Methods of permeability enhancement in wellbottom zone

Abstract

The present-day problem of the oil and gas industry is the shortage of hydrocarbon production. Modern technologies enable production of hydrocarbons in amount not more than 25–50 % of overall reserves, which impedes efficient natural wealth management. Geological conditions worsen persistently since striking and early exploitation of reservoirs. The causes of permeability degradation in wellbottom zone during drilling and operation of wells are determined. It is found that during construction and operation of a well, the fluid-bearing characteristic of the wellbore area can be infringed. The review of the available practices shows that the method of cavitation enables efficient recovery of wells with mudding of the screen and wellbottom zones to 100 %. Cavitation generators stimulate porosity and permeability of oil- gas- and fluid-bearing strata. The pressure required for fracture opening is is 2–2.5 times lower with breakaway cavitation as against the hydraulic fracturing methods. The use of a cavitation generator during hydraulic fracturing enhances efficiency of the latter. The process fluid can be fresh or reservoir water, which cuts down expenses connected with chemical agents and other expendables. The treatment of wells up to the maximum pressure lasts for not longer than 6 h. The method is applicable in wells of any type (production, injection, disposal, etc.) to 4000 m long and more. The cost of well treatment by the breakaway cavitation method is a few times less than the cost of hydraulic fracturing.