The new Badger Explorer is self-burying exploratory drilling tool capable of evaluating reservoirs characteristics without the use of a rig or support vessel. (Image courtesy BXPL)

There may be a new way of determining the extent of an offshore asset without using a rig. Sigmund Stokka, research director for the International Research Institute of Stavanger (IRIS), developed the concept of the Badger Explorer in 1999. The device was patented in 2002 in Norway and 2005 in the United States.

Procom Venture was responsible for the initial launch of Badger Explorer ASA (BXPL), and the company entered into contracts for funding and cooperation with ExxonMobil, Shell, StatoilHydro, and the Research Council of Norway as early as 2005 to develop a prototype for the tool.

The device recently passed its first initial test onshore Denmark, and is on its way to becoming a low cost, low risk method of evaluating reservoirs. The Badger Explorer is designed with a full package of logging sensors that characterize downhole environments once the tool drills into the ground and buries itself.

It penetrates the seabed using a mechanical drill bit driven by an electrical motor. As the bit loosens and crushes the formation ahead, it transports the matter through the device depositing the remains in the void behind the tool. The excess volume is forced and injected into the formation through fractures generated by the tool.

The tool connects to the surface by unspooling an interior electrical cable that powers the electrical motors and provides continuous transfer of data back to the surface.

The system drills underground without the risks, cost, or complexity of exploration drilling with a rig. It’s been labeled as a “rigless,” autonomous “fly by wire” exploration tool.

The current prototype is designed as a non-reusable tool that remains underground. It can penetrate the subsea surface to a depth of 9,843 ft (3,000 m) in approximately two months with an average rate of penetration of 6.5 ft/hr (2 m/hr) depending on rock hardness. The tool generates a 6-in. borehole and runs on 10 kW of power while recording and logging all traditional parameters of a well.

The device drills formations in gauge hole, with no drilling fluid and without overbalance, which guards against formation invasion and measurement errors due to washed out hole sections. As a result, the measurements of formation properties are simplified requiring simpler toolstrings compared to conventional drilling.

This reduces cost related to the measurement sensor package in the tool and increases the quality of the data. Because it is hardwired to surface, the data sampling rate and transmission volume for measurement/logging while drilling is much higher than traditional methods.

The new device has positive implications for the environment including a reduced impact on wild life, fisheries, and surrounding area. The method doesn’t require large drilling rigs or related logistics, so this also cuts downs on emissions to air or sea. The self-contained operation requires no vessel assistance, so it could also reduce hazards for personnel and reduce fuel consumption during operations.

Beginning in 2005, the Badger Explorer Prototype Development Project set the goals of finalizing a detail design, building a full scale prototype, performing a full scale test, and executing a pilot installation within two to five years.

BXPL recently completed the first part of its Demo50 full scale prototype test at a site in Denmark. “The achievements verify the design and the capabilities of the technology at this stage,” said the company’s Chief Executive Officer Kjell Erik Drevdal.

The first round of Demo50 tests focused on several functions including drilling and pumping, cuttings and fluid transportation. The test also provided the researchers with operational experience from the site, a chance to associate with service and equipment suppliers in the area, and ideas on how to improve techniques in separating cuttings and fluid.

The company is currently assembling the semi-autonomous drilling unit to undergo a sub-terranean, self-burying drilling test at the same site in Q3 2008, Drevdal said.

If successful, the new device could reduce the cost of exploration in some areas by a magnitude of 60 to 80% increasing the number of discoveries within a set exploration budget. It will also reduce the initial investment for each find, which could increase the value of proven and recoverable reserves and allow for better long term planning.

The joint venture partners ExxonMobil, Shell, and StatoilHydro have already secured first right of refusal to buy the full manufacturing and operational capacity of the new device for a three-year period from commercialization, which is expected in 2010.

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