METHOD FOR OPENING HIGH-PRESSURE FORMATIONS SATURATED WITH STRONG BRINES Russian patent published in 2020 - IPC E21B21/08 E21B43/00 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, namely to technology of construction of deep wells, in particular, to methods of opening and attachment of high-pressure productive formations. In implementing the method, drilling is performed with controlled pressure at equilibrium with formation pressure of high-pressure formation through creation of excess wellhead pressure, further well is deepened by 100–150 m, then interstratal overflow is created through increase of well head pressure to leakage pressure into natural cracks and further increase of bottomhole pressure to create artificial hydraulic fractures in underlying formation, further deepening of the well to the projective face at complete absorption in conditions of interstratal overflow from brine manifestation to absorbing formation in the absence of excess wellhead pressure with periodical additional filling in annular space with weighted drilling mud of 1–2 m³/h. Further, high-strength casing string is lowered to the well with periodic additional filling in annular space with weighted drilling mud of 1–2 m³/h. Fastening of the column is performed by cementing with counter pouring with overlapping of the zone of the high-pressure formation to the zone of absorption, then cementing is performed by direct pouring with insulation of the absorption zone, after which the borehole is continued to the underlying target stratum with hydrocarbon saturation.

EFFECT: possibility of controlled opening and attachment of high-pressure formations with high degree of protection against spontaneous emissions and blowout of formation fluid, as well as avoiding collapsing of casing after attachment of high-pressure formation, providing trouble-free production of oil and gas.

1 cl, 2 dwg