Hydrate Reservoir Gravel Packing and Sand Control and Production Enhancement Reactor

Abstract

The present invention discloses a reaction kettle for gravel packing and sand control and production enhancement of hydrate reservoirs, which includes a sediment cavity for placing hydrate reservoir samples; the sediment cavity is provided with a sediment cavity orifice; an axial pressure loading plate is arranged in the sediment cavity, and an external force is applied to the axial pressure loading plate to apply overburden stress to the samples in the sediment cavity for consolidation and compaction; a gravel cavity is provided with a gravel cavity orifice and is used for relative installation with the sediment cavity orifice; a transparent observation window is arranged at the position where the sediment cavity and the gravel cavity are connected and extends towards the sediment cavity and the gravel cavity, so as to observe the migration and accumulation of gravel and reservoir particles throughout the process. This reaction kettle can realize the evaluation of the influence of gravel packing processes such as gravel size, sand-carrying ratio, and pumping displacement on hydrate reservoirs in the laboratory, as well as the quantitative evaluation of the sand control and production enhancement effect after gravel packing.

Description

Technical Field

[0001] The invention relates to the technical field of gravel packing and sand control and production increase experiments, in particular to a reactor for performing hydrate reservoir gravel packing simulation and post-packing sand control and production increase experiments. Background Art

[0002] During the actual extraction of natural gas hydrates, the decomposition of hydrates weakens the sedimentary framework, causing some reservoir particles to migrate into the wellbore with the fluid, resulting in sand production. The production of large amounts of framework particles can lead to reservoir collapse and blockage or reduced formation permeability, compromising extraction efficiency and resulting in economic losses. Therefore, further research is needed to investigate sand control and production enhancement in hydrate reservoirs.

[0003] Gravel packing for sand control is a sand control process that involves filling solid particles such as gravel and ceramic gravel into the wellbore or formation. It has the advantages of good sand retention and a long effective period. It has been proven to be an effective sand control method in traditional oil and gas completion processes and has become the mainstream sand control process for loose sandstone oil and gas fields at home and abroad. The hydrate reservoirs in the Shenhu area of the South China Sea are unconsolidated ultrafine silt reservoirs, and gravel packing for sand control is considered to be one of the most effective sand control processes for such reservoirs. However, due to the relatively complex construction and high cost of such sand control processes, it is particularly important to optimize the process parameters to achieve good sand control effects. Whether gravel packing operations in hydrate reservoirs where phase change processes may occur will cause hydrate decomposition, reservoir damage, and other problems is still unclear and requires further research.

[0004] In response to the above problems, in addition to paying attention to the flow state of the gravel-carrying fluid, the gravel migration and accumulation mode, and the state of the hydrate reservoir during the gravel packing process, it is also necessary to pay attention to the impact of process parameters such as gravel size, sand-carrying ratio, pumping rate, and pumping procedure on the stability of gravel packing and hydrate reservoirs. Furthermore, it is necessary to quantitatively evaluate the sand control and production increase effect after gravel packing, so as to form a complete set of gravel packing and sand control and production increase processes. Therefore, in order to meet the needs of hydrate mining, evaluate the gravel packing effect throughout the process and optimize the process parameters, it is indeed necessary to design an indoor simulation experimental device that focuses on the gravel packing process experiment of the hydrate reservoir while taking into account the evaluation of the sand control and production increase effect.

[0005] Patent document CN111999466A discloses a detachable sand production and sand control reactor for natural gas hydrate mining. This solution can realize the observation and sand production metering functions of simulated natural gas hydrate mining, the sand filling function of filling different porous media, the simulated mining sand and water gas function and the initial water and gas injection function of generating natural gas hydrates. Different observation, sand filling, simulated mining, water and gas injection functions can be realized respectively as needed. However, this solution cannot realize the quantitative evaluation of the sand control and production increase effect after gravel filling.

[0006] Patent document CN110346529A discloses a three-dimensional radial sand production and sand control test reactor for the exploitation of natural gas hydrate horizontal wells. This solution can simulate the sand production volume, sand production law and productivity prediction under different pressure reduction schemes and different well completion sand control methods during the actual exploitation process of natural gas hydrate horizontal wells. However, this solution cannot quantitatively evaluate the sand control and production enhancement effect after gravel packing. Summary of the Invention

[0007] In order to solve at least one of the technical problems existing in the above-mentioned background technology, the present invention provides a reactor for simulating gravel packing in hydrate reservoirs and conducting sand control and production enhancement experiments after packing.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] A hydrate reservoir gravel packing and sand control and production enhancement reactor, comprising:

[0010] A sediment chamber for placing hydrate reservoir samples; the sediment chamber is provided with a sediment chamber orifice.

[0011] An axial pressure loading plate, which is arranged in the sediment chamber, and an external force is applied to the axial pressure loading plate to apply overburden stress to the samples in the sediment chamber for consolidation and compaction.

[0012] A gravel chamber, which is provided with a gravel chamber orifice and is used to be oppositely installed with the sediment chamber orifice as a channel for the gravel-carrying fluid to enter the hydrate reservoir during the gravel packing process and for the reservoir particles to migrate into the gravel layer during the sand control and production enhancement experiment.

[0013] A transparent observation window, which is arranged at the position where the sediment chamber and the gravel chamber are connected and extends towards the sediment chamber and the gravel chamber, and is used to observe the migration and accumulation of gravel and reservoir particles during the whole process of the production simulation experiment.

[0014] Further, the sediment chamber and the gravel chamber are connected and installed in a detachable manner.

[0015] Further, the outside of the sediment chamber is integrally wrapped by a sediment chamber water-cooling jacket, allowing the coolant to flow in the space formed between the inner side of the sediment chamber water-cooling jacket and the outer side of the sediment chamber reactor body to control the overall temperature of the reactor.

[0016] Further, an axial pressure liquid inlet is arranged at the upper part of the sediment chamber to inject axial pressure liquid into the space formed by the axial pressure loading plate and the sediment chamber to achieve pressure increase, and apply overburden stress to the samples in the sediment chamber for consolidation and compaction.

[0017] Further, a liquid injection port is arranged in the sediment chamber for fluid injection to conduct permeability and production simulation experiments.

[0018] Furthermore, a resistivity probe and an acoustic wave probe are provided in the sediment chamber to monitor the resistivity and acoustic wave data evolution of the sample in the sediment chamber during the experiment; a temperature sensor and a pressure sensor are also provided in the sediment chamber to monitor the temperature and pressure data of the hydrate reservoir during the experiment.

[0019] Furthermore, the gravel chamber is a hollow structure to provide gravel filling space, and the gravel chamber is entirely wrapped by a gravel chamber water-cooling jacket; a gravel-carrying liquid inlet and a water return port are provided at the upper part of the gravel chamber to serve as a gravel-carrying liquid injection channel and a discharge channel for excess fluid; a production port is provided at the lower part of the gravel chamber to be used for water production, gas production, and sand production channels during the production simulation process.

[0020] Furthermore, the sediment chamber and the gravel chamber are connected through a flange, and a sealing ring is provided on the flange.

[0021] Furthermore, the gravel cavity is a perforated well gravel cavity or an open hole well gravel cavity;

[0022] The gravel cavity opening of the perforated well gravel cavity is a structure with multiple penetrating circular holes;

[0023] The gravel cavity opening of the open hole gravel cavity is an unobstructed through hole. The lower part of the gravel-carrying fluid inlet is threadedly connected to simulate the open hole well head and is a hollow round tube serving as a channel for the gravel-carrying fluid to enter.

[0024] Furthermore, the kettle wall on the left side of the sediment chamber is a detachable structure, and after disassembly, the skeleton material is filled into the sediment chamber.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The reactor provided by the present invention integrates the sediment chamber, the gravel chamber and the transparent observation window to carry out simulation experiments of the gravel filling process of the hydrate reservoir and the sand control and production increase evaluation experiment after gravel filling. It can also directly observe the migration and accumulation of gravel and reservoir particles throughout the production simulation experiment, thereby enabling the laboratory to evaluate the impact of the gravel filling process on the hydrate reservoir, such as gravel size, sand carrying ratio, and pumping displacement, as well as the quantitative evaluation of the sand control and production increase effect after gravel filling. This is conducive to the full-process evaluation of the gravel filling sand control and production increase process and the provision of optimization suggestions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of a reactor provided by an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the sediment chamber structure provided by an embodiment of the present invention;

[0029] Figure 3It is a schematic diagram of the gravel cavity structure of a perforated well provided by an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the gravel cavity structure of an open-hole well provided by an embodiment of the present invention;

[0031] Wherein, 1 - sediment cavity, 11 - liquid injection port, 12 - sediment cavity kettle body, 13 - sediment cavity water-cooled jacket, 14 - axial pressure liquid inlet, 15 - sediment cavity flange, 16 - sediment cavity orifice, 17 - temperature sensor, 18 - pressure sensor, 2 - axial pressure loading plate, 3 - resistivity probe, 4 - acoustic wave probe, 5 - transparent observation window, 6 - gravel cavity, 61 - gravel cavity orifice, 62 - gravel cavity flange, 63 - water return port, 64 - gravel-carrying liquid inlet, 65 - gravel cavity water-cooled jacket, 66 - gravel cavity kettle body, 67 - production port, 68 - simulated open-hole wellhead. Detailed implementation manners

[0032] Embodiment:

[0033] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a signal connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be said that the interiors of two components are connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0034] In the present invention, the front, rear, up, down and other orientation words are defined based on the positions of the components in the drawings and the positions of the components relative to each other, only for the sake of clarity and convenience in expressing the technical solution. It should be understood that the use of the orientation words should not limit the scope of protection requested by this application.

[0035] The technical solution of the present invention will be further described below with reference to the drawings and embodiments.

[0036] As Figure 1 shown, this embodiment provides a hydrate reservoir gravel packing and sand control and production enhancement reactor, which can be used for simulating the gravel packing experiment of the hydrate reservoir and the sand control and production enhancement experiment after gravel packing respectively, and controlling the temperature and pressure conditions of the hydrate reservoir during the whole experiment process, monitoring the resistivity and acoustic wave evolution laws during the experiment process, directly observing the gravel migration, accumulation process during the gravel packing process and the migration process of reservoir skeleton particles in the gravel packing layer, and obtaining the sand production, water production and gas production data of the corresponding process.

[0037] Specifically, the reactor mainly includes a sediment chamber 1, an axial pressure loading plate 2 located above the sediment chamber, resistivity probes 3 and acoustic probes 4 located on the front and rear sides of the sediment chamber, a gravel chamber 6 located on the right side of the sediment chamber, and a transparent observation window 5 located on the front side of the reactor and covering the lower half of the gravel chamber 6 and the connection between the gravel chamber and the sediment chamber. That is to say, the transparent observation window 5 is set at the position where the sediment chamber and the gravel chamber are connected and extends towards the sediment chamber and the gravel chamber, so as to observe the migration and accumulation of gravel and reservoir particles throughout the process.

[0038] As Figure 2 shown, the sediment chamber 1 and the gravel chamber 6 are flat cuboids. Samples are placed in the hollow part of the sediment chamber 1, which can be used as a space for hydrate reservoir sample synthesis and testing. The outside of the sediment chamber 1 is integrally wrapped by a sediment chamber water-cooled jacket 13, allowing the coolant to flow in the space formed between the inner side of the sediment chamber water-cooled jacket 13 and the outer side of the sediment chamber kettle body 12, so as to control the overall temperature of the reactor. The left side of the sediment chamber kettle body 12 is of a detachable structure, which is convenient for loading the skeleton material after disassembly. The axial pressure loading plate 2 is located above the sediment chamber 1, and pressurization is achieved by injecting axial pressure liquid into the axial pressure liquid inlet 14, so as to apply overburden stress to the reservoir sample inside the sediment chamber 1 for consolidation and compaction. In addition, to ensure that the axial pressure loading plate is always in a horizontal position without deflection, a plurality of piston rods penetrating the sediment chamber 1 and the sediment chamber water-cooled jacket 13 can be provided on its upper part. A sediment chamber orifice 16 is provided below the right side of the sediment chamber 1, which is connected to the gravel chamber orifice 61 below the left side of the gravel chamber 6, and can be used as a channel for the gravel-carrying liquid to enter the hydrate reservoir during the gravel filling process and for the reservoir particles to migrate into the gravel layer during the sand control and production enhancement experiment. A liquid injection port 11 is provided on the left side of the sediment chamber 1, which can be used for fluid injection for permeability and production simulation experiments. A filter screen can be provided at the liquid injection port to prevent reservoir sand particles from entering the liquid injection pipeline and causing blockage. A temperature sensor 17 and a pressure sensor 18 are provided at the lower part of the sediment chamber 1, which are used to monitor the temperature and pressure data of the hydrate reservoir during the experiment. Resistivity probes 3 and acoustic probes 4 are symmetrically arranged on the front and rear sides of the sediment chamber 1, which can be used to monitor the evolution law of the resistivity and acoustic wave data of the sediment sample during the experiment. A sediment chamber flange 15 is provided on the right side of the sediment chamber 1, which is used to connect to the gravel chamber 6.

[0039] The sediment chamber 1 and the gravel chamber 6 are connected by the sediment chamber flange 15 and the gravel chamber flange 62. Preferably, they are bolted together. Sealing rings are provided on the connecting surfaces of the sediment chamber flange 15 and the gravel chamber flange 62 to form a seal and prevent the internal pressure of the reactor from leaking after connection. Installation holes for the transparent observation window 5 are reserved on the front sides of the sediment chamber flange 15 and the gravel chamber flange 62. A sealing ring gland is arranged around the transparent observation window 5 and is connected to the front side of the reactor in the form of bolts. Its area should cover the lower half of the gravel chamber 6 and the sediment chamber orifice 16 in the lower right part of the sediment chamber 1, and the gravel migration and accumulation process during the gravel filling experiment and the process of sediment particles migrating into the production port 67 during the sand control and production enhancement experiment can be clearly observed.

[0040] Thus, through the integrated application of the sediment chamber, the gravel chamber and the transparent observation window, a simulation experiment on the gravel packing process of the hydrate reservoir and a sand control and production enhancement evaluation experiment after gravel packing are carried out, and the migration and accumulation of gravel and reservoir particles during the whole process can be directly observed, realizing the evaluation of the influence of gravel packing processes such as gravel size, sand-carrying ratio, and pumping displacement on the hydrate reservoir and the quantitative evaluation of the sand control and production enhancement effect after gravel packing in the laboratory, which is beneficial to the whole-process evaluation of the gravel packing sand control and production enhancement process and the proposal of optimization suggestions.

[0041] Specifically, the gravel chamber 6 can be designed and manufactured according to the well type in actual production. Only the design schemes of the gravel chambers for two well types, namely the open-hole well and the perforated well, are listed in this embodiment.

[0042] The structure of the gravel chamber for the perforated well is as Figure 3As shown, the gravel chamber kettle body 66 is entirely wrapped by the gravel chamber water-cooled jacket 65, and the gap between the two allows the coolant to circulate therein to control the internal temperature of the gravel chamber. A gravel chamber flange 62 is provided on the left side of the gravel chamber kettle body, which can be used to connect to the sediment chamber 1. A gravel chamber orifice 61 is provided below the left side of the gravel chamber kettle body 66. For the gravel chamber of a perforated well, the gravel chamber orifice 61 is a structure with multiple through-round holes. The gravel chamber orifice 61 communicates with the sediment chamber orifice 16 and serves as a channel for the gravel-carrying fluid to enter the hydrate reservoir during the gravel packing process and for the reservoir particles to migrate into the gravel layer during the sand control and production enhancement experiment. A gravel-carrying fluid inlet 64 and a return water outlet 63 are provided above the gravel chamber 6. The gravel-carrying fluid inlet 64 is used to inject the gravel-carrying fluid into the gravel chamber 6 during the gravel packing process. Its orifice diameter is relatively wide to facilitate the injection of the gravel-carrying fluid with different gravel contents at different pumping rates into the gravel chamber 6. The return water outlet 63 is used to discharge the excess fluid in the gravel-carrying fluid during the gravel packing process. Multiple return water outlets can be provided to meet different displacement requirements, and a replaceable screen should be provided inside to prevent gravel of different sizes from flowing out therefrom. A production port 67 is provided below the gravel chamber 6, which is used as a migration channel for the fluid and the reservoir framework particles during the sand control and production enhancement experiment. The gravel-carrying fluid inlet 64, the return water outlet 63, and the production port 67 are all designed with a switching function to seal when not in use to prevent the pressure leakage in the reactor.

[0043] The structure of the gravel chamber in an open-hole well is as Figure 4As shown, the gravel chamber kettle body 66 is entirely wrapped by the gravel chamber water-cooled jacket 65, and the gap between the two allows the coolant to circulate therein to control the internal temperature of the gravel chamber. A gravel chamber flange 62 is provided on the left side of the gravel chamber kettle body, which can be used to connect with the sediment chamber 1. A gravel chamber orifice 61 is provided below the left side of the gravel chamber kettle body 66. For the open-hole gravel chamber, the gravel chamber orifice 61 is an unobstructed through-hole, and the gravel chamber orifice 61 communicates with the sediment chamber orifice 16, serving as a channel for the gravel-carrying fluid to enter the hydrate reservoir during the gravel packing process and for the reservoir particles to migrate into the gravel layer during the sand control and production enhancement experiment. A gravel-carrying fluid inlet 64 and a return port 63 are provided above the gravel chamber 6. The gravel-carrying fluid inlet 64 is used to inject the gravel-carrying fluid into the gravel chamber 6 during the gravel packing process. Its orifice diameter is relatively wide to facilitate the injection of the gravel-carrying fluid with different gravel contents at different pumping rates into the gravel chamber 6. The return port 63 is used to discharge the excess fluid in the gravel-carrying fluid during the gravel packing process. Multiple return ports can be provided to meet different displacement requirements, and a replaceable screen should be provided inside to prevent gravel of different sizes from flowing out therefrom. The gravel-carrying fluid inlet 64 is connected to a simulated open-hole wellhead below, which is a hollow round tube allowing the gravel-carrying fluid to flow downward therein. Preferably, the gravel-carrying fluid inlet 64 and the simulated open-hole wellhead 68 are connected by threads. A production port 67 is provided below the gravel chamber 6, which is used as a channel for the fluid and the reservoir framework particles to migrate during the sand control and production enhancement experiment. The gravel-carrying fluid inlet 64, the return port 63, and the production port 67 are all designed with a switching function, which acts as a seal when not in use to prevent the pressure leakage in the reactor.

[0044] Through the above structural design and component installation of the reactor, the present invention can achieve the following functions: (1) Real-time control of the temperature and pressure conditions in the reactor to realize the synthesis and decomposition processes of hydrates; (2) Simulate the overlying formation stress of the hydrate reservoir through the axial pressure loading plate to realize the consolidation and compaction of the hydrate reservoir; (3) Simulate the gravel packing process under different gravel packing process parameters. Through the transparent observation window, the gravel migration and accumulation law during the gravel packing process and the monitoring of the hydrate reservoir state can be realized; (4) Simulate the sand control and production enhancement effects of the gravel packing layer under different production conditions and observe the migration status of the reservoir particles in the gravel layer.

[0045] The beneficial effects brought by the technical solution provided by the embodiments of the present invention are as follows: (1) The left kettle wall of the sediment cavity is a detachable structure. After disassembly, the skeleton material can be filled into the sediment cavity, which is convenient for filling the skeleton material, simulating hydrate reservoirs with different composition structures, and synthesizing hydrates, truly reflecting the temperature, pressure, and stress conditions of the hydrate reservoir; (2) A transparent observation window is installed on the front side of the reactor. In addition to monitoring the reservoir temperature, pressure, gravel-carrying fluid flow rate, pressure, produced water, gas production, and sand production data through an external system, the gravel migration and accumulation during the gravel packing process and the reservoir particle migration during the production and exploitation process can be directly observed; (3) The gravel cavity is a detachable and replaceable structure, which can be designed and modified according to different production well types, so as to realize gravel packing and sand control and production enhancement experiments for different well types, further broadening the function range of the reactor; (4) The reactor integrates resistivity and acoustic probes. During the gravel packing and production simulation experiments, the state of the hydrate reservoir during the gravel packing and production process can be monitored through electrical and acoustic data, and the reservoir skeleton parameters can be inverted based on this.

[0046] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and their purpose is to enable ordinary technical personnel in the field to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the essence of the content of the present invention should be covered within the protection scope of the present invention.

Claims

1. A reaction kettle for gravel packing and sand control and production enhancement of a hydrate reservoir, characterized in that include: A sediment chamber for placing hydrate reservoir samples; the sediment chamber is provided with a sediment chamber orifice; An axial pressure loading plate is disposed in the sediment chamber, and applies an external force to the axial pressure loading plate to apply an overlying stress to the sample in the sediment chamber for consolidation and compaction; A gravel chamber is provided with a gravel chamber opening, which is installed opposite to the sediment chamber opening to serve as a channel for gravel-carrying fluid to enter the hydrate reservoir during gravel packing and for reservoir particles to migrate into the gravel layer during sand control and production enhancement experiments; A transparent observation window is provided at a position where the sediment chamber and the gravel chamber are connected and extends toward the sediment chamber and the gravel chamber, so as to observe the migration and accumulation of gravel and reservoir particles during the entire production simulation experiment; A resistivity probe and an acoustic wave probe are provided in the sediment chamber to monitor the resistivity and acoustic wave data evolution of the sample in the sediment chamber during the experiment; A liquid injection port is provided in the sediment chamber for injecting fluid to conduct permeability and production simulation experiments; The gravel chamber is a hollow structure to provide a gravel filling space, and the entire gravel chamber is wrapped by a gravel chamber water-cooling jacket; a gravel-carrying liquid inlet and a water return port are provided at the upper part of the gravel chamber to serve as a gravel-carrying liquid injection channel and a discharge channel for excess fluid; a production port is provided at the lower part of the gravel chamber to be used as a water production, gas production, and sand production channel during the production simulation process.

2. The hydrate reservoir gravel packing and sand control and production enhancement reactor according to claim 1, characterized in that, The outside of the sediment chamber is entirely wrapped by the sediment chamber water cooling jacket, allowing the coolant to flow in the space formed by the inside of the sediment chamber water cooling jacket and the outside of the sediment chamber kettle body to control the overall temperature of the reactor.

3. The hydrate reservoir gravel packing and sand control and production enhancement reactor according to claim 1, characterized in that, An axial pressure liquid inlet is provided on the upper portion of the sediment chamber. Axial pressure liquid is injected into the space formed by the axial pressure loading plate and the sediment chamber to increase the pressure, thereby applying an overlying stress to the sample in the sediment chamber to consolidate and compact it.

4. The hydrate reservoir gravel packing and sand control and production enhancement reactor according to claim 1, characterized in that A temperature sensor and a pressure sensor are also provided in the sediment chamber to monitor the temperature and pressure data of the hydrate reservoir during the experiment.

5. The hydrate reservoir gravel packing and sand control and production enhancement reactor according to claim 1, characterized in that, The sediment chamber and the gravel chamber are connected via a flange, and a sealing ring is provided on the flange.

6. The hydrate reservoir gravel packing and sand control and production enhancement reactor according to claim 1, wherein, The gravel cavity is a perforated well gravel cavity or an open hole well gravel cavity; The gravel cavity opening of the perforated well gravel cavity is a structure with multiple penetrating circular holes; The gravel cavity opening of the open hole gravel cavity is an unobstructed through hole. The lower part of the gravel-carrying fluid inlet is threadedly connected to simulate the open hole well head and is a hollow round tube serving as a channel for the gravel-carrying fluid to enter.

7. The hydrate reservoir gravel packing and sand control and production enhancement reactor according to claim 1, characterized in that, The left side kettle wall of the sediment chamber is a detachable structure, and after being disassembled, the skeleton material is filled into the sediment chamber.

Images