Gas hydrate research heats up

World Oil, June, 1999 by Perry A. Fischer

AAPG was held in April in beautiful San Antonio, Texas. Attendance was the same as last year's show, roughly 6,000, while floor space sales were about 10% more than a year ago. Also, 75 countries reserved floor space. By all accounts, the show was a success. One of the highlights was AAPG's first session on gas hydrate E&P.

Last year, the U.S. Senate unanimously passed S. 1418, a bill that would have funded gas hydrate E&P research, but the bill was tabled in the House. The bill, which provides $45 million spread over 5 years, is again in the works and has a good chance of passing this year.

Most engineers are familiar with hydrates as a production impediment. For the uninitiated, gas hydrate is a strange, frozen-like solid form of natural gas that is created whenever certain high-pressure and low-temperature conditions are met. It occurs in nearly all of the world's offshore basins and some permafrost areas.

Hydrates present a geo-hazard for drilling and platform siting. They can form in subsea flowlines, pipelines and well-head equipment, and solutions are costly. This aspect of hydrates is being investigated at the Rocky Mountain Oilfield Testing Center.

Interest in hydrate E&P has soared in recent years because of growing evidence that more hydrocarbon exists in hydrate deposits than the combined oil, gas and coal reserves worldwide. According to the U.S. Energy Information Agency in its just-released Natural Gas 1998: Issues and Trends, "Recovery of only 1% of hydrates would more than double the domestic gas resource base." A report from Ocean Drilling Program Leg 164, which investigated the huge Blake Ridge offshore the Carolinas, estimated U.S. methane hydrate reserves at 200,000 Tcf.

Japan has taken the lead in gas hydrate exploration, perhaps due to a lack of options. In late 1999, JNOC is scheduled to drill its first hydrate exploration well. Last fall, a group from Shell International Exploration and Production, B.V., discussed exploitation of hydrates at a meeting in Chiba City, Japan. The consensus was that there "is nothing that we can't handle technically. If we encounter a good accumulation of natural gas hydrates, we could develop it with existing technology," said W.J.A. Swinkels, a member of Shell's gas hydrate team.

Norway, in cooperation with several major oil companies, is researching hydrate transportation. Korea, Canada and China all have active research programs. India has earmarked $56 million for hydrate R&D and is also planning offshore leases for hydrate exploitation.

Professor Roger Sassen at Texas A&M University has been on many submarine dives and has observed and sampled hydrate outcrops. Such outcrops occur in many strange forms and colors and provide "food" for weird chemosynthetic organisms. Location of these organisms generally indicates hydrocarbon seeps and, therefore, increased potential for new discoveries. Thus far, three types of natural hydrate have been discovered: biogenic methane and two forms of heavier, thermogenic gas.

Hydrate deposits can occur anywhere from the surface to more than 4,500 ft deep. Exploration will probably comprise looking for bottom simulating reflectors with seismic. These strong seismic reflections follow the general seafloor shape. They represent a hydrate capping layer with free gas below. However, in some places, such as the GOM, seismic recordings show hydrates as fuzzy, vertical areas (see also--"What's happening in production," p. 25).

Another Linux lover. Dynamic Graphics (DG) introduced a Linux version of its EarthVision 5 subsurface modeling software. The Linux Operating System (OS) is a Unix-like OS that keeps gaining momentum from leading computer manufacturers, perhaps due to its open-source code. Linux can be customized by any competent programmer and can be used on standard PCs and laptops.

One reason for choosing Linux, according to Art Paradis, president, is that he was "surprised that the model compute time for the Linux on a Pentium II, 450-MHz PC was faster than the same data set running on a ten-times pricier Unix system."

New field discovery. The Meridian Resource company announced test results of its Thibodaux 1 well, a new field discovery at its Lily Boom prospect, located in North Turtle Bayou, Assumption Parish, Louisiana. The well, drilled to 19,270 ft TD, has more than 223 ft of pay in three separate sands, all below 17,500 ft.

The well tested at 12.664 MMcfgd and 1,224 bpd of condensate at an FTP of 13,285 psi on a 16/64 choke. Shut-in BHP was calculated at 18,000 psi.

The well was sited after extensive 3-D seismic surveys were conducted. Meridian, the operator, has a 71% working interest in the well. Burlington Resources and private investors hold the minor interest.

Brazil opens wider. Although it has taken awhile, Brazil is showing signs of seriously wanting foreign investment. PGS and Schlumberger were both awarded large, 3-D marine seismic contracts. These are the first seismic contracts awarded since the introduction of new rules and the establishment of the ANP, Brazil's new federal energy agency.