CN-120061921-B - Method and system for testing connectivity of sediment at bottom of salt mine brine-collecting old storage warehouse cavity

CN120061921BCN 120061921 BCN120061921 BCN 120061921BCN-120061921-B

Abstract

The invention provides a salt mine brine-extracting old reservoir cavity bottom sediment connectivity test method and a test system, wherein the test system comprises a reservoir, sediment exists at the reservoir cavity bottom, an injection well communicated with the reservoir cavity top, an injection flow and pressure measuring mechanism is connected to the injection well mouth, the test well is located in a sediment area at the reservoir cavity bottom and is communicated with the reservoir cavity bottom, a discharge flow and pressure measuring mechanism is connected to the test well mouth, the test method comprises the steps that test liquid injected into the reservoir by the injection well flows into the test well after flowing through sediment at the reservoir cavity bottom and is discharged through the test well, the injection flow and pressure measuring mechanism measures flow and pressure of an injection end, and the discharge flow and pressure measuring mechanism measures flow and pressure of a discharge end, so that the technical problem that sediment characteristics at the reservoir cavity bottom are difficult to test is solved.

Inventors

Guan Yueyang
ZHANG YUDA
HE QI
QU SHUAI
YUAN GUANGJIE
XIA YAN
BAN FANSHENG
LIU TIANEN
LU LIJUN
ZHUANG XIAOQIAN
FU PAN
DIAO HAOYU

Assignees

中国石油天然气集团有限公司
中国石油集团工程技术研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20231130

Claims (9)

1. A method for testing connectivity of sediment at the bottom of a salt mine brine-collecting old storage warehouse cavity is characterized in that a system for testing connectivity of sediment at the bottom of the salt mine brine-collecting old storage warehouse cavity is adopted; the sediment connectivity test system of salt mine brine-collecting old reservoir cavity bottom comprises: A reservoir with sediment at the bottom of the reservoir cavity; An injection well communicated with the top of the reservoir, wherein the wellhead of the injection well is connected with an injection flow and pressure measuring mechanism; the communication position of the test well and the storage warehouse is positioned in a sediment area at the bottom of the storage warehouse, and a wellhead of the test well is connected with a discharge flow and pressure measuring mechanism; The method for testing the connectivity of the sediment at the bottom of the brine mining old storage chamber comprises the following steps: The test liquid injected into the reservoir by the injection well flows into the test well after flowing through sediment at the bottom of the cavity of the reservoir and is discharged through the test well; The injection flow and pressure measuring mechanism measures the flow and pressure of the injection end, and the discharge flow and pressure measuring mechanism measures the flow and pressure of the discharge end; the method for testing connectivity of sediment at the bottom of the brine mining old reservoir cavity comprises a mobility test, wherein the mobility test comprises the following steps: The injection well continuously injects the test liquid into the storage warehouse at a first flow, and after the flow and the pressure of the discharge end are stable, the flow and the pressure of the discharge end and the pressure of the injection end are measured and recorded; The method for testing the connectivity of the sediment at the bottom of the brine mining old reservoir cavity comprises a maximum discharge flow test, wherein the maximum discharge flow test comprises the following steps: and closing the test well, injecting the test liquid into the reservoir through the injection well until the pressure of the injection end is the first pressure, stopping injecting the test liquid by the injection well, closing the injection well, opening the test well, and measuring and recording the flow and the pressure of the discharge end.
2. The method for testing the connectivity of sediment at the bottom of the brine mining old storage chamber according to claim 1, which is characterized in that, The flowability test comprises: after the test of the first flow is completed, the flow value is gradually increased on the basis of the first flow, and the flow and the pressure of the discharge end and the pressure of the injection end after the stabilization are respectively measured and recorded.
3. The method for testing the connectivity of sediment at the bottom of the brine mining old storage chamber according to claim 1, which is characterized in that, The maximum discharge flow test includes: After the test of the first pressure is completed, the injection well continues to inject the test liquid into the storage warehouse, the pressure value is gradually increased to the upper limit pressure of the cavity of the storage warehouse on the basis of the first pressure in a sectional boosting mode, and the flow and the pressure of the discharge end after the injection well is closed and the test well is opened are respectively measured and recorded.
4. The method for testing the connectivity of sediment at the bottom of the brine mining old storage chamber according to claim 1, which is characterized in that, The maximum discharge flow test is performed after the flowability test.
5. The method for testing the connectivity of sediment at the bottom of the brine mining old storage chamber according to claim 4, which is characterized in that, And calculating the friction resistance of the test well pipe column, the friction resistance of the injection well pipe column and the sediment friction according to the flow and the pressure of the injection end and the flow and the pressure of the discharge end.
6. The method for testing the connectivity of sediment at the bottom of the brine mining old storage chamber according to claim 1, which is characterized in that, The salt mine brine-extraction old reservoir cavity bottom sediment connectivity testing system comprises a first liquid storage tank, a water injection pump truck and a first valve which are sequentially connected in series, wherein the first valve is connected with the injection well through an injection main pipeline.
7. The method for testing the connectivity of sediment at the bottom of the brine mining old storage chamber according to claim 6, which is characterized in that, The sediment connectivity test system at the bottom of the brine mining old reservoir cavity comprises a second liquid storage tank and a second valve which are sequentially connected in series, and the second valve is connected with the test well through a main discharge pipeline.
8. The method for testing the connectivity of sediment at the bottom of the brine mining old storage chamber according to claim 7, wherein, The first liquid storage tank is connected with the second liquid storage tank, and the test liquid in the second liquid storage tank can flow into the first liquid storage tank to realize circulation.
9. A salt mine brine-collecting old storage chamber bottom sediment connectivity test system, which is characterized by being applied to the salt mine brine-collecting old storage chamber bottom sediment connectivity test method according to any one of claims 1-8, wherein the salt mine brine-collecting old storage chamber bottom sediment connectivity test system comprises: A reservoir with sediment at the bottom of the reservoir cavity; An injection well communicated with the top of the reservoir, wherein the wellhead of the injection well is connected with an injection flow and pressure measuring mechanism; a test well communicated with the side part or the bottom of the storage warehouse, wherein a wellhead of the test well is connected with a discharge flow and pressure measuring mechanism; The injection flow and pressure measuring mechanism is used for measuring the flow and pressure of an injection end, and the discharge flow and pressure measuring mechanism is used for measuring the flow and pressure of a discharge end.

Description

Method and system for testing connectivity of sediment at bottom of salt mine brine-collecting old storage warehouse cavity Technical Field The invention relates to the technical field of construction processes of gas storage libraries and energy storage libraries, in particular to a method and a system for testing connectivity of sediment at the bottom of a cavity of a brine-collecting old storage library of salt mine. Background The salt cavern gas storage cavity is formed by drilling to reach a cavity forming target layer, and fresh water is injected into a salt layer from the ground through a pipe column in a mechanical pumping mode, so that the salt minerals are easily dissolved in water, and are eroded into a cavity with a certain shape and volume in the salt layer to be used for storing gas, such as natural gas and the like. An energy storage reservoir may also be manufactured for storing the gas under pressure, using a method similar to that used for gas storage. Sediment usually exists at the bottom of the gas storage and the energy storage, and the sediment is a block-shaped and particle-shaped insoluble substance generated in the cavity dissolving process and is piled up to form loose piled up substances. The gas storage or energy storage warehouse construction areas of some blocks are affected by geological conditions, so that the rock salt taste of the stratum to which the gas storage warehouse or energy storage warehouse construction areas belong is poor, and the insoluble content is high. The main sources of the sediment are as follows (1) in the cavity making process, most indissolvable substances in the salt layer are released along with the dissolution of sodium chloride in the salt layer, so as to form insoluble substances with different particle sizes. By performing a granulometry on the brine extracted on site, only a very small fraction of the insoluble matter of fine particles (particle size <1 mm) is returned to the ground along with the brine through the brine discharge column. Most of the remaining insoluble particles settle under the action of self gravity and are gradually accumulated at the bottom of the cavity of the gas storage warehouse or the energy storage warehouse to form sediment. (2) The salt mine of the layered salt rock stratum has the characteristic that more interlayers (such as anhydrite layers, mud layers, glauber salt layers and the like) and soluble salt layers and interlayers are very typical, and part of interlayers are difficult to dissolve, so that in the cavity making process, the insoluble interlayers in the cavity making section are exposed along with the dissolution of the soluble salt layers, the interlayers are in a suspended state and are soaked in unsaturated brine for a long time along with the dissolution of the salt layers on the upper parts of the insoluble interlayers, the soluble components in the interlayers are quickly dissolved to form a large number of cracks in the interlayers, meanwhile, the clay interlayers contain relatively more clay minerals, the clay minerals swell in water, so that more microcrack cracks are generated in the interlayers, the brine enters the interlayers along the cracks, more soluble matters and the clay cement are softened and dissolved, and the cracks in the interlayers are further increased. In the process of water dissolution cavity making, a large amount of insoluble matters generated by rock salt dissolution are accumulated at the bottom of the cavity. The generation and accumulation of insoluble matters restrict the construction of the salt cavern gas storage and the energy storage in many aspects, and influence the gas storage effect of the gas storage and the energy storage effect of the energy storage while affecting the construction progress of the cavity. In the areas with lower salt rock taste in the salt cavern gas storage/energy storage warehouse building stratum condition, more insoluble matters are generated, so that the cavity forming rate of salt caverns is low, and the cost of single gas storage space is high. Meanwhile, insoluble matters accumulated at the bottom of the cavity are often in different forms such as particles or blocks, the depth of the cavity in the ground is large, the space of the cavity is large, and the sediment at the bottom of the cavity is sampled, so that the sediment at the bottom of the cavity is difficult to test due to the great difficulty in the technical process. Disclosure of Invention The invention aims to provide a method and a system for testing connectivity of sediment at the bottom of a brine-mining old storage cavity of salt mine, so as to solve the technical problem that sediment characteristics at the bottom of the storage cavity are difficult to test. The above object of the present invention can be achieved by the following technical solutions: The invention provides a method for testing connectivity of sediment at the bottom of a salt mine brine-collectin