Patent RU-2708294-C1 (RU)
Title: Method for development of mass-reservoir deposits with high viscous oil
Inventor: TARASKIN EVGENIJ NIKOLAEVICH
IPC: E21B43/24
Filed: 2019-01-11
Granted: 2019-12-05
Abstract: FIELD: oil and gas industry. 
     SUBSTANCE: invention relates to the oil-producing industry. Method for development of mass-reservoir deposits with high-viscosity oil includes extraction of upper zone for delivery of heat carrier and underlying zone for oil extraction by thickness of deposit, drilling rows of vertical production wells, horizontal injection wells and horizontal production wells located below injection wells, pumping heat carrier into injection wells and extraction of oil from production wells. At that, horizontal pressure wells are drilled towards each other in staggered order between rows of vertical wells, horizontal production wells are drilled in the form of gently-ascending perpendicular to horizontal injection wells and are also placed towards each other in staggered order between rows of vertical production wells. "Heels" of all gently-ascending production wells are located at the bottom of the deposit, and "socks" of all gently-ascending production wells are located at the roof of the oil extraction zone. All vertical production wells are perforated throughout the deposit thickness. Areas of approach of these wells are separated along the length of horizontal injection wells with upper halves-"tails" of gently-ascending production wells and perforated intervals of horizontal injection wells outside the approach sections, as well as upper half-"tails" of shafts of all gently-ascending production wells are perforated and heat carrier is pumped to horizontal injection wells. At the initial stage of heat carrier pumping oil is extracted from the gently-ascending and vertical production wells with the same rate, and at break of steam condensate into gently-ascending production wells, rate of oil withdrawal from these wells is limited and rate of oil extraction from vertical production wells is increased, while maintaining the initial rate of oil withdrawal from the deposit. After oil flow rate reduction in gently-ascending production wells below cost-effective level, all perforation intervals are isolated in upper halves-"tails" of gently-ascending production wells and most flooded perforation intervals in lower halves over thickness of vertical production wells deposit, at that, bottom half of shafts of gently-ascending production wells and horizontal injection wells approach sections are perforated, previously unopened by perforation, and oil extraction is continued at the same rate through lower half of gently-ascending production wells and through upper half through thickness of vertical wells deposit. At break of steam condensate into lower halves of shafts of gently-ascending production wells, rate of oil withdrawal from these wells is limited and rate of oil extraction from vertical production wells is increased, keeping the initial rate of oil extraction from the deposit, and oil withdrawal from gently-ascending and vertical production wells is performed till their oil flow rate is lower than profitable level. 
     EFFECT: increasing oil recovery of reservoir beds at simultaneous increase of efficiency of thermal impact due to control and activation of heat flows and filtration flows of oil in the entire volume of the deposit. 
     1 cl, 23 dwg, 2 tbl