METHOD OF NONSTATIONARY EXTRACTION OF OIL FROM ZONAL NONHOMOGENEOUS FORMATION AS TO PERMEABILITY Russian patent published in 2013 - IPC E21B43/18 

FIELD: oil and gas industry.

SUBSTANCE: method involves hydrodynamic investigations of a flooded well in steady-state extraction modes, on the basis of which there determined is a period of modulated depression action on the formation, at which the well operation is performed without stopping a pumping equipment, and change of the flow rate is at the interval of minimum value determined by the pump starvation to some maximum value. According to the invention, when the distance between adjacent production wells is equal to or more than an average size of a zone of chaotic variation of permeability, the period of modulated depression action on the formation represents reduction of the well flow rate to minimum value determined by the pump starvation. Change-over of the well to the normal operating mode as per the relationship close to quadratic one, exposure of that mode with constant value of the well flow rate during the time of oil displacement from oil-saturated zones is determined by the time of existence of positive effect of flooding reduction and increase in oil flow rate. If it is not possible to establish geometrical dimensions of oil-saturated formation zones during hydrodynamic investigations, then as a specific geometrical dimension there taken is a half of the distance between adjacent production wells, as per which a period of modulated depression action is determined.

EFFECT: reduction of volumes of produced water and increase in oil recovery of the formation.

2 ex, 3 dwg