METHOD OF MULTILAY FIELD DEVELOPMENT Russian patent published in 2014 - IPC E21B43/14 

FIELD: oil and gas industry.

SUBSTANCE: method includes well drilling below roof of the upper lay to the length not less than half of distance between bottoms of the upper and lower lay, landing and cementing of production string, then landing to production string shoe and conservation of inserted shank end with rock cutting tool installed at its end, drilling of offshoot to the upper lay and its production. When production of the upper lay is completed or when its pressure decreases below permitted value or formation pressure of the lower lay then alignment of drilling or casing tubes is made by cross-over shoe with inserted shank end and drilling of lower lay is performed. After penetration of the lower lay the inserted shank end is cemented and perforated and dual of the lower and upper lays is carried out.

EFFECT: ensuring reliability for development of gas and oil deposits in complicated conditions with abnormally high formation pressure and abnormally low formation pressure.

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