Well drilling with combined pressure control

Abstract

The research deals with the analysis of new technologies for drilling oil and gas wells including the technology of managed pressure drilling (MPD). A consideration is given to the equipment for creating differential pressure in the wellreservoir system, which is supplied by the foreign companies Schlumberger, M-I SWACO, AKROS, etc. The analysis is given to the application of the basic complex of managed pressure drilling equipment, which includes the installation of back-pressure control, nitrogen compressor station, choke manifold, separator, rotary wellhead dock, flare tower with ignition system and hardware and software complex. The article also deals with the implementation options of the managed pressure drilling technology through the use of a sealed circulation system, which simplifies the well flushing scheme and ensures smooth adjustment of the flushing agent pressure at the bottomhole. A viable possibility of the presented basic MPD equipment and the attached software and hardware complex to determine the permissible values of reservoir fracturing pressure and formation pressure is studied in order to monitor the pressure profile in the casing annulus. It has been found that managed pressure drilling as a fundamentally new primary penetration technology for the hydrodynamic conditions of the reservoir allows to perform drilling in the zones with almost any initial absorption rate. That means that we do not stop sinking by boring (i.e. circulation) and do not increase the equivalent pressure on the horizon that depends on the equivalent circulating density. The adjustment involves the approximation of the equivalent pressure on the horizon to the formation pressure. The technological process of managed pressure drilling with the use of the discussed equipment will enable better understanding of the efficiency of this drilling technology by the drilling personnel and contribute to its more conscious application by domestic companies.