METHOD DETERMINING RESTORATION OF PERMEABILITY OF ROCKS Russian patent published in 2004 - IPC

FIELD: oil and gas industry. SUBSTANCE: invention can be employed for determination of types of special fluids utilized in drilling, in development of deposits and overhauls of wells which make it possible to minimize deterioration of filtration characteristics of crack and crack-porous collectors. Technical result of invention lies in determination of types of special fluids not mudding crack and crack-porous collectors which utilization do not impair filtration characteristic of collector. Method includes selection of core sample, cutting out of cylindrical sample in parallel to bedding, extraction with alcohol-and-benzene mixture, determination of gas penetration, modeling of initial oil saturation. In this case sample of horizontal foliation, not showing pore penetration is taken, is split along axis into two halves, size of crack ( length, width ) is measured, crack opening is fixed by laying strips of aluminum foil on sides of sample ( thickness of foil determines crack opening ), is compressed by effective pressure, sample is heated to formation temperature, endured till temperature and pressure stabilize, hydrocarbon fluid-kerosene is pumped through, flow rate of kerosene through crack is established, mudding fluid is injected under pressure equal to drive on formation, crack is cleared of fluid under pressure equal to depression employed to induce inflow till escape of aqueous and solid phases terminates, kerosene is pumped and its flow rate is found. When flow rate of kerosene drops, pumping is stopped, core holder is disassembled, sample is removed, mud grouting of crack by residues of fluid is found, thickness of layer mud grouting crack is measured , crack porosity and permeability are computed with due account of new value of crack opening. EFFECT: determination of types of special fluids not mudding crack and crack-porous collectors. 1 tbl