Hidrológiai Közlöny 1942 (22. évfolyam)

Szakosztályi ügyek

Part played by water in Oil production 473 permeability of the formation and the viscosity of the oil. Under favorable circumstances the encroachment of water might proceed at such a rate as will just then make up for the decrease brought about by production in the pressure and this in actual practice is identical with the pressure's remaining unchanged and this in turn will result in a maximum production by flowing. Should production progress at a high rate then water will fail to maintain the formation pressure at the original level. An ideal production in case of water drive would be to lift only so much crude at all times as will correspond to a decrease in pressure made up by the encroaching water. In case of water at the bottom of the basin this would work theoretically, but practically only in case when such production were economically sufficient. Where, therefore, more must be produced than the quantity corresponding to the principle described above, there can be no question of the effect by water drive. Between the ideal production with water drive and that without it any transitional stage is possible. There will be such instances when a portion of decrease in pressure brought about by the oil and gas produced will be made good as far as lower permeability and lower porosity shall permit by the water drive, while the balance of such decrease shall be taken care of by gas repressuring. (This latter-mentioned means will be the case in the Budafapuszta and Lovászi Fields, while in respect of Hahót there are no sufficient data as yet, but signs appear to indicate that in that Field production shall proceed by a regular water drive.) The capacity of water to drive, under suitable conditions, crude before itself is being availed of in America in a manner different from the technical one just mentioned. In the U. S. A., especially in Pennsylvania in a number of fields abandoned long time ago water is being let into centrally located holes. Such wafer drives the crude still remainning within the porous formations towards the adjoining wells and thru these it will reach the surface. This process is called in American Literature „Water Flooding" However, in the opinion of the writer this could better be called „water injection". However, this method could be applied only in wells, respectively, fields where porosity and permeability are relatively high. Water thus injected spreads only very slowly and this is highly desirable as should this spreading proceed at a high rate, then water would be reaching the adjoining well without carrying along any crude. This can be experienced also when production progresses by water drive at a high rate. In case of producing by water flooding much care should be taken in the selection of water as~ to its quality. Should such water contain mineral salt to an excess, that is, should it be hard, spreading will for