METHOD OF SECONDARY DEVELOPMENT OF HIGH-VISCOSITY OIL FIELD Russian patent published in 1999 - IPC

FIELD: methods of secondary recovery of high-viscosity oil, particularly, methods of heat stimulation of formation. SUBSTANCE: method includes drilling of wells whose bottoms are located on region of underground wells drilled earlier from underground gallery in primary field development by mining method. Injected into these wells is steam and oil is withdrawn. Wells into which steam is injected are drilled from surface. In addition, well is drilled from surface into center of development block. Monitor well is drilled into underground gallery. Monitor well is provided with temperature- sensitive element for monitoring temperature in gallery. Then, steam is injected into wells from surface until sharp rise of temperature in gallery is evidenced. Injection of steam is discontinued and oil is withdraw from said wells until well oil production rate reaches minimal profitable level. Further on, cycles of steam injection and oil withdrawal are repeated. With temperature in underground gallery elevated up to 90 C, water is injected through monitor well. Simultaneously oil is withdrawn through other wells from surface up to maximum possible water encroachment of formation. EFFECT: higher sweep and oil recovery from formation due to secondary development of high-viscosity oil field by steam heat stimulation with maximum use of early drilled underground wells for heating of formation and oil recovery from it and prevented breakthrough of steam into existing mine workings. 6 cl