Heavy-oil recovery is limited by low fluid mobility and steam sweep efficiency.
Lateral drainholes offer advantages similar to hydraulic
fracturing in low-permeability gas zones. Increased
wellbore contact with the reservoir stimulates production
from heavy-oil deposits and thin, shallow or depleted
reservoirs. Multiple laterals reduce pressure drop
across the completion face, mitigate water and gas
breakthrough and improve injection efficiency.
2 -
In low-permeability and naturally fractured reservoirs, multiple laterals improve
the likelihood of completing economic wells. Horizontal
laterals, like hydraulic fracturing, increase well
productivity in “tight” formations; laterals perpendicular
to natural fractures significantly improve well output.
3 -
Multilateral wells also tap distinct reservoir compartments created by stratigraphic
traps and sealing faults. When reserve volumes do
not justify a dedicated single-bore well, multilaterals
can connect several reservoir compartments. Bypassed
oil and gas left as aquifer or injected water sweep
past low-permeability areas can be recovered by multilateral
wells.
4 -
Vertical laterals improve productivity and reserve recovery in laminated and
layered formations by connecting individual intervals
separated by horizontal barriers or permeability contrasts
and gradations. Simultaneously producing multiple zones
by varying lateral inclination and depth keeps production
rates above the economic limit of surface facilities
or offshore platforms and prolongs well and field economic
life.
5 -
Multilateral wells allow development of small reservoirs and outlying fields
that are not feasible to produce with conventional
vertical, high-angle or horizontal wells. Multilateral
wells can exploit low-pressure and depleted reservoirs,
particularly for infill and reentry drilling applications.
