CN110259424B - A method and device for in-situ exploitation of oil shale - Google Patents

Abstract

The present invention provides a method and device for in-situ exploitation of oil shale. The device includes: combustion reaction equipment, pulse nozzle, preheating equipment, coiled tubing inner pipe, coiled tubing outer pipe, production casing, water supply equipment, fuel supply equipment, oxygen supply equipment and pump set; The oil pipe outer pipe is connected; the water supply equipment and fuel supply equipment are connected with the coiled tubing inner pipe; the bottom of the combustion reaction equipment is provided with a pulse nozzle; the coiled tubing inner pipe, the coiled tubing outer pipe and the production casing are all connected with the combustion reaction equipment. The present invention also provides a method for in-situ production of oil shale using the above device. The method and device for in-situ mining of oil shale provided by the present invention have low mining cost and high mining efficiency.

Description

A method and device for in-situ exploitation of oil shale

technical field

The invention relates to a mining method and device, in particular to a method and device for in-situ mining of oil shale, and belongs to the technical field of oil and gas mining.

Background technique

At present, with the continuous development of the global economy, the demand for energy is also increasing. With the progress of development, the reserves of conventional oil and gas continue to decline, and the difficulty of exploitation continues to increase. Therefore, we urgently need to find alternatives to conventional oil and gas energy. Oil shale (oil shale, oil shale is deposited from the mud formed by the decay of aquatic plants, algae and other low-level organisms, and is a very rich mineral resource that has not been well utilized. According to the depositional environment, oil shale can be Divided into three basic genetic types: continental, lacustrine and marine) is a kind of unconventional oil and gas resources, which is regarded as an important supplement and alternative energy for traditional energy, and has gradually attracted widespread attention at home and abroad. my country is rich in oil shale reserves. The proven oil shale reserves are about 47.6 billion tons, which is equivalent to half of conventional oil resources. And the distribution of reserves is relatively concentrated, mainly in Jilin Province and other regions. However, the cracking, transformation and recovery technology of oil shale is the main factor affecting the development and utilization of oil shale. Therefore, it is necessary to understand the relevant mining technology and development status of oil shale.

At present, the open method utilization methods for oil shale are mainly ground retorting oil refining and underground in-situ mining. Ground retorting method refers to excavating oil shale ore, transporting it to a specific retorting furnace and heating it to 500°C to 600°C, and retorting "artificial oil". my country's oil shale ground retorting industry has a long history, but the ground retorting method not only requires a large amount of water resources, but also causes great pollution to the environment, making it difficult to develop on a large scale. In order to promote the large-scale green development and utilization of oil shale, major international oil companies have strengthened the research on underground in-situ dry distillation of oil shale, and formed a variety of in-situ extraction technologies for oil shale. In-situ mining of oil shale no longer extracts oil shale ore, but by heating oil shale in situ underground, thermally cracking organic matter (kerogen) into "oil" and "combustible gas", and then cracking the cracked oil and gas A method of recovery in which products are recovered into the formation. Due to the advantages of small surface excavation, less waste discharge, and lower pollution, in-situ mining is gradually becoming the most promising technology for oil shale mining.

At present, the in-situ mining technology of oil shale at home and abroad is divided into two categories according to the heating principle: in-situ combustion heating mining and in-situ physical heating mining technology. The combustion heating mining technology first excavates one-fifth of the bottom of the oil shale layer and fracturing or blasting the oil shale above the bottom plate, and then passes hot air and combustible gas into the target rock layer, and burns to heat the target rock layer. . However, since the bottom of the target layer is destroyed in the process of excavating the stratum, the groundwater will also be polluted. Moreover, the combustion process is not easy to control, and it is easy to consume most of the organic matter in the oil shale. Therefore, the current in-situ mining is more inclined to use in-situ physical heating to extract oil shale. In situ physical heating mining technology can be divided into three categories: conduction heating technology, radiation heating technology and fluid convection heating technology. In addition, there is also the technology of local chemical reaction thermal cracking proposed by Israel AST Company.

The conduction heating technology mainly uses the freezing wall to freeze the target rock block before construction to prevent pollution. During construction, a working well is drilled to the target rock formation and an electric heater is placed in the working well, and then the target rock formation is heated. When the target pay zone is heated to 600-700K, the organic matter inside the oil shale begins to transform, and then the traditional oil and gas recovery methods are used to recover the oil and gas products to the surface. The advantages of electrical conduction heating are that it reduces environmental pollution and the heating method is flexible and easy to control. The disadvantage is that the energy utilization rate is low and the heating speed is slow.

Radiation heating technology combines two technical characteristics of radio frequency heating and supercritical fluid extraction. In the implementation process, the well is first drilled to the target rock formation, then the RF sensor is placed in the well, and then the sensor is turned on to heat the formation to promote the transformation of organic matter inside the oil shale, and then inject supercritical carbon dioxide into the target formation to extract oil and gas products to recover. ground. The advantages of radiant heating are fast heating and high energy utilization efficiency. The disadvantage is that RF heating technology is difficult to implement downhole, and there are still problems with the use of sensors in the well. And the cost of radio frequency heating technology is relatively high.

The working principle of convection heating technology is to first drill to the target rock formation, and then form a fracture network through multi-well fracturing, which runs through the entire heating area, and finally injects high-temperature hydrocarbon gas (or high-temperature carbon dioxide) into the heat injection well to heat the target production layer. And the generated oil and gas products are produced from production wells. In addition, Jilin University has also proposed a technology for in-situ exploitation of oil shale using water vapor in the near-neighborhood. This technology takes advantage of the better extraction and dissolving power of water near the boundary, and has less pollution to the environment. The advantage of convection heat transfer technology is that the heating speed is fast, and the dry distillation gas can be fully utilized. The disadvantage is that the seam network must be formed before mining. Moreover, compared with the near-neighbor water, supercritical water has stronger extraction ability in oil shale, and the converted product has higher polarity.

In addition, some people have proposed the means of local chemical reaction to extract oil shale. The principle of this technology is to drill a well in the target interval, and then inject high-temperature air into the target formation to promote the local chemical reaction of the organic matter inside the oil shale. As the reaction progresses, a reaction unit continues to expand in the target formation. In the initial stage of the reaction, kerogen is mainly cracked and converted into bitumen, and with the progress of the reaction time, the bitumen is further converted into shale oil and part of hydrocarbon gas. However, the reaction area of this method is small, and repeated injection is required, and the control of the injection amount is complicated. If the injection amount is not suitable, a large amount of oil and gas products will be consumed.

It can be seen from the above that there is currently no cost-effective method for realizing large-scale industrial in-situ mining of oil shale.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a method and device for in-situ exploitation of oil shale using supercritical pulsed thermal jet. The method and device of the present invention can realize efficient and economic in-situ exploitation of oil shale.

In order to achieve the above technical purpose, the present invention provides a device for in-situ production of oil shale, the device comprising: combustion reaction equipment, pulse nozzles, preheating equipment, coiled tubing inner pipe, coiled tubing outer pipe, production casing, Water supply equipment, fuel supply equipment, oxygen supply equipment and pump set;

Among them, the oxygen supply equipment is communicated with the outer pipe of the coiled tubing;

The water supply equipment and the fuel supply equipment are connected with the inner pipe of the coiled tubing;

The combustion reaction equipment is arranged in the oil shale reservoir, and a pulse nozzle is arranged at the bottom of the combustion reaction equipment;

The coiled tubing inner tube, the coiled tubing outer tube, and the production casing are all communicated with the combustion reaction equipment.

The apparatus for in-situ production of oil shale of the present invention includes a raw material supply part. The raw material supply part includes water supply equipment, fuel supply equipment, oxygen supply equipment, preheating equipment and pump set. Among them, the raw material supply part is used to provide raw materials for the combustion reaction.

Specifically, the water supply equipment is used to supply water for the combustion reaction during the production process, so as to form a supercritical water jet and at the same time make up for the reservoir pressure deficit.

Specifically, the fueling device is used to fuel the combustion reaction to achieve ignition.

Specifically, the oxygen supply equipment is used to supply the oxygen-containing gas required in the combustion process.

Specifically, the preheating device is used to preheat the fuel-water mixture and the oxygen-containing gas before the combustion reaction device is not ignited.

In a specific embodiment of the present invention, the water supply equipment is communicated with the coiled tubing inner pipe; the fuel supply equipment is communicated with the coiled tubing inner pipe; the oxygen supply equipment is communicated with the coiled tubing outer pipe.

In a specific embodiment of the present invention, the preheating devices are respectively a fuel water preheater and a gas preheater; wherein, one end of the fuel water preheater is respectively connected with the water supply device and the fuel supply device, and the other end is connected with the continuous oil The tube is communicated within the tube. One end of the gas preheater is communicated with the oxygen supply equipment, and the other end is communicated with the outer pipe of the coiled tubing.

The device for in-situ exploitation of oil shale of the present invention includes combustion reaction equipment. Among them, the combustion reaction equipment is used to provide an environment for the combustion reaction.

In a specific embodiment of the present invention, the combustion reaction equipment includes a combustion reaction chamber, a fuel water inlet and an oxygen-containing gas inlet at the top of the combustion reaction chamber, and a nozzle pipe at the bottom of the combustion reaction chamber.

In a specific embodiment of the present invention, the pulse nozzle is connected at the outlet of the nozzle conduit.

Specifically, the pulsed nozzle is used to transform the generated supercritical jet into a pulsed supercritical jet.

The device for in-situ production of oil shale of the present invention comprises a coiled tubing inner tube, a coiled tubing outer tube and a production casing. Among them, the production casing is used to transport the decomposed oil and gas products to the surface (preferably, to the product separation and extraction equipment). Coiled tubing inner tube is used to transport fuel and water to combustion reaction equipment. Coiled tubing outer tube is used to transport oxygen-containing gas to combustion reaction equipment.

In a specific embodiment of the present invention, the coiled tubing inner tube is arranged in the coiled tubing outer tube and has an annulus, and the coiled tubing outer tube is arranged in the production casing and has an annulus.

In a specific embodiment of the present invention, the production casing communicates between the surface and the target location of the oil shale reservoir in the well.

Among them, the outer tube of the coiled tubing and the inner tube of the coiled tubing are all provided with thermal insulation equipment. For example, thermal insulation equipment can use thermal insulation cotton.

In a specific embodiment of the present invention, the production casing is fixed in the wellbore by a cement sheath.

In a specific embodiment of the present invention, the beginning end of the coiled tubing inner tube is communicated with the fuel water preheater, and the end of the coiled tubing inner tube is communicated with the combustion reaction chamber of the combustion reaction equipment.

In a specific embodiment of the present invention, the beginning end of the coiled tubing outer tube is communicated with the gas preheater, and the end of the coiled tubing outer tube is communicated with the combustion reaction chamber of the combustion reaction equipment.

The device for in-situ exploitation of oil shale of the present invention includes oil and gas storage and separation equipment, and product separation and extraction equipment. Among them, the product separation and extraction equipment is used to separate and extract the produced oil-gas-water mixture. The oil and gas storage and separation equipment is used to collect the separated and extracted oil and gas products.

In a specific embodiment of the present invention, the product separation and extraction equipment is arranged between the oil and gas storage and separation equipment and the production casing.

In a specific embodiment of the present invention, one interface of the product separation and extraction device is communicated with the production casing, and the other interface of the product separation and extraction device is communicated with the oil and gas storage and separation device.

The device for in-situ exploitation of oil shale of the present invention includes a pump group. Wherein, the pump group is used to communicate with the product separation and extraction equipment, the water supply equipment, the fuel supply equipment and the oxygen supply equipment respectively.

In the device for in-situ production of oil shale of the present invention, the combustion reaction chamber, nozzle pipe and pulse nozzle, preheater, coiled tubing inner pipe, coiled tubing outer pipe, production casing, water supply equipment, supply The fuel equipment, oxygen supply equipment, product separation and extraction equipment, oil and gas storage and separation equipment, and pump sets can all be conventional components and equipment in the field. The diameters of the inner coiled tubing, the outer coiled tubing, and the production casing can be adjusted by those skilled in the art according to actual needs.

The device for in-situ exploitation of oil shale of the present invention, when specifically used for in-situ exploitation of oil shale, may include the following steps:

Using pulsed thermal jet to drill multilateral wells to different layers of oil shale reservoirs;

The combustion reaction equipment is placed at the target position of each branch well; the combustion reaction equipment includes a combustion reaction chamber, a nozzle pipe located at the bottom of the combustion reaction chamber, and a pulse nozzle connected to the outlet of the nozzle pipe;

Lower the production casing from the surface to the target location of each lateral well;

The coiled tubing outer tube is sleeved with the coiled tubing inner tube, and thermal insulation treatment is performed on the coiled tubing outer tube and the coiled tubing inner tube. The coiled tubing outer tube is sleeved into the production casing, and the coiled tubing outer tube and coiled tubing The beginning end of the pipe is respectively connected with the fuel water preheater and the gas preheater, and the end of the coiled tubing outer pipe and the end of the coiled tubing inner pipe are connected with the combustion reaction equipment;

On the ground, set up fuel water pre-heater, gas pre-heater, product separation and extraction equipment, oil and gas storage and separation equipment, water supply equipment, fuel supply equipment, oxygen supply equipment and pump set. One interface of the product separation and extraction equipment is connected with the oil and gas storage and separation equipment; the other interface of the product separation and extraction equipment is connected with the production casing; The heater is connected, and the fuel water preheater is connected with the inner pipe of the coiled tubing; the oxygen supply equipment is connected with the gas preheater, and the gas preheater is connected with the outer pipe of the coiled tubing; the pump set is connected with the product separation and extraction equipment, and the water supply Connection of equipment, fuel supply equipment and oxygen supply equipment;

Turn on the pump set, pump the fuel-water mixture into the fuel-water preheater through the fuel supply equipment, and then pump the pre-heated supercritical fuel-water mixture from the inner tube of the coiled tubing to the combustion reaction chamber of the combustion reaction equipment to make the combustion reaction The internal pressure of the chamber reaches 22.1MPa or more, and the oxygen-containing gas is pumped into the gas preheater through the oxygen supply equipment, and the preheated supercritical oxygen-containing gas is pumped from the outer tube of the coiled tubing to the combustion reaction chamber of the combustion reaction equipment. After the critical fuel-water mixture is in contact with the oxygen-containing gas, spontaneous combustion occurs; when the fuel starts to burn, the preheating temperature of the fuel-water mixture and the oxygen-containing gas is slowly lowered, and the combustion products pass through the nozzle pipeline at the bottom of the combustion reaction chamber, from the pulse nozzle. The high-speed pulse jet is ejected from the outlet, and the heat generated by the combustion and the impact force of the jet act on the oil shale reservoir to thermally crack the oil shale, and the cracked oil and gas products return to the product separation and extraction equipment along the production casing. After extraction and separation, it enters the oil and gas storage and separation equipment;

Among them, by controlling the temperature of the pre-heater, when the flame appears in the combustion reaction chamber, the set temperature of the pre-heater can be lowered to 375°C ± 10°C (hydrothermal flame extinction temperature), so as to maintain the stability of the flame, and by controlling the pump unit , to ensure the continuous pumping of the fuel-water mixture and oxygen-containing gas, and control the pressure in the combustion reaction chamber to be above 25MPa±2MPa through the pump group (the pressure in the combustion reaction chamber can be adjusted by the pump group for water supply equipment, fuel supply equipment and supply equipment. At the same time, the fuel-water mixture is pumped from the inner tube of the coiled tubing to the combustion reaction chamber through the water supply equipment and the fuel supply equipment, because the pressure in the combustion reaction chamber is higher than 25MPa at this time. , the temperature in the combustion reaction chamber is higher than 374.3 °C, and the water entering the combustion reaction chamber from the inner tube of the coiled tubing is still in a supercritical state (when the pressure is greater than 22.1 MPa and the temperature is higher than 374.3 °C, the water is in a supercritical state, which can mix with alcohol Such fuels achieve good mutual solubility and support combustion), fully mix and burn with the oxygen-containing gas entering the combustion reaction chamber from the outer tube of the coiled tubing, and a high-strength and continuous supercritical water oxidation reaction occurs, adjusting the injection to combustion The flow ratio of the oxygen-containing gas and the fuel-water mixture in the reaction chamber is used to control the flame temperature in the combustion reaction chamber and ensure the stability of the flame; the oxidation product is ejected from the pulse nozzle outlet at the bottom of the combustion reaction chamber to form a high-speed pulse jet. The heat generated by the combustion and the impact force of the pulsed jet act on the oil shale reservoir, causing the oil shale to crack. At the same time, the injected supercritical water also carries a certain amount of oxygen, which will oxidize and react with the oil shale. , releasing a large amount of heat to promote the further thermal cracking of oil shale. At the same time, supercritical water also has strong dissolution and extraction properties, which can extract the cracked oil and gas products, and the extracted oil and gas products return along the production casing. Enter the product separation and extraction equipment, and then enter the oil and gas storage equipment for collection after separation and extraction, so as to realize the in-situ mining of oil shale;

Continue to pump supercritical water into the well until the bottom hole pressure reaches 25MPa±2MPa, shut down the well for 2 days, and then reopen the well to extract the cracked oil and gas products to the surface;

After the production is completed, turn off the pump set, turn off the preheater, stop pumping the fuel-water mixture and oxygen-containing gas, and lift up the production casing, the outer coiled tubing, the inner coiled tubing, and the combustion reaction device to complete the oil sheeting. In situ mining of rock.

The present invention also provides a method for in-situ exploitation of oil shale, the method is completed by the device for in-situ exploitation of oil shale of the present invention, and the method comprises the following steps:

Inject the water preheated to the set temperature (375℃±10℃) into the combustion reaction equipment until the pressure of the combustion reaction equipment reaches 22.1MPa or more (preferably 25MPa);

heating the fuel-water mixture to a supercritical state; wherein, the fuel content in the fuel-water mixture is 10%-50% (preferably 30%);

heating the oxygen-containing gas to a supercritical state;

The pressure of the combustion reaction equipment is regulated to be 25MPa±2MPa, the fuel-water mixture in the supercritical state is injected into the combustion reaction equipment, and the oxygen-containing gas in the supercritical state is injected into the combustion reaction equipment to carry out the combustion reaction;

When a spontaneous combustion reaction occurs in the combustion reaction equipment, reduce the preheating temperature of the fuel-water mixture and oxygen-containing gas to 375°C ± 10°C;

The combustion products are injected into the well in the form of pulsed jets until the bottom hole pressure reaches 25MPa±2MPa, the injection is stopped, and the well is closed and closed. After the oil shale is fully thermally cracked in the formation, the well is opened, and the generated oil and gas mixture It is extracted to the ground for separation, so as to realize the in-situ extraction of oil shale.

The method for in-situ exploitation of oil shale of the present invention injects a preheated fuel-water mixture and an oxygen-containing gas, so that the supercritical state fuel-water mixture and the oxygen-containing gas are fully contacted in the reaction chamber to cause oxidation and spontaneous combustion, resulting in A hydrothermal flame produces a large amount of heat, and the combustion products are mainly water and carbon dioxide. A pulsed thermal jet with strong impact ability is formed at the outlet pulse nozzle. The pulsed jet acts on the rock surface to form fractures and pores. The supercritical water of the combustion product carries a large amount of heat from the fractures and pores into the oil shale reservoir, promoting oil production. The organic matter inside the shale is decomposed and transformed into the corresponding oil and gas products.

Since the thermal fluid is ejected in the form of a pulsed jet, a very strong momentum exchange occurs between the high-speed jet and the air in the oscillating cavity. After the momentum exchange occurs, an unstable shear layer is generated in the direction of fluid flow, and the thickness of the shear layer will be With the continuous thickening, the liquid near the shear layer is entrained to form large-scale vortices during the flow of the jet. When the vortex moves downward and collides with the lower collision wall, a pressure disturbance will be formed. When the frequency of the pressure disturbance is the same as the natural frequency in the oscillating cavity, periodic resonance excitation will be generated, thereby generating a pulsed jet. The pulsed thermal jet can form a large number of irregular fractures on the rock surface, and the intermittent injection is beneficial to the removal of cuttings at the bottom, thereby generating new outcrops in the oil shale reservoir; the continuous injection of thermal jet makes the bottom hole pressure exceed 22.1 At MPa, the jet fluid is supercritical water. Supercritical water has high diffusion coefficient and heat and mass transfer ability, and can effectively enter the tiny cracks of oil shale to promote the thermal cracking of oil shale. Water has strong oxidizing properties, and the oxidizing substances in supercritical water will chemically react with oil shale, thereby generating a lot of heat, and the generated heat will continue to spread to the distance, promoting further thermal cracking of oil shale; , supercritical water has good solubility and can extract oil and gas products.

In the method for in-situ production of oil shale of the present invention, the well located in the oil shale reservoir is drilled by supercritical water pulse thermal jet. Among them, the drilling method disclosed in CN103790516A (application number: 201410075665.9, title of invention: a new drilling method for efficient rock breaking by thermal jet) can be referred to by thermal jet drilling.

In the method for in-situ production of oil shale of the present invention, the oxygen-containing gas can theoretically be both air and pure oxygen, in order to control the degree of reaction and prevent excessive oxidation of oil shale. In a specific embodiment of the present invention, air is used as the oxygen-containing gas.

In a specific embodiment of the present invention, the fuel used includes one or a combination of two or more of methanol, ethanol, isopropanol, and methane.

In the method for in-situ production of oil shale of the present invention, the fuel-water mixture preheated to a certain temperature and oxygen are met and spontaneously ignited to generate a hydrothermal flame, and then the liquid in the reaction chamber can be reheated to supercritical by means of the hydrothermal flame. state.

In the method for in-situ production of oil shale of the present invention, the combustion reaction equipment generates a hydrothermal flame, and when the hydrothermal flame is generated, the preheating temperature of the fuel-water mixture can be lowered. Since the combustion reaction can release a large amount of heat, when the fuel starts to burn, there is no need to provide heat, and the reaction can proceed spontaneously.

In the method for in-situ production of oil shale of the present invention, the oil and gas products generated by thermal cracking are returned to the ground through a production casing, the diameter of the production casing is larger than that of the coiled tubing outer pipe, and is sleeved outside the coiled tubing outer pipe .

In the method for in-situ production of oil shale of the present invention, the fuel-water mixture and oxygen-containing gas are continuously injected into the combustion reaction equipment, and the pressure in the combustion reaction chamber is controlled to be above 25MPa±2MPa (the pressure can be controlled by the surface pump group ).

In the method for in-situ production of oil shale of the present invention, a pulsed thermal jet is generated by the product of the combustion reaction through a pulsed nozzle, and the jet energy better utilized by the pulsed thermal jet can quickly form cracks on the surface of the oil shale, so that the The jet fluid is introduced into the fracture to improve the cracking efficiency of oil shale.

In a specific embodiment of the present invention, the oxygen content in the supercritical water injected into the oil shale reservoir is adjusted, thereby controlling the oxidative cracking rate of the oil shale.

Wherein, the ratio of the amount of oxygen-containing gas actually injected in the reaction to the theoretically required amount of oxygen-containing gas is defined as the reaction coefficient, and the reaction coefficient of the oxygen-containing gas can be adjusted to be 0.5-6.

Preferably, the reaction coefficient of the oxygen-containing gas is adjusted to be 0.5-6, which can further achieve more complete combustion of fuel and rapid oxidative cracking of oil shale.

In the method for in-situ production of oil shale of the present invention, the method further comprises the step of separating and extracting the oil and gas products produced on the ground.

In a specific embodiment of the present invention, the extracted light hydrocarbons and alcohols are mixed with water, and can be recycled as a fuel-water mixture. The oil and gas products returned to the ground are actually oil-gas-water mixtures. After extraction and separation, shale oil, bitumen substances and hydrocarbon gases can be obtained. For example, the separated water can be mixed with fuel again and injected into the generator to reduce water waste.

In the method for in-situ production of oil shale of the present invention, by injecting preheated fuel water and oxygen-containing gas into the oil shale reservoir from the ground, the fuel-water mixture in a supercritical state and the oxygen-containing gas meet to achieve Ignition and spontaneous combustion, and the hot fluid after combustion is ejected through the pulse nozzle, which promotes the thermal cracking of oil shale. Continue to inject into the well until the bottom hole pressure reaches 25Mpa, stop the pump and shut down the well for 2 days and then restart the well to return the decomposed oil and gas products to the surface, so as to realize the in-situ exploitation of oil shale.

In the method for in-situ production of oil shale of the present invention, a large amount of heat generated by the combustion promotes the thermal cracking of the oil shale, providing sufficient heat for the cracking of the oil shale; and the impact of the pulse jet can make the heat transfer When the speed increases, the crushing action of the pulsed jet can form cracks and pores in the oil shale, so that the hot fluid can better exchange heat with the oil shale; at the same time, when the bottom hole pressure is higher than 22.1MPa, the jet becomes supercritical water. Jet, the oxidizing substances carried in supercritical water can undergo oxidation reaction with oil shale, generate a lot of heat, and promote further thermal cracking of oil shale. The oil and gas products are extracted; further, the combined effect of combustion heat, jet flow and supercritical water extraction can greatly improve the production efficiency of oil shale.

The method and device for in-situ exploitation of oil shale of the present invention have the following advantages:

(1) The exploitation cost is low, and the self-ignition of fuel water is used for heating, which reduces the cost of generating supercritical water, and the mined alcohols and hydrocarbons can also be injected as fuels; at the same time, the method and device can The drilling and exploitation of oil shale can be realized at the same time by one trip, without the need for fracturing operation, which greatly improves the efficiency of oil shale exploitation and reduces the exploitation cost.

(2) The extraction efficiency is high. Since the generated supercritical water pulse thermal jet can form a large number of irregular fractures on the surface of the oil shale, the supercritical water has good heat and mass transfer ability, and can enter the oil shale interior. Promote the thermal cracking of oil shale, and at the same time, the oxides carried in supercritical water can react with oil shale, generate a lot of heat, and promote the further cracking of oil shale; at the same time, supercritical water has good dissolution and extraction performance. , the oil and gas products produced by the cracking can be extracted; and the oil shale will undergo a pyrolysis reaction in 3h-5h in the environment of supercritical water, which improves the efficiency of thermal action compared with other pyrolysis methods.

Description of drawings

FIG. 1 is a schematic structural diagram of an apparatus for in-situ production of oil shale in Example 1 of the present invention.

2 is a schematic structural diagram of a combustion reaction device and a self-excited pulse nozzle in the device for in-situ oil shale production in Example 1 of the present invention.

Description of main drawing symbols:

1. Water supply equipment 2, fuel supply equipment 3, fuel water pre-heater 4, oxygen supply equipment 5, gas pre-heater 6, product extraction and separation equipment 7, oil and gas storage and separation equipment 8, ground 9, cement sheath 10, production Casing 11, inner coiled tubing 12, outer coiled tubing 13, roof bedrock 14, oil shale reservoir 15, floor bedrock 16, combustion reaction equipment 17, oil and gas products 18, pulse jet 19, combustion reaction chamber 20 , nozzle pipeline 21, self-excited pulse nozzle 22, self-excited pulse nozzle oscillation cavity 23, self-excited pulse nozzle oscillation cavity collision wall 24, self-excited pulse nozzle outlet

Detailed ways

In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solutions of the present invention are now described in detail below, but should not be construed as limiting the scope of implementation of the present invention.

Example 1

This embodiment first provides a device for in-situ exploitation of oil shale, which has a structure as shown in FIG. 1 , and the device specifically includes:

Combustion reaction equipment 16, self-excited pulse nozzle 21, preheating equipment, coiled tubing inner pipe 11, coiled tubing outer pipe 12, production casing 10, water supply equipment 1, fuel supply equipment 2, oxygen supply equipment 4 and pump set.

The apparatus for in-situ production of oil shale in one of the embodiments includes a feedstock supply. The raw material supply part includes water supply equipment 1 , fuel supply equipment 2 , oxygen supply equipment 4 , preheating equipment and a pump set. Among them, the raw material supply part is used to provide raw materials for the combustion reaction.

Specifically, the water supply device 1 is used to supply water to the combustion reaction device 16 during the production process, so as to form a supercritical water jet and at the same time make up for the reservoir pressure deficit. The fuel supply device 2 is used to supply the combustion reaction device 16 with fuel for ignition. The oxygen supply device 4 is used to supply the oxygen-containing gas required in the combustion process.

Specifically, the water supply equipment 1 communicates with the coiled tubing inner pipe 11 ; the fuel supply equipment 2 communicates with the coiled tubing inner pipe 11 ; the oxygen supply equipment 4 communicates with the coiled tubing outer pipe 12 .

More specifically, the preheating device is used to preheat the fuel water mixture and oxygen before the combustion reaction device is not fired. The preheating devices are respectively the fuel water preheater 3 and the gas preheater 5; wherein, one end of the fuel water preheater 3 is communicated with the water supply device 1 and the fuel supply device 2 respectively, and the other end of the fuel water preheater 3 is connected to the water supply device 1 and the fuel supply device 2 respectively. The inner tube 11 of the coiled tubing is communicated; one end of the gas preheater 5 is communicated with the oxygen supply equipment 4 , and the other end of the gas preheater 5 is communicated with the outer tube 12 of the coiled tubing.

The apparatus for in situ production of oil shale in one of the embodiments includes a combustion reaction apparatus 16 . Among them, the combustion reaction device 16 is used to provide an environment for the combustion reaction. The structure is shown in Figure 2.

The combustion reaction device 16 includes a combustion reaction chamber 19 , fuel and water inlets and oxygen inlets at the top of the combustion reaction chamber 19 , and nozzle pipes 20 at the bottom of the combustion reaction chamber 19 . Among them, the self-excited pulse nozzle 21 is connected to the outlet 24 of the nozzle pipe 20 . Pulse nozzles are used to transform the resulting supercritical water jet into a pulsed supercritical water jet.

The apparatus for in-situ production of oil shale in one of the embodiments includes an inner coiled tubing pipe 11 , an outer coiled tubing pipe 12 and a production casing 10 . Among them, the production casing 10 is used to transport the decomposed oil and gas products to the surface 8 (preferably to the product separation and extraction equipment). The inner pipe 11 of the coiled tubing is used to transport fuel and water to the combustion reaction equipment. The coiled tubing outer pipe 12 is used to transport oxygen-containing gas to the combustion reaction equipment.

The coiled tubing inner tube 11 is arranged in the coiled tubing outer tube 12 , and the coiled tubing outer tube 12 is arranged in the production casing 10 . The production casing communicates between the surface and the target location of the oil shale reservoir in the well. The production casing 10 is fixed in the wellbore by the cement sheath 9 .

Among them, the coiled tubing outer pipe 12 and the coiled tubing inner pipe 11 are both provided with thermal insulation equipment. For example, thermal insulation equipment can use thermal insulation cotton.

The beginning end of the coiled tubing inner tube 11 is communicated with the fuel water preheater 3 , and the end of the coiled tubing inner tube 11 is communicated with the combustion reaction chamber 19 of the combustion reaction device 16 . The beginning end of the coiled tubing outer tube 12 is communicated with the gas preheater 5 , and the end of the coiled tubing outer tube 12 is communicated with the combustion reaction chamber 19 of the combustion reaction device 16 .

In one of the embodiments, the device for in-situ production of oil shale includes oil and gas storage and separation equipment 7 and product separation and extraction equipment 6 . Among them, the product separation and extraction equipment 6 is used for separating and extracting the produced oil-gas-water mixture. The oil and gas storage and separation equipment 7 is used to collect the oil and gas products separated and extracted.

The product separation and extraction equipment 6 is arranged between the oil and gas storage and separation equipment 7 and the production casing 10 . One interface of the product separation and extraction device 6 is communicated with the production casing 10 , and the other interface of the product separation and extraction device 6 is communicated with the oil and gas storage and separation device 7 .

In one embodiment, the apparatus for in situ production of oil shale includes a pump set. Wherein, the pump group is used to communicate with the product separation and extraction equipment, the water supply equipment, the fuel supply equipment and the oxygen supply equipment respectively.

The present embodiment also provides a method for in-situ exploitation of oil shale using supercritical water pulse thermal jet, the method is realized by the device shown in FIG. 1 , and includes the following steps:

The pulsed thermal jet is used to drill to different layers of the oil shale reservoir 14. Above the oil shale reservoir 14 is the roof bedrock 13, and below the oil shale reservoir 14 is the bottom bedrock 15. For drilling through the pulsed thermal jet, refer to CN103790516A. disclosed drilling methods;

The combustion reaction device 16 is placed at the target position in the well; the combustion reaction device 16 includes a combustion reaction chamber 19 and a nozzle pipe 20 at the bottom of the combustion reaction chamber 19 . The self-excited pulse nozzle 21 is installed at the outlet of the nozzle pipe 20 of the combustion reaction device 16;

The production casing 10 is lowered from the surface into the target position in the well; and the production casing is fixed by the cement sheath 9;

The coiled tubing inner tube 11 is sleeved inside the coiled tubing outer tube 12, and the coiled tubing inner tube 11 and the coiled tubing outer tube 12 are heat-insulated, and the coiled tubing outer tube 12 is lowered into the production casing 10, and the coiled tubing outer tube The beginning of the coiled tubing 12 is connected to the gas preheater 5 placed on the ground, the coiled tubing inner pipe 11 is connected to the fuel water preheater 3 placed on the ground; the ends of the coiled tubing outer pipe 12 and the coiled tubing inner pipe 11 are connected to the combustion reaction equipment 16 connected;

On the ground there are pump sets, fuel water pre-heater 3, gas pre-heater 5, water supply equipment 1, fuel supply equipment 2 and oxygen supply equipment 4, product separation and extraction equipment 6 and oil and gas storage and separation equipment 7; fuel water One end of the preheater 3 is connected with the water supply equipment 1 and the fuel supply equipment 2, and the other end is connected with the inner pipe 11 of the coiled tubing; One end of the product separation and extraction equipment 6 is connected to the production casing 10 , and the other end is connected to the oil and gas storage and separation equipment 7 ;

First, the method of pulsed thermal jet is used to drill to the target position in the well (the oil shale reservoir 14 ), and the combustion reaction equipment 16 is lowered to the target position in the well.

Turn on the pump set, pump the fuel-water mixture into the fuel-water pre-heater 3 through the fuel supply equipment 2, and then pump the pre-heated fuel-water mixture from the coiled tubing inner pipe 11 to the combustion reaction chamber 19 of the combustion reaction equipment 16, Make the internal pressure of the combustion reaction equipment 16 reach 25MPa, then pump the oxygen-containing gas into the gas preheater 5 through the oxygen supply equipment 4, and then send the preheated gas from the coiled tubing outer pipe 12 to the combustion reaction chamber 19 of the combustion reaction equipment 16 When the fuel-water mixture preheated to about 550°C comes into contact with oxygen, spontaneous combustion will occur, resulting in a hydrothermal flame; after the hydrothermal flame is generated, the preheating temperature of the fuel-water mixture and oxygen is slowly lowered to burn The product passes through the nozzle pipe 20 at the bottom of the combustion reaction chamber 19, and is ejected from the outlet 24 of the self-excited pulse nozzle to form a high-speed pulse jet 18. The high-speed pulse jet 18 impacts on the oil shale reservoir 14 and forms on the oil shale surface. Fractures may even be broken, and at the same time, the supercritical water of the combustion product carries a large amount of heat and can enter the generated fractures to conduct sufficient heat exchange with the oil shale, thereby promoting the thermal cracking of the oil shale; the cracked oil and gas products17 The production casing 10 is returned to the product separation and extraction equipment 6 for extraction and separation, and then enters the oil and gas storage and separation equipment 7, so as to realize the in-situ exploitation of oil shale.

Control the temperature of the fuel water pre-heater 3 and the gas pre-heater 5. When the flame in the combustion reaction device 16 appears, the set temperature of the fuel water pre-heater 3 and the gas pre-heater 5 can be lowered to above 375°C, and the flame can be maintained. stable, and by controlling the pump group to ensure the continuous pumping of the fuel-water mixture and oxygen. The pressure in the combustion reaction chamber 19 is controlled by the pump group to be above 25MPa (the pressure in the combustion reaction chamber 19 can be controlled by adjusting the injection amount of the water supply equipment 1 by the pump group), and the continuous oil The inner tube 11 pumps the fuel-water mixture into the combustion reaction chamber 19 of the combustion reaction device 16. At this time, the pressure in the combustion reaction chamber 19 is higher than 25MPa, and the temperature in the combustion reaction chamber 19 is higher than 374.3°C. The water entering the combustion reaction chamber 19 from the tube 11 becomes a supercritical state (when the pressure is greater than 22.1 MPa and the temperature is higher than 374.3 °C, the water is in a supercritical state, has good heat and mass transfer ability, and can mix with alcohols. The fuel achieves good mutual solubility, and can also accelerate the rapid progress of the oxidation reaction), and the mixed contact with the oxygen-containing gas entering the combustion reaction chamber 19 from the outer tube 12 of the coiled tubing will cause spontaneous combustion, resulting in a continuous hydrothermal flame. The flow ratio of the oxygen-containing gas and the fuel-water mixture injected into the combustion reaction chamber 19 is used to control the flame temperature in the combustion reaction chamber 19 to ensure the stability of the flame. The oxidation product enters the self-excited pulse nozzle 21 from the nozzle pipe 20 at the bottom of the combustion reaction chamber 19, and the thermal jet collides with the self-excited pulse nozzle below the self-excited pulse nozzle 21. The collision wall 23 will generate pressure disturbance. When the frequency of the pressure disturbance When the natural frequency of the oscillation cavity 22 of the self-excited pulse nozzle is the same, periodic resonance excitation will be generated, thereby generating a pulse jet. The generated pulsed thermal jet is ejected from the outlet 24 of the self-excited pulse nozzle, and acts on the oil shale reservoir 14 to form fractures and pores, and the supercritical water of the combustion product carries a large amount of heat from the pores and fractures into the oil shale reservoir 14 , to promote the thermal cracking of oil shale. At the same time, the injected supercritical water also carries a certain amount of oxygen, which will oxidize with the oil shale and release a lot of heat to promote the further thermal cracking of the oil shale. At the same time, supercritical water also has strong dissolution and extraction properties, which can extract the cracked oil and gas products. The extracted oil and gas products 17 are returned along the production casing 10 and enter the product separation and extraction equipment 6 for separation and extraction, and then enter the oil and gas storage. Collecting and separating equipment 7 to collect;

The fuel-water mixture and oxygen are continuously pumped into the combustion reaction chamber 19 to form a supercritical water pulse thermal jet 18 until the bottom hole pressure reaches 25MPa, the well is shut down for a period of time, and then the well is reopened, and the cracked oil and gas products 17 are exploited to the ground come up;

After the production is completed, turn off the pump set, turn off the preheater, stop pumping the fuel-water mixture and oxygen-containing gas, and lift up the production casing 10 , the outer coiled tubing 12 , the inner coiled tubing 11 , and the combustion reaction device 16 .

In this embodiment, the self-combustion of fuel water is used for heating, which reduces the cost of generating supercritical water. At the same time, the extracted alcohols and hydrocarbons can also be injected as fuel cyclically, and this method can be drilled once. Realize the effect of drilling and mining, avoid fracturing operations, and reduce mining costs. In addition, because the generated supercritical water pulse thermal jet can form a large number of irregular fractures on the surface of oil shale, supercritical water has good heat and mass transfer ability, and can enter into the interior of oil shale to promote the thermal conductivity of oil shale. At the same time, the oxides carried in supercritical water can undergo oxidation reaction with oil shale, generate a large amount of heat, and promote the further cracking of oil shale; at the same time, supercritical water has good dissolution and extraction properties, and can be used for cracking. Oil and gas products are extracted. In addition, oil shale will undergo pyrolysis in 3-5 hours in the environment of supercritical water, which improves the efficiency of thermal action compared to other pyrolysis methods. The combined effect of combustion heat, pulse jet and supercritical water extraction and the protection of effective hydrocarbon generation capacity, the oil shale production capacity is increased by 30%-50% compared with the conventional ground dry distillation method, which can greatly improve the production efficiency .

This embodiment utilizes the heat carried by the supercritical water to crack the oil shale, and at the same time assists the force of the pulse jet and the extraction capability of the supercritical water, thereby realizing the economical and efficient exploitation of the oil shale. The method and device for in-situ mining of oil shale of the present invention have low mining cost and high mining efficiency.

Claims (13)

1. A method of in situ extraction of oil shale, the method comprising the steps of:

injecting water preheated to a set temperature into the combustion reaction equipment until the pressure of the combustion reaction equipment reaches over 22.1 MPa;

heating the fuel-water mixture to 550 ℃ +10 ℃ to obtain a fuel-water mixture in a supercritical state; wherein, the content of the fuel in the fuel-water mixture is 10 to 50 percent;

heating the oxygen-containing gas to 400 +/-30 ℃ to obtain the oxygen-containing gas in a supercritical state;

regulating the pressure of the combustion reaction equipment to be 25MPa +/-2 MPa, injecting a fuel-water mixture in a supercritical state into the combustion reaction equipment, and injecting oxygen-containing gas in the supercritical state into the combustion reaction equipment to generate spontaneous combustion reaction;

when spontaneous combustion reaction occurs in the combustion reaction equipment, reducing the preheating temperature of the fuel-water mixture and the oxygen-containing gas to 375 +/-10 ℃;

injecting the combustion products into the well in a pulse jet mode until the bottom hole pressure reaches 25MPa +/-2 MPa, stopping injecting, closing the well, opening the well after the oil shale is subjected to full thermal cracking in the stratum, and mining the generated oil-gas mixture to the ground for separation, thereby realizing in-situ mining of the oil shale;

the method for in-situ extraction of oil shale is completed by an in-situ extraction oil shale device, and the device comprises the following steps: the device comprises combustion reaction equipment, a pulse nozzle, preheating equipment, a coiled tubing inner pipe, a coiled tubing outer pipe, a production sleeve, water supply equipment, fuel supply equipment, oxygen supply equipment and a pump set;

the oxygen supply equipment is communicated with the outer pipe of the coiled tubing;

the water supply equipment and the fuel supply equipment are both communicated with the coiled tubing inner pipe;

the combustion reaction equipment is arranged in the oil shale reservoir, and the bottom of the combustion reaction equipment is provided with a pulse nozzle;

the coiled tubing inner pipe, the coiled tubing outer pipe and the production casing are communicated with the combustion reaction equipment.

2. The method of claim 1, wherein the well is shut in for 2 days when the bottom hole pressure reaches 25 MPa.

3. The method of claim 1, wherein the temperature of the set temperature water is 375 ℃ ± 10 ℃.

4. The method of claim 1, wherein the mass flow ratio of the supercritical oxygen-containing gas to the supercritical fuel-water mixture is 2: 1-2: 3.

5. the method of claim 1, wherein the combustion reaction equipment comprises a combustion reaction chamber, a fuel water inlet at the top of the combustion reaction chamber, an oxygen inlet, and a nozzle tube at the bottom of the combustion reaction chamber.

6. The method of claim 1, wherein the pulse nozzle is connected at an outlet of a nozzle line.

7. The method of claim 1, wherein the preheating devices are a fuel water preheater and a gas preheater, respectively; one end of the fuel water preheater is respectively communicated with the water supply equipment and the fuel supply equipment, and the other end of the fuel water preheater is communicated with the inner pipe of the continuous oil pipe; one end of the gas preheater is communicated with the oxygen supply equipment, and the other end of the gas preheater is communicated with the outer pipe of the continuous oil pipe.

8. The method of claim 1, wherein the coiled tubing inner tube is disposed within the coiled tubing outer tube and has an annulus, and the coiled tubing outer tube is disposed within the production casing and has an annulus.

9. The method of claim 8, wherein the coiled tubing outer pipe and the coiled tubing inner pipe are each provided with insulation.

10. The method of claim 1, wherein the beginning of the coiled tubing inner tube is in communication with a fuel water preheater and the end of the coiled tubing inner tube is in communication with a combustion reaction chamber of the combustion reaction device.

11. The method of claim 10, wherein a beginning of the coiled tubing outer tube is in communication with a gas preheater and a terminal end of the coiled tubing outer tube is in communication with a combustion reaction chamber of the combustion reaction device.

12. The method of claim 1, wherein the apparatus further comprises hydrocarbon reservoir separation equipment, product separation extraction equipment; wherein the product separation and extraction equipment is disposed between the hydrocarbon reservoir separation equipment and the production casing.

13. The method of claim 12 wherein one interface of the production separation and extraction facility is in communication with the production casing and another interface of the production separation and extraction facility is in communication with a hydrocarbon reservoir separation facility.

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