Eect of Permeable Contacts on the Performance of a Gas-Oil Gravity Drainage Mechanism in a Stack of Matrix Blocks

In the gas invaded zone of a well fractured carbonate reservoir, gravity drainage mechanism
plays the main role in expelling oil from dense, low permeability matrix blocks. Whenever the
active mechanism is gravity drainage, reinltration and capillary continuity phenomena notably
in
uence the rate and amount of oil recovery from matrix blocks. In the current research, six
experiments were performed to study the eects of a permeable contact area (between two blocks
located on top of each other) on reinltration and capillary continuity. Two of the experiments
were performed using single blocks of 30 and 60 cm height, whilst others were stacks of two 30
cm high blocks. Results of the experiments reveal that, by increasing the permeable contact area
between blocks, due to capillary continuity and reinltration, there will be more communication
between them, consequently, both ultimate oil recovery and production rate will improve. It is
also noticeable that, if the permeable contact area is approximately greater than 20% of the total
block surface area, the stack of blocks behaves analogous to a unique block with a height equal
to that of the stack. The outcome of the present work, along with data from other studies, such
as the eects of horizontal fracture apertures and fracture dips, can be utilized in order to have
a better understanding of block to block eects. By this, the modeling of the gravity drainage
mechanism, while injecting gas into fractured carbonate formations, would be improved.