Reservoir Simulation Studies of Formation Damage for Improved Recovery on Oil-Gas Reservoirs
Thi Kim Phuong Nguyen
Australian School of Petroleum (ASP)
The University of Adelaide
This thesis is dedicated to the development of new technologies for sweep improvement due to plugging of highly permeable channels and layers by injected or lifted or mobilized fines particles. The following methods of improved waterflood have been proposed in the thesis:
- Injection of raw or poorly treated water with consequent homogenization ofthe injectivity profile due to distributed along the well skin factor.
- Injection of low salinity or fresh water resulting in lifting of reservoir fines,their migration and further capture by the rock with permeability reduction andredirection of the injected water into unswept area.
- Injection of sweet water into watered-up abandoned wells during pressureblowdown in oil and gas reservoirs with strong water support.
In the above three cases, the proposal of the new technologies was backed by
detailed reservoir simulations. In all cases, the application of the proposed
improved oil recovery technology, as forecasted by reservoir simulation, leads to
3-15% of incremental recovery and 2-3 times decrease of the amount of
produced and injected water.
The technology of raw water injection was developed using Eclipse waterflood
BlackOil simulator with modelling of injectivity decline along the well due to
plugging of porous media by injected particles. A new numerical procedure
describing skin growth with time in each section of long horizontal wells have
been developed and implemented into BlackOil Eclipse model. Different
configurations of horizontal injectors and producers have been modelled resulting
in production forecast with raw waterflooding.
The technology of low salinity water injection have been developed using Eclipse
reservoir modelling with polymer injection option, which can describe mobilization
of fines particles, their migration, capture and subsequent permeability decline.
The main physics mechanism of incremental oil recovery found is the diversion of
the injected water into unswept zones due to plugging the swept zone by capture
particles. The incremental recovery, as obtained by reservoir simulation, is 12%.
It may also result in 2 to 3 times decrease in water injection and production.
The proposal of a new technology of small bank of fresh water injection into
watered-up and abandoned production wells result in lifting of reservoir fines,
their migration and plugging the path for invaded aquifer water. It results in
decrease of water production and prolongation of oil or gas production from wells.