A Technology Study On Casing Running Safely In Highly-deviated Wells

As the exploration of oil reservoir develops in depth and in quantity, the highly-deviated wells are increasingly growing in number, especially in the developing of beach and offshore oilfields. It expanded the exploitation range of offshore platform and reduced the cost greatly when substitute highly-deviated wells for seabed development plan and artificial island. The load and deformation of casing are complicated, and it is difficult to running predetermined deep. Because of the well path is random and has larger deviation angle and long open hole, and it was hard wellbore cleaning. So, it has important operation significance to study a technology on casing running safely in highly-deviated wel s.This paper through analyzing the stresses of infinitesimal casing string in different sections, deducing a model for drag and torque of casing in highly-deviated wells, which considers the impacts of fluid viscous force and buckling load on drag and torque; As wells have curved portion, and considering any probable destruction when casing string running, and then get the optimization calculation method of the biggest borehole curvature that allowed through for the rotating casing; Through built the three-dimensional stress of casing, deduces the expression of collapse resistance and internal pressure strength and tensile strength in combined loads, which reflects the interaction among various stresses. The paper gives a method of count casing setting depth in the conditions of drag-torque and strength safety. Under the development environment of VB, developed the software of casing running in highly-deviated wells. This paper gives two highly-deviated wells as examples from Shengli oil field, the error between calculated hook-load and actual is less than twelve percent, has enough precision for actual project. And it verifies the correctness of theoretical and computational methods. The research results of the paper provide evidences to casing running in highly-deviated wells. And the software provides a simple operation platform for the user, and it provides a good method for using and researching the casing running also. It had a certain instruction to the highly-deviated wel s cementation.