CN103821487A - Simulation experiment set for thickened oil thermal recovery storage layer fractures - Google Patents

Abstract

The invention discloses a simulation experiment set for thickened oil thermal recovery storage layer fractures, and belongs to the field of thickened oil thermal recovery development. The simulation experiment set provides an experiment basis for the theoretical study on thickened oil thermal recovery development schemes and engineering design optimization. The simulation experiment set comprises experiment rock samples, a vacuum tri-axial stress loading device, a temperature loading controlling device and a sound launching monitoring device. The experiment rock samples are cuboid and comprise an actual oil deposit coring and cement mortar wrapper. The experiment rock samples reflect the rock mechanical property of actual oil deposition more truly. The temperature loading controlling device carries out local heating through heating pipes and transmits the heat to the experiment rock samples through a heat-transfer medium, the actual high-temperature thermal process is simulated, and a temperature collecting and controlling instrument collects and controls the temperature of the experiment rock samples. The simulation experiment set simulates the combined stress state of the thickened oil thermal recovery process under the different temperature and crustal stress conditions, and actual and effective evaluations on the fractures of thickened oil thermal recovery storage layers can be made.

Description

A Simulating Experimental Device for Reservoir Fracture in Thermal Recovery of Heavy Oil

technical field

The invention belongs to the field of thermal recovery and development of heavy oil, in particular to a simulation experiment device for reservoir rupture in thermal recovery of heavy oil.

Background technique

my country is rich in heavy oil resources. Thermal oil recovery is an important way to develop heavy oil resources. It heats heavy oil by injecting thermal energy carriers into oil reservoirs, reduces the viscosity of crude oil, and improves the flow capacity of crude oil, thereby increasing crude oil production and recovery. . In the process of thermal recovery of heavy oil, the injection of high-temperature heat energy causes the temperature and pressure in the reservoir to increase significantly, and the viscosity of crude oil decreases; the pore fluid and rock formation skeleton undergo non-uniform expansion due to heating, resulting in deformation and rupture of the reservoir. The study of reservoir rupture mechanism and fracture propagation process in the process of thermal recovery of heavy oil has important guiding significance for describing the development dynamics of thermal recovery reservoirs for heavy oil and optimizing the parameter process.

At present, the experimental devices and methods for studying the change of physical parameters of rock samples and the fracture process under high-temperature underground conditions are mainly based on the analysis of high-temperature overall heating of rock samples under certain confining pressure conditions. The fracture of heavy oil thermal recovery reservoirs is jointly controlled by the local high temperature load of the wellbore and the three-dimensional non-uniform ground stress. The current research is mainly based on reservoir numerical simulation methods, and there is a lack of related heavy oil thermal recovery reservoir fractures. The simulated experimental devices and methods cannot truly and effectively evaluate the rupture of the actual heavy oil thermal recovery reservoir, so it has become a difficult problem in the field of heavy oil thermal recovery development.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the present invention proposes a simulated experimental device for the rupture of heavy oil thermal recovery reservoirs. The sample wellbore is loaded with high temperature conditions to truly simulate the composite stress state under different temperature and in-situ stress conditions in the process of heavy oil thermal recovery, collect reservoir fracture information and systematically analyze the fracture mechanism of heavy oil thermal recovery reservoirs. It provides an experimental basis for theoretical research on mining schemes and engineering design optimization.

Technical scheme of the present invention comprises:

A simulated experimental device for the fracture of heavy oil thermal recovery reservoirs, including experimental rock samples, true triaxial stress loading devices, temperature loading control devices and acoustic emission monitoring devices,

The experimental rock sample includes oil reservoir coring, and the periphery of the oil reservoir coring is provided with a cement mortar coating layer. The oil reservoir core is located in the center, and the experimental rock sample is in the shape of a cube, and the center of the top surface of the experimental rock sample is downward. An open wellbore is provided; during the experiment, the test rock sample is placed in the high-pressure pressure-bearing cylinder of the true triaxial stress loading device, and pressure is applied to the outer wall of the test rock sample in three directions through the true triaxial stress loading device;

The above-mentioned temperature loading control device includes a heating tube, a thermocouple temperature sensor, and a temperature acquisition controller. The temperature acquisition controller is connected to the heating tube and the thermocouple temperature sensor respectively. A heat transfer medium layer is filled between the heating tube and the thermocouple temperature sensor is embedded in the preset position of the cement mortar wrapping layer;

The above acoustic emission monitoring device includes an acoustic emission instrument and a plurality of acoustic emission probes, the acoustic emission instrument is connected to the plurality of acoustic emission probes, and all the acoustic emission probes are arranged on the outer periphery of the cement mortar wrapping layer.

The above-mentioned heat transfer medium layer is sodium chloride.

The above-mentioned high-pressure pressure-bearing cylinder is respectively equipped with a hydraulic bottom top plate, a hydraulic side top plate, a rigid side backing plate, and a rigid upper backing plate; Arrested on two opposite sides of the test rock sample, the rigid upper backing plate is pressed on the top of the test rock sample, and the rigid upper backing plate is engaged with the top cover of the high-pressure pressure-bearing cylinder above it.

The external dimensions of the above-mentioned experimental rock samples are 100mm×100mm×100mm; the diameter of the open hole wellbore is 10mm, and the depth is 90mm.

The experimental rock sample of the present invention is formed by mixing and pouring the core of the real heavy oil reservoir and the cement mortar coating layer, while the rock sample commonly used in the reservoir fracture simulation experiment in the prior art mainly adopts the mode of manually pouring the cement mortar test piece, During the mixed pouring process of the experimental rock sample of the present invention, the core of the real heavy oil reservoir is placed in the center of the experimental rock sample cube, the thermocouple temperature sensor is pre-embedded in the designed position in the experimental rock sample, and the probe data line of the thermocouple temperature sensor is drawn out. The experimental rock sample is cured in the cement curing box to meet the strength requirements, and the diamond drill bit is used to drill the open hole wellbore on the top surface of the experimental rock sample; the present invention adopts real oil reservoir coring for simulation, which is closer to the actual situation of the actual heavy oil thermal recovery reservoir , which can truly and effectively evaluate the fracture situation of the actual heavy oil thermal recovery reservoir.

At present, in the field of geotechnical engineering, the experimental device and method for rock sample rupture under high temperature conditions are mainly aimed at analyzing the rupture event when the rock sample is heated as a whole under a certain confining pressure condition; Analysis of fracture events caused by the coupling of local high temperature load in wellbore and spatial three-dimensional non-uniform ground stress.

The true triaxial stress loading device of the present invention is used to respectively apply different pressures to the three directions of the outer space of the experimental rock sample. Oil thermal fracturing is jointly controlled by the coupling factors of the local high temperature load of the wellbore and the three-way non-uniform ground stress. The pressure can truly and effectively evaluate the rupture of the actual heavy oil thermal recovery reservoir.

The present invention proposes a simulated experimental device for the rupture of heavy oil thermal recovery reservoirs. Compared with the prior art, it adopts real heavy oil heavy oil reservoir cores and cement mortar coating mixed pouring as experimental rock samples , the experimental rock sample is a cube, compared with the experimental rock samples in the prior art, it more truly reflects the rock mechanical properties of the actual reservoir;

The true triaxial stress loading device is used to truly simulate the in-situ stress state of the actual heavy oil reservoir. By applying pressure to the three directions of the outer space of the experimental rock sample, a non-uniform pressure is formed, and the actual heavy oil is affected by the non-uniform pressure. Real and effective evaluation of the rupture of thermal recovery reservoirs;

The temperature loading control device is used to simulate the actual high temperature injection thermal process; the wellbore of the experimental rock sample is locally heated through the heating tube, the heat is transferred to the experimental rock sample through the heat transfer medium, and the probe is detected by the thermocouple temperature sensor installed on the inner wall of the experimental rock sample wellbore The temperature near the wellbore wall is displayed by the temperature acquisition controller, and the power switch of the heating tube is controlled according to the test temperature to achieve the function of temperature control;

Acoustic emission instrument is used to monitor and analyze the characteristics of reservoir rupture and fracture propagation under the combined action of thermal conditions and in-situ stress in heavy oil reservoirs;

The simulation experiment device of the invention is easy to operate and has strong practicability, and provides a reliable research means for research on reservoir rupture and fracture propagation mechanism research caused by heavy oil thermal recovery.

Description of drawings

Below in conjunction with accompanying drawing, the present invention is further clearly and completely described:

Fig. 1 is the longitudinal sectional view of the simulated experiment device of the heavy oil thermal recovery reservoir rupture of the present invention;

Fig. 2 is the partial structure schematic diagram of the simulated experiment device of the heavy oil thermal recovery reservoir rupture of the present invention;

In the figure, 1. Top cover; 2. Rigid upper backing plate; 3. High-pressure pressure-bearing cylinder; 4. Hydraulic side roof; 5. Acoustic emission probe; 6. Cement mortar wrapping layer; 8. Heat transfer medium; 9. Heating pipe; 10. Hydraulic bottom and top plate; 11. Hydraulic injection pipeline; 12. Acoustic emission signal line; 13. Insulated wire; 14. Thermocouple data line; 15. Temperature acquisition controller; 16 1. Acoustic emission instrument; 17. Thermocouple temperature sensor; 18. Rigid side backing plate; 19. Multi-channel hydraulic servo controller.

Detailed ways

The present invention proposes a simulated experimental device for thermal recovery reservoir rupture of heavy oil. In order to make the advantages and technical solutions of the present invention clearer and clearer, the present invention will be further clearly and completely described below in conjunction with specific examples.

As shown in Figure 1, the present invention proposes a simulated experimental device for thermal recovery of heavy oil reservoirs, including an experimental rock sample, a true triaxial stress loading device, a temperature loading control device and an acoustic emission monitoring device.

As shown in Figure 2, the experimental rock sample of the present invention is formed by mixing and pouring the cement mortar coating layer 6 and the core 7 of the heavy oil reservoir, and its shape is cube-shaped. Invention preferred heavy oil reservoir coring 7 is real heavy oil reservoir coring, a vertical center hole with a diameter of 10 mm and a length of 90 mm is opened at the center of the top surface of the experimental rock sample, which is used to simulate an open hole wellbore; heavy oil reservoir coring 7. The external shape is irregular and the size is small. It is difficult to process it into a cube of the standard size required by the experiment. Therefore, the present invention adopts the method of pouring 6 packs of cement mortar wrapping layer outside the coring of the heavy oil reservoir to remove the surface shape of the coring. The impact of irregularities makes the overall size of the experimental rock sample meet the experimental requirements; the cement mortar coating layer 6 is cement mortar with an appropriate proportion;

During the mixed pouring process, the core of the real heavy oil reservoir is placed in the center of the experimental rock sample, and the probe of the thermocouple temperature sensor 17 is pre-embedded in the designed position in the experimental rock sample, leading to the thermocouple data line 14, and the surface of the experimental rock sample is smooth Density ≤ 0.1mm/100mm, the experimental rock samples are cured in the cement curing box to meet the strength requirements, and the diamond drill bit is used to drill the open hole wellbore.

The present invention relates to a simulated experimental device for fracturing of heavy oil thermal recovery reservoirs, comprising an experimental rock sample, a high pressure bearing cylinder 3, a true triaxial stress loading device, a temperature loading control device, and an acoustic emission monitoring device;

The structure of the above-mentioned high-pressure pressure-bearing cylinder 3 is similar to that of the prior art high-pressure pressure-bearing cylinder, including a top cover 1, a hydraulic side top plate 4, a hydraulic bottom top plate 10, a rigid upper backing plate 2 and a rigid side backing plate 18;

As mentioned above, the true triaxial stress loading device includes a multi-channel hydraulic servo controller 19 and a hydraulic injection pipeline 11 connected thereto. The pressure control range of the multi-channel hydraulic servo controller 19 is 0-30 MPa. 11 are respectively connected with the hydraulic bottom top plate 10 and the hydraulic side top plates 4 on both sides, and apply pressure to the space outside the test rock sample in three directions respectively, which can simulate the three-dimensional stress state of the heavy oil reservoir within a well depth of 1500m;

The temperature loading control device includes a heating tube 9, a thermocouple temperature sensor 17 and a temperature acquisition controller 15. The heating tube 9 has a diameter of 8mm, a length of 60-90mm, and a power of 150W-400W. Connected with the temperature acquisition and control instrument 15, it is used to heat the temperature in the open-hole wellbore of the experimental rock sample; the thermocouple temperature sensor 17, with a temperature measurement range of -50°C to 500°C, is arranged at the wall of the experimental rock sample near the wellbore, and is passed through the thermocouple The data line 14 is connected with the temperature acquisition and control instrument 15 for measuring the temperature near the wellbore of the experimental rock sample; the heating pipe 9 is connected with the temperature acquisition and control instrument 15 through the insulated wire 13, and the temperature acquisition and control instrument 15 is used for displaying and controlling the open hole wellbore Internal temperature; Sodium chloride is pressed into the annular space between the open-hole wellbore wall of the experimental rock sample and the heating tube as the heat transfer medium in the annular space 8;

The acoustic emission monitoring device is composed of an acoustic emission probe 5, an acoustic emission signal line 12 and an acoustic emission instrument 16. There are four acoustic emission probes 5, which are respectively arranged on two relatively horizontal sides of the experimental rock sample for monitoring and recording in the open-hole wellbore. Acoustic emission ringing rate and energy rate corresponding to different temperature ranges, and locate the spatial position of the rupture point, and analyze the experimental rock sample rupture event and crack propagation law.

Below the usage method of above-mentioned simulation experiment device is described as follows:

The using method of above-mentioned simulated experiment device, it specifically comprises the following steps:

Step 1. Put the above-mentioned prepared experimental rock sample into an industrial tomographic scanning imaging device, and collect the internal crack distribution map of the experimental rock sample as image 1;

Step 2. Place the experimental rock sample in the high-pressure pressure-bearing cylinder of the above-mentioned true triaxial stress loading device, connect the above-mentioned acoustic emission instrument to multiple acoustic emission probes, and arrange all the acoustic emission probes on the outer periphery of the cement mortar coating; The heating tube is inserted into the open-hole wellbore, and a heat transfer medium is pressed into the annular space between the open-hole wellbore and the heating tube; the above-mentioned temperature acquisition and control instrument is connected to the above-mentioned heating tube and the thermocouple temperature sensor; then enter step 3;

Step 3, start the true triaxial stress loading device, and apply different pressures to three different directions of the outer space of the experimental rock sample; then enter step 4;

Step 4. Heat the open-hole wellbore of the experimental rock sample through the above-mentioned heating tube, and at the same time turn on the acoustic emission instrument, and the heating tube is controlled by the temperature acquisition and control device. When the set temperature of the temperature acquisition and control device increases by 50 ° C, the temperature is kept for 1 Hours, slowly increase until the heating temperature is 350°C; the acoustic emission instrument uses the acoustic emission probe to collect and store the current signal as signal one;

Step 5. When the temperature of the open-hole wellbore reaches 350°C, after 2 hours of heat preservation, stop heating. At this time, the acoustic emission instrument collects and stores the current signal through the acoustic emission probe as signal 2. Stop the experiment until the collected wellbore temperature returns to room temperature. ;

Step 6, take out the experimental rock sample, place it in an industrial tomographic scanning imager, and collect the internal crack distribution map of the experimental rock sample after high temperature loading, as Image 2;

Step 7, using the above acoustic signal 1, acoustic signal 2, image 1 and image 2 to carry out further research and analysis on the fracture of the heavy oil thermal recovery reservoir.

The size of the above-mentioned experimental rock sample and open-hole wellbore is not a limitation to the present invention. Those skilled in the art can make various modifications such as replacement and simple combination under the inspiration of this patent. The protection scope of the present invention should be determined by the appended claims. prevail.

Claims (4)

1. A simulated experimental device for the rupture of heavy oil thermal recovery reservoirs, comprising experimental rock samples, true triaxial stress loading devices, temperature loading control devices and acoustic emission monitoring devices, characterized in that: The experimental rock sample includes oil reservoir coring, and the periphery of the oil reservoir coring is provided with a cement mortar coating layer. The oil reservoir core is located in the center, and the experimental rock sample is in the shape of a cube, and the center of the top surface of the experimental rock sample is downward. An open wellbore is provided; during the experiment, the test rock sample is placed in the high-pressure pressure-bearing cylinder of the true triaxial stress loading device, and pressure is applied to the outer wall of the test rock sample in three directions through the true triaxial stress loading device; The above-mentioned temperature loading control device includes a heating tube, a thermocouple temperature sensor, and a temperature acquisition controller. The temperature acquisition controller is connected to the heating tube and the thermocouple temperature sensor respectively. A heat transfer medium layer is filled between the heating tube and the thermocouple temperature sensor is embedded in the preset position of the cement mortar wrapping layer; The above acoustic emission monitoring device includes an acoustic emission instrument and a plurality of acoustic emission probes, the acoustic emission instrument is connected to the plurality of acoustic emission probes, and all the acoustic emission probes are arranged on the outer periphery of the cement mortar wrapping layer. 2. A simulated experimental device for fracturing of heavy oil thermal recovery reservoirs according to claim 1, characterized in that: the heat transfer medium layer is sodium chloride. 3. A simulated experimental device for fracturing of heavy oil thermal recovery reservoirs according to claim 1, characterized in that: the high-pressure pressure-bearing cylinder is respectively provided with a hydraulic bottom top plate, a hydraulic side top plate, and a rigid side backing plate and the rigid upper backing plate; the test rock sample is fixedly installed at the center of the hydraulic bottom top plate, the hydraulic side top plate and the rigid side backing plate are respectively against the two opposite sides of the experimental rock sample, and the rigid upper backing plate is pressed against the test rock. On top of the rock sample, the rigid upper backing plate is engaged with the top cover of the high-pressure pressure-bearing cylinder located above it. 4. A simulated experimental device for thermal recovery of heavy oil reservoirs according to claim 1, characterized in that: the external dimensions of the experimental rock sample are 100mm × 100mm × 100mm; the diameter of the open hole wellbore is 10mm , the depth is 90mm.

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