CN-122016885-A - In-situ high-temperature high-pressure water displacement test device and test method suitable for CT scanning

CN122016885ACN 122016885 ACN122016885 ACN 122016885ACN-122016885-A

Abstract

The invention discloses an in-situ high-temperature high-pressure water displacement test device and a test method suitable for CT scanning, which belong to the field of petrophysical experiments, and comprise a ray source, a detector and in-situ high-temperature high-pressure water displacement test equipment which is arranged in a CT scanning area formed by the ray source and the detector and is positioned on a rotary table, the test equipment comprises a rubber tube which is wrapped and fixed outside a core sample, and a PEEK sleeve, a nonmetal heating layer and a nonmetal heat preservation and insulation layer which are sequentially arranged outside the rubber tube, wherein two ends of a test cavity surrounded by the PEEK sleeve are respectively in sealing connection with the displacement loading assembly and the synchronous monitoring assembly. By adopting the in-situ high-temperature high-pressure water displacement test device and the test method suitable for CT scanning, high synergy of in-situ high-temperature high-pressure water displacement, CT synchronous microscopic imaging and real-time quantification of the harvesting degree can be realized.

Inventors

WANG JIPENG
SHANG HAICHAO
WANG SHAOHAN
KANG ZIJIAN
WANG DANHAO
CHANG YITONG

Assignees

山东大学

Dates

Publication Date: 20260512
Application Date: 20260415

Claims (10)

1. The in-situ high-temperature high-pressure water displacement test device suitable for CT scanning is characterized by comprising a ray source, a detector and in-situ high-temperature high-pressure water displacement test equipment which is arranged in a CT scanning area formed by the ray source and the detector and is positioned on a rotary table, wherein the in-situ high-temperature high-pressure water displacement test equipment comprises a rubber tube which is wrapped and fixed outside a core sample, and a PEEK sleeve, a nonmetal heating layer and a nonmetal heat preservation and insulation layer which are sequentially arranged outside the rubber tube, wherein two ends of a test cavity surrounded by the PEEK sleeve are respectively and hermetically connected with a displacement loading assembly and a synchronous monitoring assembly through three-stage sealing assemblies, and the displacement loading assembly, the synchronous monitoring assembly and the nonmetal heating layer are electrically connected with a data processing module.
2. The in-situ high-temperature high-pressure water displacement test device suitable for CT scanning as set forth in claim 1, wherein the synchronous monitoring assembly comprises a temperature monitoring unit, a dielectric monitoring unit and a flow monitoring unit which are sequentially arranged on a produced liquid outflow pipeline communicated with a displacement liquid outlet of the test cavity, the temperature monitoring unit, the dielectric monitoring unit and the flow monitoring unit are respectively used for monitoring the real-time temperature, equivalent dielectric parameters and mass flow of the produced liquid, and monitoring signals of the three monitoring units are synchronously transmitted to the data processing module for temperature and flow correction of the dielectric parameters; One end of the produced liquid outflow pipeline, which is far away from the displacement liquid outlet, extends into the measuring cylinder, and the produced liquid outflow pipeline is an insulating nonmetallic pipe; The produced liquid outflow pipeline between the synchronous monitoring assembly and the displacement liquid outlet is also provided with a displacement outlet valve which is connected with the data processing module.
3. The in-situ high-temperature high-pressure water displacement test device suitable for CT scanning as claimed in claim 2, wherein the temperature monitoring unit is a temperature sensor embedded in the produced liquid outflow pipeline; the dielectric monitoring unit is a first annular electrode and a second annular electrode which are axially sleeved on the produced liquid outflow pipeline in sequence, and the first annular electrode and the second annular electrode take produced liquid as dielectrics to form a non-contact flat capacitor; the flow monitoring unit is a mass flowmeter.
4. The in-situ high-temperature and high-pressure water displacement test device suitable for CT scanning as claimed in claim 3, wherein the axial widths of the first annular electrode and the second annular electrode are 5mm, and the axial distance between the first annular electrode and the second annular electrode is 10mm.
5. The in-situ high-temperature high-pressure water displacement test device suitable for CT scanning according to any one of claims 2-4, wherein the displacement loading assembly comprises a displacement constant-pressure constant-flow pump and a displacement confining pressure pump which are communicated with two ends of a test cavity in a sealing manner, a pressure sensor and a confining pressure inlet valve are further arranged between the displacement confining pressure pump and the test cavity in sequence, a temperature pressure monitoring unit and a displacement inlet valve are arranged between the displacement constant-pressure constant-flow pump and the test cavity in sequence, and the pressure sensor, the confining pressure inlet valve, the temperature pressure monitoring unit and the displacement inlet valve are all connected with the data processing module; the input end of the displacement constant-pressure constant-flow pump is respectively communicated with the water phase and the oil phase.
6. The in-situ high-temperature high-pressure water displacement test device suitable for CT scanning as claimed in claim 5, wherein the three-stage sealing assembly comprises a screw rod, an O-ring rubber sleeve and a thread pair which are sequentially arranged between the end part of the PEEK sleeve and the connecting seat from outside to inside; the connecting seat at the bottom end is fixed on the rotary table; The test cavity is provided with radial flow distribution assembly towards the one end of displacement constant pressure constant flow pump still, and radial flow distribution assembly is including sealing the reposition of redundant personnel post that sets up in the test cavity inside and be a plurality of reposition of redundant personnel holes of circumference array axial evenly seting up on the reposition of redundant personnel post.
7. The in-situ high-temperature high-pressure water displacement test device suitable for CT scanning as claimed in claim 5, wherein the nonmetal heating layer is a polyimide film heating belt spirally wound on the outer circumference side of the PEEK sleeve; the winding interval of the polyimide film heating belt is 5mm.
8. The in-situ high-temperature high-pressure water displacement test device suitable for CT scanning as claimed in claim 5, wherein the nonmetal heat insulation layer comprises a vacuum heat insulation layer and a ceramic fiber aluminum silicate heat insulation layer which are sequentially arranged from inside to outside.
9. The method for testing the in-situ high-temperature and high-pressure water displacement test device suitable for CT scanning as claimed in any one of claims 6 to 8, comprising the following steps: s1, loading a clean and dry core sample into a test cavity to complete the assembly and sealing of in-situ high-temperature high-pressure water displacement test equipment; s2, fixing the assembled in-situ high-temperature high-pressure water displacement test equipment at the center of a rotary table in a CT scanning area; S3, starting a nonmetallic heating layer, heating the core sample to the in-situ temperature of the stratum, and then maintaining; s4, vacuumizing the test cavity and the all-fluid pipeline for a duration of not less than 12 hours; s5, applying confining pressure to the test cavity to the stratum in-situ pressure by driving the confining pressure pump, stabilizing the pressure for more than 2 hours, and performing first CT scanning on the dry rock core sample; s6, injecting heated and pressurized formation water into the test cavity through the displacement constant-pressure constant-flow pump, and continuously saturating the core sample for 48 hours; S7, injecting an oil phase into the core sample at a constant speed until no water flows out of the displacement fluid outlet, so that the core sample reaches a bound water state; s8, carrying out a constant-speed water displacement experiment, and carrying out secondary CT scanning on the core sample by adopting parameters which are completely the same as those of the CT scanning in the step S5; s9, adjusting the displacement rate or the injection fluid quantity, repeating the displacement operation step S8, and recording core scanning images under different working conditions; s10, acquiring a real-time capacitance value through a dielectric monitoring unit, and calculating an original equivalent dielectric constant of the produced liquid; S11, performing temperature and mass flow double correction on the equivalent dielectric constant according to real-time monitoring signals of the temperature monitoring unit and the flow monitoring unit; and S12, calculating the water phase volume fraction of the produced liquid by utilizing the inversion of the mixed dielectric model based on the corrected result in the step S11, and obtaining the water displacement recovery degree.
10. The method for in-situ high-temperature and high-pressure water-displacement test device suitable for CT scanning as claimed in claim 9, wherein the initial equivalent dielectric constant of the produced liquid in step S10 is The calculation formula is as follows: ; In the formula, Is a reference capacitance; a real-time capacitance value acquired for the dielectric monitoring unit; in step S11, the expression for temperature correction of the equivalent dielectric constant is as follows: ; In the formula, Is the dielectric constant after temperature-based correction; The temperature monitoring unit is used for acquiring real-time monitoring temperature; Is the reference temperature; Is a temperature correction coefficient; the mass flow correction for equivalent permittivity is expressed as follows: ; In the formula, The dielectric constant after double correction for temperature and mass flow; is a flow correction coefficient; real-time mass flow collected for the flow monitoring unit; is the reference mass flow; The expression of the hybrid dielectric model described in step S12 is as follows: ; In the formula, Represents the theoretical equivalent dielectric constant of the mixed medium; Is the volume fraction of the water phase; Is the dielectric constant of the water phase; Is the dielectric constant of the oil phase; the inversion formula of the volume fraction of the produced liquid water phase is as follows: ; Degree of water displacement recovery The calculation formula is as follows: ; Wherein, the ; ; In the formula, To accumulate the volume of produced oil; Is the original oil-containing volume; The total pore volume of the core is obtained by CT scanning of a dry core sample; Bounding a water volume for the core; The total volume of the produced liquid; is the volume fraction of the oil phase.

Description

In-situ high-temperature high-pressure water displacement test device and test method suitable for CT scanning Technical Field The invention relates to the technical field of petrophysical experiments, in particular to an in-situ high-temperature high-pressure water displacement test device and a test method suitable for CT scanning. Background In the fields of energy and geological engineering such as oil and gas field development, shale gas exploration, CO 2 geological storage and the like, a core is a core microscopic sample for characterizing the characteristics of an underground reservoir, and the fluid seepage characteristics (such as fluid flow rate, multiphase fluid distribution law and the like) of the core directly determine the reservoir development efficiency and the feasibility of an engineering scheme. The core displacement test is a core technical means for researching the seepage characteristics of a reservoir, and reliable experimental data highly matched with the working condition on site can be obtained only by accurately simulating the real occurrence environment of high temperature and high pressure of the underground layer. The introduction of CT scanning technology realizes the visual observation of the evolution of the pore structure in the core, the tracking of the fluid migration path and the representation of multiphase fluid distribution in the displacement process, provides visual basis for the microscopic analysis of the displacement mechanism, and becomes the main technical method of experimental study in the field. The method has the advantages that the suitability of the conventional rock core displacement equipment and a CT scanning in-situ experiment is remarkable, the integrated experiment requirement is difficult to meet, and the method has the main problems that firstly, imaging interference is serious, a core bearing component of the conventional displacement equipment has high attenuation rate to X-rays, artifacts are easy to generate in the scanning process, real structure and fluid distribution information in a rock core are covered, secondly, the device is incompatible in size, the space of a cavity of the CT scanning equipment is limited, the conventional displacement equipment is large in size and cannot be placed in, a sample is poor in suitability, the problem that a scanning field cannot cover a full rock core and imaging resolution is insufficient easily occurs, thirdly, process detection is asynchronous, the displacement process and the recovery degree measurement are separated from each other, key stage characteristics of fluid output are easy to be omitted, and core displacement mechanisms such as a channeling, a wave efficiency and the like cannot be accurately judged, so that the effectiveness of a displacement scheme is misjudged, the displacement efficiency is reduced, and the development cost is increased. Disclosure of Invention The invention aims to provide an in-situ high-temperature high-pressure water displacement test device and a test method suitable for CT scanning, and solves the technical problems. In order to achieve the above purpose, the invention provides an in-situ high-temperature high-pressure water displacement test device suitable for CT scanning, which comprises a ray source, a detector and in-situ high-temperature high-pressure water displacement test equipment which is arranged in a CT scanning area formed by the ray source and the detector and is positioned on a rotary table, wherein the in-situ high-temperature high-pressure water displacement test equipment comprises a rubber tube which is wrapped and fixed outside a core sample, and a PEEK sleeve, a nonmetallic heating layer and a nonmetallic heat preservation and insulation layer which are sequentially arranged outside the rubber tube, wherein two ends of a test cavity surrounded by the PEEK sleeve are respectively and hermetically connected with a displacement loading assembly and a synchronous monitoring assembly through three-stage sealing assemblies, and the displacement loading assembly, the synchronous monitoring assembly and the nonmetallic heating layer are electrically connected with a data processing module. Preferably, the synchronous monitoring assembly comprises a temperature monitoring unit, a dielectric monitoring unit and a flow monitoring unit which are sequentially arranged on a produced liquid outflow pipeline communicated with a displacement liquid outlet of the test cavity, wherein the temperature monitoring unit, the dielectric monitoring unit and the flow monitoring unit are respectively used for monitoring the real-time temperature, equivalent dielectric parameters and mass flow of the produced liquid, and monitoring signals of the three are synchronously transmitted to the data processing module for temperature and flow correction of the dielectric parameters; One end of the produced liquid outflow pipeline, which is far away from the displacement li