Long core nuclear magnetic resonance scanning experimental device and experimental method

Abstract

The invention relates to a long-core nuclear magnetic resonance scanning experimental device and experimental method, and relates to the technical field of oil-gas field development. Comprising the following steps: a nuclear magnetic resonance spectrometer is arranged on a rock core translation loading bed; a first guide rail is arranged on the core translation loading bed on one side of the nuclear magnetic resonance spectrometer, a second guide rail is arranged on the other side of the nuclear magnetic resonance spectrometer, and two ends of the first guide rail and the second guide rail are positioned on the same straight line; a first supporting mechanism is arranged on the first guide rail, and a second supporting mechanism is arranged on the second guide rail; one end of the long sample clamping mechanism is connected with the first supporting mechanism, the other end of the long sample clamping mechanism is connected with the second supporting mechanism, and the long sample clamping mechanism penetrates through a waveguide tube of the nuclear magnetic resonance imaging analyzer; the driving mechanism is connected with the second supporting mechanism. The problems that when an existing nuclear magnetic resonance imaging analyzer scans a rock core, only the rock core with the length smaller than 150 mm can be scanned, and the requirement for conducting a scanning experiment on the long rock core with the length larger than 300 mm cannot be met are solved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, and in particular to a long core nuclear magnetic resonance scanning experimental device and an experimental method. Background Art

[0002] At present, the most commonly used cores for water drive and oil displacement experiments in the laboratory are columnar cores with a diameter of 25mm and a length of less than 100mm. However, cores with a length of less than 100mm are small in size and poor in representativeness, and cannot simulate complex reservoirs. Therefore, it is necessary to use long cores for experiments. Long cores with a length of more than 300mm can simulate actual reservoirs well in terms of permeability and porosity, and are highly representative. The rock samples have very good experimental repeatability, but this also causes corresponding problems. The nuclear magnetic resonance scanning platform of low-field nuclear magnetic resonance imaging analyzers at home and abroad can only perform scanning imaging and nuclear magnetic resonance T2 spectrum testing on cores with a length of less than 150mm. Cores longer than 150mm are beyond the scanning imaging range and cannot meet the needs of scientific research and production practice. Summary of the invention

[0003] The present invention proposes a long core nuclear magnetic resonance scanning experimental device to solve the problem that the existing nuclear magnetic resonance imaging analyzer can only scan cores with a length of less than 150 mm when scanning cores, and cannot meet the scanning experiment requirements for cores with a length of 300 mm or more.

[0004] According to one aspect of the present invention, a long core nuclear magnetic resonance scanning experimental device is provided, comprising: a core translation carrier, a long sample clamping mechanism and a driving mechanism;

[0005] The core translation carrier is provided with a nuclear magnetic resonance instrument;

[0006] A first guide rail is provided on the core translation carrier at one side of the nuclear magnetic resonance instrument, and a second guide rail is provided on the other side, and both ends of the first guide rail and the second guide rail are on the same straight line;

[0007] A first supporting mechanism is provided on the first guide rail, and a second supporting mechanism is provided on the second guide rail;

[0008] One end of the long sample clamping mechanism is connected to the first supporting mechanism, and the other end is connected to the second supporting mechanism, and the long sample clamping mechanism passes through the waveguide of the nuclear magnetic resonance imaging analyzer;

[0009] The driving mechanism is connected to the second supporting mechanism, and is used to drive the second supporting mechanism to move along the second guide rail, thereby driving the long sample clamping mechanism to move into the nuclear magnetic resonance apparatus.

[0010] Preferably, the first supporting mechanism comprises: a first clamper supporting seat and a first long sample supporting seat;

[0011] The first clamper support seat is arranged in the middle of the first guide rail, and a pulley is arranged at the bottom of the first clamper support seat;

[0012] The first long sample support is installed on the top of the first clamp support, and the second long sample support is connected to one end of the long sample clamping mechanism.

[0013] Preferably, the second supporting mechanism comprises: a second clamper supporting seat and a second long sample supporting seat;

[0014] The second clamper support seat is arranged in the middle of the second guide rail, and a pulley is arranged at the bottom of the second clamper support seat;

[0015] The second long sample support is installed on the top of the second clamp support, and the second long sample support is connected to the other end of the long sample clamping mechanism;

[0016] The second clamper support seat is connected to the driving mechanism.

[0017] Preferably, the long sample clamping mechanism comprises: at least three sample stoppers;

[0018] The body of the sample stopper is cylindrical, and a core fixing groove is provided on the sample stopper;

[0019] One end of the sample limiting member is connected to the first supporting mechanism, and the other end is connected to the second supporting mechanism;

[0020] All the sample stoppers are parallel to each other, and the connecting lines between the radial sections of all the sample stoppers form an inverted triangle or a downwardly curved arc;

[0021] The top openings of the core fixing grooves of all the sample limiting members face the center direction of all the sample limiting members, and the shape of the space formed between all the core fixing grooves matches the external shape of the core sample.

[0022] Preferably, the driving mechanism comprises: a reduction motor and a screw rod;

[0023] The reduction motor is fixed on one end of the core translation carrier close to the second guide rail, the reduction motor is connected to one end of the screw rod, the other end of the screw rod passes through the second supporting mechanism, and the screw rod and the second supporting mechanism are connected by a threaded structure.

[0024] Preferably, it also includes: a contact sensor, a first limit fixing block and a second limit fixing block;

[0025] The contact sensor is mounted on the second supporting mechanism;

[0026] The first limit fixing block is installed on one end of the second guide rail close to the nuclear magnetic resonance instrument, the second limit fixing block is installed on one end of the second guide rail away from the nuclear magnetic resonance instrument, and the probe of the contact sensor is located between the first limit fixing block and the second limit fixing block;

[0027] The contact sensor is connected to the driving mechanism.

[0028] Preferably, it also includes: a pulley pad;

[0029] The pulley pads are arranged between the two tracks of the first guide rail and on the core translation carrier between the two tracks of the second guide rail.

[0030] According to one aspect of the present invention, a long core nuclear magnetic resonance scanning experimental method is provided, comprising:

[0031] Nuclear magnetic resonance scanning experiments were performed on core samples after oil saturation, heavy water displacement or gas displacement to obtain the corresponding complete T2 spectrum and oil distribution image;

[0032] Wherein, the method for performing the nuclear magnetic resonance scanning experiment is:

[0033] Mount the core sample on a long sample holding mechanism;

[0034] The first supporting mechanism and the second supporting mechanism are driven by the driving mechanism to move along the first guide rail and the second guide rail, thereby driving the core sample to move into the waveguide of the nuclear magnetic resonance instrument, starting the nuclear magnetic resonance instrument on the core translation carrier, scanning the core sample in sections, and obtaining a complete T2 spectrum and an oil distribution image;

[0035] According to the complete T2 spectrum and oil distribution image, the residual oil saturation of different pores of the core sample is determined using the residual oil saturation calculation formula, and the nuclear magnetic resonance scanning experiment of the core sample is completed.

[0036] Preferably, the method of performing segmented scanning on the core sample to obtain a complete T2 spectrum and an oil distribution image comprises:

[0037] The core sample is divided into several sections according to a predetermined length, and each section of the core sample is driven by a driving mechanism to move to the inside of the waveguide of the nuclear magnetic resonance instrument in sequence, and the nuclear magnetic resonance instrument is started to scan the core sample in the inside respectively. After all the sections are scanned in sequence, the T2 spectrum and oil distribution image corresponding to each section of the core sample are obtained;

[0038] The T2 spectra of each core sample are added together to obtain a complete T2 spectrum, and the oil distribution images of each core sample are spliced ​​together to obtain a complete oil distribution image.

[0039] Preferably, the residual oil saturation calculation formula includes:

[0040]

[0041] Where: S or is the residual oil saturation of different pores, %, S 饱和油 is the signal intensity of the T2 spectrum of the core after oil saturation, dimensionless, S 驱替后 It is the signal intensity of the core T2 spectrum after heavy water flooding or gas flooding, dimensionless.

[0042] The present invention has at least the following beneficial effects:

[0043] The present invention proposes a long core nuclear magnetic resonance scanning experimental device and an experimental method. By adding a core translation carrier, a first supporting mechanism, a second supporting mechanism, a first guide rail, a second guide rail and a driving mechanism, the long core is driven to move accurately in a nuclear magnetic resonance imaging analyzer, and segmented scanning imaging of the long core is achieved, which provides strong support and guarantee for scientific research, especially indoor physical simulation experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present invention and, together with the specification, are used to explain the technical solutions of the present invention.

[0045] Figure 1 A schematic structural diagram of a long core nuclear magnetic resonance scanning experimental device according to an embodiment of the present invention is shown;

[0046] Figure 2 A schematic structural diagram of a long sample support according to an embodiment of the present invention is shown;

[0047] Figure 3 A schematic structural diagram of a sample stopper according to an embodiment of the present invention is shown;

[0048] Figure 4 A schematic structural diagram of a first clamper support base according to an embodiment of the present invention is shown;

[0049] Figure 5 A schematic structural diagram of a second clamper support base according to an embodiment of the present invention is shown;

[0050] Figure 6 An oil distribution image of a core sample saturated with oil according to an embodiment of the present invention is shown;

[0051] Figure 7The oil distribution image of the core sample after water flooding according to an embodiment of the present invention is shown;

[0052] Figure 8 The nuclear magnetic resonance T2 spectrum of the core sample saturated with oil according to an embodiment of the present invention is shown;

[0053] Fig. 9 The nuclear magnetic resonance T2 spectrum of the core sample after water flooding according to an embodiment of the present invention is shown;

[0054] Fig.10 A distribution diagram of remaining oil saturation in different pores of a core sample according to an embodiment of the present invention is shown.

[0055] In the figure, 1-core translation carrier, 2-first guide rail, 3-first clamp support seat, 4-first long sample support, 5-probe coil, 6-sample limiter, 7-second long sample support, 8-second clamp support seat, 9-screw, 10-reduction motor, 11-contact sensor, 12-first limit fixing block, 13-second guide rail, 14-second limit fixing block, 15-probe coil fixing block, 16-pulley pad, 17-waveguide tube, 18-core fixing groove, 19-pulley. DETAILED DESCRIPTION

[0056] Various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0057] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0058] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0059] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0060] Figure 1 A schematic structural diagram of a long core nuclear magnetic resonance scanning experimental device according to an embodiment of the present invention is shown; Figure 2 A schematic structural diagram of a long sample support according to an embodiment of the present invention is shown; Figure 3 A schematic structural diagram of a sample stopper according to an embodiment of the present invention is shown; Figure 4 A schematic structural diagram of a first clamper support base according to an embodiment of the present invention is shown; Figure 5 A schematic structural diagram of a second clamper support base according to an embodiment of the present invention is shown; Figure 6 An oil distribution image of a core sample saturated with oil according to an embodiment of the present invention is shown; Figure 7 The oil distribution image of the core sample after water flooding according to an embodiment of the present invention is shown; Figure 8 The nuclear magnetic resonance T2 spectrum of the core sample saturated with oil according to an embodiment of the present invention is shown; Fig. 9 The nuclear magnetic resonance T2 spectrum of the core sample after water flooding according to an embodiment of the present invention is shown; Fig.10 The remaining oil saturation distribution diagram of different pores of the core sample according to the embodiment of the present invention is shown. Figure 1-10 As shown, a long core nuclear magnetic resonance scanning experimental device comprises: a core translation carrier 1, a long sample clamping mechanism and a driving mechanism; a nuclear magnetic resonance instrument is arranged on the core translation carrier 1; a first guide rail 2 is arranged on the core translation carrier 1 on one side of the nuclear magnetic resonance instrument, and a second guide rail 13 is arranged on the other side, and the two ends of the first guide rail 2 and the second guide rail 13 are on the same straight line; a first supporting mechanism is arranged on the first guide rail 2, and a second supporting mechanism is arranged on the second guide rail 13; one end of the long sample clamping mechanism is connected to the first supporting mechanism, and the other end is connected to the second supporting mechanism, and the long sample clamping mechanism passes through the waveguide 17 of the nuclear magnetic resonance imaging analyzer; the driving mechanism is connected to the second supporting mechanism, and the driving mechanism is used to drive the second supporting mechanism to move along the second guide rail 13, thereby driving the long sample clamping mechanism to move into the nuclear magnetic resonance instrument.

[0061] In the embodiment of the present invention, when performing a nuclear magnetic resonance scanning experiment on a long core, a 300 mm long core sample is fixed on the core translation bed 1 through a long sample clamping mechanism. At this time, the long sample clamping mechanism is located above the first guide rail 2, and the core sample is completely outside the nuclear magnetic resonance instrument (nuclear magnetic resonance imaging analyzer). The control driving mechanism is started to drive the second support mechanism and the long sample clamping mechanism and the first support mechanism connected thereto to move. The first support mechanism moves along the first guide rail 2, and the second support mechanism moves along the second guide rail 13, driving the core sample toward the core translation bed 1 close to one end of the second support mechanism. Since the nuclear magnetic resonance instrument is set between the first guide rail 2 and the second guide rail 13, the core sample will gradually enter the inside of the nuclear magnetic resonance instrument waveguide 17. When half (150 mm) of the core sample has entered the nuclear magnetic resonance instrument, and the 150 mm length of the core sample has been completely in the 150 probe coil 5 of the nuclear magnetic resonance instrument, the control driving mechanism is closed; the control nuclear magnetic resonance instrument is started, and the core sample inside is scanned and imaged for the first time, so as to obtain the T2 spectrum and oil distribution image of half of the core sample; after the first scan is completed, the control driving mechanism is started, and continues to drive the core sample to move into the nuclear magnetic resonance instrument until the other half of the core sample enters the nuclear magnetic resonance instrument, and the control driving mechanism is closed; the control nuclear magnetic resonance instrument is started, and the core sample inside is scanned and imaged for the second time, so as to obtain the T2 spectrum and oil distribution image of the other half of the core sample, and after adding the T2 spectra obtained by the two scans and splicing the two oil distribution images, a complete T2 spectrum and oil distribution image of the core sample are obtained. After the core sample is completely scanned, the driving mechanism is started to drive the core sample to continue to move toward one end of the core translation carrier 1 close to the second supporting mechanism until the core sample is completely outside the nuclear magnetic resonance instrument, and the driving mechanism is controlled to stop.

[0062] The length of the core sample entering the nuclear magnetic resonance instrument each time should be determined based on the maximum length that the nuclear magnetic resonance instrument can scan each time, and the core sample should be scanned in sections multiple times.

[0063] In the present invention, the first supporting mechanism includes: a first clamper supporting seat 3 and a first long sample support 4; the first clamper supporting seat 3 is arranged in the middle of the first guide rail 2, and a pulley 19 is arranged at the bottom of the first clamper supporting seat 3; the first long sample support 4 is installed on the top of the first clamper supporting seat 3, and the second long sample support 7 is connected to one end of the long sample clamping mechanism.

[0064] In an embodiment of the present invention, the first clamper support seat 3 is located between the two rails of the first guide rail 2; when the driving mechanism is started, the first long sample support 4 is driven to move through the second supporting mechanism and the long sample clamping mechanism, thereby driving the first clamper support seat 3 to move along the first guide rail 2 until the core sample is inside the nuclear magnetic resonance instrument.

[0065] In the present invention, the second supporting mechanism includes: a second clamper supporting seat 8 and a second long sample support 7; the second clamper supporting seat 8 is arranged in the middle of the second guide rail 13, and a pulley 19 is arranged at the bottom of the second clamper supporting seat 8; the second long sample support 7 is installed on the top of the second clamper supporting seat 8, and the second long sample support 7 is connected to the other end of the long sample clamping mechanism; the second clamper supporting seat 8 is connected to the driving mechanism.

[0066] In the embodiment of the present invention, the second clamper support seat 8 is located between the two rails of the second guide rail 13; when the driving mechanism is started, the second clamper support seat 8 is driven to move along the second guide rail 13, thereby driving the second long sample support 7 and the long sample clamping mechanism to move, so that the core sample moves into the nuclear magnetic resonance instrument.

[0067] The first guide rail 2, the second guide rail 13 and the nuclear magnetic resonance apparatus are in a straight line, so that the first clamper support seat 3, the second clamper support seat 8, the first long sample support seat 4 and the second long sample support seat 7 can accurately drive the core sample to move linearly into the nuclear magnetic resonance apparatus without deviation.

[0068] The bottom of the first long sample support 4 and the second long sample support 7 are arc-shaped, and the tops of the first clamp support 3 and the second clamp support 8 have grooves matching the arc. During installation, the arc-shaped parts of the long sample supports are correspondingly inserted into the grooves and fixed by bolts.

[0069] In the present invention, the long sample clamping mechanism includes: at least three sample limiters 6; the body of the sample limiter 6 is cylindrical, and a core fixing groove 18 is arranged on the sample limiter 6; one end of the sample limiter 6 is connected to the first supporting mechanism, and the other end is connected to the second supporting mechanism; all the sample limiters 6 are parallel to each other, and the connecting lines between the radial sections of all the sample limiters 6 form an inverted triangle or a downward curved arc; the top openings of the core fixing grooves 18 of all the sample limiters 6 are facing the center direction of all the sample limiters 6, and the spatial shape formed between all the core fixing grooves 18 matches the external shape of the core sample.

[0070] In an embodiment of the present invention, three sample limiters 6 form an inverted triangle support structure, one end of the sample limiter 6 is connected to the first long sample support 4, and the other end is connected to the second long sample support 7; the core fixing groove 18 is a U-shaped groove, and its length matches the length of the core sample. The core fixing grooves 18 of the three sample limiters 6 are positioned correspondingly, and the openings are all facing the middle of the three sample limiters 6.

[0071] When scanning the core sample, the core sample is placed between the three sample stoppers 6, and the core sample is clamped into the core fixing grooves 18 of the three sample stoppers 6, thereby fixing the core sample. The driving mechanism is started, and the driving mechanism drives the sample stoppers 6 to move away from the first guide rail 2 through the second long sample support 7 and the second clamp support seat 8, thereby driving the core sample into the nuclear magnetic resonance instrument.

[0072] Fixing the core sample by the sample stopper 6 makes installation and removal more convenient and quick during the experiment. At the same time, the number of sample stoppers 6 can be easily reduced or increased at any time, which is convenient for adjustment and has lower use and production costs.

[0073] In the present invention, the driving mechanism includes: a reduction motor 10 and a screw 9; the reduction motor 10 is fixed on one end of the core translation carrier 1 close to the second guide rail 13, the reduction motor 10 is connected to one end of the screw 9, the other end of the screw 9 passes through the second supporting mechanism, and the screw 9 is connected to the second supporting mechanism through a threaded structure.

[0074] In the embodiment of the present invention, a through hole is provided on the second clamp support seat 8, and an internal thread matching the external thread of the screw rod 9 is provided on the inner wall of the through hole; the other end of the screw rod 9 passes through the through hole. When the reduction motor 10 is started, the screw rod 9 is driven to rotate forward or reverse along the axis, and the screw rod 9 is matched with the through hole through the thread, driving the second clamp support column to move back and forth along the second guide rail 13, thereby driving the second long sample support 7, the sample stopper 6, the first long sample support 4, and the first clamp support seat 3 to move back and forth along the first guide rail 2, thereby driving the core sample to enter or move away from the inside of the nuclear magnetic resonance instrument.

[0075] In the present invention, it also includes: a contact sensor 11, a first limit fixing block 12 and a second limit fixing block 14; the contact sensor 11 is installed on the second supporting mechanism; the first limit fixing block 12 is installed on the second guide rail 13 at one end close to the nuclear magnetic resonance apparatus, and the second limit fixing block 14 is installed on the second guide rail 13 at one end away from the nuclear magnetic resonance apparatus, and the probe of the contact sensor 11 is located between the first limit fixing block 12 and the second limit fixing block 14; the contact sensor 11 is connected to the driving mechanism.

[0076] In the embodiment of the present invention, the contact sensor 11 is fixed on the top of the second long sample holder 7. When the reduction motor 10 of the driving mechanism drives the second long sample holder 7 to move back and forth along the second guide rail 13, the probe of the contact sensor 11 moves back and forth between the first limit fixing block 12 and the second limit fixing block 14. When the contact sensor 11 moves to contact the first limit fixing block 12 or the second limit fixing block 14, the contact sensor 11 sends a stop signal to the reduction motor 10 to control the reduction motor 10 to turn off.

[0077] When the contact sensor 11 contacts the first limit fixing block 12, the core sample in the middle of the sample limiter 6 is completely outside the nuclear magnetic resonance instrument, and the core sample is now on the side of the nuclear magnetic resonance instrument close to the first guide rail 2. When the contact sensor 11 contacts the second limit fixing block 14, the core sample in the middle of the sample limiter 6 is completely outside the nuclear magnetic resonance instrument, and the core sample is now on the side of the nuclear magnetic resonance instrument close to the second guide rail 13. The contact sensor 11 and the first limit fixing block 12 and the second limit fixing block 14 are used to prevent the reduction motor 10 from driving the first sample holder support seat and the second sample holder support seat to move, and the movement range exceeds the two ends of the first guide rail 2 and the second guide rail 13 to prevent them from falling off.

[0078] The present invention further comprises: a pulley pad 16 ; the pulley pad 16 is arranged on the core translation carrier 1 between the two tracks of the first guide rail 2 and between the two tracks of the second guide rail 13 .

[0079] In the embodiment of the present invention, the pulleys 19 of the first clamp support 3 and the second clamp support 8 are placed on the pulley pad 16, and the pulley pad 16 is used to reduce the friction between the pulley 19 and the core translation bed 1 when the pulley 19 moves, so as to protect the core translation bed 1. The pulley pad 16 is made of stainless steel.

[0080] A probe coil fixing block 15 is also provided on the core translation carrier 1 for fixing the probe coil 5 of the nuclear magnetic resonance apparatus.

[0081] The present invention also provides a long core nuclear magnetic resonance scanning experimental method, comprising: performing nuclear magnetic resonance scanning experiments on core samples after oil saturation and heavy water displacement or gas displacement, respectively, to obtain corresponding complete T2 spectra and oil distribution images; wherein the method for performing the nuclear magnetic resonance scanning experiment is:

[0082] Step S01: Mount the core sample on the long sample clamping mechanism.

[0083] In the embodiment of the present invention, a 300 mm long core sample saturated with oil is placed in the sample stopper 6. In the initial state, the core is located outside the nuclear magnetic resonance apparatus and close to the first guide rail 2. The predetermined length is the maximum scanning length of the nuclear magnetic resonance apparatus, that is, 150 mm, so the 300 mm core sample needs to be divided into two sections of 150 mm in length.

[0084] Step S02: The driving mechanism drives the first supporting mechanism and the second supporting mechanism to move along the first guide rail 2 and the second guide rail 13, thereby driving the core sample to move into the waveguide 17 of the nuclear magnetic resonance instrument, starting the nuclear magnetic resonance instrument on the core translation carrier 1, and performing segmented scanning on the core sample to obtain a complete T2 spectrum and oil distribution image.

[0085] In the present invention, the method for scanning the core sample in sections to obtain a complete T2 spectrum and an oil distribution image comprises: dividing the core sample into a plurality of sections according to a predetermined length, driving each section of the core sample to move sequentially to the inside of the waveguide 17 of the nuclear magnetic resonance instrument through a driving mechanism, starting the nuclear magnetic resonance instrument to scan the core samples therein respectively, and after all the sections are scanned sequentially, obtaining the T2 spectrum and the oil distribution image corresponding to each section of the core sample; adding the T2 spectra of each section of the core sample to obtain a complete T2 spectrum, and splicing the oil distribution images of each section of the core sample to obtain a complete oil distribution image.

[0086] In the embodiment of the present invention, the reduction motor 10 is started to drive the screw 9 to rotate, and the screw 9 cooperates with the through-hole thread to drive the second clamper support seat 8 and the second long sample support seat 7 to move along the second guide rail 13 away from the nuclear magnetic resonance instrument, thereby driving the core sample, the sample limiter 6, the first long sample support seat 4 and the first clamper support seat 3 to move into the nuclear magnetic resonance instrument.

[0087] When the first section of the core sample close to the second long sample support 7, that is, half of its 150mm length enters the nuclear magnetic resonance instrument, the reduction motor 10 is controlled to be closed. At this time, the first section of the core sample is completely in the 150 probe coil 5 of the nuclear magnetic resonance instrument, and the second section is outside the nuclear magnetic resonance instrument.

[0088] The nuclear magnetic resonance instrument is started to scan the first section of the core sample inside it to obtain the T2 spectrum and oil distribution image of this part of the core sample, that is, half of the core sample after the first scan.

[0089] Start the reduction motor 10 again, driving the second clamper support 8 and the second long sample support 7 to continue to move along the second guide rail 13 away from the nuclear magnetic resonance instrument, thereby driving the core sample to continue to move into the nuclear magnetic resonance instrument; when the second section of the core sample, that is, the remaining 150 mm, is within the 150 mm probe coil 5 of the nuclear magnetic resonance instrument, the first section of the core sample is completely outside the 150 probe coil 5 of the nuclear magnetic resonance instrument.

[0090] The nuclear magnetic resonance instrument is started to scan the second section of the core sample inside it to obtain the T2 spectrum and oil distribution image of this part of the core sample, that is, the other half of the core sample after the second scan.

[0091] The T2 spectra of the core sample saturated with oil obtained by two scans were added together to obtain a complete T2 spectrum of the 300 mm long core sample saturated with oil. The oil distribution images of the core sample saturated with oil obtained by scanning on both sides were spliced ​​to obtain a complete oil distribution image of the 300 mm long core sample saturated with oil.

[0092] After the core sample is scanned after being saturated with oil, the core sample is taken out and flooded with heavy water or gas. Then the 300 mm long core sample after heavy water flooding or gas flooding is placed in the sample stopper 6, and steps S01 to S02 are repeated to obtain a complete T2 spectrum and oil distribution image of the 300 mm long core sample after heavy water flooding or gas flooding. Figure 6 This is the complete oil distribution image after the core sample is saturated with oil. Figure 7 This is the complete oil distribution image of the core sample after water flooding. Figure 8 This is the complete NMR T2 spectrum of the core sample after it is saturated with oil. Fig. 9 This is the complete NMR T2 spectrum of the core sample after water flooding.

[0093] Step S03: According to the complete T2 spectrum and the oil distribution image, the residual oil saturation of different pores of the core sample is determined using the residual oil saturation calculation formula, and the nuclear magnetic resonance scanning experiment of the core sample is completed.

[0094] In the present invention, the residual oil saturation calculation formula includes:

[0095]

[0096] Where: S or is the residual oil saturation of different pores, %, S 饱和油 is the signal intensity of the T2 spectrum of the core after oil saturation, dimensionless, S 驱替后 It is the signal intensity of the core T2 spectrum after heavy water flooding or gas flooding, dimensionless.

[0097] In the embodiment of the present invention, according to the complete T2 spectrum of the core sample after saturation with oil and the change of T2 spectrum of the core sample after heavy water displacement or gas displacement, the residual oil saturation calculation formula can be used to calculate the residual oil saturation of different pores of the core sample, and complete the long core nuclear magnetic resonance scanning experiment. Fig.10 The remaining oil saturation distribution diagram of different pores in the core samples.

[0098] It can be understood that the above-mentioned various method embodiments mentioned in the present invention can be combined with each other to form a combined embodiment without violating the principle logic. Due to space limitations, the present invention will not go into details.

[0099] Those skilled in the art will appreciate that, in the above method of specific implementation, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of the steps should be determined by their functions and possible internal logic.

[0100] The present invention aims at the defect that the existing nuclear magnetic resonance scanning experimental technology cannot perform nuclear magnetic resonance scanning imaging and T2 spectrum testing on the core with a length of more than 150mm or 300mm. By improving the traditional nuclear magnetic resonance scanning experimental device Newmai 150 probe coil 5, adding 57 stepping reduction motor 10, guide rails, clamp support seat, long sample support, sample limiter 6, etc., the long core can be accurately moved in sections along the guide rails in the sample limiter 6, and the long core can be scanned and imaged in sections and T2 spectrum tested in the scanning probe. Finally, the images of each section of the core are spliced, and the images of each section are tested. The T2 spectra are added to obtain the complete imaging result, which solves the problem that the long core with a length of 300 mm cannot be fully imaged and T2 spectrum tested. The experimental device is not only suitable for NMR scanning of plunger cores with a length of 300 mm and a diameter of 25 mm, but can also be used for NMR scanning of rectangular cores with a length of 300 mm, a width of 50 mm, and a height of 70 mm. By adjusting the length of the long sample support and the spacing and number during installation, it can adapt to core samples of various sizes, providing strong support and guarantee for scientific research, especially indoor physical simulation experiments.

[0101] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A long core nuclear magnetic resonance scanning experimental device, characterized in that: include: A core translation carrier (1), a long sample clamping mechanism and a driving mechanism; A nuclear magnetic resonance instrument is arranged on the core translation carrier (1); A first guide rail (2) is arranged on the core translation carrier (1) at one side of the nuclear magnetic resonance instrument, and a second guide rail (13) is arranged on the other side, and the two ends of the first guide rail (2) and the second guide rail (13) are located on the same straight line; The first guide rail (2) is provided with a first supporting mechanism, and the second guide rail (13) is provided with a second supporting mechanism; One end of the long sample clamping mechanism is connected to the first supporting mechanism, and the other end is connected to the second supporting mechanism, and the long sample clamping mechanism passes through the inside of the waveguide (17) of the nuclear magnetic resonance imaging analyzer; The driving mechanism is connected to the second supporting mechanism, and is used to drive the second supporting mechanism to move along the second guide rail (13), thereby driving the long sample clamping mechanism to move into the nuclear magnetic resonance instrument.

2. The long core nuclear magnetic resonance scanning experimental device according to claim 1, characterized in that: The first supporting mechanism comprises: a first clamper supporting seat (3) and a first long sample supporting seat (4); The first clamper support seat (3) is arranged in the middle of the first guide rail (2), and a pulley (19) is arranged at the bottom of the first clamper support seat (3); The first long sample support (4) is installed on the top of the first clamp support (3), and the second long sample support (7) is connected to one end of the long sample clamping mechanism.

3. The long core nuclear magnetic resonance scanning experimental device according to claim 1, characterized in that: The second supporting mechanism comprises: a second clamper supporting seat (8) and a second long sample supporting seat (7); The second clamper support seat (8) is arranged in the middle of the second guide rail (13), and a pulley (19) is arranged at the bottom of the second clamper support seat (8); The second long sample support (7) is installed on the top of the second clamp support (8), and the second long sample support (7) is connected to the other end of the long sample clamping mechanism; The second clamper support seat (8) is connected to the driving mechanism.

4. The long core nuclear magnetic resonance scanning experimental device according to claim 1, characterized in that: The long sample clamping mechanism comprises: at least three sample limiting members (6); The body of the sample stopper (6) is cylindrical, and a core fixing groove (18) is provided on the sample stopper (6); One end of the sample limiting member (6) is connected to the first supporting mechanism, and the other end is connected to the second supporting mechanism; All the sample stoppers (6) are parallel to each other, and the connecting lines between the radial sections of all the sample stoppers (6) form an inverted triangle or a downwardly curved arc; The top openings of the core fixing grooves (18) of all the sample limiting members (6) are oriented toward the center direction of all the sample limiting members (6), and the shape of the space formed between all the core fixing grooves (18) matches the external shape of the core sample.

5. The long core nuclear magnetic resonance scanning experimental device according to claim 1, characterized in that: The driving mechanism comprises: a reduction motor (10) and a screw rod (9); The reduction motor (10) is fixed on one end of the core translation carrier (1) close to the second guide rail (13), the reduction motor (10) is connected to one end of the screw rod (9), the other end of the screw rod (9) passes through the second supporting mechanism, and the screw rod (9) is connected to the second supporting mechanism through a threaded structure.

6. The long core nuclear magnetic resonance scanning experimental device according to claim 1, characterized in that: Also includes: A contact sensor (11), a first limit fixing block (12) and a second limit fixing block (14); The contact sensor (11) is mounted on the second supporting mechanism; The first limit fixing block (12) is mounted on one end of the second guide rail (13) close to the nuclear magnetic resonance apparatus, the second limit fixing block (14) is mounted on one end of the second guide rail (13) away from the nuclear magnetic resonance apparatus, and the probe of the contact sensor (11) is located between the first limit fixing block (12) and the second limit fixing block (14); The contact sensor (11) is connected to the driving mechanism.

7. The long core nuclear magnetic resonance scanning experimental device according to any one of claims 1 to 6, characterized in that: Also includes: Pulley pad (16); The pulley pad (16) is arranged on the core translation carrier (1) between the two rails of the first guide rail (2) and between the two rails of the second guide rail (13).

8. A long core nuclear magnetic resonance scanning experimental method, characterized in that: include: Nuclear magnetic resonance scanning experiments were performed on core samples after oil saturation, heavy water displacement or gas displacement to obtain the corresponding complete T2 spectrum and oil distribution image; Wherein, the method for performing the nuclear magnetic resonance scanning experiment is: Mount the core sample on a long sample holding mechanism; The first supporting mechanism and the second supporting mechanism are driven by the driving mechanism to move along the first guide rail and the second guide rail, thereby driving the core sample to move into the waveguide of the nuclear magnetic resonance instrument, starting the nuclear magnetic resonance instrument on the core translation carrier, scanning the core sample in sections, and obtaining a complete T2 spectrum and an oil distribution image; According to the complete T2 spectrum and oil distribution image, the residual oil saturation of different pores of the core sample is determined using the residual oil saturation calculation formula, and the nuclear magnetic resonance scanning experiment of the core sample is completed.

9. The long core nuclear magnetic resonance scanning experimental method according to claim 8, characterized in that: The method of scanning the core sample in sections to obtain a complete T2 spectrum and an oil distribution image comprises: The core sample is divided into several sections according to a predetermined length, and each section of the core sample is driven by a driving mechanism to move to the inside of the waveguide of the nuclear magnetic resonance instrument in sequence, and the nuclear magnetic resonance instrument is started to scan the core sample in the inside respectively. After all the sections are scanned in sequence, the T2 spectrum and oil distribution image corresponding to each section of the core sample are obtained; The T2 spectra of each core sample are added together to obtain a complete T2 spectrum, and the oil distribution images of each core sample are spliced ​​to obtain a complete oil distribution image.

10. The long core nuclear magnetic resonance scanning experimental method according to claim 8 or 9, characterized in that: The residual oil saturation calculation formula includes: Where: S or is the residual oil saturation of different pores, %, S 饱和油 is the signal intensity of the T2 spectrum of the core after oil saturation, dimensionless, S 驱替后 It is the signal intensity of the core T2 spectrum after heavy water flooding or gas flooding, dimensionless.

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