Light Drilling, Well Completion and Deep Monitoring

Drilling is within the core activities of CO2 geological storage since the more wells are drilled the higher amount of data is managed for site characterization and for a successful decision making on project viability. Most of commercial projects worldwide are at the early stage where the costs related to exploration play a key role, as is the case of the traditional drilling techniques from Oil and Gas industry that are usually expensive for on-shore projects whose business model still has to be proven. How to save drilling costs is addressed in the chapter, showing the experiences gained during the construction of the on-shore pilot: Hontomin Technology Development Plant (Burgos, Spain). Hontomin well drilling/completion was a success as the depth of 1600 m was reached using light drilling rigs (mining technique), achieving cost saving close to 60% in comparison to traditional techniques. Some experiences exist in the use of these rigs for mining, shale gas and oil and geothermal recovery, but for CO2 geological storage they are limited to the Hontomin case. The existing technological drilling gaps identified during the plant construction and the future works for improving these rigs to reach the depth of 2500 m with a well geometry adequate to install advanced monitoring, are also addressed in this chapter.