METHOD OF OIL RECOVERY Russian patent published in 2001 - IPC

FIELD: oil producing industry, more precisely, technology of oil recovery from non-flowing wells. SUBSTANCE: method includes reciprocation of piston in cylinder located in packed pipe string. Piston is actuated by electric motor. The latter is installed on wellhead and connected with piston by tie-rod. Preparation for recovery of oil and its recovery are carried out with continuous washing of filter and bottom-hole formation zone by alternating supply of fluid upward-downward by piston in cylinder. Cylinder is installed at any depth up to formation level. Packer on pipes is installed mainly on formation roof. Piston is weighted by weight. It is mounted on cable or rope which is wound on drum and connected with electric motor. Piston is moved down under gravity with motor or drum disengaged. Piston is located at different depths, for instance, of 1, or 2 or 3 km. In these points, equal number, for instance, three piston reciprocations are executed for equal value of stroke with different or same speed of lifting and lowering. Volume of fluid withdrawn by piston is measured for each point. Volume of piston strokes in each pint is calculated and coefficient of fluid overflow in gaps between piston and cylinder is determined by ratio of said volumes. Then, well production rate in each point is determined as quotient of division of volume of fluid withdrawn by piston for tome of its operation for said coefficient. The same procedure is repeated for other values of stroke and motion speed of piston. Check valve is installed in zone of packer, and all indicated above is repeated. Production rate graphs are constructed for each point. Graphs are compared and zone of piston installation is selected and expediency of valve installation to produce maximum production rate in process of oil recovery is decided. Piston is installed into calculated zone and oil is withdrawn by piston reciprocation under conditions selected on the basis of graph with maximum production rate. EFFECT: increased productivity of oil recovery and depth of oil withdrawal. 3 cl, 1 dwg