Schlumberger

Technical Paper: Effect of Layered Heterogeneity on Fracture Initiation in Tight Gas Shales

Society: SPE
Paper Number: 103327
Presentation Date: 2006
 Download: Effect of Layered Heterogeneity on Fracture Initiation in Tight Gas Shales (0.36 MB PDF) Login | Register

 

Since the horizontal lateral Bakken dolomite play began in 1999 in eastern Montana, more than 330 wells have been permitted and more than 200 wells are now producing. The lateral play began in Richland County, Montana, and the success there is not only accelerating the transfer of technology to the North Dakota side of the Bakken trend, but is also attracting operators to the area. Different drilling and completion techniques have been tried since the start of the play with different degrees of success.

In June 2005, a new technique was introduced using chopped fibers within the fracturing gel slurry to help suspend proppant in the slurry both during the fracture pumping and also during fracture closure. The primary goal was to be able to create a more even distribution of proppant in the created fracture while reducing the polymer requirement for the fracturing gel slurry. A secondary goal was to use slugs of the fiber to bridge at the fracture entry face and divert the treatment into new fracture planes, thereby improving the completion efficiency of the treatment. Lastly, it was hoped that the introduction of the fiber, which would dissolve shortly after placement, would improve proppant retention within the hydraulic fracture and impede flowback into the horizontal leg of the wellbore.

The results from this new technique have been encouraging; with an estimated 24% improvement in average well productivity since the fiber designs have been implemented. Additional benefits include elimination of chokes cutting out because of sand production and associated wellbore fill clean out, lower polymer requirements reducing gel costs, and a reduction in premature screenouts.