Design of 5 Liner Drilling System for Directional Drilling

摘要

The application of classical field development systems in the modern world is becoming more and more complicated. The global portfolio of oil and gas fields virtually ran short of reservoirs located in favorable conditions for geologists and drilling & completion engineers. New fields are either located in adverse climatic conditions (e.g., Arctic projects) or are faced with various problems related to unconventional reservoirs, complex geological structure, high pressures and temperatures. One of those problems, which has become a particularly pressing issue in recent years, is the problem of incompatibility of borehole pressures, which causes complications in the well construction: borehole wall collapses, fluid losses and sticking of drilling tools. For the well construction process this means an increased non-productive time (NPT) and extra costs. One of the solutions to such challenges is a liner drilling technology, which is actively used as a means to lower NPT and operational risks. Liner drilling systems, including those for directional drilling, are available, but for strings 178 mm (7″) and more in diameter. Smaller diameter liner drilling is carried out using directionally-uncontrollable systems, which restricts the application of the technology. In this regard the authors are offering the technology of directional drilling with a 127 mm (5″) liner, which would reduce the rig time and address the above technical problems. The task is completed by the use of a disposable bottom-hole directional assembly - a drilling bit and a bent-housing positive displacement motor (PDM with adjustable bent sub) and a retrievable telemetry system. The coil tubing (CT) can be used to extract the retrievable telemetry system. All the system elements are available on the market, the article describes the calculation results that demonstrate the possibility of the use of such a system in drilling of deep directional and horizontal wells.