Study On Gelled Foam As In-depth Profile Control And Oil Displacement Agent For High Temperature Reservoir In Zhao’ao Oilfield

Aiming at the characteristics of the high temperature reservoir of Anpeng area inZhao’ao oilfield and the problems of water channeling in the development process,temperature resistance profile control agents of gelled foam are developed. In addition, theinfluencing factor of the gelled foam stability and profile control and displacement property isevaluated, profile control mechanism is analysed, contruction parameter is optimized, and thefield test is carried out.Based on the foam property for determining, the gelled foam is optimized by Ross-milesmethods and the GSC methods, and the appropriate ingredient of gelled foam is that the massfraction of comblike polymers0.25%~0.35%, the resin prepolymer is0.6%~0.8%, and theHN-1foaming agent is0.2%~0.3%. The foaming volume of gel foam is160mL～175mL,the half-life period is1997s～2299s, and the foam comprehensive value increased largely to329505mL s～367840mL s.It is found that the visco-elastic interfacial film of gel foam is more stable compared tothe ordinary foam by the optical microscope and SEM. The surface tension, viscosity andviscoelasticity of gel foam is even greater than ordinary foam, and grew over crosslinkingtime. However, the foaming ability shrinked and the increased structural strength of gelcaused the better foam stability with the growth of the surface tension, viscosity andviscoelasticity. Consequently, the best value of surface tension, viscosity and viscoelasticity ofgel is existed for the best foam property.It is found that the best injection mode of gel foam is gas-liquid mix injection, the bestgas liquid ratio is1:1, the approviate gas injection rate is0.5mL/min by the core flowexperiment. The plugging performance of gel foam gets better with the growth ofpermeability in the range of certain permeability and the selective plugging performance getsbetter with the growth of permeability contrast. The gel foam could migrate to the deepformation in the condition of Zhao’ao oilfield and enhance the oil recovery by44.6%.It is found that the gel foam has the best profile control property and could increase the oil recovery by42.9%by the visualization physical simulation device. Addition, the profilecontrol and oil displacement function of gel foam is mainly depended on the Jamin effect offoam, the plugging performance of gel, the emulsification of surfactant, the pulling andextrusion of the gel.Based on the laboratory research achievement, six water injection wells are chosen toimplement profile control field tests, and the water injection profile gets improved and theinterlayer contradiction gets relieved after the test. Until September in2012, the production ofoil had increased by494.8t altogether and the production of water had decreased17623m3intotal.