STIMULATION METHOD OF FORMATION FLUID INFLUX FROM WELL Russian patent published in 2013 - IPC E21B43/25 

FIELD: oil and gas industry.

SUBSTANCE: method involves lowering of the tubing to the well; drop of pressure on productive formation with replacement of fluid column in the well with gas-liquid mixture by its supply with booster unit; provision of the required ratio of mixture components in order to achieve the specified value of pressure drop on productive formation. When formation pressure is equal to 0.5-0.7 of value of hydrostatic pressure of fluid column in the well, prior to lowering of tubing to the well there installed is a remote downhole pressure gauge on lower end of the tubing. After the tubing is lowered to the well, stimulation of formation fluid influx from the well is performed in two cycles. The first cycle involves replacement of fluid column in the well with gas-liquid mixture-foam with density that is lower than fluid density in the well, which is pumped via the tubing with the aeration degree providing the rise of bottomhole pressure in the well above formation pressure as per readings of remote downhole pressure gauge by 25-30%. As gas-liquid mixture there used is aerated mixture of water solution of surface active substance (SAS) and stabilising agent providing the foam stability and preservation of collecting properties of the formation at foam penetration into the bottom-hole zone. The second cycle of stimulation of formation fluid influx from the well involves replacement of foam obtained during the first cycle with the foam of lower density by its pumping to annular space of the well with increase in aeration degree. Besides, backpressure on productive formation is decreased, the value of which is controlled as per readings of remote downhole pressure gauge; foam is destructed when it leaves the well during stimulation process of formation fluid influx from the well by throttling for repeated use.

EFFECT: improving well development efficiency.

2 dwg