A good understanding of the fracture characteristics is essential for a successful development of a tight, heavily fractured reservoir. The fractures play a major role for both reservoir fluid flow and well productivity. An efficient fracture characterization is required to understand the recovery mechanism, which is critical for field development and optimal production strategy decisions. It is imperative that state-of-the-art dual-porosity/dual-permeability models are populated with accurate fracture descriptions to provide reliable forecasts.
This paper describes a novel approach to characterize fracture properties by using image logs, formation tester with straddle packers, and pressure transient analysis (PTA). The image logs are used to identify fracture systems along the wellbore. The formation tester with a straddle packer is used to isolate each system shown on the image logs for separate pressure drawdown and buildup testing. The fluid type filling the fractures can be identified during drawdown. The acquired pressure responses are interpreted by PTA to calculate the fracture properties and to determine the fracture role in the recovery efficiency.
Several essential results have been obtained. Range of matrix anisotropy, kv/kh, has been concluded. Role of small scale fractures on recovery mechanism has also been better understood.