CN111323834A - Imbibition device for on-line monitoring of spontaneous imbibition combined with nuclear magnetic resonance technology - Google Patents

Abstract

The invention discloses an imbibition device for on-line monitoring of spontaneous imbibition combined with nuclear magnetic resonance technology. It includes: a low-field nuclear magnetic resonance instrument; a non-magnetic imbibition component, which includes: an imbibition cavity holder, a non-magnetic imbibition chamber and a liquid level sensor, and the non-magnetic imbibition chamber is screwed with the imbibition chamber holder through a screw. It is connected to the low-field nuclear magnetic resonance apparatus, and is provided with a liquid level sensor and an electric valve; a non-magnetic metal mesh is arranged in the non-magnetic imbibition cavity; the martensitic flask assembly includes: a martensitic flask and an iron stand, The Martens bottle is connected with the electric valve through a non-magnetic pipeline; and a computer control system is connected with the low-field nuclear magnetic resonance instrument, the liquid level sensor and the electric valve for control, and is connected with a nuclear magnetic spectrometer. The imbibition device can continuously acquire the NMR experimental data during the spontaneous imbibition process in an online manner, reveal the characteristics of fluid migration in the core during the spontaneous imbibition process, optimize the experimental process, and reduce the error of the experimental results.

Description

Imbibition device for on-line monitoring of spontaneous imbibition combined with nuclear magnetic resonance technology

technical field

The invention relates to the technical field of unconventional natural gas reservoir exploration and research, in particular to an imbibition device for on-line monitoring of spontaneous imbibition combined with nuclear magnetic resonance technology.

Background technique

With the continuous growth of the scale of exploration and development of unconventional natural gas resources, the research on unconventional natural gas reservoirs such as coalbed methane, tight sandstone gas and shale gas is gradually deepening. The low-porosity and low-permeability tight reservoirs represented by shale must undergo large-scale hydraulic fracturing before they can be put into production. During the fracturing operation, due to the strong capillary pressure, a large amount of fracturing fluid enters the reservoir matrix and the internal fracture network through imbibition. The flowback of fracturing fluid is very important for the production of shale gas wells. Field construction data at home and abroad show that the flowback rate of fracturing fluid is generally lower than 30%. Water lock damage has caused a sharp drop in gas well production, and some shale gas wells have an abnormal phenomenon of "low flowback rate and high gas production". In conclusion, in-depth understanding of the spontaneous imbibition of tight rocks and its mechanism has important guiding significance for the scientific and efficient development of unconventional natural gas resources.

Low-field NMR technology is widely used in the research of various fields of oil and gas reservoir development due to its advantages of rapidity, non-destructiveness and sensitivity, and can quantitatively characterize the content and migration characteristics of hydrogen-containing fluids in cores under different conditions. At present, most of the NMR tests that study spontaneous imbibition in the industry are offline tests, that is, at different times during the imbibition process, cores are taken out of the imbibition device for NMR tests. Due to the sensitivity of NMR equipment and the complexity of experimental operation, the offline test of spontaneous imbibition has a large experimental error and cannot obtain accurate and continuous test results. Therefore, it is necessary to explore and design an NMR online imbibition experimental device to reveal the characteristics of core fluid migration during the spontaneous imbibition process, and to provide theoretical guidance for hydraulic fracturing of unconventional natural gas.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an imbibition device for online monitoring of spontaneous imbibition in combination with nuclear magnetic resonance technology with a simple and reasonable structure, which can continuously acquire nuclear magnetic experimental data in the process of spontaneous imbibition in real time in an online manner, and reveal the process of spontaneous imbibition. The fluid migration characteristics in the central core optimize the experimental process and reduce the error of the experimental results.

In order to achieve the above purpose, the present invention provides an imbibition device for on-line monitoring of spontaneous imbibition combined with nuclear magnetic resonance technology, including: a low-field nuclear magnetic resonance instrument; Magnetic imbibition chamber and liquid level sensor, the upper part of the non-magnetic imbibition chamber is provided with a screw, and the screw is an internal hollow structure; the imbibition chamber holder spans the port of the low-field nuclear magnetic resonance instrument, so The screw is screwed with the imbibition cavity holder to arrange the non-magnetic imbibition components in the low-field nuclear magnetic resonance apparatus; the non-magnetic imbibition chamber is provided with a non-magnetic metal mesh; the lower part of the non-magnetic imbibition chamber is identical The horizontal position is respectively provided with a liquid injection port, a sensor middle opening and a valve opening, the middle opening of the sensor is provided with a liquid level sensor, and the valve opening is provided with an electric valve; a martens bottle assembly, which includes a martens bottle and an iron stand , the Martens bottle can be adjusted in height and is arranged on the iron stand, and is connected with the electric valve through a non-magnetic pipeline; and a computer control system, which is controlled by the low-field nuclear magnetic resonance instrument, the liquid level sensor and the electric valve connected, and connected to the NMR spectrometer.

In a preferred embodiment, the non-magnetic imbibition chamber comprises: an imbibition chamber cover and a imbibition chamber body, the upper part of the imbibition chamber cover is provided with a screw, and the lower part is fastened to the imbibition chamber body.

In a preferred embodiment, the imbibition chamber cover and the imbibition chamber body are rotatably connected through a plastic bayonet.

In a preferred embodiment, a scale is provided on the screw.

In a preferred embodiment, the computer control system includes: a data acquisition module, a data processing module, a data display module, a data storage module, a liquid level control module and a data export module, a data acquisition module and a non-magnetic imbibition component and a low field The nuclear magnetic resonance instrument communicates, and the collected experimental data is handed over to the data processing module and the liquid level control module for processing to obtain spontaneous imbibition experimental data; the data display module displays the spontaneous imbibition experimental data; The data storage module stores the spontaneous imbibition experimental data and transmits it to the data export module, and the data export module exports the required experimental data to the experimental result file according to user instructions.

In a preferred embodiment, the imbibition chamber holder and the non-magnetic imbibition chamber are made of non-magnetic plastic; the liquid level sensor, electric valve and non-magnetic pipeline are all made of non-magnetic metal.

In a preferred embodiment, the imbibition chamber holder and the non-magnetic imbibition chamber are made of non-magnetic PEEK plastic; the non-magnetic metal mesh, liquid level sensor, electric valve and non-magnetic pipeline are made of non-magnetic stainless steel and \Or made of copper.

Compared with the prior art, the imbibition device for on-line monitoring of spontaneous imbibition in combination with nuclear magnetic resonance technology according to the present invention has the following beneficial effects:

1. The NMR experimental data during the spontaneous imbibition process can be continuously obtained in real time in an online manner, and the characteristics of fluid migration in the core during the spontaneous imbibition process can be revealed;

2. The dual-constant design with constant core position and constant imbibition liquid level overcomes the defect of continuous monitoring of the off-line NMR spontaneous imbibition test, optimizes the experimental process, and reduces the error of experimental results;

3. While obtaining the overall dynamic fluid migration characteristics of spontaneous imbibition cores, use the saturation curve and space T ₂ technology to analyze the fluid occurrence and migration characteristics in different parts of the core during the imbibition process.

Description of drawings

FIG. 1 is a schematic structural diagram of an imbibition device for on-line monitoring of spontaneous imbibition combined with nuclear magnetic resonance technology according to an embodiment of the present invention.

2 is a schematic structural diagram of a non-magnetic imbibition component of an imbibition device for on-line monitoring of spontaneous imbibition in combination with nuclear magnetic resonance technology according to an embodiment of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

Unless expressly stated otherwise, throughout the specification and claims, the term "comprising" or its conjugations such as "comprising" or "comprising" and the like will be understood to include the stated elements or components, and Other elements or other components are not excluded.

As shown in FIG. 1, the specific structure of the imbibition device for on-line monitoring of spontaneous imbibition in combination with nuclear magnetic resonance technology according to a preferred embodiment of the present invention includes: a low-field nuclear magnetic resonance instrument 1, a non-magnetic imbibition component, a Martens bottle component, and Computer control system. Among them, the non-magnetic imbibition component is arranged in the low-field nuclear magnetic resonance apparatus 1 to accommodate the tight core and imbibition liquid, and the non-magnetic imbibition component is connected with the Martens bottle assembly, so that the core position is constant and the imbibition liquid level is adopted. The constant bi-constant design overcomes the inability to continuously monitor the off-line NMR spontaneous imbibition test, optimizes the experimental process, and reduces the error of experimental results.

Specifically, the low-field nuclear magnetic resonance apparatus 1 is provided with a left low-field nuclear magnetic resonance apparatus magnet 2 and a low-field nuclear magnetic resonance apparatus magnet 3, which are used to quantitatively characterize the content and migration characteristics of the hydrogen-containing fluid in the core under different conditions. In the process of spontaneous imbibition of tight rocks, the amount of imbibition liquid is small, and the amount of imbibition liquid measured by conventional balance weighing method has great errors due to experimental operations. Spontaneous imbibition monitoring, the fluid identification accuracy can reach 0.01cc, and the online NMR detection simplifies the experimental process and further reduces the experimental error.

As shown in FIG. 2, the non-magnetic imbibition assembly includes: imbibition chamber holder 4, non-magnetic imbibition chamber 5 and liquid level sensor 6, and the non-magnetic imbibition chamber 5 includes: imbibition chamber cover 51 and imbibition chamber body 52 , the upper part of the suction chamber cover 51 is provided with a screw 53 , and the lower part is buckled with the suction chamber body 52 . The screw 53 has an internal hollow structure, so that the imbibition cavity is communicated with the outside atmosphere, which is beneficial to the spontaneous imbibition experiment in the imbibition cavity. The imbibition cavity holder 4 spans the port of the low-field nuclear magnetic resonance apparatus 1 , and the screw 53 is screwed with the imbibition cavity holder 4 to arrange the non-magnetic imbibition component into the low-field nuclear magnetic resonance apparatus 1 . The non-magnetic imbibition cavity 5 is provided with a non-magnetic metal mesh 58 for receiving the core 7 . The lower part of the non-magnetic imbibition chamber 5 is provided with a liquid injection port 56, a sensor middle opening and a valve opening respectively. The sensor middle opening is used to set the liquid level sensor 6, and the valve opening is provided with an electric valve 57. The liquid injection port 56 is used to inject imbibition liquid 59 .

In one embodiment, the screw 53 is provided with a scale 54, the scale of the scale 54 is 5 cm, and the minimum scale is 0.2 cm.

In one embodiment, the imbibition chamber cover 51 and the imbibition chamber body 52 are rotatably connected through a plastic bayonet 55 .

The Martens vial assembly includes: a Martens vial 8 and an iron stand 9 . The Martens vial 8 is arranged on the iron stand 9 in a height-adjustable manner, and is connected to an electric valve 57 through a non-magnetic pipeline 10 .

As shown in FIG. 1 , the computer control system 11 is controlled and connected with the low-field nuclear magnetic resonance instrument 1 , the liquid level sensor 6 and the electric valve 57 , and is connected with the nuclear magnetic resonance spectrometer. Place the assembled non-magnetic imbibition components in the low-field NMR instrument, use the core position correction function to detect the position of the core in the magnetic field, and adjust the screw so that the bottom of the core and the bottom of the magnetic field of the low-field NMR instrument are in the same horizontal position. Next, inject the imbibition liquid into the non-magnetic imbibition chamber to the height specified by the liquid level sensor, inject imbibition liquid into the Martens bottle, and open the electric valve to make the imbibition liquid in the non-magnetic chamber and the imbibition liquid phase in the Martens bottle. Connect, adjust the height of the Martens bottle so that the liquid level reaches the liquid level indicated by the liquid level sensor, fix the Martens bottle with an iron stand, and use the computer control system to detect the height of the imbibition liquid level and the generation of imbibition liquid interference signals. The sampling parameters of the low-field NMR instrument were set, and the on-line NMR test was performed on the imbibition characteristics of the core fluid during the spontaneous imbibition process. The screw 53 is screwed with the imbibition cavity holder 4 to arrange the non-magnetic imbibition components into the low-field nuclear magnetic resonance instrument 1, and keep the position of the core in the spectrometer constant, while the liquid level sensor 6 and the electric valve 57 The liquid level control system composed of the Martens bottle assembly and the liquid level control system can ensure that the imbibition liquid level is always in contact with the bottom surface of the core during the imbibition experiment. The "double constant design" of constant core position and constant imbibition liquid level can ensure the real-time online NMR spontaneous imbibition experiment.

In one embodiment, the computer control system includes: a data acquisition module, a data processing module, a data display module, a data storage module, a liquid level control module and a data export module, a data acquisition module and a non-magnetic imbibition component and a low-field nuclear magnetic resonance The instrument 1 communicates, and the collected experimental data is handed over to the data processing module and the liquid level control module for processing to obtain spontaneous imbibition experimental data (such as imbibition liquid level height, _imbibition T spectrum, saturation Curve, etc.); the data display module displays the data of the spontaneous imbibition experiment for the experimenter to view; at the same time, the data storage module stores the data of the spontaneous imbibition experiment and transmits it to the data export module, and the data export module Export the required experimental data to the experimental result file (chart, text, etc.) according to the user's instructions, and provide it to the user for viewing.

In one embodiment, the imbibition cavity holder 4 and the non-magnetic imbibition cavity 5 are made of non-magnetic plastic. The liquid level sensor, electric valve and non-magnetic pipeline are all made of non-magnetic metal. These components made of non-magnetic material will not generate nuclear magnetic interference signals during the experiment, so as to ensure the accuracy of the results of the spontaneous imbibition experiment .

In one embodiment, the imbibition cavity holder 4 and the non-magnetic imbibition cavity 5 are both made of non-magnetic PEEK (Poly EtherEtherKetone, polyetheretherketone) plastic. The non-magnetic metal mesh 58, liquid level sensor, electric valve and non-magnetic pipeline are made of non-magnetic stainless steel and/or copper.

The imbibition device for on-line monitoring of spontaneous imbibition combined with nuclear magnetic resonance technology can be used for on-line nuclear magnetic resonance testing of the microscopic fluid movement dynamics of tight rock cores during the spontaneous imbibition process, including the following operation steps:

1. Load the tight core into the non-magnetic imbibition chamber, and assemble the imbibition chamber holder, liquid level sensor, electric valve, non-magnetic pipeline and Martens bottle with the non-magnetic imbibition chamber, and then assemble the assembled non-magnetic imbibition chamber. The magnetic imbibition component is placed in the low-field NMR instrument, and the core position correction function is used to detect the position of the core in the magnetic field.

2. Inject the imbibition liquid into the non-magnetic imbibition chamber to the height specified by the liquid level sensor, inject imbibition liquid into the Martens bottle, and open the electric valve to make the imbibition liquid in the non-magnetic imbibition chamber and the Martens bottle infiltrate. The suction liquid is connected, adjust the height of the martensitic bottle so that the liquid level reaches the liquid level indicated by the liquid level sensor, fix the martensitic bottle with an iron stand, and detect the height of the imbibition liquid level and whether there is any imbibition liquid interference signal generated by the computer control system . The imbibition liquid level in the non-magnetic imbibition chamber is kept at the same horizontal position as the liquid level in the Martens bottle, and the imbibition liquid level is kept constant through the liquid level control system to prevent the imbibition liquid from entering the low-field NMR magnetic field. area produces interfering signals. Compared with the offline NMR spontaneous imbibition experiment, the online spontaneous imbibition experiment realized by this device can not only monitor the microscopic fluid migration characteristics during the imbibition process of the seepage core, but also optimize the experimental process to reduce the experimental error.

3. Set the sampling parameters of the low-field NMR instrument to conduct an online NMR test on the imbibition characteristics of the core fluid during the spontaneous imbibition process, and at the same time, the computer control system collects and records the imbibition experimental data.

4. During the experiment, the liquid level control module of the computer control system is used to detect the height of the imbibition liquid level in real time to avoid the imbibition liquid entering the magnetic field area of the NMR instrument to generate interference signals, and to ensure the reliability of the NMR spontaneous imbibition experimental data.

To sum up, the imbibition device combined with nuclear magnetic resonance technology for on-line monitoring of spontaneous imbibition can continuously obtain the nuclear magnetic experimental data during the spontaneous imbibition process in an online manner in real time, and reveal the characteristics of fluid migration in the core during the spontaneous imbibition process. The bi-constant design with constant position and constant imbibition level overcomes the defect of inability to continuously monitor the off-line NMR spontaneous imbibition test, optimizes the experimental process, and reduces the error of experimental results.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and obviously many changes and modifications are possible in light of the above teachings. The exemplary embodiments were chosen and described for the purpose of explaining certain principles of the invention and their practical applications, to thereby enable one skilled in the art to make and utilize various exemplary embodiments and various different aspects of the invention. Choose and change. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims (7)

1. an imbibition device for carrying out spontaneous imbibition on-line monitoring in conjunction with nuclear magnetic resonance technology, is characterized in that, comprising: Low-field NMR instrument; A non-magnetic imbibition assembly, comprising: an imbibition cavity fixer, a non-magnetic imbibition chamber and a liquid level sensor, the upper part of the non-magnetic imbibition chamber is provided with a screw, the screw is an internal hollow structure; the imbibition chamber The fixer spans the port of the low-field nuclear magnetic resonance apparatus, and the screw is screwed with the imbibition cavity fixer to arrange the non-magnetic imbibition component in the low-field nuclear magnetic resonance apparatus; in the non-magnetic imbibition cavity A non-magnetic metal mesh is provided; the lower part of the non-magnetic suction chamber is provided with a liquid injection port, a sensor middle opening and a valve opening respectively, the middle opening of the sensor is provided with a liquid level sensor, and the valve opening is provided with an electric motor valve; A martens bottle assembly, comprising: a martens bottle and an iron stand, the martens vial can be set on the iron stand in a height-adjustable manner, and is connected to the electric valve through a non-magnetic pipeline; and The computer control system is connected with the low-field nuclear magnetic resonance instrument, the liquid level sensor and the electric valve control, and is connected with the nuclear magnetic resonance spectrometer. 2 . The imbibition device for on-line monitoring of spontaneous imbibition in combination with nuclear magnetic resonance technology according to claim 1 , wherein the non-magnetic imbibition chamber comprises: an imbibition chamber cover and an imbibition chamber. The upper part of the cavity cover is provided with a screw rod, and the lower part is fastened with the imbibition cavity. 3 . The imbibition device for on-line monitoring of spontaneous imbibition combined with nuclear magnetic resonance technology according to claim 2 , wherein the imbibition chamber cover and the imbibition chamber are rotatably connected through a plastic bayonet. 4 . 4 . The imbibition device for on-line monitoring of spontaneous imbibition in combination with nuclear magnetic resonance technology according to claim 1 , wherein a scale is provided on the screw. 5 . 5. The imbibition device for on-line monitoring of spontaneous imbibition in conjunction with nuclear magnetic resonance technology as claimed in claim 1, wherein the computer control system comprises: a data acquisition module, a data processing module, a data display module, and a data storage module , the liquid level control module and the data export module, the data acquisition module communicates with the non-magnetic imbibition component and the low-field nuclear magnetic resonance instrument, and hands the collected experimental data to the data processing module and the liquid level control module for processing , obtain the experimental data of spontaneous imbibition; the data display module displays the experimental data of spontaneous imbibition; the data storage module stores the experimental data of spontaneous imbibition and transmits it to the data export module, and the data export module according to the user The command exports the required experimental data to the experimental results file. 6. The imbibition device for on-line monitoring of spontaneous imbibition in combination with nuclear magnetic resonance technology as claimed in claim 1, wherein the imbibition cavity holder and the non-magnetic imbibition cavity are all made of non-magnetic plastic; The liquid level sensor, electric valve and non-magnetic pipeline are all made of non-magnetic metal. 7. the imbibition device for carrying out spontaneous imbibition on-line monitoring in conjunction with nuclear magnetic resonance technology as claimed in claim 6, is characterized in that, described imbibition cavity fixer, non-magnetic imbibition cavity are all made of non-magnetic PEEK plastic; The non-magnetic metal mesh, liquid level sensor, electric valve and non-magnetic pipeline are made of non-magnetic stainless steel and/or copper.

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