EXCAVATION METHOD OF HIGH VISCOUS OIL DEPOSITS WITH GAS CAP Russian patent published in 2017 - IPC E21B43/24 E21B7/04 

FIELD: oil and gas industry.

SUBSTANCE: excavation method of high viscous oil deposits with gas cap includes the drilling of horizontal wells with the location of producing wells horizontal shafts under the injection wells horizontal shafts, the steam injecting into the productive formation of the deposit, warming up of the formation with creation of steam chamber, the steam and gas injecting into the injection horizontal wells and selection of products from the producing horizontal wells. According to the horizontal wells drilling data, determine the presence of gas cap and specify the structure of the deposit. The vertical production well is drilled in the dome part of the deposit and it is perforated near the formation roof. The gas from the gas cap is selected through this well and sent to the container for gas collection. After the formation warming up and creation of the steam chamber, the steam P and also the gas G produced from the gas cap is injected in the horizontal injection wells, mixing it with the steam in the ratio P:G = 5-50:1. Moreover, to maintain this ratio of working agents and its mixing, the produced gas from the indicated container, and steam from the steam generator is supplied to the booster unit, from which the mixture is injected directly into the injection wells. After breaking into the gas cap of the injected steam-gas, the gas selection from the vertical well is transferred to the periodic mode, determined by the time required for the gas in the gas cap redistribution into the dome part of the deposit. If the volume of the gas accumulated in the container is reduced below the level needed to maintain the ratio of injected working agents, move to the only steam injecting into the injection wells. After the produced gas volume increase in the container upto the value at which the steam-gas injection is possible at the specified ratio during for at least 10 days, move to the steam-gas injection. The frequency of steam-gas injection, if necessary, is repeated. In general, after the creation of the steam chamber, the injection ratio of the liquid and gas amount by injection in the amount of steam and steam-gas is maintained at the deposit at the level of 40-100%, thus, the deposit is developed in the steam-gas gravitational drainage mode .

EFFECT: increase of the field high viscous oil recovery with a gas cap.

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