allow industry to utilize the results to evaluate and potentially produce gas hydrate resources in the near future. The drilling, completion and production tests were a first in testing these unusual gas reservoirs and the coring and logging tools utilized were very successful in identifying the hydrate. It is anticipated that they will be applied to actual quantitative analysis of further research in the offshore environment. Access to a reservoir onshore greatly reduced the costs of acquiring the reservoir characterization data and will allow companies to model the hydrate stability zones and predict the economics for future development.
The Mallik gas hydrate field, located at the northeastern edge of Canada's Mackenzie Delta, occurs within a sequence of Tertiary sediments in an area underlain by over 1970 ft (600 m) of permafrost. Data from the original discovery well drilled in 1971/72, and a scientific research well program completed in 1998 (Mallik 2L-38), have documented gas hydrate occurrences. Quantitative well log determinations and core studies reveal at least 10 discrete hydrate layers from 2920 to 3628 ft (890 to 1106 m) depth, exceeding 360 ft (110 m) in total thickness. High gas hydrate saturation values, in some cases exceeding 80% of pore volume, establish Mallik as one of the world's most concentrated gas hydrate accumulations.
Beginning in December 2001 and continuing to March 2002, a research program was carried out that included the drilling of a 3940 ft (1200 m) deep main production research well and two nearby observation wells. The program was a collaborative effort among the Geological Survey of Canada, Japan National Oil Corporation, Germany’s GeoForschungs Zentrum Potsdam, the U.S. Geological Survey, the U.S. Department of Energy, BP-Chevron-Burlington Joint Venture Group. and the Gas Authority of India Ltd./Oil and Natural Gas Corporation Ltd. The Geological Survey of Canada coordinated the science for the project and JAPEX Canada Ltd. was the designated operator for the fieldwork.
Primary objectives of the Mallik 2002 production research well program were to advance fundamental geological, geophysical and geochemical studies of the Mallik gas hydrate field and to undertake for the first time, advanced production testing of a concentrated gas hydrate reservoir. Full-scale field experiments monitored the physical behavior of the hydrate deposits in response to depressurization and thermal stimulation. The observation wells facilitated cross-hole tomography experiments (before and after production testing) as well as longer term monitoring of in situ formation conditions. A wide-ranging science and engineering research program included collection of gas-hydrate-bearing core samples and downhole geophysical logging. Laboratory and modeling studies under-taken during the field program, and subsequently as part of a post-field research program will document the sedimen-tology, physical and petrophysical properties, geochemistry, geophysics, reservoir characteristics and production behavior of the Mallik gas hydrate accumulation.
The primary field program lasting 35 days was completed in March of 1998. The primary objectives of the pro-duction testing program were to assess the production potential and characteristics of natural gas hydrate accumulations and to obtain the necessary data to develop and evaluate gas hydrate reservoir simulation models.
The first observation hole spudded December 25, 2001 and drilling was completed January 5, 2002. Distributed temperature survey (DTS) cable, a fiber optic cable attached to the outside of the casing, was successfully installed by team from GeoForschungsZentrum in Potsdam, Germany. The cable records sediment and gas hydrate formation temperatures over time, providing critical information required to understand the temperature conditions under which gas hydrates are stable. The second observation well was started, January 11, 2002. Gas released from the drilled sediments and hydrate layers was separated from re-circulated drilling mud and automatically analyzed for 12 different gases using three different analytical instruments. Once a pre-set concentration threshold was reached, gas samples were collected automatically for future detailed analysis in the laboratory.
The main well (Mallik 5L-38) was spudded on January 25, 2002. Drill cuttings were sampled every 33 ft (10 m), samples for biogeochemistry were collected and mud gas sampling was continued as with the earlier hole. A mud temperature system deployed at the rig assessed the various sources of heat in the drilling process, with a goal of reducing the amount of mechanical heating of the mud and thus the degree of thermal erosion that occurs when drilling through the permafrost.
The coring operation began at 2906 ft (886 m) on February 12, 2002. Core recovery was initially low but improved rapidly to 72%. Gas hydrate was most frequently found filling the pore space of medium-grained sand horizons. Scientists sampled the gas hydrate-rich core and stored the samples in sealed pressure vessels, cooled with liquid nitrogen. An excellent recovery rate allowed researchers to obtained representative samples of gas hydrate through the entire hydrate-bearing interval.
Coring was completed on February 18, with 48 lengths of core recovered. The hole was deepened to 3825 ft (1166 m) and open-hole logging was successfully completed. Casing with two DTS cables was cemented in place. A cross-well tomography survey which was successfully carried out to construct a three dimensional image of the interval penetrated by the main well.
A new sampling tool (the Modular Dynamics Formation Tester or MDT), specially designed for the Mallik program was deployed in the main well. This tool can isolate a half-meter section of the well, perforate the casing, “melt” the neighboring gas hydrate, collect samples of gas and water and measure changes in pressure and flow rates. Six hydrate-rich zones in a range of sediment types were successfully tested using the MDT tool.
Production testing of an upper gas hydrate layer over a 43 ft (13 m) interval was begun on March 5. Water at over 60 °C was circulated to the test interval and dissociated gas hydrates were returned to the surface. Production testing continued until midnight on March 11. While the testing was underway a team from University of Alberta and University of Toronto conducted seismic experiments that hopefully will capture time-lapse images of the gas hydrate dissociating. During testing the heated circulating fluid was periodically spiked with a known quantity of a tracer chemical to allow researchers to calculate how much water was being added to the drill mud from the gas hydrate layer.
Finally, cased-hole logging was carried out using a variety of tools, including one with the potential to map the dissociation interface in three dimensions. All three wells were capped and abandoned. The DTS cables, still deployed down the two observation wells, were placed in protective monuments that can be revisited for temperature measurements.
The partners of the Mallik 2002 Gas Hydrate Production Research Well Program presented the results of the Mallik Program at an International Symposium: "From Mallik to the Future", held in Chiba City, Japan on December 7-8, 2003. The Symposium was the first public release of the production test results and hydrate science research from the Mallik research wells. A report was released in April 2004 as a GSC publication.
In addition to the information provided here, a full listing of project related publications and presentations as well as a listing of funded students can be found in the Methane Hydrate Program Bibliography [PDF].
Review of Mallik 2002 [PDF-9430KB] - October 2003
Topical Report - Numerical Studies of Gas Production from Several CH4-Hydrate Zones at the Mallik Site [PDF-185KB]
USGS’ Mallik Website
"Mallik 2002" International Program Site. Natural Resources Canada (NRCan) website.
ICDP - Mallik 2002 - A companion Mallik 2002 Web site
The Research Consortium for Methane Hydrate Resources in Japan. (also known as the MH21 Research Consortium) - Web site shares Gas Hydrate research activities including information from the "Mallik International Symposium" (Dec. 8-10, 2003).
Dallimore, S.R., Uchida, T. and Collett, T.S., Eds., 1999. Scientific results from JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, Mackenzie Delta, Northwest Territories, Canada. Geological Survey of Canada, Bulletin 544.
Collett, T.S., 2000. Permafrost-associated gas hydrate. in Max, M.D., ed., Natural Gas Hydrate in Oceanic and Permafrost Environments. Kluwer Academic Publishers, The Netherlands, p. 43-60.
Collett, T.S., 2001. A review of well-log analysis techniques used to assess gas-hydrate-bearing reservoirs. in Paull, C.P., and Dillon, W.P., eds., Natural Gas Hydrates: Occurrence, Distribution, and Detection, American Geophysical Union, Geophysical Monograph 124, p. 189-210.
Collett, T.S., and Dallimore, S.R., 2002. Integrated well log and reflection seismic analysis of gas hydrate accumulations on Richards Island in the Mackenzie Delta, N.W.T., Canada. Recorder, v. 27, p. 28-41.
Collett, T.S., 2002. Energy resource potential of natural gas hydrates. American Association of Petroleum Geologists, v. 86, no. 11, p. 1971-1992.