SYSTEM AND METHOD FOR MULTI-STAGE STIMULATION OF WELLS Russian patent published in 2021 - IPC E21B34/14 

FIELD: oil and gas industry.

SUBSTANCE: inventions group relates to the oil and gas industry. A liner system for stimulating one or more stages of a subterranean wellbore comprises one or more fracturing valves installed in the liner and having an identical internal profile. The dart contains an adjustment mechanism configured to adjust one or more first positions to allow the dart passing through one or more fracturing valves without opening them. In the second position, the dart interacts with one or more other fracturing valves to open said one or more other fracturing valves. The adjustment mechanism contains an indexing sleeve mounted for movement on the outer diameter of the dart mandrel to control the movement of the dart from one or more first positions to the second position. The upper and lower collets are formed on the indexing sleeve and are radially inwardly displaced towards the mandrel. On the outer surface of the mandrel, a sequence of circular grooves is formed to interact with the collets of the indexing sleeve. At the end of the mandrel located above the wellbore, a retaining surface is formed that allows the said upper collet extending radially when the indexing sleeve is in the second position. The mandrel collar, formed at the end of the mandrel located above the wellbore, is designed to stop the axial movement of the indexing sleeve in the second position. A method for stimulating one or more stages of a subterranean wellbore is claimed.

EFFECT: invention provides an increase in the efficiency of stimulation of the stages of an underground wellbore by increasing the reliability of the hydraulic fracturing valves in a certain sequence.

22 cl, 14 dwg