Iceland Deep Drilling Project (IDDP): The challenge of drilling and coring into 350-500?C hot geothermal systems and down to 5 km

Abstract

The technology and engineering challenges of drilling and coring the proposed well for the Iceland Deep Drilling Project (IDDP) to 5 km have been evaluated. The results were published in a Feasibility Study (2003) and his paper is a short summary of the findings. In order to meet the major goals set by the project sponsors a ?-dual purpose?… hole had to be designed to: a) allow fluid to be produced to meet the engineering goals of the power companies and b) meet the scientific goals by continuously coringthe lower part of the hole where the very high temperatures are expected. Two wells were designed of different diameters. Top part of the anchor casing has to be from special creep resistant steel, but conventional API grade K-55 can be used for other casing strings. The greatest danger to the casing is thermal cycling, as the steel is stressed beyond the yield point due to limited thermal expansion. The risks in terms of blow outs and other geologic risks were addressed and it found coring to be most critical. Finally cost- and time estimates were prepared for the two wells. The cost was estimated to be US$ 14.4 ?? 15.5 million and taking 258-270 days. An alternative where existing wells would be cased to 2400 m and then cored to 4000 m was estimated to cost US$ 5.8 million..