METHOD OF INCREASE OF WELL PRODUCTIVITY Russian patent published in 2003 - IPC

FIELD: mining industry using wells for recovery of water and minerals; applicable in preparation for operation and operation of artesian and hydrogeological wells for restoration or increase of their productivity, and also oil and gas wells for reduction of water cutting of well production and increase of its recovery at late stage of deposit development. SUBSTANCE: method includes stimulation of well strainer zone of, at least, one well by passing through well strainer zone of unlike-polarity bursts of like-polarity quasi-square current pulses with spaces between positive and negative pulse bursts. Character of variation of well strainer zone permeability is determined by character of like-polarity pulse repetition rate in burst. Duration of like-polarity pulse burst shall not exceed 500 ms. Duration of space is established equal to difference of period of pulse repetition and duration of the first pulse in burst. Power of each current pulse is preliminarily determined by mathematical relationship. To reduce permeability of well strainer zone to water, values of stimulation parameters are preset to ensure positive value of temperature gradient and partial pressure differentials sufficient for gas colmatation of pores and capillaries. Duration τ of like-polarity pulses in burst and pulse period-to-pulse duration ratio are set in form of constant value. Increase of well strainer zone permeability to water is effected with variable duration τ of like-polarity pulses in burst. Pulse period-to-pulse duration ratio of current pulses in burst is varied by varying current pulse duration from maximum τ_max to minimal τ_min with variation increment Δτ with constant period of pulse repetition rate in burst. Parameters of stimulation are set in values ensuring demudding of pores and capillaries of well strainer zone and zero value of temperature gradient until moment of ending of each pulse burst. During stimulation, value of average of current of pulse bursts and duration of rear front of last pulse in burst are monitored and moment of ending of stimulation is determined depending on their values. In course of stimulation, temperature is monitored with help of thermometer located in well strainer and, if required, parameters of pulse bursts are corrected. Passage of unlike-polarity bursts of like-polarity quasi- square pulses of electric current through well strainer zone is provided by location in zone of metal electrode connected by cable with pulse current source, and the second metal electrode also connected with pulse current source by the second cable is located in same formation at some distance from the first electrode. Invention provides for increase of well productivity due to variation of producing formation permeability to water in well strainer zone. Invention allows reduction of permeability to water by means of gas bubble colmatation of pores and capillaries that in its turn results in reduction of water cutting of production of oil and gas wells and facilitates oil production. Invention also provides, by means of destruction of colmatant partitions and formations in pores and capillaries of well strainer zone, for increase of permeability to increase in this way of water inflow to well thus increasing productivity of water wells of various applications. EFFECT: higher efficiency of method. 3 cl, 3 ex