Numerical Simulation Research Of Horizontal Storage Stability During Construction And Operation In Salt Deposit

As an supporting project of West-East gas transmitting project—the construction of storage in salt rock is mainly aiming to meet the demand of an emergency gas supply in the case of pipeline damage or unbalanced adjustment of peak-load due to periodical climate changes.The storage caverns generally build in the deep salt domes in the foreign countries, the majority of storage is vertical. The salt deposits have geological characteristic of thin momolayer thickness and flabbiness interlayer in China. In this way, not only the difficulty and complexity of storage construction has increased, the stability of the storage caverns in the later running will be greatly affected. Based on building the storage caverns in the bedded salt rock deposit by water-soluble duilding cavity, the paper combines the experiment and numerical simulation to preliminary study the construction of horizontal storage caverns in the salt deposits, the result provide a reference on the construction of horizontal storage caverns in the salt deposits.The main results are generalized as follows:(1) This paper describes the currently used widely in Germany the HOU/ LUX model, and a comprehensive system for the derivation of the model described addition MDCF the model and CPOWE model also detailed description.(2) By assuming a model of cross-sectional area of980square meters, the ratio of major to minor axes, respectively1.5:1,2:1,2.5:1,3:1. In accordance with the proportion of such major axis and a minor axis of21.65x14.4,25x12.5,27.95x11.15,30.6x10.2. The caprock thickness of10m,20m,30m,40m. For these types of situations, numerical simulation, to identify the most suitable for the optimization of the terrain on the thickness of the cover of rock salt, the ratio of the length of the shaft, and the minimum internal pressure. The dissolving chamber at the same time for different gas recovery rate, respectively, through the analysis is performed from the maximum inner pressure decreased after the smallest inner pressure volume shrinkage ratio, to perform the analysis to determine the most optimal gas recovery rate.(3) Greisen salt mines terrain full numerical simulation Coulomb mole model built chamber simulation the melting chamber operators process using cpower model, the model has few parameters, can be better the volume shrinkage analog caverns under a variety of working conditions, as well as the distribution of plastic zone around the melting chamber.(4) In the same the ratio of the length of the shaft, the same internal pressure, the different thickness of the layer, the dissolved cavity surrounding the volume of the plastic zone is first decreases and then increases as the thickness of the layer, this is because of the rock salt upper part glauberite-layer, its cohesion and angle of internal friction, tensile strength of rock salt should flac inside the plastic zone damage volume was mainly due to the three decided. Therefore, when the top salt is10meters thick, from the glauberite layer near the plastic zone destroy the very destruction of the plastic zone is mainly due to the distance the distance glauberite decision. The top salt thickness decreases after to from glauberite layer will reduce the destruction will reduce plastic zone. But when the stress due to the depth of the reason will be growing with the increase in the thickness of the top salt, destruction will increase the plastic zone, the plastic zone destruction due to the depth of decision(5) For of greisen the geological conditions in the equivalent section under different capping layer thickness, the ratio of the length of the shaft, different internal pressure, numerical simulation, in the caverns after three years creep around plastic volume, can be drawn the greisen optimization the caprock thickness of30m, the ratio of the length of the cross-sectional shape of the shaft can not be greater than2, internal pressure not less than the minimum operational process4MPa.