Water-bearing stratum

Van Dam, J., 1967, The Migration of Hydrocarbons in a Water Bearing Stratum In Joint Problems of the Oil and Water Industries (edited by P Hepple), Institute of Petroleum, London. 

The following problem is of special interest. Assume a water-bearing stratum on an impermeable base with the well penetrating into it. When water is pumped, its normal level is reduced. If the pump is stopped for a sufficient length of time, the water level will return to its normal level. Let the height of the normal water level from the impervious layer be hi, and h2 the level after pumping a volume qt, where q is the volume of flow per unit-time, and t the time of pumping. Thfen... 

Deep-well pumps of the bucket type are designed for use on non-flowing wells where the water does not stand within suction distance. Two methods are employed In the plain tube well (Fig. 6) the well pipe with open ends is sunk to the proper depth where a sufficient water-bearing stratum is penetrated. The strainer A is then lowered to bottom of the well and the well pipe drawn back far enough to expose the slotted portion. The working barrel B is then lowered into the gum packer on top of strainer and tapped firmly into place. The top of the well pipe is provided with a tee for discharge connection. The... 

A water-bearing stratum of porous rock, sand, or gravel is called a(n)... 

If geo-electric mapping is required, the electrode spacings are kept constant and the whole set-up is moved along to different locations. In this way a map showing lines of equal resistivity is obtained, e.g., enabling large sand inclusions, the surface of a water-bearing stratum or the undersurface of a raw material deposit to be mapped. 

Coal Face 1031 in Taoyuan Coal Mine mines coal seam No. 10, with burial depth is 327-445 m. Strata in roof and floor of cod seam No. 10 usually are siltstone, fine sandstone or interbedding of siltstone and packsand, which water-bearing feature is weak about 58 m below the floor of coal seam No. 10, there is a stratum of Taiyuan formation limestone (limestone No. 1) of a thickness of 2-3 m, which is one of the major aquifers of mine. 

As a very general rule-of-thumb, deep caissons (say above 10 m) in water bearing ground with sand content above 50% would require careful consideration. The safety of workers should not be compromised and an alternative foundation system should be explored where there is doubt. Alternatively, pre-excavation soil treatment may be instituted. This can be in the form of curtain grouting or jet grouting at the permeable stratum. 

Permeability of the subsoil (aquifers, underlying stratum of the ground water, water-bearing layers)... 

As moisture barriers, slurry walls are most effective when the bottom of the wall is keyed into an impermeable stratum. When used to support structural loads, the bottom should be keyed into rock, or other suitable bearing material. Hanging walls (those not keyed into clay or rock) may be used to buttress the walls of shallow excavations, or for containing contaminents floating on the surface of the water table. 

Sherman mining area is located in north of Shaanxi province. Its west is Mu Us Desert covered with flat aeoUan sand layer-the most significant aquifer and east is the Loess Plateau with serious hydraulic cutting. The stratums, typically from top to bottom, are sand layer (aquifer, mainly distributed in the west), Lishi formation (loess, widespread in the whole area), Baode formation (laterite, widespread in the whole area) and Yanan formation (the major coal-bearing strata). The sand aquifer has suitable permeability coefficient to hold water not to run... 

---