As a non-renewable rare industrial gas resource,the decreasing production of helium has stimulated the demand for large-scale storage.Dewar tanks,storage tanks and other liquid helium storage methods are difficult to ...As a non-renewable rare industrial gas resource,the decreasing production of helium has stimulated the demand for large-scale storage.Dewar tanks,storage tanks and other liquid helium storage methods are difficult to meet the needs of largescale and long-term storage.Salt caverns have been widely used in gas energy storage due to their low permeability,which has been proven by decades of stable operation of natural gas storage.However,helium has higher permeability under the same storage conditions,and the feasibility of using rock salt for helium storage has not yet been evaluated by mature theories and standards.In addition,an overlooked fact is that the permeability characteristics of rock salt and micro-permeable layers(MPL)are very different,and MPL can provide leakage channels for high-pressure helium.In this paper,a seepage movement model of small molecule gas in MPL is established.Its calculative accuracy and engineering applicability are verified by the seepage test results.The MPL has crystal structure,which makes the permeability change with different confining pressure and gas injection pressure.The change of permeability is caused by the residual brine in the crystal void.The compaction and the increase of flow velocity of salt rock crystal void increase the viscous resistance and decrease the flow velocity.The permeability of nitrogen and helium in the MPL is different,but the difference decreases at high confining pressure and high injection pressure.In deep salt formations with plateau potential stress,the difference of surrounding rock leakage characteristics between helium and natural gas is smaller,and the expected leakage amount of helium is lower.The paper proposes a numerical calculation model suitable for predicting leaks in salt cavern helium storage facilities with known faults and structural planes,completing the assessment of helium leakage in salt caverns considering the gas physical properties,injection and production conditions,operating pressure,and in-situ stress of surrounding rocks.The above achievements can provide technical references for early-stage leakage prediction and parameter optimization in helium storage salt cavern engineering.展开更多
Increasing the allowable gas pressure of underground gas storage(UGS) is one of the most effective methods to increase its working gas capacity. In this context, hydraulic fracturing tests are implemented on the targe...Increasing the allowable gas pressure of underground gas storage(UGS) is one of the most effective methods to increase its working gas capacity. In this context, hydraulic fracturing tests are implemented on the target formation for the UGS construction of Jintan salt caverns, China, in order to obtain the minimum principal in situ stress and the fracture breakdown pressure. Based on the test results, the maximum allowable gas pressure of the Jintan UGS salt cavern is calibrated. To determine the maximum allowable gas pressure, KING-1 and KING-2 caverns are used as examples. A three-dimensional(3D)geomechanical model is established based on the sonar data of the two caverns with respect to the features of the target formation. New criteria for evaluating gas penetration failure and gas seepage are proposed. Results show that the maximum allowable gas pressure of the Jintan UGS salt cavern can be increased from 17 MPa to 18 MPa(i.e. a gradient of about 18 k Pa/m at the casing shoe depth). Based on numerical results, a field test with increasing maximum gas pressure to 18 MPa has been carried out in KING-1 cavern. Microseismic monitoring has been conducted during the test to evaluate the safety of the rock mass around the cavern. Field monitoring data show that KING-1 cavern is safe globally when the maximum gas pressure is increased from 17 MPa to 18 MPa. This shows that the geomechanical model and criteria proposed in this context for evaluating the maximum allowable gas pressure are reliable.展开更多
1.Definition of deep underground energy storage Deep underground energy storage(DUES)is an important strategic practice for ensuring China’s energy supply,its national defense,and the realization of China’s strategi...1.Definition of deep underground energy storage Deep underground energy storage(DUES)is an important strategic practice for ensuring China’s energy supply,its national defense,and the realization of China’s strategic goals of achieving a carbon peak and carbon neutrality(CPCN).In 2021,China’s oil and natural gas consumption reached 712 million tonnes and 372.6 billion cubic meters,respectively,while its external dependence reached about 72%and 45%.China’s reserves only met about 30%of the requirements for a safe supply and peak shaving.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42072307,52404066)the Hubei Province Outstanding Youth Fund(Grant No.2021CFA095)+1 种基金the Natural Science Foundation of Wuhan(Grant Nos.2024040701010062,2024040801020255)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDC10020300)。
文摘As a non-renewable rare industrial gas resource,the decreasing production of helium has stimulated the demand for large-scale storage.Dewar tanks,storage tanks and other liquid helium storage methods are difficult to meet the needs of largescale and long-term storage.Salt caverns have been widely used in gas energy storage due to their low permeability,which has been proven by decades of stable operation of natural gas storage.However,helium has higher permeability under the same storage conditions,and the feasibility of using rock salt for helium storage has not yet been evaluated by mature theories and standards.In addition,an overlooked fact is that the permeability characteristics of rock salt and micro-permeable layers(MPL)are very different,and MPL can provide leakage channels for high-pressure helium.In this paper,a seepage movement model of small molecule gas in MPL is established.Its calculative accuracy and engineering applicability are verified by the seepage test results.The MPL has crystal structure,which makes the permeability change with different confining pressure and gas injection pressure.The change of permeability is caused by the residual brine in the crystal void.The compaction and the increase of flow velocity of salt rock crystal void increase the viscous resistance and decrease the flow velocity.The permeability of nitrogen and helium in the MPL is different,but the difference decreases at high confining pressure and high injection pressure.In deep salt formations with plateau potential stress,the difference of surrounding rock leakage characteristics between helium and natural gas is smaller,and the expected leakage amount of helium is lower.The paper proposes a numerical calculation model suitable for predicting leaks in salt cavern helium storage facilities with known faults and structural planes,completing the assessment of helium leakage in salt caverns considering the gas physical properties,injection and production conditions,operating pressure,and in-situ stress of surrounding rocks.The above achievements can provide technical references for early-stage leakage prediction and parameter optimization in helium storage salt cavern engineering.
基金financial supports of National Natural Science Foundation of China (Grant No. 41502296)Youth Innovation Promotion Association, Chinese Academy of Sciences (CAS) (Grant No. 2016296)+1 种基金National Natural Science Foundation of China Innovative Research Team (Grant No. 51621006)Natural Science Foundation for Innovation Group of Hubei Province, China (Grant No. 2016CFA014)
文摘Increasing the allowable gas pressure of underground gas storage(UGS) is one of the most effective methods to increase its working gas capacity. In this context, hydraulic fracturing tests are implemented on the target formation for the UGS construction of Jintan salt caverns, China, in order to obtain the minimum principal in situ stress and the fracture breakdown pressure. Based on the test results, the maximum allowable gas pressure of the Jintan UGS salt cavern is calibrated. To determine the maximum allowable gas pressure, KING-1 and KING-2 caverns are used as examples. A three-dimensional(3D)geomechanical model is established based on the sonar data of the two caverns with respect to the features of the target formation. New criteria for evaluating gas penetration failure and gas seepage are proposed. Results show that the maximum allowable gas pressure of the Jintan UGS salt cavern can be increased from 17 MPa to 18 MPa(i.e. a gradient of about 18 k Pa/m at the casing shoe depth). Based on numerical results, a field test with increasing maximum gas pressure to 18 MPa has been carried out in KING-1 cavern. Microseismic monitoring has been conducted during the test to evaluate the safety of the rock mass around the cavern. Field monitoring data show that KING-1 cavern is safe globally when the maximum gas pressure is increased from 17 MPa to 18 MPa. This shows that the geomechanical model and criteria proposed in this context for evaluating the maximum allowable gas pressure are reliable.
基金financial support of National Natural Science Foundation of China(42072307)Hubei Province Outstanding Youth Fund(2021CFA095)+1 种基金Strategic Research and Consulting Project of Chinese Academy of Engineering(HB2022B08)Strategic Priority Research Program of the Chinese Academy of Sciences(XDPB21 and XDC10020300)。
基金financial support from the National Natural Science Foundation of China(42072307)Hubei Province Outstanding Youth Fund(2021CFA095)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDC10020300)。
文摘1.Definition of deep underground energy storage Deep underground energy storage(DUES)is an important strategic practice for ensuring China’s energy supply,its national defense,and the realization of China’s strategic goals of achieving a carbon peak and carbon neutrality(CPCN).In 2021,China’s oil and natural gas consumption reached 712 million tonnes and 372.6 billion cubic meters,respectively,while its external dependence reached about 72%and 45%.China’s reserves only met about 30%of the requirements for a safe supply and peak shaving.
