Method and apparatus for pumping fluids from bore holes

Abstract

Well pumping method and apparatus by means of which the liquid level and, correspondingly, the hydrostatic pressure, in a bore hole or well casing, is controlled by means of a vertically adjustable sump for receiving liquid from the bore hole or casing before it is pumped to the surface, the sump having therein a pump which is actuated by the liquid level in the sump so that liquid cannot rise in the bore hole or casing above the top or inlet of the sump, as the liquid enters the sump at this point and is pumped to the surface from the sump, the operation being such that the liquid level in the bore hole or casing is controlled by vertically positioning the sump so that the height of the column of liquid in the casing or borehole above the point where liquid is coming from the formation can be maintained at a minimum with consequent increase in the differential hydrostatic pressure between that in the well bore and that in the formation in the direction of the well bore, enabling the maximum rate of liquid entry into the well bore. The sump prevents water from the lower portion of the formation from coming into direct contact with the pump and being pumped directly to the surface to exclude oil from being pumped to the surface. Using the sump, the action of the water is such that the water will rise in the annulus between the outer sump wall and the inner wall of casing or bore hole and pass over the lip and into the sump without impeding the flow of oil from out of the upper portion of the formation, the oil also passing into the sump and also being pumped to the surface together with the water entering the casing or bore hole.