Research On Frictional Resistance Of Horizontal Shaft Casing

The development of horizontal wells brought a series of problems to casing running, As a result, completing the casing running operation is not smooth in horizontal wells. Furthermore, It will bring hidden danger for the next production. Casing running is studied through the influence of different types of casing centralizers on casing running friction and through the calculation of casing running friction as well as through passing capacity of casing string at the curve section for the characteristics of casing running attached with centralizers in horizontal wells.Friction coefficient influence factor is researched during the process of casing running in horizontal wells. Experimental apparatus is developed and casing friction coefficient of different types of centralizers are provided by test and analysis. The research showed that friction drag of casing running with different centralizers in horizontal wells is not equal. the friction drag of elastic centralizer is maximum, the friction drag of rigid centralizer is second, The friction drag of roller centralizer is minimum. In order to provide a theoretical basis for optimizing centralizer to reduce friction during the process of casing running, the features of different types of centralizers is studied.Continuous Beam Column model is established according to the mechanical characteristics of casing running attached with centralizers in horizontal wells.The parameters of the model are projected to Inclination Plane and Dogleg Angle Plane in order to turn3-D problem to two2-D problem. Frictional resistance and hook load are calculated by solving the two2-D bend problems.Based on the pass model of casing without centralizer at the curve section in horizontal wells, the pass model of casing attached with centralizers is established by introducing Centralizer Impact Factor. The range of Centralizer Impact Factor is put forward. The maximum wellbore curvature passed through by casing attached with centralizers is calculated.Based on the friction calculation model in horizontal wells, Calculation software is developed by Visual Basic program. The friction of casing running attached with different types of centralizers is compared. The research was showed to have great significance to the friction prediction in horizontal wells in field.