Clean natural gas exploiting method

Abstract

The invention discloses a clean natural gas exploiting method which comprises the following steps of: 1) adding an ice inhibitor, 2) separating liquid from natural gas, 3) sending the gas obtained in step 2) into an open container, 4) adding alkali into the open container for regeneration, 5) separating waste slag, 6) sending the gas obtained in step 5) into another open container, 7) ventilatingand removing moisture, 8) conducting separation and purification, and 9) recycling the ice inhibitor solution. The invention has the advantages that the clean natural gas exploiting method overcomes the defects of the existing natural gas exploiting method, effectively exploits natural gas, effectively solves the problems that natural gas hydrate or ice affects the exploitation of the natural gasand that the natural gas exploitation causes environmental pollution and has high energy consumption, effectively eliminates potential safety hazards in the natural gas exploitation, significantly reduces the fixed investment, exploitation cost, energy consumption, self gas consumption, management workload and the like of the exploitation of the natural gas, and is characterized by easy implementation, safety, reliability, wide application range, easy promotion, high economic and environmental benefits and obvious safety benefits.

Description

technical field [0001] The invention relates to an oil and gas extraction method, in particular to a clean natural gas extraction method. Background technique [0002] At present, domestic natural gas mining methods include natural pressure alcohol-containing mining method, natural pressure hydrate inhibitor mining method, natural pressure heating mining method, natural pressure mining method, natural pressure pressurized mining method, surface throttling alcohol-containing mining method, ground Throttling hydrate inhibitor mining method, surface throttling heating mining method, surface throttling mining method, surface throttling surface pressurized mining method, underground throttling alcohol-containing mining method, underground throttling hydrate inhibitor mining method, underground Throttling heating mining method, underground throttling mining method, underground throttling surface pressurized mining method, drainage mining method, air extraction mining method, pumpi...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that when the natural gas is extracted from the ground, some form of water is inevitably extracted at the same time, and these waters are very easy to form gas hydrates under relatively high pressure conditions during the process of mixing and flowing with the natural gas. Commonly known as combustible ice), or when the temperature of natural gas is lower than the freezing point, it is easy to freeze, block the wellbore, pipeline, equipment, etc., seriously affect the natural gas exploitation or storage and transportation, and even make the natural gas exploitation or storage and transportation unable to proceed normally

The disadvantage of this method is that in order to solve the problem of natural gas hydrate blocking the wellbore, pipelines, and equipment during natural gas exploitation, it is necessary to add hydrate inhibitors instead of methanol and other alcohols to inhibit the formation and harm of natural gas hydrate; There are different drawbacks of chemical inhibitors, or they will increase the cost of natural gas extraction, or they are toxic, or they cannot be recovered, or they have other side effects, or they cannot effectively solve the problem of gas hydrate and icing in winter environments, or in the natural gas flow itself. When the temperature is low, the problem of natural gas hydrate and icing cannot be effectively solved, or when the pressure of the natural gas flow itself is high, the problem of natural gas hydrate cannot be effectively solved, so it cannot meet the actual needs of normal natural gas exploitation

The defect of this method is that in order to solve the problems such as natural gas hydrate or ice blocking the wellbore, pipeline, and equipment in natural gas exploitation, it is necessary to use heating methods (such as the method of heating furnace heating) to increase the temperature of the natural gas flow to prevent natural gas hydrate, ice, etc. Form or reduce the hazards of natural gas hydrates and ice; heating requires a large amount of energy, which will lead to increased energy consumption, increased costs, increased fixed investment, complicated processes, and increased management workload and other disadvantages in natural gas mining; and the heating method is easy on the ground. Implementation, it is very difficult to implement inside the wellbore, and it is difficult to solve the problem of gas hydrate plugging the wellbore

The disadvantage of this method is that when the ambient temperature on the ground is low (such as winter), the temperature of the natural gas flow will drop significantly due to the heat dissipation of the gathering pipelines and equipment, and it is very easy to form natural gas hydrate or freeze under low temperature conditions.

The disadvantage of this method is that when the ambient temperature is low (such as winter), the temperature of the pressurized natural gas flow will drop significantly due to the heat dissipation of the gathering pipeline and equipment. Very easy to form gas hydrate, or freeze

The disadvantage of this method is that: due to the high pressure of the natural gas flow in the underground wellbore, if the temperature of the natural gas flow is low, it is easy to form natural gas hydrates to block the wellbore, seriously affecting the normal gas production of natural gas; if the temperature of the natural gas flow in the underground wellbore is high If the natural gas hydrate is not formed at a high temperature, the temperature of the natural gas flow will be greatly reduced due to the throttling and pressure reduction of the ground gathering and transportation after rising to the ground, and it is easy to form natural gas hydrate or ice to block the ground gathering and transportation pipelines, valves, and equipment etc., which seriously affect the normal gathering and transportation of natural gas. For this reason, methanol or other alcohols must be added to the natural gas flow before the natural gas is throttled and depressurized to inhibit the formation and damage of natural gas hydrate or ice.

The disadvantage of this method is that: due to the high pressure of the natural gas flow in the underground wellbore, if the temperature of the natural gas flow is low, it is easy to form natural gas hydrates to block the wellbore, seriously affecting the normal gas production of natural gas; if the temperature of the natural gas flow in the underground wellbore is high If the natural gas hydrate is not formed at a high temperature, the temperature of the natural gas flow will be greatly reduced due to the throttling and pressure reduction of the ground gathering and transportation after rising to the ground, and it is easy to form natural gas hydrate or ice to block the ground gathering and transportation pipelines, valves, and equipment etc., which seriously affect the normal gathering and transportation of natural gas. Therefore, it is necessary to add hydrate inhibitors to the natural gas flow before throttling and reducing the pressure of the natural gas.

The disadvantage of this method is that: due to the high pressure of the natural gas flow in the underground wellbore, if the temperature of the natural gas flow is low, it is easy to form natural gas hydrates to block the wellbore, seriously affecting the normal gas production of natural gas; if the temperature of the natural gas flow in the underground wellbore is high If the natural gas hydrate is not formed at a high temperature, the temperature of the natural gas flow will be greatly reduced due to the throttling and pressure reduction of the ground gathering and transportation after rising to the ground, and it is easy to form natural gas hydrate or ice to block the ground gathering and transportation pipelines, valves, and equipment etc., which seriously affect the normal gathering and transportation of natural gas. Therefore, heating must be used to increase the temperature of natural gas flow before throttling and reducing the pressure of natural gas, so as to prevent the formation of natural gas hydrate and ice or reduce the hazards of natural gas hydrate and ice.

The disadvantage of this method is that the temperature of the natural gas flow will decrease due to throttling on the ground. It is easy to form gas hydrate or ice

The disadvantage of this method is that the temperature of the natural gas flow will decrease due to throttling on the ground. Gas hydrates or ices are easily formed at lower temperatures

The defect of this method is that the temperature of the natural gas flow will be greatly reduced due to the throttling and depressurization process of the natural gas flow in the underground wellbore. If the natural gas flow cannot pass through the wellbore in time to absorb enough When the natural gas flow rises to the ground, if the temperature of the natural gas flow is not high, or the ground environment temperature is low (such as winter), or the natural gas The local heat dissipation of pipelines, equipment, and valves is relatively fast, or the flow of natural gas is throttled at valves, etc., and it is easy to form natural gas hydrate or ice to block ground pipelines, valves, and equipment, which seriously affects the normal gathering and transportation of natural gas. Dosing methanol and other alcohols into the natural gas flow in the wellbore or on the ground

The disadvantage of this method is that the temperature of the natural gas flow will be greatly reduced due to the throttling and depressurization process of the natural gas flow in the underground wellbore. If the natural gas flow cannot pass through the wellbore in time to absorb enough When the natural gas flow rises to the ground, if the temperature of the natural gas flow is not high, or the ground environment temperature is low (such as winter), or the natural gas The local heat dissipation of pipelines, equipment, and valves is relatively fast, or the flow of natural gas is throttled at valves, etc., and it is easy to form natural gas hydrate or ice to block ground pipelines, valves, equipment, etc., seriously affecting the normal gathering and transportation of natural gas. Dosing hydrate inhibitors into natural gas streams in the wellbore or on the ground

The disadvantage of this method is that the temperature of the natural gas flow will be greatly reduced due to the throttling and depressurization process of the natural gas flow in the underground wellbore. If the natural gas flow cannot pass through the wellbore in time to absorb enough When the natural gas flow rises to the ground, if the temperature of the natural gas flow is not high, or the ground environment temperature is low (such as winter), or the natural gas The local heat dissipation of pipelines, equipment, and valves is relatively fast, or the natural gas flow is throttled at valves, etc., and it is easy to form natural gas hydrate or ice to block the ground pipelines, valves, equipment, etc., which seriously affects the normal gathering and transportation of natural gas. Therefore, it is necessary to use Heating methods increase the temperature of natural gas streams

The defect of this method is that the temperature of the natural gas flow will be greatly reduced due to the throttling and depressurization process of the natural gas flow in the underground wellbore. If the natural gas flow cannot pass through the wellbore in time to absorb enough When the natural gas flow rises to the surface, if the temperature of the natural gas flow is not high, the natural gas flow will be released when the surface ambient temperature is low (such as in winter). The flow temperature will further drop due to the heat dissipation of gathering pipelines and equipment, and it is easy to form natural gas hydrate or ice to block ground pipelines, valves, equipment, etc. under low temperature conditions, seriously affecting the normal gathering and transportation of natural gas

The disadvantage of this method is that although the method of throttling and depressurization in the underground wellbore can reduce the pressure of natural gas below the pressure of natural gas hydrate formation and avoid the formation of natural gas hydrate in the wellbore, the process of throttling and depressurization will greatly reduce the If the natural gas flow cannot absorb enough heat from the ground through the wellbore in time, the temperature of the natural gas flow will be lower than the freezing point of water, which will easily form ice to block the wellbore and seriously affect the normal gas production; After the ground, if the temperature of the natural gas flow is lower than the freezing point, or the ground ambient temperature is lower than the freezing point, or the metal wall temperature of the natural gas pipelines, equipment, valves, etc. is lower than the freezing point, it is very easy to form ice to block the ground pipelines, valves, equipment, etc., seriously Affect the normal gathering and transportation of natural gas; since the pressure of the natural gas flow rises to the ground is very low, it cannot meet the requirements of natural gas gathering, transportation and storage and transportation, and equipment and facilities such as compressors must be used to increase the pressure of the natural gas flow, which will consume a lot of money On the other hand, the pressure of natural gas flow will be higher than the formation pressure of natural gas hydrate, which will easily form natural gas hydrate to block ground pipelines, valves, equipment, etc., seriously affecting the normal gathering and transportation of natural gas or storage and transportation

[0018] Gas extraction method: When the pressure of the underground formation is low and the water output is low, natural gas is exploited by mechanically extracting natural gas with an air pump, compressor, etc. The defect of this method is that if the natural gas is not pressurized after rising to the ground, It is difficult to meet the requirements of natural gas gathering, transportation, storage and transportation. After the natural gas is pressurized, when the ambient temperature is low (such as winter), the temperature of the pressurized natural gas flow will drop significantly due to the heat dissipation of the gathering and transportation pipelines and equipment. It is easy to form gas hydrate or ice under the temperature and pressure after pressurization

The disadvantage of this method is that if the pressure of natural gas rises to the surface is low, pressurization is required to meet the requirements of natural gas gathering, transportation and storage. If the natural gas is raised to the surface and the pressure is high, when the ambient temperature is low (such as winter), this method has similar defects to the "natural pressure extraction method"

[0020] Chinese patent ZL02820253.8 discloses a "method for recovering hydrocarbons from hydrates", which can effectively solve the problem that natural gas hydrates or ice affect the normal operation of natural gas mining

) With a mining scale of 30 billion / year standard cubic meters, about 200 million tons of water need to be evaporated by "heating" every year, and 0.138 million tons of calcium, magnesium and other scaling ions need to be removed in the "heating" and heat exchange process equipment every year Scale prevention work; if the "boiler" heating method disclosed in this invention is used, about 138 million tons of solids in about 6,000 large boilers need to be removed every year, and an average of about 23,000 tons of solids will be removed per boiler per year. About 63 tons of solids should be removed every day, and an average of about 2.625 tons of solids should be removed per hour for each boiler. The solids that need to be removed are equivalent to about 66% of its evaporation; it is carried out in "heating" and heat exchange process equipment Such a huge anti-scaling work requires huge costs; the workload of removing such a huge amount of solids from the "heating" process equipment is not only extremely huge, but also greatly shortens the effective "heating" capacity of the boiler, making it impossible for the boiler to work normally heating, evaporation or work; yet, this invention does not propose a corresponding solution or method, and there is no corresponding technical method or solution to effectively solve this problem both at home and abroad

Therefore, although the method disclosed in this invention to remove "dilute aqueous solution" by "heating" is feasible in theory, it cannot be practically implemented, thus causing this invention to be unable to be used in domestic natural gas exploitation

[0023] 3) If the "heating" method of this invention is used to evaporate "remove" the water in the "dilute aqueous solution", a huge amount of money needs to be invested to build a huge and complicated heating process, equipment, and facilities, and a huge amount of money needs to be invested to solve the problem of heating with existing effective methods. Complicated issues such as antiscaling, descaling, anticorrosion, equipment overhaul, safety etc. of " dilute aqueous solution " process need consume a large amount of electric energy; A huge amount of money needs to be invested in the construction of complex and huge heat exchange processes, facilities, and equipment; it is also necessary to invest a huge amount of money to use existing effective methods to solve the anti-scaling of "dilute aqueous solution" in processes, facilities, and equipment such as heat exchange, power generation, or heat energy recovery. Complicated issues such as scale removal, anti-corrosion, equipment maintenance, safety, etc. also need to consume a large amount of electric energy; according to the "water solution" being diluted by one time to become a "dilute aqueous solution", if the "underground hydration" described in the invention is calculated every year The scale of recovery of gaseous hydrocarbons in the physical system has reached the production scale of 30 billion / year standard cubic meters of a large domestic natural gas field (such as the Ordos Basin gas field), and about 200 million tons of water need to be evaporated every year, so about 400 million tons of water needs to be solved every year. Heating, heat exchange, power generation or heat energy recovery and utilization of dilute aqueous solution, as well as the resulting complex issues such as power consumption, scale prevention, scale removal, corrosion protection, equipment maintenance, safety, etc.

[0025] 5) The published data of natural gas fields at home and abroad show that hydrogen sulfide generally exists in natural gas, which is also dissolved in "aqueous solution" and ionized, and will form water-insoluble sulfides with non-alkali metal ions such as iron ions; but the invention disclosed The literature does not solve the problem of waste substances such as sulfides entering the "dilute aqueous solution", does not solve the harmless problem of the huge amount of solids produced by the "heating" process equipment, does not solve the process of "dilute aqueous solution" being concentrated and regenerated into "water solution" and the process of "heating". ", anti-scaling, descaling, anti-corrosion and other problems during heat exchange, did not solve the problem of continuous enrichment of metal ions and mineral ions in the "regenerated aqueous solution", did not solve the "regenerated aqueous solution" before "recycling" The problem of various water-insoluble substances, sulfides, supersaturated crystals and precipitates produced during the "regeneration" process has not solved the purification problem of the "regenerated aqueous solution" before "recycling"; not only seriously affects the "aqueous solution" Recycling, and if these waste substances are discharged into the environment, it will seriously pollute the environment; allowing these waste substances to "recycle" into the wellbore and pipeline with the "regenerated aqueous solution" will aggravate the fouling of the wellbore and pipeline, and even blockage dead wellbore, pipeline

Therefore, it is difficult to directly implement the invention, and it is difficult to directly implement and be applied to domestic natural gas exploitation.

[0026] 6) The original natural state of the natural gas (that is, the natural gas referred to in the present invention) in the underground formation is not the state of natural gas hydrate, and does not form natural gas hydrate with water, and there is no "hydrate system" , the hydrocarbon or natural gas can be released from the subterranean formation without the method disclosed in this invention, and the exploitation of natural gas (that is, the natural gas referred to in the present invention) in non-"permafrost regions" on land by the method disclosed in this invention will result in natural gas The complexity of mining methods and processes, equipment, facilities, etc. is not as economical and practical as the above-mentioned domestic natural gas mining methods

Therefore, the method disclosed in this invention is difficult to be directly used in domestic natural gas exploitation, and the method in this invention has not been applied in domestic natural gas exploitation at present.

[0027] 7) The "water solution" described in this invention is added to the natural gas flow in the underground wellbore or surface pipeline during natural gas production to prevent the formation of natural gas hydrate or ice in the underground wellbore or surface pipeline and affect the normal gas production and gathering of natural gas production. , instead of using the temperature of the "water solution" itself to prevent the formation of natural gas hydrate or ice in underground wellbores or surface pipelines, there is no requirement for the temperature of the "water solution" in actual use, even if the temperature of the "water solution" is below zero degrees Celsius It also does not affect its ability to prevent natural gas hydrates or ice from forming in underground wellbores or surface pipelines; when "water solution" with a relatively high temperature is added to the wellbore or pipeline, no matter what method is used, no insulation measures are taken. The temperature of the "aqueous solution" will decrease, and if thermal insulation measures are taken, it will not only have no practical value, but also need to pay a higher price for thermal insulation; because the "aqueous solution" after the "dilute aqueous solution" is evaporated and concentrated by the "heating" method contains a lot of heat energy; Calculated according to the 50% total heat recovery and reuse rate that can be achieved by the current domestic technical level, the temperature of the "water solution" after heat energy recovery by heat energy recovery technology is still high, and still contains a large amount of heat energy that cannot be effectively utilized, resulting in a large amount of waste of energy.

Therefore, no matter whether the method disclosed in this invention is carried out in the laboratory or in the field, it is impossible to complete the steps of the invention, and the purpose of the invention cannot be realized, so it cannot be used for domestic natural gas exploitation.

[0030] In summary, there is no effective clean natural gas extraction method in the prior art