An experimental simulation system for the joint development of marine oil and gas reservoirs and hydrate reservoirs and its usage method

Abstract

The present invention discloses an experimental simulation system for the joint development of marine oil and gas reservoirs and hydrate reservoirs and a method of using the same, which relates to the technical field of oil and gas field development. The system includes: a high-pressure hydrate synthesis part and an oil and gas reservoir simulation development part; a double-layer pipe is arranged in a hydrate synthesis kettle in the high-pressure hydrate synthesis part; the high-pressure hydrate synthesis part is connected with a first pressure device through an outer layer pipeline, the oil and gas reservoir simulation development part is connected with a second pressure device through an inner layer pipeline, and the inner layer pipeline penetrates through the upper and lower end faces of the hydrate synthesis kettle. The present invention can improve the accuracy of the measurement results of the system and is easy to operate.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, and in particular to an experimental simulation system for joint development of marine oil and gas reservoirs and hydrate reservoirs and a use method thereof. Background Art

[0002] The seabed is rich in oil resources. According to incomplete statistics, the world's marine sedimentary basins with oil and gas prospects are about 7,800 square kilometers, roughly equivalent to the land. The total potential oil and natural gas reserves under the seabed within 300 meters of water in the world are 235.6 billion tons. In addition, there are more abundant natural gas hydrate resources and shallow gas in the shallow and surface layers of the seabed. At present, there are no technical barriers to the development of near and shallow oil and gas reservoirs, but the development of natural gas hydrate resources, shallow gas, and ultra-deepwater oil and gas reservoirs is still in the research stage or experimental stage.

[0003] During the development of marine oil and gas reservoirs, the temperature transfer of high-temperature and high-pressure oil and gas through the wellbore will affect the stability of the shallow hydrate reservoir on the seabed. This impact will not only endanger the stability of the wellbore, but also cause the waste of shallow resource gas. In recent years, the joint development of deep oil and gas and shallow resources has been put on the agenda, but the synergy and mutual influence between the development of different resources are unknown, which affects the formulation of implementation plans and process parameters. Therefore, the development of relevant simulation devices and related methods has important practical guiding value, but there is little related research at present. Summary of the invention

[0004] The purpose of the present invention is to provide a marine oil and gas reservoir and hydrate reservoir joint development experimental simulation system and a use method, which can improve the accuracy of system measurement results and is easy to operate.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A marine oil and gas reservoir and hydrate reservoir joint development experimental simulation system comprises: a high-pressure hydrate synthesis part and an oil and gas reservoir simulation development part; a double-layer pipe is arranged in a hydrate synthesis kettle in the high-pressure hydrate synthesis part; the high-pressure hydrate synthesis part is connected to a first pressure device through an outer pipe, and the oil and gas reservoir simulation development part is connected to a second pressure device through an inner pipe, and the inner pipe runs through the upper and lower end surfaces of the hydrate synthesis kettle.

[0007] Optionally, the high-pressure hydrate synthesis part specifically includes: a data acquisition system, a low-temperature test box and a high-pressure natural gas bottle; the low-temperature test box is equipped with a hydrate synthesis kettle; the data acquisition system and the high-pressure natural gas bottle are both connected to the hydrate synthesis kettle.

[0008] Optionally, the data acquisition system includes a computer and a plurality of temperature sensors connected in sequence; each of the temperature sensors is arranged on the left side of the hydrate synthesis reactor, and each of the temperature sensors is distributed at a set position.

[0009] Optionally, the first pressure device and the second pressure device have the same structure, both comprising a back pressure valve, a pump and a gas meter; wherein the back pressure valve is connected to one end of the pipeline and is also connected to the pump and the gas meter respectively.

[0010] Optionally, small holes are arranged on the outer layer pipe, and the small holes are used for injecting natural gas synthetic hydrate reservoirs or exploiting natural gas hydrates.

[0011] Optionally, the oil and gas reservoir simulation development part specifically includes: a high-temperature oven, a sample preparer and a high-pressure pump; the high-temperature oven is equipped with a core clamp and a first valve connected in sequence; the core clamp is also connected to the sample preparer and the inner layer pipeline respectively; the first valve and the sample preparer are also connected to the high-pressure pump.

[0012] Optionally, it further includes: a second valve and a container; the second valve is arranged on the inner layer pipe and connected to the container.

[0013] The present invention also provides a method for using a marine oil and gas reservoir and hydrate reservoir joint development experimental simulation system, which is applied to the system as described above, and comprises:

[0014] Step 1: Stir a certain amount of sand and water evenly and put them into the hydrate synthesis kettle, seal the experimental device, and then set the natural gas hydrate storage synthesis temperature in a low-temperature test box;

[0015] Step 2: Wash and dry the core, put it into a holder, prepare simulated formation water according to the formation water data and the formation water composition, and evacuate the core to re-saturate it with formation water;

[0016] Step 3: Prepare enough crude oil or natural gas samples in the sample dispenser according to the standard GB / T 26981-2020 "Analysis Methods for Physical Properties of Oil and Gas Reservoir Fluids", and set the experimental temperature of the core holder in a high-temperature oven;

[0017] Step 4: After the temperature of the high-temperature oven and the low-temperature test box is stable for at least 10 hours, natural gas is injected into the hydrate synthesis reactor through a gas cylinder to synthesize a natural gas hydrate reservoir simulation reservoir; crude oil or natural gas fluid is injected into the core through a sample dispenser until no water is produced, so as to establish the original oil and gas reservoir conditions;

[0018] Step 5. Set the working pressure of the back pressure valve connected to the core holder to the simulated development pressure of oil and gas reservoir depletion, and set the working pressure of the back pressure valve connected to the hydrate synthesis reactor to 0.3-0.5MPa above the equilibrium pressure of the hydrate reservoir phase, and conduct an oil and gas reservoir depletion simulation development experiment. During the depletion development process, the piston in the sampler connected to the core holder is driven to ensure that the pressure in the core holder remains unchanged. During the experiment, the heat transfer of high-temperature and high-pressure crude oil or natural gas through the wall of the fluid production pipeline may cause the decomposition of natural gas hydrates in the hydrate synthesis reactor. When the pressure in the hydrate synthesis reactor is greater than the working pressure of the back pressure valve, it indicates that hydrate decomposition gas is produced in the hydrate reservoir, and the gas production time t is recorded. 1 and volume L, to grasp the hydrate decomposition rate L / t;

[0019] Step 6: Monitor the temperature distribution in the radial direction of the hydrate reactor by using the temperature sensor buried in the hydrate synthesis reactor to determine the distance of the temperature change in the hydrate reservoir during the high-temperature oil and gas development process and the impact on the stability of the hydrate reservoir;

[0020] Step 7: Reduce the working pressure of the back pressure valve connected to the hydrate synthesis reactor, conduct a joint simulation development of the hydrate reservoir and the oil and gas reservoir, and determine the effect of high-temperature oil and gas heat transfer and pressure reduction on the development of the hydrate reservoir.

[0021] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0022] The present invention discloses a marine oil and gas reservoir and hydrate reservoir joint development experimental simulation system and a method for use, the system comprising a high-pressure hydrate synthesis part and an oil and gas reservoir simulation development part; a double-layer pipe is arranged in a hydrate synthesis kettle in the high-pressure hydrate synthesis part; the high-pressure hydrate synthesis part is connected to a first pressure device through an outer layer pipe, the oil and gas reservoir simulation development part is connected to a second pressure device through an inner layer pipe, and the inner layer pipe runs through the upper and lower end surfaces of the hydrate synthesis kettle. The system of the present invention has a reliable principle, is easy to operate, and has accurate and reliable measurement results. It can simultaneously evaluate the degree of influence on the stability of the seabed hydrate reservoir during the development of the marine oil and gas reservoir and the joint exploitation of the two resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 This is a schematic diagram of the structure of the marine oil and gas reservoir and hydrate reservoir joint development experimental simulation system of the present invention.

[0025] Figure numerals: 1. computer; 2. temperature sensor; 3. low temperature experiment box; 4. hydrate synthesis reactor; 5. second back pressure valve; 6. first back pressure valve; 7. second pump; 8. first pump; 9. second gas meter; 10. first gas meter; 11. second valve; 12. container; 13. core holder; 14. first valve; 15. high temperature oven; 16. sample preparation device; 17. high pressure pump; 18. high pressure natural gas cylinder. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The purpose of the present invention is to provide a marine oil and gas reservoir and hydrate reservoir joint development experimental simulation system and a use method, which can improve the accuracy of system measurement results and is easy to operate.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] like Figure 1 As shown, the present invention provides an experimental simulation system for the joint development of marine oil and gas reservoirs and hydrate reservoirs, comprising: a high-pressure hydrate synthesis part and an oil and gas reservoir simulation development part; a double-layer pipe is arranged in the hydrate synthesis kettle 4 in the high-pressure hydrate synthesis part; the high-pressure hydrate synthesis part is connected to a first pressure device through an outer pipe, and the oil and gas reservoir simulation development part is connected to a second pressure device through an inner pipe, and the inner pipe runs through the upper and lower end surfaces of the hydrate synthesis kettle 4.

[0030] As a specific implementation, the system constructed in this embodiment includes:

[0031] High-pressure hydrate synthesis part (hydrate synthesis reactor 4, low-temperature test box 3, data acquisition system, first back pressure valve 6, first gas meter 10) and oil and gas reservoir simulation development part (core clamp 13, high-pressure intermediate container 12, second back pressure valve 5, second gas meter 9). A double-layer pipe is arranged in the hydrate synthesis reactor 4, and the inner pipeline runs through the upper and lower end surfaces of the hydrate synthesis reactor 4. One end of the pipeline is connected to the core clamp 13 and the other end is connected to the second back pressure valve 5, which is used for oil and gas production; small holes are arranged on the outer pipeline for injecting natural gas synthetic hydrate reservoirs, and also for extracting natural gas hydrates.

[0032] In addition, the tail end of the sampler 16 is connected to a high-pressure pump 17, and the front end is connected to a core holder 13. The core holder 13 is also connected to the first valve 14, and is connected to the hydrate synthesis reactor 4 and placed in a high-temperature oven 15. A second valve 11 is installed in the middle, and the second valve 11 is also connected to the container 12. The hydrate synthesis reactor 4 is placed in a low-temperature experimental box 3. The left side of the hydrate synthesis reactor 4 is connected to a temperature sensor 2 distributed at different positions of the hydrate synthesis reactor 4, and is connected to a computer 1 for detecting and monitoring the temperature distribution in the hydrate reactor. The first back pressure valve 6 and the second back pressure valve 5 are respectively connected to the corresponding first pump 8 and the second pump 7, which are used to detect whether the high-temperature oil and gas fluid will cause hydrate decomposition through the heat transfer of the pipe wall. The high-pressure natural gas bottle 18 is used to add natural gas to the hydrate synthesis reactor 4.

[0033] The above experimental system is used to evaluate the development of marine oil and gas reservoirs and seabed hydrate reservoirs, including the following steps:

[0034] (1) A certain amount of sand and water are mixed evenly and then placed in a hydrate synthesis reactor 4, the experimental device is sealed, and then the natural gas hydrate storage synthesis temperature is set in a low temperature test box 3.

[0035] (2) Wash and dry the core and place it in a holder. According to the formation water data, simulate the formation water according to the formation water composition, and evacuate the core to re-saturate it with formation water.

[0036] (3) Prepare enough crude oil or natural gas samples in the sample preparation device 16 according to the standard GB / T 26981-2020 "Analysis Methods for Physical Properties of Oil and Gas Reservoir Fluids", and set the experimental temperature of the core holder 13 (oil and gas reservoir temperature) through the high-temperature oven 15.

[0037] (4) After the temperature of the high-temperature oven 15 and the low-temperature test box 3 has been stable for at least 10 hours, natural gas is injected into the hydrate synthesis reactor 4 through a gas cylinder to synthesize a natural gas hydrate reservoir simulation reservoir; crude oil or natural gas fluid is injected into the core through the sample dispenser 16 to displace until no water is produced, thereby establishing the original oil and gas reservoir conditions.

[0038] (5) The working pressure of the back pressure valve connected to the core holder 13 is set to the simulated development pressure of oil and gas reservoir depletion, and the working pressure of the back pressure valve connected to the hydrate synthesis reactor 4 is set to 0.3-0.5MPa above the equilibrium pressure of the hydrate reservoir phase, and the oil and gas reservoir depletion simulation development experiment is carried out. During the depletion development process, the piston in the sample dispenser 16 connected to the core holder 13 is driven to ensure that the pressure in the core holder 13 remains unchanged. During the experiment, the heat transfer of high-temperature and high-pressure crude oil or natural gas through the fluid production pipeline (the section in the hydrate synthesis reactor 4) may cause the decomposition of natural gas hydrates in the hydrate synthesis reactor 4. When the pressure in the hydrate synthesis reactor 4 is greater than the working pressure of the back pressure valve, it indicates that hydrate decomposition gas is produced in the hydrate reservoir, and the gas production time t is recorded. 1 and volume L, to grasp the hydrate decomposition rate L / t;

[0039] (6) The temperature sensor 2 embedded in the hydrate synthesis reactor 4 monitors the temperature distribution in the radial direction of the hydrate reactor, and understands the impact of the high-temperature oil and gas development process on the temperature change in the hydrate reservoir and the stability of the hydrate reservoir.

[0040] (7) On this basis, the working pressure of the back pressure valve connected to the hydrate synthesis reactor 4 can be further reduced, and the combined simulation development of hydrate reservoirs and oil and gas reservoirs can be carried out to understand the effects of high-temperature oil and gas heat transfer and pressure reduction on the development of hydrate reservoirs.

[0041] Therefore, through the experiments of this embodiment, it can be seen that the system has reliable principles, simple operation, accurate and reliable measurement results, and overcomes the shortcomings of the existing technology. It provides important basic data for evaluating the degree of impact on the stability of hydrate reservoirs during oil and gas reservoir development, which is of great significance to the rational development of oil and gas reservoirs.

[0042] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0043] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for using a marine oil and gas reservoir and hydrate reservoir joint development experimental simulation system, characterized in that: The marine oil and gas reservoir and hydrate reservoir joint development experimental simulation system comprises: A high-pressure hydrate synthesis part and an oil and gas reservoir simulation development part; a double-layer pipe is arranged in the hydrate synthesis kettle in the high-pressure hydrate synthesis part; the high-pressure hydrate synthesis part is connected to a first pressure device through an outer pipe, and the oil and gas reservoir simulation development part is connected to a second pressure device through an inner pipe, and the inner pipe runs through the upper and lower end surfaces of the hydrate synthesis kettle; The high-pressure hydrate synthesis part specifically includes: a data acquisition system, a low-temperature test box and a high-pressure natural gas bottle; the low-temperature test box is equipped with a hydrate synthesis kettle; the data acquisition system and the high-pressure natural gas bottle are both connected to the hydrate synthesis kettle; the data acquisition system includes a computer and a plurality of temperature sensors connected in sequence; each of the temperature sensors is arranged on the left side of the hydrate synthesis kettle, and each of the temperature sensors is distributed at a set position; the first pressure device and the second pressure device have the same structure, both including a back pressure valve, a pump and a gas meter; wherein the back pressure valve is connected to one end of the pipeline, and is also connected to the pump and the gas meter respectively; the outer layer pipeline is also arranged with small holes, and the small holes are used to inject natural gas synthesis hydrate reservoirs or exploit natural gas hydrates; the oil and gas reservoir simulation development part specifically includes: a high-temperature oven, a sample dispenser and a high-pressure pump; the high-temperature oven is equipped with a core holder and a first valve connected in sequence; the core holder is also connected to the sample dispenser and the inner layer pipeline respectively; the first valve and the sample dispenser are also connected to the high-pressure pump; The method of using the system includes: Step 1: Stir a certain amount of sand and water evenly and put them into the hydrate synthesis kettle, seal the experimental device, and then set the natural gas hydrate storage synthesis temperature in a low-temperature test box; Step 2: Wash and dry the core, put it into a holder, prepare simulated formation water according to the formation water data and the formation water composition, and evacuate the core to re-saturate it with formation water; Step 3: Prepare enough crude oil or natural gas samples in the sample dispenser according to the standard GB / T 26981-2020 "Analysis Methods for Physical Properties of Oil and Gas Reservoir Fluids", and set the experimental temperature of the core holder in a high-temperature oven; Step 4: After the temperature of the high-temperature oven and the low-temperature test box is stable for at least 10 hours, natural gas is injected into the hydrate synthesis reactor through a gas cylinder to synthesize a natural gas hydrate reservoir simulation reservoir; crude oil or natural gas fluid is injected into the core through a sample dispenser until no water is produced, so as to establish the original oil and gas reservoir conditions; Step 5. Set the working pressure of the back pressure valve connected to the core holder to the simulated development pressure of oil and gas reservoir depletion, set the working pressure of the back pressure valve connected to the hydrate synthesis reactor to 0.3-0.5MPa above the equilibrium pressure of the hydrate reservoir phase, and conduct an oil and gas reservoir depletion simulation development experiment. During the depletion development process, the piston in the sampler connected to the core holder is driven to ensure that the pressure in the core holder remains unchanged. During the experiment, high-temperature and high-pressure crude oil or natural gas may cause the decomposition of natural gas hydrates in the hydrate synthesis reactor due to heat transfer through the wall of the fluid production pipeline. When the pressure in the hydrate synthesis reactor is greater than the working pressure of the back pressure valve, it indicates that hydrate decomposition gas is produced in the hydrate reservoir. Record the gas production time t and volume L, and master the hydrate decomposition rate L / t. Step 6: Monitor the temperature distribution in the radial direction of the hydrate reactor by using the temperature sensor buried in the hydrate synthesis reactor to determine the distance of the temperature change in the hydrate reservoir during the high-temperature oil and gas development process and the impact on the stability of the hydrate reservoir; Step 7: Reduce the working pressure of the back pressure valve connected to the hydrate synthesis reactor, conduct a joint simulation development of the hydrate reservoir and the oil and gas reservoir, and determine the effect of high-temperature oil and gas heat transfer and pressure reduction on the development of the hydrate reservoir.

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