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24-stage frac job planned for Sanish Three Forks well

Guntis Moritis
OGJ Production Editor

HOUSTON, Oct. 28 -- Whiting Petroleum Corp. plans to use 24-stages for hydraulically fracture its Ogden 11-3 TFH horizontal well, completed in the Three Forks reservoir in the Sanish field, Mountrail County, ND.

Rick Ross, Whiting’s operations vice-president, told OGJ the company typically fractured its Sanish horizontal wells with 10-stages because of the inability to install more interval isolation equipment in the horizontal lateral. The 10-stage frac jobs were the most it could run without making multiple trips in the hole, he said. Whiting has completed and fraced about 55 wells in the Sanish field.

Ross said Whiting helped developed a new multistage fracturing system (FracPoint EX) with Baker Hughes Inc. that now allows isolating up to 24 intervals and fracturing all zones without having to run multiple trips in the hole.

The system run in the Ogden well has swellable elastomer packers that allow the string to navigate through tight spots. Whiting has installed the Baker Hughes system in the well and has scheduled a frac treatment, Ross said. Baker Hughes notes that this is the first time the system has been deployed in a well.

Ross explained that the well is completed with 7-in. casing set in the Three Forks at about a 10,000-ft vertical depth and a 6 1/8-in. 10,000-ft horizontal lateral. The Baker Hughes swellable packers and frac sleeves were run in the 6 1/8-in. hole on a 4 1/2-in. liner. Oil in the Three Forks swells the packers and creates isolated intervals.

Ross said the fracturing procedure involves first dropping the smallest ball downhole. This ball seats in the furthest sleeve and actuates it to open. After fracturing that zone, the next smallest ball is dropped to actuate the next sleeve and seal off the first zone. This continues until all 24 zones are fraced.

Ross expects all 24 zones to be fraced in 18-24 hr, considerably less than the week it might take with procedures that require multiple trips in the hole.

Ross said Whiting usually fracs with a hybrid slickwater system. This involves using slick water in the pad and the first three stages. The remaining stages are fraced with a borate or zirconat fluid containing 100,000-200,000 lb of white sand proppant.

Whiting's well in Sanish field with the highest initial potential was the Richardson Federal 11-9H, completed in October 2008. On a 24-hr test, the well flowed 4,570 boe/d. The average rate during the first 30 days was 1,274 boe/d, and during the first 60 days it was 1,195 boe/d.

Contact Guntis Moritis at guntism@ogjonline.com.


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