Method for analyzing strength and rigidity of geologic structure

Abstract

The invention discloses a method for analyzing the strength and rigidity of a geologic structure. The method comprises the following steps of: (a) establishing a solution domain, and discretizing the solution domain into a finite element; (b) supposing a shape function representative of an element physical behavior; (c) establishing an element equation; (d) constructing an element global stiffness matrix; (e) applying boundary conditions, initial conditions and loads; (f) solving linear or nonlinear differential equations, and thus obtaining a node solution result such as the displacement of different nodes, strain variables or temperature values in a thermodynamics issue; and (g) acquiring other important information. The strength and rigidity of the geologic structure can be quickly analyzed, the method is accurate in analysis result and simple in analysis step, and analysis cost is greatly reduced.

Description

technical field [0001] The invention relates to an analysis method for the strength and stiffness of geological structures. Background technique [0002] The so-called horizontal well refers to a special type of oil and gas well with a maximum inclination angle of 90 degrees and a horizontal or near-horizontal well section in the pay zone. Since the 1990s, with the increasing perfection and popularization of horizontal well drilling technology, horizontal wells have been widely adopted by countries all over the world. Since the first horizontal well was drilled in the east of the South my country Sea in China, various oil fields have successively carried out horizontal well drilling. Technical research and practice, especially through the "Eighth Five-Year Plan" scientific and technological breakthroughs, have brought my country's horizontal well mining technology close to the international advanced level. [0003] Casing is a steel pipe that protects the well wall and the w...

AI Technical Summary

Problems solved by technology

When the wellbore is bent, the casing string is close to the downhole wall, and the casing string may be stuck in the curved section of the wellbore due to the high rigidity of the casing and cannot be run in.

After entering the horizontal section, the casing string will be partially attached to the downhole wall. It may be due to the continuous growth of the contact section between the casing string and the formation, and the total frictional resistance of the formation to the casing string will also gradually increase. At this time, the hook load will increase accordingly. Reduced, when the load on the hook is reduced to zero, the casing running operation is hindered