88 PETROLEUM TECHNOLOGY, ECONOMICS, AND POLITICS
devices to assist in lump size reduction and a size ejector at the
outlet end.
One of the economic issues that arises from the hot water process
is the disposal and control of the tailings. The fact is that each ton
of oil sand in place has a volume of about 16 cubic feet, which will
generate about 22 cubic feet of tailings giving a volume gain on the
order of 40%. If the mine produces about 200,000 tons of oil sand
per day, the volume expansion represents a considerable solids disposal problem.
3.4.2 Non-Mining Methods
In principle, the non-mining recovery of bitumen from tar sand
deposits is an enhanced recovery technique and requires the injection of a fluid into the formation through an injection wall. This
leads to the in situ displacement of the bitumen from the recovery
and bitumen production at the surface through an egress (production well). However, there are several serious constraints that are
particularly important and relate to bulk properties of the tar sand
and the bitumen. In fact, both must be considered in toto in the context of bitumen recovery by non-mining techniques. For example,
such processes need a relatively thick layer of overburden to contain the driver substance within the formation between injection
and production wells.
One of the major deficiencies in applying mining techniques to
bitumen recovery from tar sand deposits is (next to the immediate
capital costs) the associated environmental problems. Moreover, in
most of the known deposits, the vast majority of the bitumen lies
in formations in which the overburden/pay zone ratio is too high.
Therefore, it is not surprising that over the last two decades a considerable number of pilot plants have been applied to the recovery
of bitumen by non-mining techniques from tar sand deposits where
the local terrain and character of the tar sand may not always favor
a mining option.
The steam processes are the most advanced of all enhanced oil
recovery methods in terms of field experience and thus have the
least uncertainty in estimating performance, provided that a good
reservoir description is available. Steam processes are most often
applied in reservoirs containing viscous oils and tars, usually in
place of rather than following secondary or primary methods.
Commercial application of steam processes has been underway
devices to assist in lump size reduction and a size ejector at the
outlet end.
One of the economic issues that arises from the hot water process
is the disposal and control of the tailings. The fact is that each ton
of oil sand in place has a volume of about 16 cubic feet, which will
generate about 22 cubic feet of tailings giving a volume gain on the
order of 40%. If the mine produces about 200,000 tons of oil sand
per day, the volume expansion represents a considerable solids disposal problem.
3.4.2 Non-Mining Methods
In principle, the non-mining recovery of bitumen from tar sand
deposits is an enhanced recovery technique and requires the injection of a fluid into the formation through an injection wall. This
leads to the in situ displacement of the bitumen from the recovery
and bitumen production at the surface through an egress (production well). However, there are several serious constraints that are
particularly important and relate to bulk properties of the tar sand
and the bitumen. In fact, both must be considered in toto in the context of bitumen recovery by non-mining techniques. For example,
such processes need a relatively thick layer of overburden to contain the driver substance within the formation between injection
and production wells.
One of the major deficiencies in applying mining techniques to
bitumen recovery from tar sand deposits is (next to the immediate
capital costs) the associated environmental problems. Moreover, in
most of the known deposits, the vast majority of the bitumen lies
in formations in which the overburden/pay zone ratio is too high.
Therefore, it is not surprising that over the last two decades a considerable number of pilot plants have been applied to the recovery
of bitumen by non-mining techniques from tar sand deposits where
the local terrain and character of the tar sand may not always favor
a mining option.
The steam processes are the most advanced of all enhanced oil
recovery methods in terms of field experience and thus have the
least uncertainty in estimating performance, provided that a good
reservoir description is available. Steam processes are most often
applied in reservoirs containing viscous oils and tars, usually in
place of rather than following secondary or primary methods.
Commercial application of steam processes has been underway