Abstract: A clay-free wellbore fluid having thixotropic properties, good surface handling characteristics and excellent subterranean characteristics such as particle handling gel strength, and low water loss has been devised by the combination of a heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates, modified starch and MgO. In some situations a salt of lignosulfonate is added to maintain the desirable properties of the wellbore fluid.
Abstract: Starch derivatives have been found to be effective water loss control additives in clay-free wellbore fluids. Generally the starch derivatives are starch ethers, starch esters and partially oxidized starch. The starch derivatives can be added to the wellbore fluid in either the gelatinized or ungelatinized form. Unlike ordinary unmodified starch, the starch derivatives are soluble in acids, stable in the presence of calcium chloride, do not undergo retrogradation and are stable at higher temperatures than unmodified starch.
Abstract: Starch derivatives have been found to be effective water loss control additives in clay-free wellbore fluids. Generally the starch derivatives are starch ethers, starch esters and partially oxidized starch. The starch derivatives can be added to the wellbore fluid in either the gelatinized or ungelatinized form. Unlike ordinary unmodified starch, the starch derivatives are soluble in acids, stable in the presence of calcium chloride, do not undergo retrogradation and are stable at higher temperatures than unmodified starch.
Abstract: Starch derivatives have been found to be effective water loss control additives in clay-free wellbore fluids. Generally the starch derivatives are starch ethers, starch esters and partially oxidized starch. The starch derivatives can be added to the wellbore fluid in either the gelatinized or ungelatinized form. Unlike ordinary unmodified starch, the starch derivatives are soluble in acids, stable in the presence of calcium chloride, do not undergo retrogradation and are stable at higher temperatures than unmodified starch.
Abstract: A clay-free wellbore fluid having thixotropic properties, good surface handling characteristics and excellent subterranean characteristics such as particle handling gel strength, and low water loss has been devised by the combination of a heteropolysaccharide prepared by the action of bacteria of the genus Xanthomonas on carbohydrates, modified starch and MgO. In some situations a salt of lignosulfonate is added to maintain the desirable properties of the wellbore fluid.