f Well completion design for tight reservoirs: A 3D dynamic simulation approach

A new 3D black oil simulator, Quiklook by Halliburton, was tested in order to assess the effectiveness of hydraulic fracturing both in term of FOI (Fold of Increase) and RF (Recovery Factor). The actual way of modelling hydraulically fractured wells in 3D reservoir simulators is to approximate the fracture behaviour with a modified skin or productivity index. Neither methods can be considered realistic because of neglecting the modification of fluid flow into the reservoir and through the fracture itself. Quiklook, can easily generate accurate prediction of post-fracture performances thanks to an automatic grid generation of the reservoir and to the possibility of a local grid refinement (LGR) in the region of the wellbore and the fracture tip, as well as in the blocks adjacent to the fracture plane. A conceptual reservoir model with low permeability characteristics (1 mD horizontal, 0.1 mD vertical) was built using realistic parameters. In the first step of the work the fracture characteristics were optimized in terms of geometry and conductivity for a vertical well. In case of horizontal wells, efforts were made to deliver the optimal fractures number and spacing. The performance of the traditional unfracturated wells were compared with the fractured ones in term of Productivity Index and Recovery Factor both a medium term (5 years) and in a longer term view (10 years). Results of the study show that the optimal completion strategy has to be established on production and economical constraints and the horizontal well with multiple fractures shows better production performances compared with traditional horizontal well or vertical fracturated well.