YARDIE EAST—1: A DIRECTIONALLY DRILLED WILDCAT

Abstract

Under the terms of a farmout agreement a well to 4200 metres true vertical depth was required to test an offshore structure in the Indian Ocean 3.4 kilometres from the Cape Range landfall. Western Australia.

Due to the structure being located in an offshore environmentally sensitive area and the proximity of the structure to the Ningaloo Reef, the decision was taken by the consortium to drill a directionally controlled wildcat well, Yardie East-1, from the nearest landfall point, in a designated National Park.

With the co-operation of the regulatory authorities a drilling plan was approved which entailed a critical analysis and modifications to the drilling rig, Rig No. 15 contracted from Oil Drilling and Exploration Limited, to satisfy the loads associated with a directionally drilled well to a worst condition programmed measured depth of 5650 m.

Utilising modern technology the wildcat well was drilled to the target at the top of the structure at 5110 m at a penetration angle of 50° and an azimuth of 308° in 142 days from spud.

Earning conditions were satisfied with an eventual total drilled depth of 5593 m. Logging and an open hole drill stem test were conducted prior to abandoning the well 186 days after spud.

It is believed that Yardie East-1 is the longest well, in terms of measured depth, drilled onshore or offshore Australia.