CN111720109A - A dry gas well production simulation device and method based on constant production - Google Patents

Abstract

The invention discloses a dry gas well production simulation device and method based on constant production production, which can carry out physical simulation of the gas production law of the dry gas well and obtain the gas production law of the dry gas well. Including the first constant speed and constant pressure pump, the first control valve, the intermediate container, the second control valve, the first core holder, the third control valve, the pressure regulating valve, the second core holder, the back pressure valve and flowmeter, a fourth control valve and a nitrogen gas cylinder are sequentially connected between the intermediate container and the second control valve through a three-way joint, the temperature of the first core holder is controlled by a heating system, and the first core The gripper sets the confining pressure through the confining pressure system, the second core holder sets the confining pressure through the confining pressure automatic tracking pump, the back pressure valve sets the back pressure through the second constant speed and constant pressure pump, and the first core clamp sets the confining pressure through the confining pressure system. The two ends between the holders and the two ends of the second core holder are respectively provided with pressure sensors for pressure tracking.

Description

A dry gas well production simulation device and method based on constant output production

technical field

The invention belongs to the technical field of oil and gas exploitation experiments, and mainly relates to a physical simulation device and method for indoor simulation of the gas production law of a gas well under the condition of a constant production production system.

Background technique

The production decline law of traditional gas wells is mainly studied based on the existing production data using the method of gas reservoir engineering or numerical simulation. The method of determining the production of traditional gas wells is mainly based on the reference of similar gas wells, and the gas wells in the same gas reservoir basically use the same method. yield determination standard. However, due to the unidirectionality of actual gas well production (production cannot be reproduced and parameters cannot be reset), the difference between the actual well production and the optimal production is too large.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a dry gas well production simulation device and method based on constant production production, which can perform physical simulation of the gas production law of dry gas wells to obtain the gas production law of dry gas wells.

The object of the present invention is achieved in this way:

A dry gas well production simulation device based on constant output production, comprising a first constant speed and constant pressure pump, a first control valve, an intermediate container, a second control valve, a first core holder, a third control valve, A pressure regulating valve, a second core holder, a back pressure valve, and a flow meter. A fourth control valve and a nitrogen gas cylinder are sequentially connected between the intermediate container and the second control valve through a three-way joint. The first core The temperature of the holder is controlled by the heating system, the confining pressure of the first core holder is set by the confining pressure system, the confining pressure of the second core holder is set by the confining pressure automatic tracking pump, and the back pressure valve is set by the second The constant speed and constant pressure pump is provided with back pressure, and the two ends between the first core holder and the two ends of the second core holder are respectively provided with pressure sensors for pressure tracking.

Preferably, the first core holder is connected to a first pressure gauge, and the second core holder is connected to a second pressure gauge for detecting confining pressure.

Preferably, a data acquisition system is also included, wherein the flowmeter and each pressure sensor are respectively connected to the data acquisition system for collecting pressure data and flow data.

Preferably, the tracking pipeline of the automatic confining pressure tracking pump is connected to the inlet end of the second core holder for tracking the pressure at the inlet end of the second core holder.

Preferably, a fifth control valve is arranged on the pipeline between the first core holder and the confining pressure system to stabilize the confining pressure.

A dry gas well production simulation method based on constant production production, comprising:

The tight sandstone of the target layer is taken to prepare the first core and the second core, and the first core is loaded into the first core holder, and the second core is loaded into the second core holder;

Start the heating system and the confining pressure system, simulate the external environment of the target layer in the first core holder, and set the formation pressure of the target layer to be P;

Close the first control valve and the second control valve, open the fourth control valve, fill a sufficient amount of nitrogen into the intermediate container, and then close the fourth control valve;

Open the first control valve and the second control valve, start the first constant speed and constant pressure pump, and fill the first core holder with nitrogen gas. When the pressure P is reached, turn off the first constant speed and constant pressure pump in turn. control valve and second control valve until the pressure stabilizes;

Adjust the pressure regulating valve according to the required production pressure difference to decompress the air pressure at the inlet end of the second core holder. After decompression, the gas pressure at the inlet end of the second core holder is P ₁ , and the outlet of the second core holder The end pressure is P ₂ ;

Use the confining pressure automatic tracking pump to set the pressure difference, track the gas pressure P ₁ at the inlet end of the second core holder, and then automatically transform to generate the confining pressure;

According to the waste pressure of the gas layer, the second constant speed and constant pressure pump is used to give a back pressure P ₃ to the back pressure valve, the third control valve is opened, the pressure regulating valve is adjusted to start simulating production, and the pressure sensor is used to monitor the relationship between the first core holder and the first core holder. The variation curve of the pressure at both ends of the second core holder with time, and the variation curve of the gas flow rate with time in the flowmeter is monitored synchronously until the end of production;

The system production pressure difference is ΔP=P ₁ -P ₃ . When P>P ₁ , the gas well production simulation system is in the stable production stage. When P=P ₁ , the gas well production simulation system begins to change from the stable production stage to the declining stage. At this time, P At the same time as P ₁ decreases, when P=P ₁ =P ₃ , the gas well production simulation system stops simulating production.

Preferably, the preparation method of the first core and the second core is as follows: drying the core to a constant weight, placing it in a cooler, cooling to room temperature, measuring the length and diameter of the core, and the permeability of the second core is lower than that of the first core Core permeability.

Preferably, before simulating production, the first core holder and the second core holder are pre-filled with gas to ensure the continuity of experimental data.

Preferably, the gas production law of the dry gas well is obtained by changing the production pressure difference and performing production simulation for many times.

Owing to adopting the above-mentioned technical scheme, the present invention has the following beneficial effects:

The physical simulation device and method provided by the present invention are mainly based on the production characteristics of dry gas wells and the physical properties of gas reservoirs, and use reservoir cores or artificial cores to simulate gas reservoirs under the conditions of indoor simulated reservoir temperature and pressure; The pressure automatic tracking control technology is invented to simulate the wellhead throttling device of the gas well during the experimental process; the existing production decline and pressure decline analysis methods can be used to analyze the laws presented by the experimental test data.

The advantages of the present invention mainly include:

(1) Compared with the traditional gas well production allocation method in which a model is established by simplifying the formation seepage process for theoretical calculation, the present invention is based on the gas production process of the tight sandstone gas layer, which more realistically reduces the conditions for reservoir gas production and reduces the Less production error;

(2) Using the similarity principle, a bridge between the results of indoor experiments and the production data of the mine is established, which can guide the rational allocation of production on site;

(3) The operation process is simple and the economic cost is low;

(4) It has strong pertinence and good repeatability, which is convenient to carry out experiments for a long time.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Figures 2-5 are the results of the simulated production experiments.

1. Nitrogen gas cylinder, 2, 5, 7, 13, 17. Control valve, 3, 8, 15, 25. Tee joint, 4. Intermediate container, 6, 26. Constant speed and constant pressure pump, 9, 16, 20, 24. Pressure sensor, 10. First core holder, 11, 21. Pressure gauge, 12. Heating system, 14. Confining pressure system, 18. Pressure regulating valve, 19. Four-way joint, 22. Second Core holder, 23. Confining pressure automatic tracking pump, 27. Back pressure valve, 28. Flow meter, 29. Data acquisition system.

Detailed ways

A dry gas well production simulation device based on constant production production, comprising a first constant speed and constant pressure pump 6, a first control valve 5, an intermediate container 4, a second control valve 7, a first core holder 10 ( 38mm core holder), the third control valve 17, the pressure regulating valve 18, the second core holder 22 (25mm core holder), the back pressure valve 27, the flow meter 28, the intermediate container 4, the second core holder A fourth control valve 2 and a nitrogen gas cylinder 1 are sequentially connected between the control valves 7 through the three-way joint 3. The temperature of the first core holder 10 is controlled by the heating system 12, and the first core holder 10 is passed through the enclosure. The confining pressure system 14 sets the confining pressure, the confining pressure system 14 adopts the conventional confining pressure system, and the second core holder 22 sets the confining pressure through the confining pressure automatic tracking pump 23. This part selects the automatic tracking pump to set the pressure difference because it is to be adjusted After the pressure is passed, the pressure at the outlet end of the pressure regulating valve will be slightly unstable. Using the automatic tracking pump can more easily adjust the pressure difference between the confining pressure and the inlet end of the second core holder, and at the same time eliminate the influence of stress-sensitive effect. Using the automatic tracking pump can control the pressure more conveniently, in order to better maintain stable production. The back pressure valve 27 is provided with back pressure by the second constant speed and constant pressure pump 26, and pressure sensors are respectively provided at both ends of the first core holder 10 and at both ends of the second core holder 22 for Stress tracking.

The tracking pipeline of the confining pressure automatic tracking pump 23 is connected to the inlet end of the second core holder 22 for tracking the pressure at the inlet end of the second core holder 22 . The first core holder 10 is connected to the first pressure gauge 11, and the second core holder 22 is connected to the second pressure gauge 21 for detecting the confining pressure. A fifth control valve 13 is provided on the pipeline between the first core holder 10 and the confining pressure system 14 to stabilize the confining pressure. During the experiment, the confining pressure is very high. When the hand pump reaches the end and needs to be sucked again, the valve 13 should be closed. When the pressure is continued after the suction is completed, the fifth control valve 13 should be kept closed, and the pressure of the confining pressure pump should be first Increase to be substantially equal to the confining pressure of the holder, and then open the fifth control valve 13 to continue to increase the confining pressure of the holder. Prevent the pressure of the pump body from reducing after the hand pump sucks liquid, resulting in a decrease in the confining pressure of the gripper, so as to stabilize the confining pressure. A data acquisition system 29 is also included. The flow meter 28 and each pressure sensor are respectively connected to the data acquisition system 29 for acquiring pressure data and flow data.

A dry gas well production simulation method based on constant production production, comprising:

The tight sandstone of the target layer is taken to prepare the first core and the second core, and the first core is loaded into the first core holder 10, and the second core is loaded into the second core holder 22; The preparation method of the second core is as follows: drying the core at 100°C to constant weight, placing it in a cooler, cooling to room temperature, measuring the length and diameter of the core, and making it fit into the core holder. The permeability of the second core is lower than that of the first core so as to correspond to the required pressure, and the second core is selected according to the speed of the degassing speed.

Before simulating production, the first core holder 10 and the second core holder 22 are pre-filled with gas to ensure the continuity of experimental data.

Start the heating system 12 and the confining pressure system 14, simulate the external environment of the target layer in the first core holder 10, and set the formation pressure of the target layer to be P;

Close the first control valve 5 and the second control valve 7, open the fourth control valve 2, fill a sufficient amount of nitrogen into the intermediate container 4, and then close the fourth control valve 2;

Open the first control valve 5 and the second control valve 7, start the first constant speed and constant pressure pump 6, fill nitrogen into the first core holder 10, and close the first constant speed and constant pressure in turn after reaching the pressure P Pump 6, first control valve 5 and second control valve 7 until the pressure stabilizes;

Adjust the pressure regulating valve 18 according to the required production pressure difference to decompress the air pressure at the inlet end of the second core holder 22. After decompression, the gas pressure at the inlet end of the second core holder 22 is P ₁ , and the second core holder 22 The pressure at the outlet end of the holder 22 is P ₂ ;

Use the confining pressure automatic tracking pump 23 to set the pressure difference, track the gas pressure P1 at the inlet end of the second core holder 22, and then automatically change to generate the confining pressure;

According to the waste pressure of the gas layer, the second constant speed constant pressure pump 26 is used to give the back pressure P ₃ to the back pressure valve 27 , the third control valve 17 is opened, and the pressure regulating valve 18 is adjusted to start simulating production, and the pressure sensors 9 and 16 are used respectively. , 20 and 24 monitor the change curve of the pressure at both ends of the first core holder 10 and the second core holder 22 with time, and synchronously monitor the change curve of the gas flow rate with time in the flow meter 28 until the end of production;

The system production pressure difference is ΔP=P ₁ -P ₃ . When P>P ₁ , the gas well production simulation system is in the stable production stage. When P=P ₁ , the gas well production simulation system begins to change from the stable production stage to the declining stage. At this time, P At the same time as P ₁ decreases, when P=P ₁ =P ₃ , the gas well production simulation system stops simulating production.

By changing the production pressure difference and performing production simulations many times, the gas production law of the dry gas well is obtained.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should Various changes may be made in details without departing from the scope of the invention as defined by the claims.

Claims (9)

1. A dry gas well production simulation device based on constant output production is characterized in that, comprising the first constant speed and constant pressure pump, the first control valve, the intermediate container, the second control valve, the first core holder connected in series in turn , the third control valve, the pressure regulating valve, the second core holder, the back pressure valve, the flow meter, the fourth control valve and the nitrogen gas cylinder are sequentially connected between the intermediate container and the second control valve through a three-way joint. , the temperature of the first core holder is controlled by the heating system, the confining pressure of the first core holder is set by the confining pressure system, the confining pressure of the second core holder is set by the confining pressure automatic tracking pump, and the confining pressure is set by the second core holder. The back pressure valve sets back pressure through the second constant speed and constant pressure pump, and the two ends between the first core holder and the two ends of the second core holder are respectively provided with pressure sensors for pressure tracking. 2. A dry gas well production simulation device based on constant production production according to claim 1, wherein the first core holder is connected to the first pressure gauge, and the second core holder is connected to the first pressure gauge. Two pressure gauges, used to detect confining pressure. 3. A dry gas well production simulation device based on constant production production according to claim 1, characterized in that: further comprising a data acquisition system, wherein the flowmeter and each pressure sensor are respectively connected to the data acquisition system for collecting Pressure data, flow data. 4. a kind of dry gas well production simulation device based on constant output production according to claim 1 is characterized in that: the tracking pipeline of confining pressure automatic tracking pump is connected to the inlet end of the second core holder, for tracking the first Inlet side pressure of two core holders. 5. A dry gas well production simulation device based on constant production production according to claim 1, characterized in that: a fifth control valve is arranged on the pipeline between the first core holder and the confining pressure system, and a to stabilize the confining pressure. 6. A dry gas well production simulation method based on fixed output production, is characterized in that, comprising: The tight sandstone of the target layer is taken to prepare the first core and the second core, and the first core is loaded into the first core holder, and the second core is loaded into the second core holder; Start the heating system and the confining pressure system, simulate the external environment of the target layer in the first core holder, and set the formation pressure of the target layer to be P; Close the first control valve and the second control valve, open the fourth control valve, fill a sufficient amount of nitrogen into the intermediate container, and then close the fourth control valve; Open the first control valve and the second control valve, start the first constant speed and constant pressure pump, and fill the first core holder with nitrogen gas. When the pressure P is reached, turn off the first constant speed and constant pressure pump in turn. control valve and second control valve until the pressure stabilizes; Adjust the pressure regulating valve according to the required production pressure difference to decompress the air pressure at the inlet end of the second core holder. After decompression, the gas pressure at the inlet end of the second core holder is P ₁ , and the outlet of the second core holder The end pressure is P ₂ ; Use the confining pressure automatic tracking pump to set the pressure difference, track the gas pressure P ₁ at the inlet end of the second core holder, and then automatically transform to generate the confining pressure; According to the waste pressure of the gas layer, the second constant speed and constant pressure pump is used to give a back pressure P ₃ to the back pressure valve, the third control valve is opened, the pressure regulating valve is adjusted to start simulating production, and the pressure sensor is used to monitor the relationship between the first core holder and the first core holder. The variation curve of the pressure at both ends of the second core holder with time, and the variation curve of the gas flow rate with time in the flowmeter is monitored synchronously until the end of production; The system production pressure difference is ΔP=P ₁ -P ₃ . When P>P ₁ , the gas well production simulation system is in the stable production stage. When P=P ₁ , the gas well production simulation system begins to change from the stable production stage to the declining stage. At this time, P At the same time as P ₁ decreases, when P=P ₁ =P ₃ , the gas well production simulation system stops simulating production. 7. a kind of dry gas well production simulation method based on constant output production according to claim 6 is characterized in that: the preparation method of the first rock core, the second rock core is: the rock core is dried to constant weight, and then the cooler is placed , cooled to room temperature, and the length and diameter of the core were measured. The permeability of the second core was lower than that of the first core. 8. A kind of dry gas well production simulation method based on fixed output production according to claim 6, it is characterized in that: before simulating production, the first core holder and the second core holder are pre-filled with gas to ensure the experiment data continuity. 9 . The dry gas well production simulation method based on constant production production according to claim 6 , wherein the gas production law of the dry gas well is obtained by changing the production pressure difference and performing production simulation for many times. 10 .

Images