With a strong push from the leading producer offshore ofCanada’s East Coast, an intense development effort is under way ona new marine technology intended to tap natural gas on the GrandBanks of Newfoundland sooner than anyone now thinks possible.Andrew Adams, vice-president in charge of Mobil Oil Canada’sNewfoundland exploration and production business unit, told anindustry conference in St. John’s the technique “looks like it hasgreat potential.”
The method, invented by the Calgary engineering firm of Cran& Stenning Technology Inc., adapts the methods of high-volumecontainer shipping to transporting CNG or compressed natural gas bysea. The new element is a container called the Coselle, which isshort for coiled and carousel. Each container is a coil ofsmall-diameter pipe. The engineers calculate 3.09 MMcf of gas canbe carried at a pressure of 3,000 pounds per square inch in ninemiles of 6.6-inch-diameter pipe wound into a single Cosellecontainer 50 feet across and 11 feet tall.
The concept has advanced as far as designs for an 800-foot,60,000-ton vessel that would transport 330 MMcf of gas in 108Coselles arranged in 18 stacks of 10. The idea is especially aimedat fetching “associated gas” from oil production platforms. Thedesign includes handling raw gas to be loaded after a minimum ofprocessing to remove water and corrosive hydrogen-sulphide.
In St. John’s, the engineers tantalized Atlantic Canada’sbudding oil and gas industry with a portrait of the new system asan easy alternative to long pipelines. The inventors project aUS$1.40 per MMBtu toll for a fleet of seven Coselle carriers totransport gas continuously to Boston 1,100 miles from the Jeanned’Arc Basin on the Grand Banks, where the Hibernia project has beenproducing since November of 1977 and at least three more offshoreplatforms are advancing towards construction.
That rate is competitive with the cost of reaching Boston viathe Maritimes & Northeast Pipeline, now under constructionsimultaneously with the Sable Offshore Energy Project. MobilCanada, which has been drilling offshore of Atlantic Canada since1943, is the senior partner in both Hibernia and SOEP.
The C$5.8-billion (US$4-billion), 150,000 b/d Hibernia platformtaps 3.5 Tcf of gas but has to re-inject it. While SOEP taps aregion offshore of Nova Scotia estimated to harbor 18 Tcf of gas,Canadian authorities project the more remote regions farther northaround Newfoundland have 33 Tcf or more.
The eastern Canadian gas endowment prompted Tatham Offshore Inc.of Houston to step forward in late 1997 with a US$3-billionproposal for a 1,330-mile subsea pipeline grid linking New Englandand Canadian markets with Newfoundland and Nova Scotia gas.
The Tatham proposal was shelved following Canadian approval ofMNE, but hopes of tapping East Coast gas did not fall dormant withit. Mobil Canada is one of six companies that have signed up for ajoint industry project to do further work on the Coselle system. BGInternational (formerly British Gas) has also revealed it isparticipating in the group. Other partners remain undisclosed,although industry sources in Calgary say keen interest is beingshown by an inner circle of planners from the producer-marketercommunity that founded Alliance Pipeline Project.
The technology’s developers say Coselle CNG technology has atleast the potential to be the lowest-cost delivery system in caseswhere production and markets are less than 2,500 miles apart. Thesystem is billed as overcoming processing costs and safety issuesassociated with liquefied natural gas and subsea pipelines -especially offshore of Atlantic Canada, where the industry has tocontend with annual iceberg migrations. In Mobil’s view, theCoselle plan “is an excellent example of the kind of innovativethinking that’s helping to move development of Newfoundland naturalgas resources closer to reality,” Adams said.
Gordon Jaremko, Calgary
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