The Research On Casing Designing And Casing Running For Extended Reach Well

In recent years, with the development of offshore oil field exploration expands in shallow and deep oil field, the application of extended reach wells becomes widely used for its cost advantage. However, for the complex drilling conditions of extended reach wells, higher requirements in casing string design and casing running technology are required. Because the large deviation angle, long open hole and deep casing point, the load on the casing becomes increasingly heavier and complex. During the casing design process, we should not only consider the influence of friction drag, but also the influence of the bending of the casing produce additional axial force, thermal loading, high temperature in the pit, casing wear, casing corrosion etc. In current design standard of casing strength in petroleum and gas (SY/T5724-2008), force analysis of casing and its string is not quite comprehensive, influencing factors are not systematic, oil and gas casing strength industry the casing stress analysis consider insufficient system, and lack of design method and casing technology for the casing string of extended reach wells.Therefore, aiming at the optimization design and casing running technology for ultra-deep casing string of extended reach wells, to form a set of scientific optimal design and casing running technology can contribute to the security of extended reach wells’cementing string; lower the cost of cementing and meet the growing cementing project needs of extended reach wells.This article comprehensively considers many influencing factors, focuses on the external loading analysis of casing string, calculation of casing strength, theoretical approach of casing strength design in the extended reach wells’ drilling conditions, to put forward suitable design procedures for casing strength of extended reach wells. In addition, the casing running technology of extended reach wells, the casing feasibility of casing running from the perspective of geometry and force, the calculation method for fluctuating pressure of casing running and maximum allowable casing speed, matching technology for casing running by floating and its field application, those are all lucubrately studied in this paper. To form a systematic construction technique for casing running of extended reach wells, and provide technical guidance for the site under the casing construction.