WO2020006973A1

WO2020006973A1 - Pulsed laser wave and hydraulic fracturing compounded reforming method and apparatus for physical attribute of reservoir

Info

Publication number: WO2020006973A1
Application number: PCT/CN2018/118084
Authority: WO
Inventors: 刘毅; 刘思维; 李志远; 李化; 林福昌
Original assignee: 华中科技大学
Priority date: 2018-07-04
Filing date: 2018-11-29
Publication date: 2020-01-09
Also published as: CN109083624A

Abstract

A pulsed laser wave and hydraulic fracturing compounded reforming apparatus for a physical attribute of a reservoir, comprising a continuous oil pipe (200), an ejecting apparatus, and a pulsed laser wave transmitter (400). The continuous oil pipe (200) is used for injecting a liquid with high static pressure until the internal pressure of the continuous oil pipe reaches a hydrostatic pressure threshold and the internal pressure is kept unchanged. The ejecting apparatus is connected to the tail end of the continuous oil pipe (200) and is used for, when the internal pressure of the continuous oil pipe (200) reaches the hydrostatic pressure threshold, continuously ejecting the liquid with high static pressure out to generate hydraulic fracturing. The pulsed laser wave transmitter (400) is wrapped in the ejecting apparatus and is used for generating laser waves with a repeated frequency in the liquid with high static pressure, the laser waves radiating outward to generate pulsed laser wave fracturing. Also disclosed is a pulsed laser wave and hydraulic fracturing compounded reforming method for a physical attribute of a reservoir. By compounding hydrogalvanic pulsed laser waves and hydraulic fracturing, the present reforming apparatus and method induce more micro fractures around main fractures formed by hydraulic fracturing, and implement better connection with natural fractures of a rock formation, so as to effectively construct a multi-dimensional reservoir seepage network comprising hydraulic fractures, natural fractures, micro fractures, and the like, thereby significantly improving the yield of an oil well.

Description

Reservoir physical property reconstruction method and device based on composite pulse shock and hydraulic fracturing

[Technical Field]

The invention belongs to the field of oil and gas production, and more particularly, relates to a method and a device for reforming the physical properties of a reservoir by a composite pulse shock wave and hydraulic fracturing.

【Background technique】

During the oil and gas production process, due to the continuous high and stable production of oil and gas, it is necessary to timely clean up the blockage formed by the perforation of the pipeline due to the deposition of soluble salts and the increase in the viscosity of crude oil. Permeability, restore oil and gas production from oil wells. Low-permeability oil and gas resources are an important part of China's new oil exploration reserves. Its reservoirs are mainly composed of fine-fine throats, small pore throats, dense reservoirs, and poor physical properties. They face complex reservoir development and development difficulties. , Poor efficiency and a series of problems.

Traditional hydraulic fracturing has been used as a conventional method for reservoir reconstruction in ultra-low permeability reservoirs. When the hydrostatic pressure acts on the reservoir, a static load is approximately applied, and it is easy to form a main fracture in the reservoir and move forward. However, hydraulic fracturing generally only forms large and distant main fractures with a wide range of action, but fewer microfractures are formed, making it difficult to improve the permeability of the rock formation as a whole. The combination of unconventional physical vibratory oil recovery and fracturing technology, chemical flooding technology, microbial oil recovery technology, advanced water injection and gas flooding oil recovery technology have been applied and achieved certain results, but there are limitations due to low efficiency and small scope.

Hydroelectric pulse shocks use purely physical means to release the perforation blockage, increase the permeability of nearby rock formations, and then increase oil and gas production. Shock waves act on rock formations equivalent to the application of dynamic loads, which are more likely to form dispersive micro-fractures and improve the overall permeability of rock formations. It has the characteristics of environmental friendliness, simple technology, and high economy. The disadvantages are that the shock wave propagates and decays rapidly in the rock formation, and the action distance is limited. Therefore, in the process of oil and gas well production, it is necessary to have efficient and environmentally-friendly technical means to remove the blockage of oil fields, improve the permeability of rock formations, and increase oil and gas production.

[Summary of the Invention]

Aiming at the defects of the prior art, the present invention supplements the hydraulic fracturing technology by using the hydraulic pulse shock, and induces more micro-fractures around the main fracture formed by the hydraulic fracturing, and achieves better connection with the natural fractures of the rock formation. Effectively constructing multi-scale reservoir seepage networks such as hydraulic fractures-natural fractures-microfractures, which has the characteristics of large working distance and improving the overall permeability of nearby reservoirs, and significantly improves the production of oil wells.

In order to achieve the above object, in a first aspect, an embodiment of the present invention provides a method for reforming a reservoir property with a composite pulse shock wave and hydraulic fracturing, and the method for reforming the property property of the reservoir includes:

Inject high static pressure liquid into the coiled tubing until its internal pressure reaches the hydrostatic pressure threshold;

Keep the internal pressure of the coiled tubing constant, and continuously spray high static pressure liquid outward to produce hydraulic fracturing;

Repetitive frequency shock waves are generated in high static pressure liquids, which shock waves radiate outward to produce pulsed shock fracturing.

Specifically, the hydraulic fracturing is used to form a main fracture, and the pulse shock fracturing is used to induce microfractures near the main fracture.

Specifically, the high static pressure liquid acts on the reservoir, and the repetitive frequency shock waves act on a horizontal well.

To achieve the above object, in a second aspect, an embodiment of the present invention provides a reservoir physical property reforming device for composite pulse shock and hydraulic fracturing. The reservoir physical property reforming device includes a coiled tubing, a jet device, and a pulse shock wave emission Device

The coiled tubing is used to inject a high hydrostatic liquid until its internal pressure reaches a hydrostatic pressure threshold and keep the internal pressure constant;

The spraying device is connected to the end of the coiled tubing, and is configured to continuously spray a high hydrostatic liquid outward to generate hydraulic fracturing after the internal pressure of the coiled tubing reaches a hydrostatic pressure threshold;

The pulse shock wave transmitter is wrapped in the spraying device, and is used to generate a repetitive frequency shock wave in a high static pressure liquid, and the shock wave is radiated outward to generate a pulse shock fracture.

Specifically, the high static pressure liquid acts on a reservoir, and the shock wave acts on a horizontal well.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention have the following beneficial effects:

(1) The present invention combines hydraulic and electric shock with hydraulic fracturing. Based on the idea of composite fracturing, a device that can perform hydraulic fracturing and shock at the same time is proposed. Realize downhole composite fracturing, which has the advantages of wide operating range, strong controllability, and significantly improving the overall permeability of nearby reservoirs;

(2) The present invention induces more micro-fractures around the main fractures formed by hydraulic fracturing, and achieves better connection with the natural fractures of the rock formation, effectively constructing multi-scale reservoirs such as hydraulic fractures-natural fractures-micro fractures. The seepage network can significantly increase the production of oil wells.

[Brief Description of the Drawings]

FIG. 1 is a schematic structural diagram of a reservoir physical property reforming device of composite pulse shock wave and hydraulic fracturing according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a pulse shock wave transmitter provided by an embodiment of the present invention.

FIG. 3 is a schematic diagram of a composite pulse shock wave and hydraulic fracturing loading provided by an embodiment of the present invention.

FIG. 4 is a schematic view of fracture seepage after the composite pulse shock wave and hydraulic fracturing transformation provided by an embodiment of the present invention.

【detailed description】

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

FIG. 1 is a schematic structural diagram of a reservoir physical property reforming device of composite pulse shock wave and hydraulic fracturing according to an embodiment of the present invention. As shown in FIG. 1, the device includes a work vehicle 100, a coiled tubing 200, an electric cable 300, a pulse shock wave transmitter 400, a sand blaster 500, and a packer 600.

The operation vehicle 100 sets electrical parameters and mechanical parameters according to geological conditions and operation requirements, and is used to provide power and control of high-pressure liquid, sand filler, and shock wave transmitter to the underground.

The coiled tubing 200 is used as a transmission carrier for continuously ejecting a high static pressure liquid through an injection device and acting on a perforation section of an oil well, thereby inducing a major fracture in the reservoir. The bottom of the coiled tubing 200 is connected to an injection device. The perforation section of an oil well corresponds to the area where the oil is actually extracted, that is, the position where the device operates.

There is an electrical cable 300 inside the coiled tubing 200. The function of the electrical cable 300 is to transmit electrical energy, control signals, and feedback operating status information to the shock wave transmitter. A separate logging cable arranged inside the coiled tubing or a coiled tubing with a conductor can be used. Core wire form. There are 4 core wires in the electrical cable 300, of which 2 core wires are used as the high-voltage wires of the pulse shock wave transmitter 400, and the other two conductors are used as signal transmission wires to locate the device.

The pulse shock wave transmitter 400 is transported to the working reservoir, wrapped in a spray device, and generates repetitive frequency shock waves in a high static pressure liquid, and implements the cooperative operation of dynamic shock waves and hydraulic fracturing.

Sand blaster 500 is used to spray sand filler into cracks to prevent cracks from closing.

The packer 600 is used to seal the static high pressure inside the coiled tubing 200, the pulse shock wave transmitter 400 and the sand blaster 500, so that the scope of the shock wave is concentrated in the reservoir section in the packer, and the shock wave transmitter is separated. Segment operation.

The triangles in Figure 1 represent the main fractures formed by hydraulic fracturing, and the surroundings are micro-fractures generated by hydroelectric pulse shock transmitters.

FIG. 2 is a schematic structural diagram of a pulse shock wave transmitter provided by an embodiment of the present invention. As shown in FIG. 2, the pulse shock wave transmitter 400 is composed of a boosting unit 401, an energy storage unit 402, a pulse compression unit 403, and a pulse shock discharge unit 404. The outer diameter is 102mm, and the diameter of the bottom of the coiled tubing 200 injection device is 110mm. The pulse shock wave transmitter 400 can be completely enclosed and coaxially distributed, which is conducive to the joint operation of the oil well perforation section.

The specific operation process of oil well stimulation based on the synergy of pulse shock and hydraulic fracturing is: setting the electrical parameters and mechanical parameters of the working vehicle 100; increasing the injection pressure of the oil well by continuously injecting liquid water into the coiled tubing 200. The internal pressure of 200 reaches the set value, keeping the static liquid pressure constant. The coiled tubing injection device operates in the perforation section, which induces the formation of large cracks in the rock formation. The booster unit 401 realizes rectified boosting through the electrical cable 300, and then The energy storage unit 402 is charged. After the energy storage unit 402 reaches the set value, the pulse compression unit 403 is turned on, and the energy of the energy storage unit 402 is instantaneously input to the pulse shock discharge unit 404. The pulse discharge unit 404 may A strong shock wave is generated in the weakly compressible discharge liquid, and it propagates outward along the coiled tubing's injection device to perform the hydroelectric pulse shock operation.

The process of generating a strong shock wave in a weakly compressive discharge liquid by a pulsed large current is: generating a high-power arc discharge in the liquid, using the liquid's incompressibility to radiate a strong shock wave, including direct gap discharge forms and wire burst forms As well as electrically driven explosive gas forms.

The principle of the cooperative operation of the dynamic shock and static hydraulic pressure of the device is that when the hydrostatic pressure of the hydraulic fracturing produced by the coiled tubing acts on the reservoir, the static load is approximately applied, and it is easy to form a main fracture in the reservoir and develop forward. Its characteristic is that the action distance is long, but generally only the main fracture is formed; and the dynamic shock generated by the pulse shock transmitter can complement the hydraulic fracturing technology, and induce more micro-fractures around the main fracture formed by the hydraulic fracturing. And to achieve better connection with the natural fractures of the rock formation, suitable for horizontal wells running through the reservoir. Once the artificial fractures communicate with the macroscopic and microscopic fractures of the rock formation itself, an interlaced fracture network can be formed, and a reasonable modification of the reservoir fracture network can significantly increase the production of the oil well.

A method for reforming reservoir properties with composite pulse shock and hydraulic fracturing. The method for reforming reservoir properties includes:

Repetitive frequency shocks are generated in high static pressure fluids, which radiate outwards to produce pulsed shock fracturing.

FIG. 3 is a schematic diagram of a composite pulse shock wave and hydraulic fracturing loading provided by an embodiment of the present invention. As shown in Figure 3, the composite pulse shock and hydraulic fracturing loading waveforms are actually superimposed shock waves with a certain frequency on the basis of hydrostatic pressure, which is beneficial to the transformation effect of the rock formation.

FIG. 4 is a schematic view of fracture seepage after the composite pulse shock wave and hydraulic fracturing transformation provided by an embodiment of the present invention. As shown in Figure 4, the composite pulse shock and hydraulic fracturing technology induce more micro-fractures around the main fracture, and achieve better connection with the natural fractures of the rock formation, effectively constructing hydraulic fractures-natural fractures-micro-fractures, etc. Multi-scale reservoir seepage network has the characteristics of larger working distance and improved overall permeability of nearby reservoirs, which can significantly increase the production of oil wells.

The above are only the preferred embodiments of this application, but the scope of protection of this application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in this application. All should be covered by the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

Claims

A method for reforming reservoir properties with composite pulse shock and hydraulic fracturing, characterized in that the method for reforming reservoir properties includes:

Inject high static pressure liquid into the coiled tubing until its internal pressure reaches the hydrostatic pressure threshold;

Keep the internal pressure of the coiled tubing constant, and continuously spray high static pressure liquid outward to produce hydraulic fracturing;

Repetitive frequency shock waves are generated in high static pressure liquids, which shock waves radiate outward to produce pulsed shock fracturing.
The method of claim 1, wherein the hydraulic fracturing is used to form a main fracture, and the pulse shock fracturing is used to induce microfractures near the main fracture.
The method of claim 1, wherein the high static pressure liquid acts on the reservoir, and the repetitive frequency shock acts on a horizontal well.
A reservoir physical property reconstruction device with composite pulse shock and hydraulic fracturing, characterized in that the reservoir physical property reconstruction device includes a coiled tubing, a jet device, and a pulse shock wave transmitter;

The coiled tubing is used to inject a high hydrostatic liquid until its internal pressure reaches a hydrostatic pressure threshold and keep the internal pressure constant;

The spraying device is connected to the end of the coiled tubing, and is configured to continuously spray a high hydrostatic liquid outward to generate hydraulic fracturing after the internal pressure of the coiled tubing reaches a hydrostatic pressure threshold;

The pulse shock wave transmitter is wrapped in the spraying device, and is used for generating a repetitive frequency shock wave in a high static pressure liquid, and the shock wave is radiated outward to generate a pulse shock fracture.
The reservoir physical property reconstruction device according to claim 4, wherein the hydraulic fracturing is used to form a main fracture, and the pulse shock fracturing is used to induce a micro fracture near the main fracture.
The reservoir physical property reforming device according to claim 4, wherein the high static pressure liquid acts on the reservoir, and the shock wave acts on a horizontal well.