JPS5845555B2 - Thermal oil extraction method for petroleum products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to oil field development technology, and more particularly, the present invention relates to a method for thermal extraction of petroleum products.

The present invention can be most advantageously used in the development of oil fields with highly viscous crude oil and fluid bitumen.

The present invention can also be used to exploit petroleum deposits characterized as depleted reservoir energy.

Currently, such oil deposits generally cannot be efficiently exploited by conventional methods of extracting oil from oil wells drilled from the surface.

So the recovery rate is very low.

As a method for developing oil fields containing highly viscous crude oil or fluid bitumen, a method of oil recovery by tunnel drilling, which does not involve bringing oil-bearing rocks to the surface, is known in the art (A, Ya .

“The Mining of D” by Krems et al.
eposit″jG ostoptehizdat P
ublisherss j1955 jMoscow.

(See page 274).

The method involves constructing a system of underground working shafts above the ceiling of the oil-bearing bed, which system includes a drill room of a peripheral shaft.

From this drill room, inclined oil well buttons and vertical oil wells are drilled, the depth of which varies depending on the thickness of the oil-bearing bed and the distance in the drill room 1 from the top of the oil-bearing bed.

After drilling a well, oil is recovered from the oil-bearing bed by artesian injection and then by airlift.

Oil rises through the oil-bearing bed or well into the drill room by the pressure of the reservoir during artesian blowing, and by the injection of compressed air through pipes placed in the well during airlift.

From the drill room, the oil is fed through underground working shafts to a central underground oil collector from which, after primary treatment and heating, it is pumped into above-ground tanks.

The above method increases the recovery rate of oil from oil-bearing beds by more than three times compared to exploitation by oil wells drilled from the surface.

However, the absolute value of the recovery is only about 6 times.

This low recovery rate necessitates the use of extraction methods that involve physical impact on oil-bearing beds and oil-saturated pond beds.

It is also known in the art to thermally extract petroleum products by heat-treating an oil-bearing bed with steam (V
, N., Mi 5hakov et al., On the
Use of Heat T reahn ent Me
thods When MiningHigh-Vis
cosity Oi I Deposit x Ne
ftyancyye Hozyaistvo-Journ
al of Petroleum Econo-mys
Nojlo, 1974 m pages 31-35).

In this latter method, a system of underground working shafts is constructed above the oil-bearing bed, which system includes a shaft, a shaft bottom workshop, a shaft, and a drill room.

Vertical buttonholes, inclined injection wells, and production wells are drilled from a drill room in the side shaft.

A heat carrier (steam) is supplied through the injection well to the oil-bearing bed so that the heat carrier forces oil from the injection well to the production well.

Airlift oil from the production well face to the drill room.

In this process, water vapor leaks into production wells and underground working shafts, resulting in a reduction in the efficiency of the thermal oil recovery method.

According to yet another prior art method of oil recovery by shaft drilling (see US Pat. No. 1,634,235), oil wells are drilled from underground working shafts located both above and below an oil-bearing bed.

Steam treatment of the oil well face area and extraction of oil therefrom is carried out through shallow oil wells drilled above or below the underground working shaft.

Heating the oil well face region is accomplished by supplying water vapor to the oil well face through pipes within the well;
On the other hand, oil is extracted from the same oil well.

The disadvantage of this method is that there is no displacement of oil from the oil-bearing bed by the carrier, and therefore the recovery is low.

Yet another method of oil recovery by tunnel drilling (U.S. Pat. No. 152)
0737) involves constructing a vertical shaft through an oil-bearing bed and providing a drill room below the oil-bearing bed.

A tilted oil well is drilled radially from the drill house, pointing upward and into the oil-bearing bed.

This method alternates between delivering a heat carrier through the well into an oil-bearing bed and withdrawing oil from the same well after heating the oil-bearing bed in the face region of the well.

The method further includes supplying a thermal carrier (e.g. steam) through a pipe passing through the well for the purpose of cleaning the face region of the well from oxidized oil and tar-like substances and for extracting the output of the well. .

Oil recovery is done by gravity.

The method of oil recovery by shaft drilling described above is not as advantageous as the previously described method since there is no effective expulsion of the oil from the oil-bearing bed, resulting in a low recovery rate.

The heat carrier is delivered from an underground working shaft located above the production shaft.

A method of developing oil deposits by tunnel drilling is further known (U.
, S, S, R Inventor's Certificate No. 468529 Specification, Classification E
21b43/24).

This production bed is heated by intermittent delivery of steam through a system of injection wells.

While the steam continues to be delivered, liquids (oil, water) are intermittently withdrawn, then hot water and then cold water are intermittently delivered in place of the steam, while the fluids are withdrawn through the production well. continues.

This latter method suffers from high heat losses with injected antibiotics.

The heat carrier is delivered into the oil-bearing bed through an injection well drilled from an underground working hole located above the oil-bearing bed, while the oil is recovered through an inclined oil well drilled from an underground working hole (production) located on the oil-bearing bed. Thermal oil extraction method for oil deposit development is also known (U, S, S.

R0 inventor's certificate No. 446631 specification, classification E21 b
43/18).

According to this method, underground working pits located in oil-bearing beds (production volume)
is filled with water when oil is recovered from a drilled oil well.

The liquid level in the production volume is kept constant during operation by pumps.

The last mentioned method suffers from high heat losses in the underground working shaft (injection method) in which the intake well is drilled.

Such heat losses are primarily due to water vapor escaping from the oil-bearing bed through cracks, as well as heat conduction through the rock.

The underground atmosphere of injection antibiotics becomes unbearable for humans due to the release of heat.

As the temperature of the injection tube increases, it becomes necessary to increase the amount of air pumped into the hole to bring the temperature inside the hole to an acceptable value for safety reasons.

Doing so reduces the development area, reduces production, and reduces the rate of oil recovery from oil deposits.

The present invention is intended to solve the problems in developing oil recovery methods by thermal extraction, and by applying heat to an oil-bearing bed with high efficiency, the oil-bearing bed can be used to produce higher oil production and higher oil production. Achieve recovery speed.

The present invention provides a system of underground working pits, constructing at least one injection well and at least one production volume, and drilling an injection well from the above injection method and a production well from the above production volume. , a heat carrier is applied to the oil-bearing bed through an injection well in order to heat the oil-bearing bed to a temperature at which the oil in the oil-bearing bed assumes the necessary fluidity and to force the oil to flow through the oil-bearing bed or into a production well. Thermal oil recovery method involves supplying, extracting oil from a production well to a production volume, supplying the oil from said production volume to the surface through an underground working hole, using a heat carrier. The method is characterized in that the injection method is filled with an insulating medium that prevents the heat carrier from leaking from the oil-bearing bed into the shaft when it is delivered to the oil-bearing bed.

Increased heat transfer efficiency to the oil-bearing bed is achieved by filling the injection method with backing material to reduce heat loss in the injection method where the injection well is drilled from the oil-bearing bed, allowing water vapor to pass through the cracks and leave the oil-bearing bed. This is achieved by preventing leakage and reducing heat losses caused by thermal conduction through the rock.

Increases in immediate oil production and oil recovery rates from oil deposits reduce the number of underground working shafts to be ventilated per unit area, and the integrated underground ventilation network only ventilates a limited number of underground working shafts. This can be achieved by increasing the oil development area.

A reduction in the number of underground working shafts to be ventilated can be achieved by cutting the injection method with an insulating medium and disconnecting it from the general underground ventilation network.

If the injection is located at a significant distance above or below the oil-bearing bed and in a stable rock with no major cracks connecting the injection to the oil-bearing bed, the injection must be filled with an insulating medium. Before this, it is a good idea to plug the injection well that is in direct communication with the production well.

Preferably, a solid backing material is used as the insulating medium.

The backing material placed in the press-fit antibiotic becomes a solid mass;
This seals cracks, passageways and highly permeable parts of the rock and prevents heat carriers from escaping from the oil-bearing bed.

In some cases it may be advisable to use a fluid medium as the insulating medium.

The fluid medium filling the injection method penetrates cracks and passageways into which heat carriers, such as water vapor, can enter, reducing heat losses.

If the injection method is filled with a fluid medium, there is no need to evacuate the shaft.

The heat released by conduction cannot be eliminated by the prior art air injections that serve to air vent the injection process.

Preferred embodiments of the invention will now be described with reference to the accompanying drawings.

The method of the present invention is carried out in the following manner.

Two shafts, namely the elevator shaft and shaft 1 (Fig. 1, Fig. 2)
and ventilation room, pit 2, locomotive depot, pumping station, supply warehouse, etc.
Work area 3 (second
An underground working shaft system including a horizontal shaft 4 (Figs. 1 and 2), and inclined underground working shafts 5 and 6 is constructed.

The shafts 4 are arranged above the top of the oil-bearing bed, and these shafts have an inclination of 1 to 3-0 with respect to the horizontal.

Oil field development will be carried out in each section.

All sections are identical to each other and may be regular polygons, such as hexagons as shown in FIG. 1, or rectangular shapes, or any other shape.

(U4 underground working shafts 5 and 6 run into the area of the shaft 4 (Figs. 1, 2) and the oil-bearing bed 7 (Fig. 2); An injection hole 8 is provided, and a production hole 9 is provided in or below the oil-bearing bed 7.

These shafts may be straight, curved, or circular in shape.

The injection well 10 is drilled from the injection hole 8 , and the production well 11 is drilled from the production hole 9 .

These injection wells are divided into groups according to the desired direction of the development process, and the injection wells included in each group are connected to a heat carrier supply pipe.

The heat carrier (e.g. steam) is supplied to the injection well 10 of the injection well 8.
is delivered into the oil-bearing bed through the oil-bearing oil bed and heats the oil-bearing bed to a temperature at which the oil assumes the required fluidity.

At the same time, the previously opened production wells are kept under surveillance.

A heat carrier such as steam is supplied from the boiler installation 12 through an above-ground pipeline 13 to the wellhead of the injection well 10 through a steam supply valve 14 and an underground pipeline (not shown) provided in the shaft 4.

Since the injection wells 10 and 11 are drilled in a dense network from different heights, the relative positions of the respective faces of the injection wells 10 and 11 may be close to each other, or they may even intersect. can also occur.

In reality, these injection wells and production wells may be in direct contact with each other, and in such cases, water vapor cannot be injected as described above even at a low steam delivery pressure (1 to 3 kg/cIrL2). When delivered to well 10, the steam is delivered to production well 9.
Leak immediately inside.

If water vapor leaks directly into any of the production wells 11, the injection well 10 where the leak has occurred must be located and sealed.

When steam is delivered into the oil-bearing bed 7, the steam cracks,
Heat loss also occurs due to penetration into the injection well 8 through the annular space of the injection well 10 and the fitting portion of the injection well 10 .

When heating all development sections 15 of the oil-bearing bed 7, heat losses also occur through the top and bottom of the oil-bearing bed, where the injection wells are located.

As the surface of the injection shaft 80 is heated, heat is transferred into the underground atmosphere, thereby increasing the temperature within the underground working shaft.

When the injection well 8 is ventilated with air in a prior art manner, a large amount of heat is carried away by the air injection.

As the temperature in an underground mine increases, it becomes necessary to pump large amounts of air through it.

As a result of this, the air movement rate in underground working shafts is high.

But this speed is limited by mine regulations.

If the heat loss through the injection shaft 8 becomes significant (for example, if the temperature conditions and the air injection rate in the injection shaft 8 become inconsistent with current safety regulations), this shaft is equipped with an insulating medium. Fill it.

A backing material or a fluid medium can be used as the insulating medium.

Backing materials include rock dust, smelter rejects (if any), etc.

The backing material placed in the press-fit antibiotic forms a solid backing mass that fills cracks, passageways, and highly permeable areas to prevent heat carrier from escaping from the oil-bearing bed.

Depending on the hot oil extraction conditions, the backing (filling with backing material) of the injection well 8 can be performed in a number of ways: hydraulically, gravity button and mechanically.

The backing method when the backing material is loaded with the aid of water is hydraulic backing.

The backing method when the backing material is loaded by gravity is gravity backing.

Mechanical backing is a backing method in which the backing material is loaded by a mechanical device.

Hydraulic and mechanical backing methods are quite often used in thermal oil extraction.

In the case of hydraulic backing, the sandstone is deposited into the injection shaft 8 by means of water jets.

The backing solid mass undergoes shrinkage.

That is, vertical tightening of the backing material reduces its volume.

Cracks through which water vapor can penetrate are closed, thereby reducing heat loss.

By densely filling part or all of the injection shaft space with backing material, the heat released by thermal conduction in the rock can no longer be carried away by the air jets used to ventilate the injection process. .

Since the method of the present invention reduces heat loss due to the press-fitting method 8,
This serves to reduce the water vapor consumption per ton of oil recovered and, as a result, to respectively increase the efficiency of heat supply to the oil-bearing bed 7.

Backing material from the nearest underground workshop can be used.

By carrying out the method of the invention, it is no longer necessary to transport the rock excavated from underground working shafts to the surface.

This rock can simply be transferred to a nearby work site where it is to be filled.

The rock deposited by the hydraulic backing densely fills the entire space of the injection method 8 and poses a risk of harm to the equipment provided with the wellhead (this danger usually occurs when the ceiling of an underground workshop caves in). It disappears.

For horizontal injection methods flush with the main excavation level, a concrete channel should be provided prior to hydraulic backing.

This is not necessary when filling a collapsed underground working shaft.

For the purpose of heating the oil-bearing bed to a temperature at which the oil in the oil-bearing bed assumes the necessary fluidity, a heat carrier is distributed uniformly throughout the oil-bearing bed 7 so that the oil enters the production well 11 and is further heated to the production volume 9. Heat carriers are periodically delivered to the oil-bearing bed 7 through each of the aforementioned groups of injection wells in sequence.

Oil is periodically recovered from production wells 11.

During this recovery, the oil-bearing bed 7 is supplied with a heat carrier in the amount necessary to maintain the temperature necessary for the exploitation of the oil deposit and to remove the oil from the oil-bearing bed 7.

The oil recovered from the production well 11 and supplied to the production volume 9 is further sent to a trench provided in the side shaft 4.

The oil together with the water supplied to this trench is conveyed by gravity, i.e. with the aid of tilting the underground working shaft at an angle of about 1 to 3 degrees to the horizontal, to a device (not shown) that separates oil from water. .

Alternatively, the recovered oil and water can be pumped from production volume 9 to inclined underground working shafts 5 and 6 and side shaft 4.
It can also be conveyed through a pipeline along the line to the above-mentioned water separation device.

From this equipment, oil is pumped to an underground central oil collector (not shown) for primary treatment and preheating.

Thereafter, the oil is supplied through a pipeline through a special oil well 16 or upwelling to an oil storage tank 17 located above ground.

A mine ventilation network can only ventilate a certain number of underground working shafts.

In other words, there are certain limits regarding the development area,
And as a result, there are certain limits to immediate oil production.

If the volume of the underground working shaft that can be ventilated is reduced, the number of sections 15 that can be operated at the same time will be reduced, since the development of the oil field during thermal oil extraction is carried out in sections.

The number of ventilated underground working shafts in each compartment 15 will vary depending on the development method used.

The fewer the number of parcels 15 under development, the less oil will be produced from that oil deposit, and the lower the oil recovery rate will be.

By reducing the required volume of underground working shafts to be ventilated in the area of a single compartment 15, it becomes possible to develop a large number of compartments and thereby reduce the oil output from the oil deposit. can be increased.

Operating the well under unfilled development well conditions similarly reduces heat losses.

In this case, an unrestricted penetration of water vapor into the output through the production well 11 can be prevented by controlling the operation of this well in a suitable manner.

Such control is possible by providing a free passage at the mouth of the production well 11.

Better drainage and higher oil recovery from oil deposits can also be achieved by removing the back pressure on the oil-bearing bed from the measurement of production9.

Due to the unfilled output 9, the pressure gradient in the oil-bearing bed increases at the same delivery pressure.

By increasing the pressure gradient in the oil-bearing bed and controlling the operation of the production well 11, thermal gearing can be transmitted more fully throughout the oil-bearing bed 7, thereby increasing both immediate oil production and ultimate oil recovery. It will increase it.

Heat losses due to production 9 are reduced by providing special areas (pillars) where injection wells are not drilled.

If necessary, this area adjacent to the production volume 9 can be cooled by cold water passing through special wells.

Lower heat losses and higher immediate oil yields result in lower water vapor consumption per ton of oil recovered and higher heat transfer efficiency.

In another embodiment of the invention, the injection well 10 is in direct communication with the production well 11 when the injection well 8 is located in stable debris at a significant distance (above or below) from the oil-bearing bed 7. The injection well 8 is then filled with a fluid medium (for example water).

The fluid medium filling the injection well 8 penetrates the crack buttons and passages where water vapor can enter, reducing heat losses.

As the fluid medium, stratum water, spring or pond water, waste water, clay mortar, etc. can be used.

By filling the injection shaft 8 with a fluid medium such as water, there is no need to ventilate the shaft.

This injection shaft 8 is no longer continuous with the underground ventilation network, as a result of which the heat loss due to heat conduction through the surface of the injection shaft 80 is reduced, thus making it possible to create a new section of the developed oil deposit.

If the injection shaft 8 is located at the same height as the main system of underground working shafts, a concrete waterway is provided in the shaft.

This channel prevents the fluid medium from flowing out of the injection shaft into the underground working shaft where people are present.

In the case of the development of oil deposits, it is necessary to perform a preliminary inspection of the injection wells 8 or to plug several injection wells 10.

Under such conditions, when steam is injected, it is preferable to periodically fill the injection well 8 with a fluid medium (for example water).

The period varies depending on the geography of the oil-bearing bed and process parameters, such as the delivery pressure of the heat carrier.

The rock debris containing the injection well 8 should be suitably stable.

If this is not the case, supports should be provided to allow regular filling of the shaft with fluid media.

If a channel is provided in the injection shaft 8 prior to filling with a fluid medium such as water, a special manhole is provided in the channel to provide access for personnel to the shaft and to ensure adequate ventilation. .

The present invention can also be used advantageously for the recovery of fluid picumen.

[Brief explanation of drawings]

FIG. 1 shows the area of an underground working shaft with injection and production wells (underground working shafts are customarily shown as being located in a single horizontal plane); FIG. It is a sectional view taken along the line ■-■. In the figure, 7...oil-containing bed, 8...injection well, 9...production well, 10...injection well, 11...production well.

Claims (1)

[Claims] 1. Constructing a large number of underground working pits, at least one injection pit button, and at least one production pit, and drilling an injection well from the injection pit and a production well from the production pit. , a heat carrier is passed through an injection well into the oil-bearing bed in order to heat the oil-bearing bed to a temperature at which the oil in the oil-bearing bed assumes the necessary fluidity and to force the oil from the oil-bearing bed into the production well. The method of thermal extraction of petroleum products includes supplying, extracting oil from a production well to a production well, supplying the oil from the production well to the surface through an underground working pit, using a heat carrier. The hot oil extraction method as described above, characterized in that the injection hole is filled with an insulating medium that prevents the heat carrier from leaking from the oil-bearing bed into the injection hole when the oil is delivered to the oil-bearing bed. 2. The thermal oil extraction method according to claim 1, characterized in that before filling the injection well with an insulating medium, the injection well that is in direct communication with the production well in the oil-bearing bed is plugged. 3. The thermal oil extraction method according to claim 1 or 2, characterized in that a solid backing material is used as the insulating medium. 4. The thermal oil extraction method according to claim 1 or 2, characterized in that a fluid medium is used as the insulating medium.