Preliminary study of the interaction between backfill body and surrounding rock salt mass

2012 ◽  
Author(s):  
Y Xu ◽  
C Yang ◽  
Y Li ◽  
Y Guo ◽  
W Ji
Keyword(s):  
Rock Salt ◽  
Surrounding Rock ◽  
Salt Mass ◽  
Preliminary Study

Rock salt mass in the Paleoproterozoic sequence of the Onega trough in Karelia (from the Onega parametric well data)

2010 ◽  
Vol 435 (1) ◽  
pp. 1483-1486 ◽  
Author(s):  
A. F. Morozov ◽  
B. N. Khakhaev ◽  
O. V. Petrov ◽  
V. I. Gorbachev ◽  
G. V. Tarkhanov ◽  
...  
Keyword(s):  
Rock Salt ◽  
Salt Mass ◽  
Well Data

scholarly journals Pilot plant tests to demonstrate the functionality of sealing elements made of salt cut bricks

2021 ◽  
Vol 1 ◽  
pp. 117-119
Author(s):  
Uwe Düsterloh ◽  
Svetlana Lerche ◽  
Juan Zhao
Keyword(s):  
Rock Mass ◽  
Rock Salt ◽  
Salt Solution ◽  
Pilot Plant ◽  
Research Work ◽  
Surrounding Rock ◽  
Bonding System ◽  
Joint Volume ◽  
Sealing Elements

Abstract. The long-term safe containment of high-level radioactive waste in a repository in rock salt is ensured if the geological barriers in conjunction with the geotechnical barriers are permanently impermeable to fluids. As such, an essential factor in underground disposal is to confirm that the interfaces between the biosphere and the lithosphere, i.e., shafts, boreholes, and galleries, created during the excavation of underground cavities can be sufficiently tightly sealed. An essential element of the sealing system required to this end is shaft closure. All shaft closure concepts developed thus far include sealing and supporting elements in repository shafts, but differ in the arrangement of these structural elements and the materials used. The materials currently proposed and planned for the construction of the sealing elements include: clay/bentonite, asphalt/bitumen, crushed salt, and salt/sorel cement. In addition to the materials mentioned above, a research project funded by the German Federal Ministry for Economic Affairs and Energy (Bundesministerium für Wirtschaft und Energie, BMWi) is investigating the possibility of integrating a layer of salt cut bricks several decameters to 100 m thick into the shaft closure system as a sealing element that provides the option of allowing the geological barrier to heal in the long term. Like the surrounding rock mass, the salt cut bricks are made of natural rock salt. According to this plan, the profile of the bricks is designed to minimize joint volume as far as possible by cutting them to match the geometry of the shaft. The joints between the salt cut bricks can either be filled with, for example, a supersaturated salt solution, Magnesium building materials, molten salt, crushed salt, etc., or directly brought into contact by wetting the surface of the salt cut bricks. Once the salt solution has hardened (cooling of the solution, evaporation of the mixing water), only the pore space in the crushed-salt joint sealant filled with salt solution or air, or the joint volume resulting from the mismatch between individual rock salt bricks are susceptible to a reaction. This means that the sealing element consisting of salt cut bricks develops early supporting pressure against the creeping rock salt of the rock mass compared to crushed salt, has a low initial porosity and already shows a strong sealing effect in the short term (regression of the loosened zone). One can also assume that cohesive bonding between the surrounding rock and the sealing element can already be achieved by introducing the joint filling or by wetting the contact surfaces of the salt cut bricks (no or reduced separation planes in the contact zone). Essential prerequisites for the investigation of the geomechanical-geohydraulic effectiveness of a sealing element made of salt cut bricks included the development and construction of a pilot plant to analyze the mechanical and hydraulic material properties of the bonding system comprising salt cut bricks and joint sealing (FKZ 02E11223, FKZ 02E11425), as well as preliminary investigations on the production of salt cut bricks and joint sealant (→ cutting technique/processing of salt cut bricks; maufacture/workability of jointing material) and on the spatial arrangement of the salt cut bricks (→ avoidance of continuous axial joints in the bonding system, Fig. 1). The presentation includes the results of the research work on the development, construction and commissioning of the pilot plant, as well as the first successful test results demonstrating the functionality of sealing elements made of salt cut bricks.

Rock Long-Term Strength Parameters Determination of a Salt Cavern Gas Storage

2013 ◽  
Vol 353-356 ◽  
pp. 1685-1688
Author(s):  
Li Na Ran ◽  
Hua Bin Zhang ◽  
Zhi Yin Wang
Keyword(s):  
Mechanical Properties ◽  
Rock Salt ◽  
Gas Storage ◽  
Surrounding Rock ◽  
Creep Process ◽  
Term Strength ◽  
Salt Cavern ◽  
Study Results ◽  
Salt Cavern Gas Storage

In order to determine the long-term mechanical properties of surrounding rock of salt cavern gas storage, long tri-axial creep test studies on rock salt of the field were carried out. Based on the test data, long-term strength of rock salt was determined, and comparatively analysis was conducted combined with of the instantaneous test. The study results show that: Considering the axial strain, radial strain and volumetric strain to determine the long-term strength of rock salt can ensure reliability of the results. Under the same condition, the less salt content, the value of long-term strength is higher. Tri-axial creep process has a different effect degree between cohesion and internal friction angle; it is more sensitive to cohesion. The strain limit should be considered for the stability analysis of multi-bedded salt cavern gas storage construction and pay more attention about the mechanical properties of the interlayer parts. The study results provide references for researching the surrounding rock long-term mechanical properties of salt cavern gas storage.

scholarly journals Microscopic Pore Structure of Surrounding Rock for Underground Strategic Petroleum Reserve (SPR) Caverns in Bedded Rock Salt

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1565 ◽  
Author(s):  
Nan Zhang ◽  
Wei Liu ◽  
Yun Zhang ◽  
Pengfei Shan ◽  
Xilin Shi
Keyword(s):  
Crude Oil ◽  
Pore Structure ◽  
Rock Salt ◽  
Surrounding Rock ◽  
Self Healing ◽  
Rock Interaction ◽  
Salt Cavern ◽  
Term Operation ◽  
Strategic Petroleum Reserve ◽  
Salt Caverns

Using salt caverns for an underground strategic petroleum reserve (SPR) is considered as an ideal approach due to the excellent characteristics of low porosity, low permeability, self-healing of damage, and strong plastic deformation ability of rock salt. Salt deposits in China are mostly layered rock salt structures, with the characteristics of many interlayers, bringing great challenges for the construction of SPR facilities. Studying the microscopic pore characteristics of the rock surrounding SPR salt caverns in different environments (with brine and crude oil erosion) is necessary because the essence of mechanical and permeability characteristics is the macroscopic embodiment of the microscopic pore structure. In this paper, XRD tests and SEM tests are carried out to determine the physical properties of storage media and surrounding rock. Gas adsorption tests and mercury intrusion tests are carried out to analyze the microscopic pore structure, specific surface area variation and total aperture distribution characteristics of SPR salt cavern host rock. Results show that: (1) Large numbers of cores in interlayer and caprock may provide favorable channels for the leakage of high-pressure crude oil and brine. (2) The blockage of pores by macromolecular organic matter (colloid and asphaltene) in crude oil will not significantly change the structural characteristics of the rock skeleton, which is beneficial to the long-term operation of the SPR salt cavern. (3) The water–rock interaction will bring obvious changes in the micro-pore structure of rock and increase the leakage risk of the storage medium. The results can provide theoretical bases and methods for the tightness analysis of China’s first underground SPR salt cavern.

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