OIL POOL DEVELOPMENT METHOD Russian patent published in 1995 - IPC

FIELD: oil industry. SUBSTANCE: oil pool development method involves injection of some working agent through injection wells in the cyclic mode and oil withdrawal through producing wells. All available producing wells are divided into three categories. The first category of producing wells includes those showing virtually entire well stream watering. The second category includes producing wells with nearly ultimate economic well stream watering and daily fluid production rate in excess of 50 cu.m. Those producing wells that show well stream watering in excess of 50% and daily fluid production rate less than 10 cu.m are included in the third category. Producing wells grouped in the first category are operated in the following cyclic mode: well shut-in for two years followed by operation until the stream watering is virtually entire. The second category of producing wells is subdivided into zonal subcategories. Producing wells in neighboring subcategories in the antiphase are operated for 4-6 months in the following cyclic mode: regular stoppages while the water-oil ratio decreases followed by operation until the water-oil ratio rises to its peak value of maximum well stream watering. Then all producing wells in all zonal subcategories are shut down for 6-8 months. The zonal subcategories of producing wells are determined assuming equivalent fluid withdrawal in each zonal subcategory and location of the producing wells in the zonal subcategory in the zone of influence of the group of producing wells receiving supplies of the working agent from one source. The cyclic mode of operation of producing wells comprising the third category is as follows: for 4-6 months regular stoppages for periods shorter than 24 h and operation for periods shorter than 24 h, then the producing wells are shut down for 6-8 months. During the periods of shut-in of the producing wells of the second category in zonal subcategories the volume of working agent injection are reduced to be 25% of average volume passing through the groups of injection wells influencing the zonal subcategory. When operating the producing wells, the volume of working agent injection is increased to 25% of average value. EFFECT: higher efficiency.