METHOD OF STACKED DEPOSIT WELL OPERATION Russian patent published in 2008 - IPC E21B43/14 E21B33/14 

FIELD: mining.

SUBSTANCE: first guiding casing string has 426 mm diametre and is lowered to the depth of 25-40 m and fixed with cement. Fresh water interval depth is defined; as a rule it comprises up to 300 m. The second conductor casing string has 324 mm diametre and is lowered to the depth overriding fresh water interval and fixed with cement. Depth of the upper productive formation is defined, the third casing string has 245 mm diametre and is lowered to the depth overriding upper production formation and fixed with cement. Forecast depth of the lowest productive formation is defined, the fourth casing string has 146 or 168 mm diametre and is lowered to the depth overriding lower productive formation, tube side between the third and fourth casing strings is filled with inhibited clay solution, the tube side in the upper productive formation interval is filled with light cement grout of 1.4-1.5 g/cm³ density, while the annular space of the fourth casing string is fixed with cement grout of 1.83-1.85 g/cm³ density, lower productive formation interval is perforated. Lower productive formation stock is developed. Inside the fourth casing string a cement bridge is mounted above the lowest production formation. Upper part of the fourth casing string above the upper production formation is removed from the well, at the third casing string above the upper production interval and offshoot kickoff is made. Horizontal hole at the upper productive formation is drilled, and upper productive formation is developed. Upper and lower stratum operations are performed together with packer operating separately to the fourth string below the upper stratum. The fourth casing string is made as a liner until the third casing string bottom is overridden by 50-100 m, and lower and upper strata operation is performed simultaneously and separately.

EFFECT: development of several productive formations by horizontal holes.

1 ex, 2 dwg