METHOD FOR DEVELOPING EXTRA-VISCOUS OIL DEPOSITS (OPTIONS) Russian patent published in 2023 - IPC E21B43/24 

FIELD: oil industry.

SUBSTANCE: method for the development of extra-viscous oil. Method for developing a superviscous oil deposit includes the construction of appraisal vertical wells, as well as pairs of horizontal production and injection wells arranged one above the other. The coolant is injected through injection wells with heating of the productive formation and creation of a steam chamber. Product is sampled. Appraisal vertical wells are constructed on a square grid with a distance between wells of 250 m in plane. Core sampling and geophysical studies of appraisal vertical wells are carried out. A single geological model of the reservoir is built and data is obtained on the distribution of porosity and permeability coefficients, oil-saturated thicknesses. A structural map of oil-saturated thicknesses of the productive formation is built. The contour of the productive formation is allocated. With an L-shaped selected contour, two parts of the contour are conditionally distinguished with a coaxial direction of the strike of the productive formation. Horizontal production wells are designed with a length of the horizontal part of at least 600 m, with a mutually perpendicular location of shafts in two parts of the circuit. Adjacent horizontal production wells are designed at a distance of 100 m. The horizontal production well closest to the perpendicularly located horizontal production wells is designed at a distance of no more than 75 m from the bottomholes of equidistant perpendicularly located horizontal production wells. A section is allocated limited by 50 m to the axis of the horizontal production well, which is closer in plane than the other ones to the perpendicularly located horizontal production wells. The weighted average coefficients of porosity and permeability are determined in the selected area. Horizontal injection wells are designed, located 5 m above and parallel to horizontal production wells. Two tubing strings are placed in horizontal injection wells. The end of the string of smaller diameter is located at the beginning of the horizontal wellbore; the end of the string of larger diameter is located in the area with oil saturation of more than 60%. For steam injection in a horizontal production well, one or two tubing strings are placed with its end or ends horizontally offset relative to the ends of the horizontal injection well tubing by at least 10 m. The coolant is injected through horizontal production and injection wells. The wells are shut for soaking for thermocapillary impregnation. A fiber optic cable and an electric centrifugal pump run on a tubing string are placed in horizontal production wells. After creating a permeable zone, steam is supplied only to horizontal injection wells.

EFFECT: increased oil recovery by increasing the coverage of steam exposure, reduced losses for steam injection, uniform steam exposure, increased productivity of pumping equipment by reducing the risk of overheating.

2 cl, 4 dwg