Sakhalin extended-reach well a new world’s record

ExxonMobil has broken its own world record for extended-reach drilling. The new record at the Sakhalin-1 oil project on Russia’s east coast was for an offshore well in the Chayvo field, drilled from shore at a distance of nearly 7 miles (11 km).

The well was drilled with the 230-ft-tall Yastreb rig, operated by Houston-based Parker Drilling and reportedly the world’s most powerful land drilling rig. Extended-reach technology, which allows wells to begin vertically on land and then curve to bore horizontally under the seabed to offshore reservoirs, was used to drill the Z-12 well at a depth of 8,350 ft beneath the Sea of Okhotsk. The rig-to-reservoir distance of 38,322 ft is roughly equivalent to 125 US football fields.

This well breaks the 2007 record of 37,016 ft held by the Z-11 well, also located in Sakhalin-1’s Chayvo field.

In announcing the record, ExxonMobil confirmed that the harsh arctic conditions at Sakhalin necessitated the use of extended-reach technology. “Employing extended-reach technology to drill onshore beneath the seafloor to offshore oil and gas deposits eliminates the need for additional offshore structures, pipelines and associated activities,” said Morris Foster, president of ExxonMobil Production Company. This type of drilling also reduces environmental impacts and gives the operator greater flexibility in its drilling schedule.

ExxonMobil employed several technologies that allowed the drill bit to withstand the massive pressures and temperatures encountered during the drilling process. For example, the company’s Integrated Hole Quality technology was used to manage well variables such as rock strength and stresses and wellbore hydraulics. The drillers also used an optimization process called Fast Drill to analyze the power requirements during drilling in order to make the process faster and more efficient.

Technologies such as these allowed ExxonMobil to drill extended-reach wells in approximately 2 months, half the time required by conventional technology.

The Sakhalin-1 project includes three offshore fields - Chayvo, Odoptu, and Arkutun Dagi - and reportedly contains 17 of the world’s 30 longest extended-reach wells. These wells were a major contributor to Sakhalin-1 meeting its targeted peak production rate of 250,000 BOPD in February 2007.

Sakhalin-1 is operated by ExxonMobil’s Russian subsidiary, Exxon Neftegas Limited, which holds a 30% share of the project. Other investors include the Japanese company Sakhalin Oil and Gas Development Co. Ltd. (30%); an affiliate of the Russian state-owned oil company Rosneft, RN-Astra (8.5%); Sakhalinmorneftegas-Shelf (11.5%); and the Indian state-owned oil company ONGC Videsh Ltd. (20%).

More information on the Sakhalin-1 project can be found at http://www.exxonmobil.com/Corporate/news_publications_sakhalin.aspx.

Ted Moon is the Technology Editor of JPT Online. He brings information on emerging technologies, R&D successes, new field applications, updates from SPE papers about recent innovations, and more. If you have a question or suggestion for future article topics, email Ted at teched@spe.org.