Method and apparatus for improving steam dryness of steam injection boiler

Abstract

The method and an apparatus for improving the steam dryness of a steam injection boiler includes injecting wet saturated steam and gas into an oil layer together in a sealed way, after the dryness of the wet saturated steam at an outlet of the steam injection boiler is improved by a dryness raiser. The dryness raiser includes a combined spray head, a steam heating chamber, a combustion chamber, and a mixing chamber. The gas generated by the combustion chamber enters into the mixing chamber and is fully mixed with the steam from the steam injection boiler. The dryness of the wet saturated steam at the outlet of the steam injection boiler can be improved to 95%-100%, and the effects of improving steam enthalpy, replenishing stratum energy and enlarging the steam wave and size are realized, so as to heat up the oil layer more effectively, and improve heavy oil development.

Claims

1. A method for improving steam dryness of a steam injection boiler, comprising the steps of: setting dryness of wet saturated steam at an outlet of a steam injection boiler by a dryness raiser; and injecting the saturated steam together with gas generated by said dryness raiser into an oil layer in a sealed way; wherein said dryness raiser comprises: a combined spray head, a steam heating chamber, a combustion chamber, and a mixing chamber, wherein fuel oil and air are supplied into said combustion chamber by a fuel oil pump and an air compressor under control of an automatic control system of said dryness raiser, wherein fuel oil and air are combusted in said combustion chamber, wherein said wet saturated steam at said outlet of said boiler enters into said steam heating chamber of said dryness raiser (4) at a same time as said fuel oil and air are combusted, wherein said wet saturated steam is heated in said steam heating chamber by heat created by combustion in said combustion chamber, wherein gas generated in said combustion chamber enters into said mixing chamber, and mixes in said mixing chamber with said wet saturated steam with increased dryness from said steam heating chamber, and wherein dryness of the wet saturated steam is further improved by controlling an amount of fuel oil with said automatic control system, dryness of said wet saturated steam being improved to 95%-100%, a temperature of a gas-steam mixture being controlled after mixing, said gas-steam mixture being injected into said oil layer through a steam injection string in a sealed way.

2. The method for improving the steam dryness of a steam injection boiler according to claim 1, further comprising the following steps: starting up a steam injection boiler with an automatic control valve of a steam inlet, an automatic control valve of a gas-steam outlet in closed state, an automatic-control valve, and an automatic-control bypass valve of the steam outlet of the boiler in open state, wherein steam generated by said steam injection boiler is injected through the automatic control bypass valve into an oil well; and after parameters of said steam injection boiler become normal, starting said dryness raiser, opening said automatic control valve and a discharge valve of the steam inlet, closing said automatic control bypass valve, operating said dryness raiser with preset working parameters, and controlling the fuel oil pump and air compressor with said automatic control system of said dryness raiser to supply the fuel oil in a fuel oil tank and compressed air to said dryness raiser, wherein fuel oil and air enter into the combustion chamber, ignite by an igniter, and are combusted in said combustion chamber, wherein, when combustion is detected as normal, said automatic control valve of said gas-steam outlet opens and said discharge valve closes, said dryness raiser in normal operation state improving dryness of the wet saturated steam supplied from the steam injection boiler to 95%-100%, and wherein said wet saturated steam with improved dryness is mixed with gas generated from combustion in said dryness raiser and then injected together with said gas into said oil layer through a steam injection string in a sealed way.

3. The method for improving the steam dryness of a steam injection boiler according to claim 1, wherein said steam heating chamber is arranged with a steam inlet on a head end thereof and an annular multi-orifice nozzle on a tail end thereof, and wherein said tail end of said combustion chamber communicates with the annular multi-orifice nozzle on said tail end of said steam heating chamber and the mixing chamber.

4. The method for improving the steam dryness of a steam injection boiler according to claim 1, wherein said mixing chamber is provided with an additional steam inlet on an upper end thereof, wherein a branch of the steam supplied from said steam injection boiler enters into said steam heating chamber through said steam inlet on said head end of said steam heating chamber, and wherein another branch of steam supplied from said steam injection boiler enters into said mixing chamber directly through said steam inlet of said mixing chamber.

5. The method for improving the steam dryness of a steam injection boiler according to claim 1, wherein said combustion chamber is arranged with a preheating chamber at a head end thereof, and wherein fuel oil and air are preheated in the preheating chamber, facilitating combustion of the fuel oil in atomized state.

6. An apparatus for improving steam dryness, said apparatus, comprising: a steam injection boiler having a steam outlet with a steam branch connected through an oil injection pipe to an automatic control bypath valve and being in fluid connection with a steam injection well mouth through said automatic control bypath valve; a dryness raiser having an automatic control valve of said steam inlet in fluid connection with said steam injection boiler through said oil injection pipe, said automatic control bypath valve and said automatic control valve of said steam so as to set dryness of wet saturated steam of said steam injection boiler by said dryness raiser and to inject the saturated steam into said oil layer according to claim 1; an automatic control system being connected to said dryness raiser: an automatic control system of said steam injection boiler being connected to said steam injection boiler and said automatic control system; a fuel oil pump being connected to said automatic control system; an air compressor being connected to said automatic control system; an automatic control valve of a gas-steam outlet in fluid connection with said dryness raiser and said steam injection well mouth; and a check valve in fluid connection with said automatic control valve of said gas-steam outlet, wherein said dryness raiser is comprised of a fuel oil nozzle and an air nozzle, said fuel oil pump being connected to said fuel oil nozzle, said air compressor being connected to said air nozzle, wherein said dryness raiser is comprised of a gas-steam outlet, said automatic control valve of gas-steam outlet and said check valve being in fluid connection to said steam injection well mouth through said gas-steam outlet, wherein said dryness raiser is comprised of a combined spray head, a steam heating chamber, a combustion chamber, and a mixing chamber, wherein a supply of fuel oil from said fuel oil pump and said combustion chamber is determined by said automatic control system, a supply of air from said air compressor and said combustion chamber being determined by said automatic control system so as to combust said fuel oil and said air in said combustion chamber and so as to produce gas, wherein said wet saturated steam from said steam injection boiler enters into said steam heating chamber through said automatic control bypath valve so as to heat said wet saturated steam when said fuel oil and said air combust in said combustion chamber and so as to produce a heated wet saturated steam with increased dryness compared to said wet saturated steam, and wherein said gas and said heated wet saturated steam from said steam heating chamber enter into said mixing chamber, said mixing chamber being in fluid connection with said gas-steam outlet so as to form a gas-steam mixture to be injected into said oil layer.

7. The apparatus for improving the steam dryness, according to claim 6, wherein said dryness raiser further comprises: a combined spray head having an air nozzle, an igniter, and a fuel oil nozzle and being connected to said combustion chamber, said combustion chamber being cylindrical; and a steam heating chamber being fitted over said combustion chamber in a circular form and having a head end with a steam inlet and a tail end with an annular multi-orifice nozzle; and wherein said combustion chamber has a tail end in communication with said annular multi-orifice nozzle and said mixing chamber, said mixing chamber having an outlet end in fluid connection with said gas-steam outlet.

8. The apparatus for improving the steam dryness, according to claim 6, wherein said dryness raiser comprises: a combined spray head having an air nozzle, an igniter, and a fuel oil nozzle and being connected to said combustion chamber, said combustion chamber being cylindrical; and a steam heating chamber being fitted over said combustion chamber in a circular form and having a head end with a steam inlet and a tail end; and wherein said combustion chamber has a tail end in communication with said tail end of said steam heating chamber and said mixing chamber, said mixing chamber having an upper end and an outlet end in fluid connection with said gas-steam outlet.

9. The apparatus for improving steam dryness, according to claim 7, wherein said dryness raiser is further comprised of a preheating chamber, wherein said combustion chamber has a head end, said preheating chamber being arranged on said head end of said combustion chamber, wherein said preheating chamber is connected to said combined spray head, wherein said preheating chamber and said combustion chamber are comprised of an integral cylindrical structure, said preheating chamber having a top side and a bottom side, said preheating chamber being comprised of holes arranged opposite to each other on said top side and said bottom side, and wherein said air nozzle, igniter, and fuel oil nozzle communicate with said combustion chamber through said preheating chamber.

10. The apparatus for improving steam dryness according to claim 8, wherein said dryness raiser is further comprised of a preheating chamber, wherein said combustion chamber has a head end, said preheating chamber being arranged on said head end of said combustion chamber, wherein said preheating chamber is connected to said combined spray head, wherein said preheating chamber and said combustion chamber are comprised of an integral cylindrical structure, said preheating chamber having a top side and a bottom side, said preheating chamber being comprised of holes arranged opposite to each other on said top side and said bottom side, and wherein said air nozzle, igniter, and fuel oil nozzle communicate with said combustion chamber through said preheating chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flow chart of a processing apparatus that utilizes the method disclosed in the present invention.

(2) FIG. 2 is a schematic view of a diagram of a first structural implementation of the dryness raiser.

(3) FIG. 3 is a schematic view of a diagram of a second structural implementation of the dryness raiser.

(4) FIG. 4 is a schematic view of a diagram of a third structural implementation of the dryness raiser.

(5) FIG. 5 is a schematic view of a diagram of a fourth structural implementation of the dryness raiser.

(6) FIG. 6 is a schematic view of a diagram of a fifth structural implementation of the dryness raiser.

(7) FIG. 7 is a schematic view of a diagram of a sixth structural implementation of the dryness raiser.

(8) Among the drawings: 1steam injection boiler, 2automatic control valve of steam outlet of boiler, 3automatic control valve of steam inlet, 4dryness raiser, 5discharge valve, 6automatic control valve of gas-steam outlet, 7check valve, 8automatic control bypass valve, 9automatic control system of steam injection boiler, 10automatic control system of dryness raiser, 11fuel oil tank, 12high-pressure fuel oil pump, 13air compressor, 14steam injection well mouth, 4.1steam inlet, 4.2steam heating chamber, 4.3combustion chamber, 4.4combined spray head, 4.5high-pressure air nozzle, 4.6igniter, 4.7high-pressure fuel oil nozzle, 4.8preheating chamber, 4.9annular multi-orifice nozzle, 4.10mixing chamber, 4.11gas-steam outlet, 4.12steam inlet of mixing chamber.

DETAILED DESCRIPTION OF THE DRAWINGS

(9) Embodiment 1: Hereunder the present invention will be further detailed with reference to FIG. 1 and FIG. 2:

(10) The present invention utilizes the principles in combustion, hydrodynamics, heat transfer, and engineering thermodynamics with engineering technology in combination, and designs a method that utilizes a developed dryness raiser to heat up the wet saturated steam with 70%-75% dryness at the outlet of a steam injection boiler and improve the dryness to 95%-100%, and then injects the saturated steam with improved dryness into the oil layer through an steam injection string together with gas in a sealed way. The apparatus mainly comprises a steam injection boiler 1, a dryness raiser 4, a high-pressure fuel oil pump 12, an air compressor 13, and an automatic control system 10 of the dryness raiser. The steam outlet of the steam injection boiler is connected to an automatic control valve 3 and an automatic control bypass valve 8 at the steam inlet of the dryness raiser 4 through a steam injection pipe; the automatic control system 9 of the steam injection boiler is connected with the automatic control system 10 of the dryness raiser, wherein, the automatic control system 9 of the steam injection boiler and the automatic control system 10 of the dryness raiser are implemented with known techniques in the prior art, and therefore will not be detailed here; the high-pressure fuel oil pump 12, air compressor 13, igniter 4.6 are connected to the automatic control system 10 of the dryness raiser; the high-pressure fuel oil pump 12 and the air compressor 13 are connected to a high-pressure fuel oil nozzle 4.7 on a combined spray head 4.4 and a high-pressure air nozzle 4.5 arranged of the dryness raiser respectively; a gas-steam outlet 4.11 arranged on the dryness raiser 4 is connected to a discharge valve 5, an automatic control valve 6 of the gas-steam outlet, and a check valve 7, and the check valve 7 is connected to a steam injection well mouth 14.

(11) The method is implemented as follows: first, the steam injection boiler 1 is started, with the automatic control valve 3 of the steam inlet and the automatic control valve 6 of the gas-steam outlet of the dryness raiser in closed state, and the automatic control valve 2 and automatic control bypass valve 8 of the steam outlet of the boiler in open state, and, in that state, the steam generated by the steam injection boiler is injected into the oil well through the automatic control bypass valve 8; after the parameters of the steam injection boiler become normal, the dryness raiser 4 is started, and the automatic control valve 3 and discharge valve 5 of the steam inlet of the dryness raiser are opened and the automatic control bypass valve 8 is closed at the same time, so that the dryness raiser 4 operates with preset working parameters, and the fuel oil in a fuel tank 11 and compressed air are supplied by the high-pressure fuel oil pump 12 and air compressor 13 to the dryness raiser 4 under the control of the automatic control system; the fuel oil and air enters into the combustion chamber 4.3 of the dryness raiser 4, ignited by the igniter 4.6 and combusted; when the combustion is detected by 20 s automatic detection as normal, the automatic control valve 6 of the gas-steam outlet is opened automatically and the discharge valve 5 is closed under program control, so that the dryness raiser 4 in normal operation state improves the dryness of the wet saturated steam with 70%-75% dryness supplied from the steam injection boiler to 95%-100%, and then the wet saturated steam with improved dryness is injected together with the gas into the oil layer through a steam injection string in a sealed way.

(12) If the dryness raiser 4 is detected as by 20 s automatic detection as failed or abnormal after it is started, the high-pressure fuel oil pump 12 and air compressor 13 will be shut off automatically, and the automatic control valve 3 of the steam inlet and the automatic control valve 6 of the gas-steam outlet will be closed and the discharge valve 5 and automatic control bypass valve 8 will be opened at the same time; in addition, the failure point will be displayed on the display screen of a monitoring and control system. The restart procedure is the same as the procedure described above. The steam heating chamber 4.2 around the combustion chamber 4.3 is heated by the approx. 2000 C. high temperature created by the combustion in the combustion chamber 4.3, the saturated water in the wet saturated steam absorbs heat and is vaporized in the steam heating chamber 4.2, so that the steam dryness is improved; the saturated water cools the outer wall of the combustion chamber 4.3 as it absorbs heat and is vaporized, because the saturated water has high latent heat of vaporization and the vapor temperature remains unchanged in the heat absorption and vaporization process of the saturated water; therefore, the temperature of the outer wall of the combustion chamber 4.3 will not be too high, and the combustion chamber 4.3 of the dryness raiser 4 will not be ablated, which is to say, the combustion chamber 4.3 can operate safely in a long time. The wet saturated steam with improved dryness is sprayed by the annular multi-orifice nozzle 4.9 on the tail end of the steam heating chamber 4.2 into the mixing chamber 4.10, and is fully mixed with the high-temperature and high-pressured gas generated in the combustion chamber 4.3, most of the saturated water is vaporized instantly under the heat, and the steam dryness is further improved in the mixing chamber 4.10, for example, to 95%-100%, depending on the volume of fuel oil used. In addition, the temperature of the gas-steam mixture can be controlled, and then the gas-steam mixture is injected into the oil layer through the gas-steam outlet 4.11 and a steam injection string. The design parameters and working parameters of the dryness raiser 4 are displayed on the display screen of an automatic control system in real time and are stored automatically.

(13) The dryness raiser mainly comprises a combined spray head 4.4, a steam heating chamber 4.2, a combustion chamber 4.3, and a mixing chamber 4.10, wherein, the combined spray head 4.4 has a high-pressure air nozzle 4.5, an igniter 4.6, and a high-pressure fuel oil nozzle 4.7, and is connected to the combustion chamber 4.3; the combustion chamber 4.3 is in a cylindrical structure; the steam heating chamber 4.2 is fitted over the combustion chamber 4.3 in a circular form, and has a steam inlet 4.1 on its head end and an annular multi-orifice nozzle 4.9 on its tail end; the tail end of the combustion chamber 4.3 communicates with the annular multi-orifice nozzle 4.9 on the tail end of the steam heating chamber 4.2, and communicates with the mixing chamber 4.10; the mixing chamber 4.10 has a gas-steam outlet 4.11 on its outlet end, and the gas-steam outlet 4.11 is connected through a discharge valve 5, a gas-steam automatic control valve 6, and a check valve 7 to a steam injection string.

(14) Embodiment 2:

(15) Embodiment 1: Hereunder the present invention will be further detailed with reference to FIG. 1 and FIG. 3:

(16) The difference between this embodiment and embodiment 1 is: the annular multi-orifice nozzle 4.9 on the tail end of the steam heating chamber 4.2 of the dryness raiser 4 is omitted, and an additional steam inlet 4.12 is arranged on the upper end of the mixing chamber 4.10; one branch of steam supplied from the steam injection boiler enters into the steam heating chamber 4.2 through the steam inlet 4.1, and the other branch of steam supplied from the steam injection boiler directly enters into the mixing chamber 4.10. With this scheme, the gas and steam can be fully mixed, the steam dryness can be improved to 95%-100%, and the object of the present invention can also be attained.

(17) Embodiment 3:

(18) Embodiment 1: Hereunder the present invention will be further detailed with reference to FIG. 1 and FIG. 4:

(19) The difference between this embodiment and embodiment 1 is: the annular multi-orifice nozzle 4.9 on the tail end of the steam heating chamber 4.2 of the dryness raiser 4 is omitted, and the mixing chamber 4.10 is extended outwards to enlarge its volume, so that the gas from the combustion chamber can be fully mixed with the steam from the steam injection boiler and the steam dryness can be improved to 95%-100%; of course, the mixing chamber can be in a horn shape, cone shape, or cylinder shape, not limited to the structure illustrated in the drawings. With this scheme, the gas and steam can also be mixed fully, and the object of the present invention can also be attained.

(20) Embodiment 4:

(21) Embodiment 1: Hereunder the present invention will be further detailed with reference to FIG. 1, FIG. 5, FIG. 6, and FIG. 7:

(22) The difference between this embodiment and embodiment 1 is: a preheating chamber 4.8 is arranged at the head end of the combustion chamber 4.3 of the dryness raiser 4, according to the properties of the fuel; other structural changes can also be implemented in this embodiment, similar to the case of embodiment 2 or embodiment 3. The object of the present invention can also be attained with this scheme.

(23) The preheating chamber 4.8, annular multi-orifice nozzle 4.9, steam inlet 4.12 of mixing chamber, and mixing chamber 4.10 involved in the above schemes of the dryness raiser 4 can be used fully or partially in the dryness raiser 4, according to the specific conditions of implementation; for example, the preheating chamber 4.8 can be used or not used, according to the properties of the fuel oil; either the annular multi-orifice nozzle 4.9 on the tail end of the steam heating chamber 4.2 or the steam inlet 4.12 of the mixing chamber can be used, or both of them can be used, or neither of them is used if the volume of the mixing chamber 4.2 is large enough; of course, the mixing chamber 4.10 can be used or not used, depending on the distance to the well mouth; in addition, in the present invention, the fuel is not limited to fuel oil; for example, fuel gas can be used as the fuel, of course, in that case, a high-pressure fuel gas pump and a fuel gas pipeline instead of a fuel oil tank should be used accordingly; such structures are well-known by those skilled in the art.

(24) The structural variations of the dryness raiser 4 include, but are not limited to the forms described in above embodiments and illustrated in the accompanying drawings, and any ordinary structural variation shall be deemed as falling in the protection domain of the present invention.