Stručni rad

Special features of fracture network in Iranian fractured reservoirs

Saeed Razzagh Famian ; Department of Chemical & Petroleum Engineering, Sharif University of Technology, Azadi Ave., Tehran, Iran, PO Box 11365-9465
M. Masihi ; Department of Chemical & Petroleum Engineering, Sharif University of Technology, Azadi Ave., Tehran, Iran, PO Box 11365-9465

Sažetak

Due to the presence of two different types of porous media, namely matrix blocks and fractures; there are varieties of reservoir performance behaviors in fractured oil reservoirs. Because of this complex structure of fractured reservoirs, oil recovery is the result of the combination of several production mechanisms such as gravity drainage and imbibition. Two main forces controlling these production mechanisms are capillary and gravity forces.
This work is focused on the influence of non-zero fracture capillary pressure, non-straight line fracture relative permeability, reinfiltration phenomenon and matrix block height on the performance of active mechanisms in fractured reservoirs during natural depletion and immiscible gas injection project. The field simulation studies were performed using ECLIPSE commercial simulator with black oil formulation and dual porosity option. Simulator results considering non-zero fracture capillary pressure indicated that the influence of this parameter on reservoir performance depended not only on fracture physical properties, but also it depended on matrix threshold capillary pressure and matrix block height. Simulation results indicated that oil recovery was affected by the range from 1% to 2% considering matrix threshold capillary pressure of 0.1 psi (0.007 bar) to 3.1 psi (0.214 bar). Also oil recovery was affected by the range from 1.5% to 0.5% considering matrix block heights of 15 ft (4.57 m) to 60 ft (18.29 m). Our simulation results suggest that for the fractured reservoirs with small block heights or with large matrix threshold capillary pressure, the appropriate non-zero fracture capillary pressure curve is necessary. Subsequently we have investigated the effect of non-straight line fracture relative permeability on reservoir performance. The results emphasized that the matrix block height depended on the influence of linear line fracture relative permeability. Simulation results acquired by applying different matrix block heights indicated the enhancement in oil recovery by immiscible gas injection in the range from 2.3% to 5.2% considering matrix block heights of 15 ft (4.57 m) to 60 ft (18.29 m). Hence, these results showed that the fractured reservoirs with the highest matrix block heights could be good candidates for implementing the immiscible gas injection operation.

Ključne riječi

fractured reservoirs; capillary pressure; reinfiltration; block-to-block interaction

Hrčak ID:

49019

URI

https://hrcak.srce.hr/49019

Datum izdavanja:

31.1.2010.

Podaci na drugim jezicima: hrvatski

Posjeta: 2.399 *