An experimental method for different gas-water distribution patterns under high temperature and high pressure conditions

Abstract

The present application relates to a kind of different gas-water distribution mode experimental methods under high temperature and high pressure condition, comprising the following steps: obtaining the well logging curve of research area, according to the occurrence relationship of gas and water, three kinds of gas-water distribution models are established: semi-closed baffle model, semi-permeable baffle model, no baffle model;Using the above three kinds of gas-water distribution model, load gas-water mutual drive test bench, carry out gas-water mutual drive experiment, obtain experimental results;According to the experimental results, a physical model of gas-water distribution mode is established.The gas-water distribution mode experiment of the present application highly approximates the simulation of gas-water occurrence relationship, establishes the physical model of different gas-water distribution mode, carries out gas-water mutual drive experiment by setting different injection speed and different gas-water distribution mode, obtains comprehensive gas-water mutual drive experimental data, and accurately restores the real reservoir gas-water distribution mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of experimental methods for oil and gas field development engineering, and particularly relates to an experimental method for different gas-water distribution patterns under high temperature and high pressure conditions. BACKGROUND

[0002] With the development of oil and gas field exploration and development technology, while deepening the development of shallow oil and gas resources, it is constantly extended to deep layers with lower exploration and development degree. Carbonate gas reservoirs play an important role in the natural gas reserves in Sichuan Basin, and their production can account for more than half of the total conventional natural gas production in Sichuan Basin. According to statistics, more than 95% of the developed carbonate gas reservoirs in Sichuan Basin have edge and bottom water, and gas-water two-phase flow exists universally in the process of accumulation and development. Deep carbonate gas wells are generally affected by water invasion in the process of production and development, which seriously affects the recovery of gas reservoirs. Therefore, it is of great practical significance to depict the gas-water distribution characteristics in carbonate gas reservoirs and reveal the gas-water two-phase flow mechanism for scientific management of gas wells and production dynamic prediction.

[0003] Research shows that deep carbonate gas reservoirs have great storage scale and development potential, and have become an important replacement and production gas reservoir in Sichuan Basin, but also face many challenges. Compared with medium and shallow oil and gas reservoirs, deep carbonate reservoirs have experienced a long geological history of more than 100 million years, as well as multiple tectonic movements and diagenetic reconstruction, forming a pattern of multiple media coexisting in pores, holes and fractures. The vertical and horizontal distribution of various media is complex and variable, resulting in strong heterogeneity, extremely high temperature and pressure, special percolation mechanism and complex gas-water relationship. The Yuanba Changxing Formation gas reservoir is a bottom water gas reservoir, and the low structural position region generally contains water, and there are great differences in different water invasion modes, resulting in unclear understanding of micro-flow mechanism of different gas-water distribution patterns in Yuanba gas field. The reservoir temperature and pressure of Yuanba Changxing Formation gas reservoir are high (temperature 149-164℃, pressure 66-77MPa), and the gas-water relationship is complex, and the existing research has insufficient understanding of the micro-flow mechanism under high temperature and high pressure conditions.

[0004] Therefore, at present, there are problems such as unclear understanding of water invasion law, unclear gas-water micro-flow mechanism of different gas-water distribution patterns, and insufficient research on gas-water micro-flow mechanism under high temperature and high pressure conditions in the development process of Yuanba Changxing Formation gas reservoir. It is urgent to carry out high temperature, high pressure, visual gas-water mutual driving percolation experiment to study the micro-flow law of gas-water two-phase, and provide reliable basis for efficient development of gas reservoirs.

[0005] Microscopic visualization experiments offer significant advantages for studying the gas-water two-phase flow mechanism. However, research on different gas-water distribution patterns and visualized gas-water flow under high temperature and high pressure is limited. Given the different gas-water distribution patterns and high-temperature and high-pressure characteristics of the Yuanba gas reservoir, there is an urgent need to conduct high-temperature and high-pressure visualized gas-water mutual-driven flow experiments. Therefore, an experimental method for different gas-water distribution patterns under high temperature and high pressure conditions is proposed. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies, such as unclear understanding of water intrusion patterns, unclear understanding of gas-water micro-flow mechanisms, and limited visualization studies. It provides an experimental method for different gas-water distribution patterns under high temperature and high pressure conditions, to restore the gas-water distribution patterns and gas-water two-phase seepage characteristics under formation conditions, and to provide a scientific basis for the efficient development of gas reservoirs in the later stage.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] An experimental method for gas-water distribution patterns includes the following steps:

[0009] Well logging curves of the study area were obtained, and three gas-water distribution models were established based on the gas-water occurrence relationship: semi-closed baffle model, semi-permeable baffle model, and baffle-free model.

[0010] Semi-enclosed partition model: The partition used in the model has a length of 2 / 5 to 3 / 5 of the model width and a width of 2 / 30 to 4 / 30 of the partition length. The partition is set in the middle of the model.

[0011] Semi-permeable baffle model: The baffle length used in the model is approximately equal to the model width, and the baffle width is 2 / 30-4 / 30 of the baffle length. The baffle is set in the middle of the model; the diameter of the seepage channel in the semi-permeable baffle is 0.01-3mm.

[0012] The pore structure is extracted from the pore structure diagram of the core casting thin section, and then characterized and connected to obtain a pore-free physical model.

[0013] Using the above three gas-water distribution models, a gas-water mutual drive test rig was installed to conduct gas-water mutual drive experiments and obtain experimental results.

[0014] A physical model of the gas-water distribution pattern was established based on the experimental results.

[0015] This invention designs a semi-closed baffled type and a semi-permeable baffled type based on different gas-water distribution patterns, and together with a baffle-less model, constructs a total of three different gas-water distribution patterns, conforming to the physical models of different gas-water distribution patterns. Then, gas-water mutual drive experiments are conducted. By setting different injection rates and different gas-water distribution patterns, comprehensive gas-water mutual drive experimental data are obtained, accurately reproducing the real reservoir gas-water distribution pattern.

[0016] Further, in the semi-closed partition model, the partition length is about 1 / 2 of the model width, and the partition width is about 1 / 10 of the partition length, and the partition is arranged in the middle of the model.

[0017] Further, in the semi-closed partition model, the size and position of the semi-closed partition, and the size and distribution of the seepage channel are optimally designed.

[0018] Preferably, the partition length is 0.4-0.6 times the model width, and the position is arranged near the middle of the model, which can be arranged at a position deviating by ±10% from the middle of the model. The foregoing deviation is calculated with the width of the model as the denominator.

[0019] Preferably, the partition width is about 5 / 60-7 / 60 of the partition length. For example, the partition width is about 1 / 10 of the partition length.

[0020] For example, the model uses a cylindrical model with a model width of 20 mm, the partition length is set to 10 mm (half of the model width), and the width of the partition is set to 1 mm (1 / 10 of the partition length), and the partition is arranged in the middle of the model.

[0021] In the semi-closed partition model, the partition is closed and prevents flow.

[0022] Further, in the semi-permeable partition model, the size and position of the semi-permeable partition, and the size and distribution of the seepage channel are optimally designed.

[0023] Preferably, the seepage channel in the semi-permeable partition is in the shape of X.

[0024] The length of the semi-permeable partition can refer to the length of the partition in the semi-closed partition model, for example, it can be 0.4-0.6 times the width of the model. The position is arranged near the middle of the model, and there can be a deviation of ±10% from the position, and the deviation is calculated with the width of the model as the denominator.

[0025] The size and distribution of the seepage channel of the semi-permeable partition can refer to the semi-closed partition. For example, the size of the seepage channel is 0.01-3 mm, for example, the size of the seepage channel is 0.02 mm, 0.05 mm, 0.07 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.5 mm, etc. The seepage channel is a pore, and the proportion of the pore in the template is 1-20%, for example, the porosity is 5%, 8%, 10%, 12%, 15%, 16%, 18%, etc.

[0026] Preferably, the diameter of the seepage channel in the semi-permeable partition is about 0.1 mm.

[0027] Further, using three gas-water distribution models, load the gas-water mutual displacement test bench, and conduct gas-water mutual displacement experiments of different gas-water distribution modes at different injection speeds to obtain experimental results.

[0028] Further, before the gas-water mutual displacement experiment, clean the experimental device and the model.

[0029] Preferably, the cleaning process refers to washing the model and the holder with deionized water and drying them in an oven for standby use.

[0030] Further, place the model on the holder support, connect the experimental instrument, and detect the sealing performance. After passing the detection, start the experiment.

[0031] Preferably, after passing the sealing performance detection, perform a vacuum extraction process, and then start the experiment. The air in the experimental device and the model is discharged through the vacuum extraction to ensure that the experimental gas is not contaminated by air.

[0032] Further, after starting the experiment, first heat the model and the pipeline to reach the experimental design temperature. Preferably, the experimental design temperature is the formation temperature.

[0033] Further, conduct gas-water mutual displacement experiments of different gas-water distribution modes at different injection speeds. The gas-water distribution modes include semi-closed, semi-permeable, and no barrier types, and the experiments are conducted using semi-closed baffle models, semi-permeable baffle models, and no baffle models, respectively.

[0034] Further, in the gas-water mutual displacement experiment, the temperature of the model is controlled at 40-180℃, and the confining pressure is controlled at 8-100 MPa. The gas-water mutual displacement scene under different gas-water distribution conditions under high temperature and high pressure conditions is maximized.

[0035] Preferably, in the gas-water mutual displacement experiment, the temperature of the model is controlled at 60-170℃, and the confining pressure is controlled at 12-80 MPa.

[0036] More preferably, the temperature of the model is controlled at 145-165℃, and the confining pressure is controlled at 25-80 MPa.

[0037] For example, the temperature of the model can be controlled at 70, 80, 90, 100, 110℃, etc. For example, the confining pressure of the model can be controlled at 20, 30, 40, 50, 60, 70 MPa, etc.

[0038] Further, the gas-water mutual displacement experiment includes gas displacement water and water displacement gas experiments.

[0039] Further, in the gas-water mutual displacement experiment, the injection speed is 0.01-0.1 mL / min. The injection speed corresponds to the displacement speed, and the injection is continuously performed until no water or gas is produced at the outlet end.

[0040] Further, according to the obtained gas-water distribution mode physical model, the gas-water distribution state is quantitatively characterized and analyzed. Preferably, the analysis of different gas-water distribution states under high temperature and high pressure conditions is used.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] (1) The gas-water distribution mode experiment of the present application designs a semi-closed partition type and a semi-permeable partition type according to different gas-water distribution modes, and adds a model without a partition to construct three gas-water distribution modes of a non-partition type, a semi-closed partition type and a semi-permeable partition type, which are consistent with the gas-water occurrence relationship and meet the physical model of different gas-water distribution modes.

[0043] (2) The gas-water distribution mode experiment method of the present application carries out gas-water mutual displacement experiments by setting different injection rates and different gas-water distribution modes to obtain comprehensive gas-water mutual displacement experiment data, and accurately restores the real reservoir gas-water distribution mode. This model simulates the gas-water two-phase percolation characteristics under different gas-water distribution modes in real formation conditions.

[0044] (3) The gas-water distribution mode experiment of the present application simulates the inhibition of the "water cone" in the water invasion process and the influence of different displacement rates on displacement efficiency, and provides a scientific basis for efficient development of a large number of deep gas reservoirs in the later period.

[0045] (4) The experimental results obtained by the gas-water distribution mode experiment method of the present application are subjected to gas, water and skeleton multi-phase segmentation processing to realize quantitative characterization of the whole process of gas-water distribution. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The well logging curve chart in the present application.

[0047] Figure 2 The three different gas-water distribution mode physical model charts in the present application.

[0048] Figure 3 The experimental device system schematic diagram and flow chart of Example 2 of the present application.

[0049] Figure 4 The gas-water distribution quantitative characterization method schematic diagram of multi-phase segmentation in the present application. DETAILED DESCRIPTION

[0050] The present application will be further described in detail below in combination with examples and drawings.

[0051] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0052] The present application uses "about" or "approximately" and the like to indicate that the corresponding number is an approximate value, and each numerical value can have a difference fluctuation of ±1%, ±2% or ±5%, which does not affect the implementation of the present application. All numerical values within the foregoing difference fluctuation range should be included in the protection scope of the present application.

[0053] Embodiment 1

[0054] An experimental method for different gas-water distribution patterns under high temperature and high pressure conditions, comprising the following steps:

[0055] (1) For the logging curve pictures of the research area, three different gas-water distribution patterns are established according to the occurrence relationship of gas and water: semi-closed baffle type, semi-permeable baffle type and no baffle type.

[0056] (2) Specifically as follows:

[0057] Based on a large number of core casting thin section pore structure pictures, pore structure is extracted and described connectivity to obtain a no baffle type physical model.

[0058] According to different gas-water distribution patterns, semi-closed baffles and semi-permeable baffles are designed. Among them, the semi-closed baffle type is designed as a baffle with a length of 1 / 2 of the model width and a width of 1 / 10 of the baffle length, which is in the middle of the model; the semi-permeable baffle type is designed as a baffle with a length of the model width and a width of 1 / 10 of the baffle length, which is in the middle of the model; the seepage channel diameter in the semi-permeable baffle is 0.1 mm, and the seepage channel is in X shape.

[0059] (3) For the above three different gas-water distribution patterns, gas-water mutual displacement experiments are carried out; and different gas-water distribution patterns with different injection rates are set to carry out gas-water mutual displacement experiments respectively. Among them, the gas-water mutual displacement experiment includes gas displacement water and water displacement gas experiment.

[0060] (4) According to the experimental results of the above gas-water mutual displacement experiment, the physical model of different gas-water distribution patterns is established, which restores the real reservoir gas-water distribution pattern.

[0061] Embodiment 2

[0062] An experimental method for different gas-water distribution patterns under high temperature 150℃ and high pressure 40 MPa conditions, specifically comprising the following steps:

[0063] Step 1: Logging curve picture for the study area, as shown in Figure 1 Three gas-water distribution modes of no barrier, semi-closed barrier and semi-permeable barrier were established according to the gas-water occurrence relationship.

[0064] Step 2:

[0065] As shown in Figure 2 According to the three different gas-water distribution modes obtained in step 1: no barrier, semi-closed barrier and semi-permeable barrier.

[0066] As shown in Figure 2 The no barrier model shown in the left image is based on the extraction of pore structure from the core casting thin section pore structure diagram, and the no barrier physical model is obtained by description and connection.

[0067] As shown in Figure 2 The semi-closed barrier model shown in the middle image is based on the no barrier model. The barrier length is designed to be 10 mm, the model width is 20 mm (the barrier length is about 1 / 2 of the model width), and the width is 1 mm (equivalent to 1 / 10 of the barrier length), which is in the middle of the model.

[0068] As shown in Figure 2 The semi-permeable barrier model shown in the right image is based on the no barrier model. The barrier length is designed to be 20 mm, which is the same as the model width, and the width is 1 mm (equivalent to 1 / 10 of the barrier length, semi-closed barrier model), and the same barrier is in the middle of the model. The seepage channel diameter in the semi-permeable barrier is 0.1 mm, and the seepage channel is X-shaped.

[0069] Step 3:

[0070] Use the device as shown in Figure 3 Connect the experimental device, and refer to the process shown in Figure 3 Based on the three different gas-water distribution modes, carry out gas drive water experiment and displacement velocity gas drive water experiment on the three different gas-water distribution physical models obtained in step 2. The specific experimental process is as follows.

[0071] S1, wash the model and holder with deionized water, and dry in an oven for standby.

[0072] S2, place the model on the holder support and connect the experimental instrument.

[0073] S3, test the sealing of the device by injecting high-purity nitrogen, then vacuum the model for 30 min.

[0074] S4, heat the model and pipeline and keep the initial formation temperature at 150°C.

[0075] S5, inject formation water into the model at a flow rate of 0.01 mL / min until the saturation pressure reaches 40 MPa.

[0076] S6, then inject natural gas into the model at different displacement speeds (0.01 mL / min, 0.1 mL / min) respectively until no water is produced at the outlet end.

[0077] S7, repeat steps S1-S6 for other models. Through visual experiments, not only local microscopic images are obtained for analyzing percolation mechanism and occurrence characteristics, but also the overall flow process of fluids in the model is recorded, and different time images can be obtained through subsequent video editing, which can be quantitatively characterized by image analysis method.

[0078] Step 4:

[0079] Referring to Figure 3 , on the basis of the three different gas-water distribution modes, water drive gas experiments and displacement speed water drive gas experiments are carried out on the three different gas-water distribution physical models obtained in step 2.

[0080] The experimental process is similar to step 3, the difference is that gas is injected first until the saturation pressure reaches 40 MPa; then water is injected into the model at different displacement speeds respectively until no gas is produced at the outlet end.

[0081] Repeat the displacement experiment of the three different gas-water distribution physical models, through the visual experiment, not only the local microscopic image is obtained for analyzing the percolation mechanism and occurrence characteristics, but also the overall flow process of fluids in the model is recorded, and different time images can be obtained through subsequent video editing, which can be quantitatively characterized by image analysis method.

[0082] Step 5:

[0083] On the basis of the three different gas-water distribution modes, the results of the gas-water mutual displacement experiment of the three different gas-water distribution physical models obtained in steps 3 and 4 are quantitatively characterized for the whole process of gas-water distribution.

[0084] Specifically comprising the following steps:

[0085] S1, extract the images frame by frame during the experiment.

[0086] S2, extract the saturated fluid image and the target image in the displacement process.

[0087] S3, identify the initial saturated fluid distribution.

[0088] S4, identify the gas-water distribution of the target image.

[0089] S5, segment the initial saturated fluid image to calculate the number of pixels as N.

[0090] S6, the number of gas / water pixels of the target image is calculated as n by multi-phase segmentation.

[0091] S7, displacement efficiency E is calculated by gas-water saturation.

[0092] E = n / N x 100%

[0093] In summary, three different gas-water distribution mode physical models are established according to gas-water occurrence relationship, and gas-water two-phase seepage law under the conditions of formation temperature and pressure is restored by using a high-temperature and high-pressure micro-visualization physical system. The gas-water distribution quantitative characterization method established based on the method can realize quantitative characterization of the whole process of gas-water distribution by calculating gas-water saturation based on the visualization experimental result image.

[0094] The semi-closed partition type and semi-permeable partition type physical models established based on the method can simulate the formation of "water cone" in the process of water invasion of a gas reservoir and the inhibition of the two partitions on the "water cone".

[0095] The above merely describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the embodiments of the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of experiment of air-water distribution pattern, characterized in that, It comprises the following steps: Obtaining the logging curves of the study area, and establishing three gas-water distribution models according to the occurrence relationship of gas and water: semi-closed partition model, semi-permeable partition model and no partition model; In the semi-closed partition model, the length of the partition is 2 / 5-3 / 5 of the width of the model, the width of the partition is 2 / 30-4 / 30 of the length of the partition, and the partition is set in the middle of the model; In the semi-permeable partition model, the length of the partition is about equal to the width of the model, the width of the partition is 2 / 30-4 / 30 of the length of the partition, and the partition is set in the middle of the model; the diameter of the seepage channel in the semi-permeable partition is 0.01-3mm; In the no partition model, the pore structure is extracted based on the core casting thin section pore structure diagram, and is described and connected to obtain a no partition physical model; Using the above three gas-water distribution models, load the gas-water mutual displacement test bench, and conduct gas-water mutual displacement experiments to obtain experimental results; According to the experimental results, a gas-water distribution mode physical model is established.

2. The experimental method of air-water distribution pattern according to claim 1, characterized in that, In the semi-closed partition model, the length of the partition is 0.4-0.6 times the width of the model, the width of the partition is 5 / 60-7 / 60 of the length of the partition, and the partition is set in the middle of the model.

3. The experimental method of air-water distribution pattern according to claim 1, characterized in that, Using the three gas-water distribution models, load the gas-water mutual displacement test bench, and conduct gas-water mutual displacement experiments of different gas-water distribution modes at different injection rates to obtain experimental results.

4. The experimental method of air-water distribution pattern according to claim 1, characterized in that, Before the gas-water mutual displacement experiment, the experimental device and the model are cleaned.

5. The experimental method for gas-water distribution pattern according to claim 1, characterized in that, Place the model on the holder support, connect the experimental instruments, detect the sealing performance, and start the experiment after passing the test.

6. The experimental method for gas-water distribution pattern according to claim 1, characterized in that, After passing the sealing performance test, perform vacuum extraction, and then start the experiment.

7. The experimental method for gas-water distribution pattern according to claim 1, characterized in that, After starting the experiment, first heat the model and the pipeline to the designed temperature.

8. The experimental method of air-water distribution pattern according to claim 7, characterized in that, Conduct gas-water mutual displacement experiments of different gas-water distribution modes at different injection rates.

9. The experimental method of air-water distribution pattern according to claim 7, characterized in that, In the gas-water mutual displacement experiment, the temperature of the model is controlled at 40-180℃, and the confining pressure is 8-100 MPa.

10. The experimental method for gas-water distribution pattern according to claim 1, characterized in that, According to the obtained gas-water distribution mode physical model, the gas-water distribution state is quantitatively characterized and analyzed.

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