New Technologies Combine to Reduce Drilling Costs in Ultradeepwater Applications
As the oil and gas industry matures, so does its technology and equipment. As a drilling rig gets older, it becomes increasingly challenging to use it to explore for untapped deep reserves. Offshore rig builders are constantly manufacturing rigs with new, sophisticated capabilities, thereby widening the technology gap between the new rigs and the aging ones. As a result, many operators of older rigs are modifying their rigs to compete with newer ones. Using a modified second-generation semi-submersible rig in Indonesia, Total was able to reach target depth in an ultradeepwater well by deploying a combination of surface stack drilling technology, a subsea shut-off device known as an environmental safe guard (ESG), and solid expandable tubular technology. If conventional casing had been used, the optimal hole size at total depth (TD) would have been impossible to attain and economically unfeasible without the use of a fourth or fifth generation semi-submersible or drillship. This paper describes the safe and successful integration of new technologies that enable surface stack drilling with modified second- or third-generation semi-submersible rigs in environmentally less-benign areas, including the Gulf of Mexico. In addition, the paper will discuss the deployment of solid expandable tubular technology from a modified secondgeneration rig and show how this technology enabled the operator to achieve a sufficient hole size at total depth while maintaining an economically viable operation.