Performance and economics of methane hydrate reservoirs

• Main Author: Nyayapathi, Lavanya
• Format: Text
• Language: unknown
• Published: The Research Repository @ WVU 2010
• Subjects: Chemical engineering; Petroleum engineering; Arctic; Methane hydrate; permafrost; Prudhoe Bay
• Online Access: https://researchrepository.wvu.edu/etd/3300; https://researchrepository.wvu.edu/cgi/viewcontent.cgi?article=4304&context=etd

In order to address the world's growing energy demand, the necessity to explore more and more unconventional sources of energy arises. Recently there has been increased interest in the potential of natural gas hydrates as an alternate energy resource. Hydrates are distributed worldwide and have a high energy density in that 1 m3 of methane hydrates can release as much as 164 m3 of gas.;Hydrates were studied as a laboratory curiosity until and then naturally occurring hydrates were discovered in 1934 clogging gas and oil pipelines. The first naturally occurring hydrate deposits were suggested in 1965 by Makogon in Russia. Kvenvolden published the amount of first in situ estimate of methane hydrates as 3053 x 1015m3 . Since then a number of researchers estimated the total resource of methane hydrates present throughout the oceans and the permafrost around the world. Today the estimates range from 105 trillion cubic feet (TCF) to 2.7 x 108 TCF; however, the estimates are speculative and debatable. It is widely believed that gas hydrates have an energy potential greater than that of the total conventional gas reserve.;Several researchers have reported preliminary economics of arctic hydrates. In 2004, Hancock et al., modeled a reservoir with Mallik's geological characters and estimated the production and economics using only depressurization of the hydrate reservoir. Hancock et al., in 2008 reported the lowest price that enabled economically-viable production from hydrates in the absence of associated free gas to be {dollar}CDN2005 12/Mscf and that in the presence of associated free gas to be {dollar}CDN2005 7.5/Mscf. The paper also stated that it was more expensive to produce gas from oceanic hydrates. This work will focus mainly on the Alaskan hydrate deposits and their economics.;In this work, Problem 7 of the DOE Code Comparison study was analyzed using reservoir simulations performed with the CMG STARS simulator and the Downdip of Prudhoe Bay L-Pad site was found to be the most economic site when gas is produced only by depressurization and as a basic estimate gas produced from this well would cost about {dollar}2.25. Because it has been suggested that the introduction of horizontal wells into a gas hydrate reservoir would yield higher gas rates at early times, the Prudhoe Bay down dip type reservoir was modeled using a vertical well and a horizontal well. The two well settings are compared based on production rates of gas and water and horizontal well produced at a wellhead breakeven price of {dollar}2.87 and the vertical well produced at {dollar}7.51/MMSCF after taxes and at a discount rate of 15%.;A financial Monte Carlo analysis was carried out on the Prudhoe Bay L-Pad like reservoir as this could be the most likely site to be drilled for gas production from hydrates in the near future. Wireline log data from the Mount Elbert stratigraphic test well was used to model the 100 different reservoir settings used in the MC analysis. The propagation of uncertainty of the reservoir parameters to the economics has been presented in this document and temperature has been found to be the most sensitive factor in the economics of a hydrate well site.