Bale et al. documented the benefit of high conductivity propped fractures in the Gullfaks field in the North Sea. Hydraulic fractures were designed to allow a more uniform vertical production profile, and thereby maximize sand-free rates over the perforated section of the reservoir. Although the expected proppant stress was predicted to be merely 1700 psi, 16/20 LWC was selected due to superior conductivity and beta characteristics.
Hydraulic fracturing has historically been a prime engineering tool for improving well producing rates, either by circumventing near-well damage or by stimulating well performance. This paper describes a somewhat new fracturing application where increasing rate was not the primary goal. In this case, the goal for fracturing was modification of the flow profile to allow a more uniform vertical production profile and thereby maximize sand-free rates over the perforated section of the reservoir. In best cases for such applications, this technique allows perforating of "weak" rock to be skipped, reduces risks of sand production, and allows greater wellbore drawdown through perforated intervals in more competent reservoir rock. This allows better long-term productivity and improved recovery and total project economics. In short, it was hoped that propped fractures would improve reservoir management of the Etive/ Rannoch formations in the Gullfaks field.
Author(s): SPE, SPE, Arthur Bale, and Kjell Owren, Statoil, and Michael B. Smith, NSI Technologies Inc.
Paper Number: SPE 24992