Effect of Certain Micro-organisms on the Injection of Water into Sand

Abstract

Abstract This paper describes briefly some of the common micro-organisms that occurin waters obtained from tanks in the Luling and east Texas oil fields;discusses in some detail the effect of the organisms on the chemical content ofthe waters; describes the bioproducts and precipitates resulting from thegrowth of bacteria and algae; and illustrates by means of experiments theeffect of these organisms and their precipitates on the permeability of oilsands into which contaminated water is introduced. The experiments anddiscussion are designed with special reference to waterflooding andwater-disposal problems. Early Work on Micro-Organisms in Oil-Field Waters It has long been known that microorganisms are present in oil-field waters.Rogers, Bastin, Gahl and Anderson Ginsburg-Karagitscheva, Ginter, and Bushnelland Haas have pointed out their presence and possible chemical effects onoil-field waters. Sanders has found them in oil and Klinkenberg has mentionedthe possible effect of bacteria on the flow of water through sand. However, very little has been published by petroleum engineers on the quantitativeeffect of micro-organisms on the permeability of oil-field fluids or on methodsof counteracting harmful chemical effects of oil-field bacteria or on methodsof sterilizing and purifying oil-field waters on a large scale. Mostpublications on the microorganisms of springs and ponds are by biologists andwritten from a biological point of view, and they do not deal particularly withoil-field waters. Description of Micro-Organisms Four types of organisms are present in oil-field waters and appear to play aprincipal part in producing harmful precipitates; that is, iron bacteria, sulphur-oxidizing bacteria, sulphate-reducing bacteria, and blue-greenalgae. The iron bacteria were discovered by Ehrenberg in 1836. Many kinds occur.One of the commonest forms in Texas waters is Gallionella. This form is longand ribbonlike or tapelike, and under the microscope it looks like evenlytwisted, tiny, spiral threads or bands (Fig. I). The spiral bands may occur assingle filaments or may be twisted together. The filaments are covered withferric hydroxide secreted by the bacterial cell (Fig. 2). The terminal cellstructure, only 1.2 by 0.5 microns in size, consists of two coccuslike cells,0.3 by 0.5 microns in size. T.P. 1678