TWO WELLS BROUGHT MONTHLY ON PRODUCTION USING UNDERBALANCED CTD

While the number of underbalanced coiled tubing drilling (CTD) operations has significantly grown in the USA and Canada where oil companies have been using this technology for over 30 years, Russian oil companies are just entering the world of coiled tubing drilling.

In October 2004, Surgutneftegas started underbalanced drilling of a horizontal well at Zapadno-Surgutskoye field using an CTD rig developed from the original design by American and Canadian firms and customized to meet Surgutneftegas’ needs. After the well was brought on line, its daily production doubled surpassing all expectations.

So far, the CTD rig has drilled underbalanced 17 wells at various fields and formations and started drilling the 18^th well. Every two or three weeks Surgutneftegas brings on production one more well drilled using underbalanced CTD. The pilot tests proved successful: production rates of such wells are many times higher than those of conventionally drilled wells. Moreover, underbalanced drilling minimizes damage to producing formations and deterioration of reservoir properties, which is vital for production of difficult-to-recover reserves in low productive Achimovsky and Jurassic deposits.

The CTD rig is serviced by Surgutneftegas’ Sidetracking and Workover Division whose employees were trained in Canada. According to Sergei Kolbin, the head of the Division, the drilling crew that operates the CTD rig is a highly professional team able to cope with the most challenging tasks. The growing number of these tasks that have to be solved as soon as possible includes drilling at Ulyanovskoye and Ai-Pimskoye fields with their highly abnormal Bazhenovsky reservoirs and underbalanced drilling at Talakanskoye field in Yakutia.

“Our company is an undisputed leader in Russia in terms of innovative technology,” says Anatoly Nuryaev, First Deputy Director General of  OJSC “Surgutneftegas”. “Huge sums of money we invested in equipment and technologies are paying off a hundredfold. Our experts have mastered such advanced technologies as horizontal drilling, sidetracking and others, which allowed us to increase oil recovery at our fields and add tens of millions of tons to cumulative oil production. Apart from the CTD rig, we currently operate as many as 24 CT units used for workovers. By now, our company has successfully introduced and mastered the CT technology.”

Press Service of OJSC “Surgutneftegas”