Carbon dioxide storage methods

Abstract

The present invention addresses the problem of effectively utilizing a used floating offshore petroleum / gas facility and shortening a step for constructing the facility in a method for storing carbon dioxide in a cavity formed by excavating petroleum or gas in an underwater oil field or underwater gas field, or a method for constructing a facility for the same. Remodeling, such as installing an injection device (6), etc. for injecting carbon dioxide, is performed on a floating offshore petroleum / gas facility (2) previously used in underwater oil field or underwater gas field to store carbon dioxide, so as to configure a floating remodeled facility (3). The floating remodeled facility (3) is used in an underwater oil field or underwater gas field that was already being used, and therefore, it is not necessary to modify portions thereof designed on the basis of oceanographic conditions or the like, and it is possible to produce the facility at a comparatively low cost. Furthermore, it is possible to produce the floating remodeled facility in a shorter time than constructing an offshore platform or underwater pipes, for example, thereby shortening the construction period.

Description

Technical Field

[0001] The present invention relates to a method for storing carbon dioxide (CO2) in cavities generated by the extraction of oil or gas in a subsea oilfield or subsea gasfield, and a method for constructing facilities for implementing this storage method.

Background Art

[0002] As facilities for extracting, storing, and / or offloading oil or gas from a subsea oilfield or subsea gasfield, floating offshore oil and gas production, storage, and offloading facilities, floating offshore oil and gas storage and offloading facilities, floating offshore oil and gas production and storage facilities, etc., are known (for example, Patent Document 1). Also, it is known to store carbon dioxide in cavities generated by the extraction of oil or gas in a subsea oilfield or subsea gasfield.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Floating offshore oil and gas (FOLGS) equipment is designed specifically for a particular oil or gas field, taking into account its oceanographic conditions, installation conditions, production volume, and production period. If it is to be used in another oil or gas field after its initial use, redesign and modification are necessary. Furthermore, because FOLGS equipment is installed on the sea, it is susceptible to corrosion from seawater salinity, including galvanic corrosion and bacterial corrosion, making it an extremely corrosive environment. Therefore, by the time its use in the target oil or gas field ends, the equipment is often significantly corroded. When modifying FOLGS equipment for oil or gas extraction from other fields, it is desirable to replace corroded components due to handling hazardous materials such as oil and high-pressure gas, in addition to making changes to accommodate oceanographic conditions. For these reasons, reusing equipment installed on FOLGS equipment has been difficult.

[0005] On the other hand, storing carbon dioxide in offshore oil or gas fields has been time-consuming due to processes such as selecting storage sites and constructing offshore platforms.

[0006] In view of the above background, the present invention aims to shorten the construction process of a facility for storing carbon dioxide in cavities created by the extraction of oil or gas in an offshore oil field or offshore gas field, and a method for storing carbon dioxide using said facility, by effectively utilizing spent floating offshore oil and gas facilities. [Means for solving the problem]

[0007] To solve the above problems, one aspect of the present invention provides a method for constructing a facility (1) for storing carbon dioxide in a cavity created by extracting oil or gas in an offshore oil field or offshore gas field, comprising the steps of: selecting an offshore oil field or offshore gas field to which the carbon dioxide should be stored; modifying a floating offshore oil and gas facility (2) that was used to extract, store and / or ship oil or gas from the selected offshore oil field or offshore gas field by installing an injector (6) for injecting the carbon dioxide into the cavity, thereby converting the floating offshore oil and gas facility (2) into a floating modified facility (3); and arranging the floating modified facility (3) on the sea surface of the offshore oil field or offshore gas field and connecting the injector (7) to a riser pipe communicating with the cavity.

[0008] According to this embodiment, since the floating conversion equipment is used in the same location where the floating offshore oil and gas facility was used before the conversion, there is no need to modify parts of the floating offshore oil and gas facility that were designed based on oceanographic conditions, etc., and the floating conversion equipment can be manufactured at a relatively low cost. Furthermore, compared to the construction of offshore platforms and subsea pipelines for conventional carbon dioxide injection facilities, the conversion of the floating conversion equipment can be completed in a short period of time, thus shortening the construction process for facilities for storing carbon dioxide.

[0009] In the above embodiment, the selection step includes selecting the offshore oil field or offshore gas field using a computer system (11) which comprises a storage device (15) storing information on a plurality of candidate locations for the offshore oil field or offshore gas field, and a control device (12) that selects the offshore oil field or offshore gas field by comparing the information with specifications required for a carbon dioxide storage facility entered by the user, wherein the information may include data accumulated in connection with the extraction of the oil or gas.

[0010] According to this embodiment, since a database can be constructed using data accumulated in connection with the extraction of oil or gas in each oil or gas field, the construction of the database becomes relatively easy.

[0011] In the above embodiment, the riser pipe may include a pipe that was used to extract the oil or gas.

[0012] According to this embodiment, since riser pipes used for oil or gas extraction are also used for carbon dioxide injection, the cost of constructing the equipment can be reduced.

[0013] One aspect of the present invention is a method for storing carbon dioxide in a cavity using the equipment (1) for storing carbon dioxide constructed according to the above aspect, comprising the steps of transporting the carbon dioxide to the floating modification equipment (3) and injecting the carbon dioxide into the cavity via the riser pipe (7) using the injector (6).

[0014] According to this embodiment, carbon dioxide can be stored on the seabed using equipment that can be constructed at a lower cost and in a shorter time than conventional methods.

[0015] In the above embodiment, the present invention further comprises a step of using the pressure of the carbon dioxide injected into the cavity by the injection step to extract the oil or gas remaining in the offshore oil field or offshore gas field by another floating offshore oil and gas facility.

[0016] According to this embodiment, oil or gas can be extracted efficiently, and since there is no need to install oil or gas extraction equipment on the floating modified facility, safety is not compromised. [Effects of the Invention]

[0017] According to the above embodiments, in a method for constructing equipment for storing carbon dioxide in cavities created by extracting oil or gas in an offshore oil field or offshore gas field, and in a method for storing carbon dioxide using said equipment, it is possible to effectively utilize spent floating offshore oil and gas equipment and shorten the process of constructing the equipment. [Brief explanation of the drawing]

[0018] [Figure 1] Flowchart for constructing equipment for storing carbon dioxide in a subsea oil field or subsea gas field according to an embodiment [Figure 2] Flowchart for selecting a storage site according to an embodiment [Figure 3] Block diagram of a computer system used for selecting a storage site [Figure 4] Flowchart for selecting a floating offshore oil and gas facility according to an embodiment [Figure 5] Explanatory diagram showing the flow of carbon dioxide capture and storage (CCS) according to an embodiment (during the operation of a floating offshore oil and gas facility) [Figure 6] Explanatory diagram showing the flow of carbon dioxide capture and storage (CCS) according to an embodiment (after the operation of a floating offshore oil and gas facility) [Figure 7] Explanatory diagram showing the flow of carbon dioxide capture and storage (CCS) according to an embodiment (arrangement of a floating retrofit facility) [Figure 8] Explanatory diagram showing the flow of carbon dioxide capture and storage (CCS) according to an embodiment (injection of carbon dioxide by a floating retrofit facility) [Figure 9] Explanatory diagram of a carbon dioxide injection method according to an embodiment

Mode for Carrying Out the Invention

[0019] Hereinafter, referring to the drawings, a method for constructing equipment 1 for storing carbon dioxide in a subsea oil field or subsea gas field according to an embodiment (see FIG. 8; hereinafter referred to as "carbon dioxide storage equipment 1") and a method for storing carbon dioxide using the equipment will be described.

[0020] The carbon dioxide storage facility 1 according to this embodiment includes a modified floating facility 3, which is a modified floating offshore oil and gas facility 2 that was used to extract, store, and / or ship off oil or natural gas at an offshore oil or gas field selected as a storage site. The floating offshore oil and gas facility 2 is, for example, a floating offshore oil and gas production, storage and shipping facility, a floating offshore oil and gas storage and shipping facility, or a floating offshore oil and gas production and storage facility. The modified floating facility 3 injects carbon dioxide into cavities created by the extraction of oil or gas at an offshore oil or gas field.

[0021] Figure 1 shows the overall flow of the method for constructing carbon dioxide storage facility 1. First, an offshore oil field or offshore gas field (storage site) where carbon dioxide should be stored is selected (ST1).

[0022] Figure 2 shows the flow of storage site selection, and Figure 3 shows the computer system 11 used to select the storage site. The computer system 11 includes a control device 12 such as a CPU, an input device 13 such as a keyboard that receives input from the user, an output device 14 such as a display that outputs information, and a storage device 15 such as a hard disk or random access memory. The control device 12 receives information from the input device 13 and the storage device 15, processes the information, and sends the received information and the processed information to the output device 14 and the storage device 15. The storage device 15 includes a database in which information on candidate offshore oil and gas fields is stored, and the database may be configured to send and receive information with the control device 12 and other computer systems via the internet or the like. The database stores information such as the service life and size of the floating offshore oil and gas facilities 2 used at each candidate site, the carbon dioxide storage capacity of the candidate site, and the end of service date of the candidate site. This information includes data accumulated in relation to oil or gas extraction.

[0023] In selecting a storage site, the user inputs the specifications required for the carbon dioxide storage facility, such as the planned amount of carbon dioxide to be stored, the start date of carbon dioxide injection, and the starting point of carbon dioxide transportation (ST11). After inputting the information, the user causes the control device 12 to execute a program that selects a storage site by comparing the input information with the information stored in the database (ST12~ST17).

[0024] Based on the program, the control device 12 compares the specifications required for a carbon dioxide storage facility stored in the storage device 15 with the information on oil and gas fields (sites), calculates the shortest transport route for carbon dioxide for sites (ST12) where the amount of carbon dioxide that can be stored is greater than or equal to the planned storage amount (ST13), excludes sites from the candidates if the transport route passes through politically unstable areas (ST14), and extracts a group of candidate storage sites (ST15). Furthermore, the control device 12 identifies one site from the group of candidates (ST16), and if there is a floating offshore oil and gas facility 2 (see Figure 5) suitable for conversion into a carbon dioxide injection facility near that site, it selects that site as a storage site and selects that floating offshore oil and gas facility 2 to be converted into a floating conversion facility 3 (see Figure 7) (Yes in ST17).

[0025] Figure 4 shows a detailed flow of ST17 in Figure 2. The control device 12 extracts two groups of floating offshore oil and gas facilities located near the identified storage site (ST21), identifies one of them (ST22), and selects that floating offshore oil and gas facility 2 if the time required for modification, plus the time at which the identified floating offshore oil and gas facility 2 will be taken out of service, is before the start of carbon dioxide injection (Yes in ST23). If this timing requirement is not met (No in ST23), the timing requirements are checked for other floating offshore oil and gas facilities 2 (ST22, ST23).

[0026] As shown in Figure 2, if there is no floating offshore oil and gas facility 2 suitable for modification (No. in ST17), the control device 12 modifies the conditions based on the predetermined policy and restarts the selection of a storage site from ST12. Modifications to the conditions based on the predetermined policy may include, for example, reducing the planned amount of carbon dioxide to be stored at each location by storing carbon dioxide at multiple locations, or extending the permissible transport distance. Instead of the control device 12 modifying the conditions, the user may return to ST11 and restart from the input.

[0027] As shown in Figure 1, after the selection of a storage site (ST1), equipment used to inject carbon dioxide into the storage site, namely a tank 4 for temporarily storing liquefied carbon dioxide, a heater 5 for heating liquid carbon dioxide to turn it into a gas, and an injector 6 for injecting the gaseous carbon dioxide into the seabed, is manufactured at a factory, and trial runs and performance tests of these are conducted (ST2).

[0028] On the other hand, at the selected storage site, once the operation of the selected floating offshore oil and gas facility 2 ends, decommissioning measures for the floating offshore oil and gas facility 2 will be taken, such as disconnecting the floating offshore oil and gas facility 2 from the riser pipe 7 and mooring device 8 (see Figure 6) that pump up oil or gas (ST3).

[0029] The decommissioned floating offshore oil and gas facility 2 is towed to the dock and converted into a floating modified facility 3 (ST4). The conversion of floating offshore oil and gas facility 2 includes removing unnecessary equipment, such as equipment used for oil or gas extraction, and installing tanks 4, heaters 5, and injectors 6. In parallel with the work at the plant and / or dock, piping work is carried out to inject carbon dioxide into the seabed (ST5). The riser pipes 7 that were used for oil or gas extraction are used to inject carbon dioxide into the seabed.

[0030] After completion in the dock, the floating modification facility 3 is towed to the selected storage site at sea, where the riser pipe 7 and mooring device 8 (see Figure 7) are installed (ST6), the entire system is commissioned (ST7), performance tests are conducted (ST8), and then carbon dioxide injection using the floating modification facility 3 begins (ST9).

[0031] Figures 5 to 8 are explanatory diagrams showing the overall flow of carbon capture and storage (CCS) according to the embodiment.

[0032] As shown in Figure 5, the floating offshore oil and gas facility 2 extracts oil or gas from an offshore oil or gas field. Meanwhile, on land, carbon dioxide emitted from the carbon dioxide emission source 21 is recovered, cooled in a cooling device 22 to a liquid state, and stored in a temporary storage tank 24 installed in the port via an onshore pipeline 23.

[0033] As shown in Figure 6, the floating offshore oil and gas facility 2, having completed its service, is towed to a dock in the harbor (corresponding to the arrow from ST3 to ST4 in Figure 1). The floating offshore oil and gas facility 2 is modified to become the modified floating facility 3 (ST4 in Figure 1), and as shown in Figure 7, the modified floating facility 3 is towed to the offshore oil or gas field where it was used before the modification, and connected to the riser pipe 7 and mooring device 8 (ST6 in Figure 1).

[0034] As shown in Figure 8, carbon dioxide is injected from the floating modification facility 3 into cavities created by the extraction of oil or gas from offshore oil or gas fields (ST9 in Figure 1). The carbon dioxide to be injected is transported in liquid form from the port to the floating modification facility 3 by a carbon dioxide carrier 25. The transported liquid carbon dioxide is temporarily stored in a tank 4, heated by a heater 5 to become a gas, and then injected into the seabed via a riser pipe 7 by an injector 6.

[0035] Figure 9 is an explanatory diagram illustrating the case where carbon dioxide is injected by the floating modification facility 3, while remaining oil or gas is pumped up by another floating offshore oil and gas facility 2 (a floating offshore oil and gas facility 2 separate from the one that was modified to become the floating modification facility 3). The carbon dioxide injected by the floating modification facility 3 fills the cavity created by the extraction of oil or gas, forming a carbon dioxide reservoir 26. Below the carbon dioxide reservoir 26 is an oil and gas layer 27 containing oil or gas. The oil and gas layer 27 is subjected to pressure from the carbon dioxide injected from the carbon dioxide reservoir 26, and this pressure assists in pumping up the oil or gas contained in the oil and gas layer 27.

[0036] The effects and benefits of the carbon dioxide storage facility 1 according to the above embodiment will be explained.

[0037] Since the floating modification equipment 3 will be used in the same location where the floating offshore oil and gas facility 2 was used before modification, there is no need to modify parts of the floating offshore oil and gas facility 2 that were designed based on sea conditions, etc., and the floating modification equipment 3 can be manufactured at a relatively low cost. In addition, using the riser pipes 7 that were used for oil or gas extraction for carbon dioxide injection also contributes to reducing the cost of constructing the carbon dioxide storage facility 1.

[0038] Because the floating modification facility 3 does not carry hazardous materials such as petroleum or high-pressure gas, the level of maintenance required and the frequency of maintenance inspections can be reduced compared to the floating offshore oil and gas facility 2, which carries such hazardous materials. As a result, it is easier to reuse equipment from the floating offshore oil and gas facility 2, which has been used in an environment where corrosion is extremely likely to occur, and maintenance inspections are also easier.

[0039] Compared to the construction of offshore platforms and subsea pipelines in conventional carbon dioxide injection facilities, the modification of the floating modification facility 3 can be completed in a shorter period of time, thus shortening the construction process for the carbon dioxide storage facility 1.

[0040] The database information used to select storage sites includes data accumulated in connection with oil or gas extraction at each oil or gas field. In other words, since the database can be constructed using data accumulated in connection with oil or gas extraction at each oil or gas field, the construction of the database is relatively easy.

[0041] When carbon dioxide is injected while oil or gas is being pumped up, the pressure of the carbon dioxide injected into the oil or gas field assists in the pumping of oil or gas, thus improving the pumping efficiency. Furthermore, since oil or gas is pumped up by a floating offshore oil and gas facility 2 separate from the floating modification facility 3, hazardous materials such as oil or high-pressure gas are not loaded onto the floating modification facility 3, which is equipped with relatively corroded equipment, thus ensuring safety.

[0042] This concludes the description of specific embodiments, but the present invention is not limited to the above embodiments and can be broadly modified and implemented. For example, the carbon dioxide to be stored may include that generated during the extraction of oil or gas at the storage site. [Explanation of Symbols]

[0043] 1: Carbon dioxide storage equipment 2: Floating offshore oil and gas facilities 3: Floating Modification Equipment 6: Press-fitting tool 7: Riser tube 8: Mooring device 11: Computer Systems 12: Control device 15:Storage device

Claims

1. A method for constructing a facility for storing carbon dioxide emitted on land in a cavity created by the extraction of oil or gas in an offshore oil field or offshore gas field, The steps include selecting the offshore oil field or offshore gas field where the carbon dioxide should be stored, The steps include: modifying a floating offshore oil and gas facility, which was used to extract, store, and / or ship oil or gas from the selected offshore oil or gas field, by installing an injector for injecting carbon dioxide into the cavity, thereby converting the floating offshore oil and gas facility into a floating modified facility; The floating modification equipment is positioned on the sea surface of the offshore oil field or offshore gas field, and the press-in device is connected to a riser pipe that communicates with the cavity. A construction method that includes the following features.

2. The selection step includes selecting the offshore oil field or offshore gas field using a computer system comprising a storage device that stores information on multiple candidate locations of the offshore oil field or offshore gas field, and a control device that selects the offshore oil field or offshore gas field by comparing the information with specifications required for a carbon dioxide storage facility entered by the user. The construction method according to claim 1, wherein the information includes data accumulated in connection with the extraction of oil or gas.

3. The construction method according to claim 1, wherein the riser pipe includes a pipe that was used for extracting the oil or gas.

4. A method for storing carbon dioxide in a cavity using the equipment for storing carbon dioxide constructed by the construction method described in any one of claims 1 to 3, The steps include transporting the carbon dioxide to the floating modification facility, The steps include: pressurizing the carbon dioxide into the cavity via the riser tube using the pressurizer; A method for providing this.

5. The method according to claim 4, further comprising the step of using the pressure of the carbon dioxide injected into the cavity by the injection step to extract the oil or gas remaining in the offshore oil field or offshore gas field using another floating offshore oil and gas facility.

Images