Petrobras' Garoupa: Where it stands, how it got there

A little more than 4 years after first oil was produced, the world's largest subsea production system using dry, atmospheric pressure, ocean floor chambers installed at water depths ranging from 390 to 545 ft is delivering about 23,200 b/d of oil. Planned as a provisional system to accomplish two main objectives - the gathering of reservoir data under a wide spacing configuration not attainable by directional wells drilled from a single site, and early production of oil from the limestone pays of Garoupa and the sandstone pays of Namorado - the system achieved both goals. Up to the end of March 1983, cumulative production reached 28.2 million bbl of oil, and the reservoir's history shows that Namorado field bears the largest individual proved reserve among Brazilian oil fields. Besides that, reservoir pressure and gas-oil ratio profiles from Garoupa indicate that gas lift operations will be scheduled for the second half of 1983 in two or three wells. Solving problems that would cause many to give up, Petrobras engineers, working with CanOcean personnel, now have seven of the scheduled nine wells in the Garoupa and Namorado fields offshore Brazil, on production, with wellheads housed in dry wellhead cellars delivering crude tomore » a dry manifold center. An eighth well was severely damaged by an anchor cable which bent the conductor pipe at an approximate 45/sup 0/ angle. The wellhead cellar is not damaged, however, and can be used on a subsequent installation. The ninth well was drilled but never completed.« less