JPS6020555B2 - Steam or hydrothermal plants for offshore oil fields - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steam or hot water plant for an undersea oil field that injects steam or hot water into an oil field, which is one method for improving the yield of crude oil in an undersea oil field.

Steam or hot water injection methods are particularly suitable for highly viscous petroleum (usually AP).
It can be used to great effect in oil fields that produce 1°C (22 to below).

The oil field boiler for this purpose has been used as a kind of hot water boiler, so a through boiler has been in practical use for a long time.
Further, when the steam temperature is 30,000 or less, the fluidity of crude oil can be sufficiently increased and oil extraction can be facilitated. However, one of the problems with this method is securing the boiler water supply.
In particular, the issue is how to economically secure a large amount of boiler water supply in offshore oil fields. Another issue is whether wastewater separated from extracted crude oil (mostly oil field water) can be treated without regard to pollution problems. The present invention provides a steam or hot water plant for submarine oil fields that can solve the above-mentioned problems in the steam or hot water injection method, and embodiments thereof will be described below with reference to the drawings.

In FIG. 1, 1 is a boiler that heats boiler feed water a supplied from a water tank 2 by a water pump 3 to produce superheated steam b. Natural gas or crude oil, which is extremely abundantly produced in ordinary oil fields 4, is used as the boiler fuel c and is burned in the burner 5. Reference numeral 6 denotes a hot waste water heater, which injects superheated steam b generated in the boiler 1 to heat the hot waste water d supplied from the hot waste water tank 7 through the hot waste water pressurizing pump 8.

The hot water or steam e generated by this is directly injected into the oil field 4 by opening the pressure reducing valve 9, and is also depressurized by the pressure reducing valve 9 to self-evaporate, increasing the proportion of steam in the injected fluid. Press-fitted. Note that if hot water injection is more advantageous for crude oil exploration, the pressure reducing valve 9 may be omitted. On the other hand, superheated steam b from the boiler drives a turbine 10 to generate a generator 1.
Drive 1. Exhaust steam f discharged from the turbine 10
is sent to the freshwater generator 12 and used as heating steam. Product water h produced from seawater g sent through the seawater pump 13 in the water generator 12 is sent to the water supply tank 2 by the product water transfer pump 14 and stored.
Further, the exhaust steam f of the turbine 10 is used as heating steam in the freshwater generator 12 and condensed, and is circulated to the boiler 1 again as boiler feed water a by the feed water pump 3. Furthermore, in the water production device 12, about 4000 g of hot wastewater d (concentrated wastewater and cooling wastewater) generated when producing water h from seawater g is partially purged and left as overflow wastewater. It is sent to tank 7 and stored. 15 is an oil extraction pump driven by the generator 11, and the crude oil i pumped up by this pump is
is sent to the oil-water separator 16.

The crude oil i separated by this oil-water separator 16 is sent to a tank on land, and the heated waste water d (separated water, which is quite high temperature since the extracted crude oil has a temperature of around 80 qo) is sent to a tank on land. The hot waste water is sent to the heated waste water tank 7 and stored. j
is an exhaust gas, and 17 to 22 are valves, respectively. Next, its operation will be explained.

In the plant of the present invention, the steam or hot water injection process and the launching and oil extraction process are selected by operating the valves 17 to 22. First, hot water or steam e is injected into the oil field 4 at a fixed period, e.g. After about a day, oil is extracted using a nearby oil well or steam injection well, and at the same time, water is generated for boiler water supply a using a water generation device 12, etc., and these two types of processes are repeated. be driven. FIG. 2 shows a hot water or steam injection process, in which valves 18, 20, 22 corresponding to the turbine 10 and the water generator 12 are shown.
is closed, and the remaining 17, 19, and 21 are open.

Boiler feed water a supplied from a water supply tank 2 via a water supply pump 3 is converted into superheated steam b in the boiler 1, and the superheated steam b is injected into a hot waste water heater 6. This hot waste water heater 6
Overflow water d is supplied from the hot waste water tank 7 via the hot waste water pressurizing pump 8. Therefore, the hot waste water d is heated by the superheated steam b, becomes hot water or steam e, and is sent to the oil field 4. entered. Figure 3 shows the water production and oil extraction process,
At this time, the valves 19, 21 corresponding to the overflow water heater 6 are closed, and the remaining valves 17, 18, 20' are opened.
Crude oil i in the Kamenai oil field, whose viscosity has been reduced by the hot water or steam e injected in the previous step, is extracted by an oil extraction pump 15 and sent to a water-hydration device 16 . The crude oil i separated in the oil-water scaler 16 is sent to a tank on land, and the heated wastewater d is sent to the heated wastewater tank 7. Superheated steam b generated in boiler 1 during oil extraction as described above
drives the turbine 10 and operates the generator 11. This provides power for the oil extraction pump 15 and other pumps. Further, the exhaust steam f is used as heating steam for the fresh water generator 12, and the condensate is circulated to the boiler 1 again through the water feed pump 3. In addition, the water generator 12 is passed through the seawater pump 13.
The produced water h' obtained from the seawater g supplied to the tank is stored in the water supply tank 2 through the produced water transfer pump 14. The above-mentioned equipment 1 to 22 can be installed on the platform for oil drilling, but if large capacity water tanks 2 and hot waste water tanks 7 are required, they can be installed at sea without being exposed on the platform. It's better to let it float.

Although the above embodiment has been described based on the evaporative water generation device 12 that uses exhaust steam f, a reverse osmosis membrane water generation device that uses seawater g may also be adopted.

In this case, the wastewater from the fresh water generator has no advantage in terms of temperature, but instead has a residual pressure of about 10k9/g,
This has the advantage of being able to be used as part of the injection water. As described above, the present invention has the following advantages.

1. Low-quality water can be used for steam or hot water to be pumped into oil fields.

That is, since superheated steam generated in a boiler is injected into the overflow water heater to heat it, low-quality water can be used as water for irrigation. Therefore, the hot wastewater separated by the oil-water separator and the hot wastewater discharged from the fresh water generator can be used as water for injection. In particular, it is extremely advantageous because it can fully utilize and process the separated hot wastewater from oil-water separators that cannot be disposed of into rivers, oceans, etc. due to pollution problems.0 Wastewater can be recovered and used as thermal energy.

In other words, steam injection is carried out in oil fields containing high-viscosity car oil, and oil is extracted by increasing the fluidity of the oil using the injection steam. Therefore, the extracted crude oil has a temperature of around 8000°C, and therefore the temperature of the separated water is also high. Also, the concentrated wastewater and cooling water discharged from the water production equipment are approximately 40°C.
The use of such wastewater is thermally advantageous. m From the previous paragraph (b), when the same amount of heat is injected, this method is better than the method of reducing the temperature of boiler-generated steam using some boiler feed water, for example, because the boiler, water production equipment, water supply tank, etc. This is extremely advantageous since it requires only a small capacity.

[Brief explanation of drawings]

FIG. 1 is an overall system diagram showing an embodiment of the present invention, FIG. 2 is a system diagram for the hot water or steam injection process, and FIG. 3 is a system diagram for the water generation and oil extraction processes. 1...Boiler, 2...Water tank, 4...
・・・Oil field, 6... Warm waste water heater, 7...
・・Warm wastewater tank, 12・・・・ Fresh water generator, 16・
・・Oil/water container, a・・Boiler feed water, b・Superheated steam, d・・Hot waste water, e・・Hot water or steam, i・・・・・·crude oil. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A water supply tank, a boiler that burns natural gas or crude oil obtained from an oil field and heats the boiler feed water supplied from the water tank to produce superheated steam, and is operated by the superheated steam supplied from the boiler. A power plant, a water supply device that heats seawater with exhaust steam discharged from the power plant to produce produced water, and a produced water transfer pump that transfers the produced water produced by the water production device to the water supply tank. , an oil-water separator that separates hot wastewater from extracted crude oil, a hot wastewater tank that stores the hot wastewater separated from the oil-water separator and hot wastewater discharged from the water production equipment, and a hot wastewater tank supplied from the hot wastewater tank. An undersea oil field characterized by having a hot waste water heater that injects superheated steam generated in the boiler to heat the heated waste water and pressurizes the hot water or steam generated thereby into the oil field. steam or hot water plants.