Through-tubing rotary drilling a success on StatoilHydro's Asgard field

A new technology called through tubing rotary drilling (TTRD) is helping StatoilHydro to improve oil recovery from subsea fields, the company said. Now successfully tested on the Åsgard field in the Norwegian Sea, the technology has proven to enable the drilling of new sidetracks through existing tubing on subsea fields. This simplifies and reduces the costs to reuse old wells. Øystein Arvid Håland, head of subsurface technology in StatoilHydro, said the technology has been under development with FMC Technologies for four to five years. He estimates that drilling operation from the Åsgard field alone will produce extra oil worth around NOK 1.4 billion.

Source: FMC Technologies. The TTRD equipment is connected to a subsea installation on the seabed.

“The new concept will highly improve the efficiency of this type of operations in connection with subsea well operations, and enables us to produce oil that we would normally not have recovered,” Mr Håland said.

A conventional rig was used on Åsgard for the test, but the company expects the technology to bring even better results when used on a purpose-built rig.

“In the autumn we plan to invite bids for a rig to be tailored to such operations, and the aim is to get the new rig into place in 2012-2013,” Mr Håland said.

The rig will contain only the equipment needed for this type of operation and will be a brand-new type of rig.

Today, more than 40% of StatoilHydro’s oil and gas production comes from some 500 wells on subsea fields. This new technology may be used in waters down to 500 m. The goal is to reach even deeper.

“In the future we wish to utilise this technology in deep waters, for example in the Gulf of Mexico,” Mr Håland said.