An Exploration Case Study Of A World Record Deepwater Wildcat Well Drilled In The Orphan Basin, Newfoundland: Blue H-28
Authors: Koning T. , Campbell R.H. , Hibbs D.C. , Leonhardt G.W. 
Published: October 2008

A rank wildcat well, Texaco Shell et al Blue H-28, was drilled offshore Newfoundland in 1979 in 1,486 m (4,876 ft) water and significantly extended the world water depth record for oil and gas drilling. Blue H-28 provided abundant geological and geophysical data which has advanced industry's assessment of the hydrocarbon potential of the almost unexplored Orphan Basin. Blue H-28 also proved industry's capability to drill a deep water well in one of the world's most difficult drilling environments.

INTRODUCTION

In mid-1979 the Texaco Shell et al Blue H-28 wildcat well was drilled on the continental slope of Newfoundland in 1,486 m (4,876 ft.) water depth and established a new world record water depth for oil and gas drilling. Prior to the drilling of Blue H-28, the world water depth record for oil and gas exploratory drilling had been held by a well drilled offshore Spain in early 1979 in 1,354 m (4,441 ft.) of water (Fig. 1). The Blue H-28 well also established a new Canadian water depth record for oil and gas drilling. Blue H-28 obtained additional distinction since it was drilled to a total depth of 6,103 m (20,023 ft.) there by setting a new Canadian onshore and offshore drilling depth record (Fig. 2).

The Blue H-28 well was drilled 340 km northeast of St. John's, Newfoundland in the Orphan Basin. Only two oil and gas exploration wells and a Joides DSDP core hole had been drilled in the Orphan Basin prior to the Blue H-28 drilling project. The closest control well for Blue H-28 was the BP et al Bonavista C-99 well located ISO km southwestwards (Fig. 3). Accordingly, Blue H28 represented a true pioneering effort to drill in an almost unexplored basin as well as to extend drilling technology beyond its proven capability.

Blue H-28 did not prove to be an oil or gas discovery well, however the well did achieve two significant accomplishments. Firstly, Blue H-28 provided a wealth of stratigraphic, paleontological and geochemical data pertinent to the geology of the Orphan Basin. Secondly, Blue H-28 proved that deep water drilling could be efficiently performed in an operationally difficult area characterized by high seas and numerous icebergs.

REGIONAL GEOLOGY

Regional Tectonic Elements

A series of sedimentary basins onlap the southern flank of the Appalachian Orogen in Eastern Canada (Fig. 4). The basins contain up to 14 km sediments of Mesozoic to Cenozoic age (Wade, 1981). Three major tectonic elements dominate the Canadian Atlantic margin: the Scotian Basin, the Avalon Uplift and the East Newfoundland Basin. The general structural configurations of the basins and the intervening basement highs are outlined by a regional map of basement structure (Fig. 5).

Regional Basement Structure

The sedimentary basins have been subdivided by basement uplifts into a number of discrete "sub-basins". The Orphan Basin occurs within the East Newfoundland Basin and is separated from the Jeanne D'Arc Basin by an east-to-west trending basement ridge.