Unocal Netherlands BV has increased production by 160% in Helder field in the Dutch North Sea with a $19.5 million redevelopment program involving horizontal wells.
The program involved Unocal drilling five horizontal wells and kicking off horizontal laterals from nine of 10 existing vertical wells. Prior to the program, the field was producing 4,200 b/d. After the horizontal program was completed in February, production jumped to 10,900 b/d.
Gary E. Carlson, Unocal resident manager, said the program amounts to complete redevelopment of Helder field. Fourteen of the 15 wells in the field are horizontal.
Unocal installed Helder platform in 1982. Unocal drilled more than 18,000 ft of horizontal interval during 1986-91.
The company expects the redevelopment to yield an incremental 7 million bbl to total recovery, increasing that to a projected 31.1 million bbl.
Helder field reservoir is a highly permeable sandstone overlying an active aquifer, resulting in high water production rates early in field development. Horizontal drilling has allowed the company to increase oil production while reducing the water cut, resulting in lower operating expenses, smaller downhole pumps, and fewer workovers.
Unocal operates the license on Block Q-1 with 80% working interest. Nedlloyd Energy BV holds the remaining 20%.
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