Equilibrium equations for nonlinear buckling analysis of drill-strings in 3D curved well-bores

Abstract

With the development of drilling technology, the oil/gas well has evolved from its early vertical straight form to the inclined, horizontal, plane curved, or even 3D curved well-bore. Understanding of the buckling behavior of a drill-string in a well-bore is crucial for the success of a drilling operation. Therefore, equilibrium equations for analyzing the buckling behavior of a drill-string in a 3D curved well-bore are required. Based on Love's equilibrium equations for a curved and twisted rod in space, a set of equilibrium equations for the nonlinear buckling analysis of a drill-string in a 3D curved well-bore are derived by introducing a radial constraint of the well-bore. The proposed formulae can account for the well curvature and tortuosity. Thus, it can be used to analyze the buckling behaviors of a drill-string constrained in a well-bore and subjected to axial compression, torsion at its upper end, and gravity simultaneously. It is worth noting that the existing equations in the literature for a drill-string in a straight and plane curved well-bore with a constant curvature are a special case of the proposed model. Thus, the present model can provide a theoretical basis for the nonlinear buckling analysis of a drill-string constrained in a 3D curved well-bore.

Performance of Protective Coatings for Aluminum Alloys in the Operating Conditions of Oil Production Equipment

“…Development of oil and gas industry leads to constant complication of well drilling conditions, which requires the use of new materials for the manufacture of drill pipes and their reasonable choice for specific conditions [1][2][3][4][5]. Research has shown the advantages and prospects of using aluminum alloys (in comparison with steels) as a drill pipe material in the development of oil fields [6][7][8][9][10].…”

The Influence of Boundary Constraint Conditions on the Buckling Displacement of Horizontal Drill String

“…Lifei Gan [3] analyzed the nonlinear buckling of drill string in slant well with the method of DQ element, ignoring the effect of contact friction force; Lihong Jiang, Meilan Tan [4,5] analyzed the end restrain condition of drill string with weight in slant well and the influence from hole deviation angle on drill string sinusoidal buckling; Deli Gao, Wenjun Huang [6][7] established the buckling differential equation of drilling string with weight in horizontal well by using the energy variation principle, they recently focus on researching the behavior of horizontal string after buckling from drill rod subs and the influence of boundary conditions on the buckling, etc. Above research can be a base for further studies on horizontal drill string buckling problem.…”

A simple and accurate numeric solution procedure for nonlinear buckling model of drill string with frictional effect

“…Because of the high frequency of drill string failure, drill string lock-up, and casing wear, the stability of drill string has been a serious problem in oil/gas field operations for many years (Gulyayev et al, 2009;Tan and Gan, 2009). On the other hand, with the development of drilling technology, oil/gas and deep continental scientific drilling wells become very long currently, even more than ten kilometers.…”