Research on borehole stability of shale based on seepage-stress-damage coupling model
Journal Title: Frattura ed Integrità Strutturale - Year 2014, Vol 8, Issue 27
Abstract
In oil drilling, one of the most complicated problems is borehole stability of shale. Based on the theory of continuum damage mechanics, a modified Mohr-Coulomb failure criterion according to plastic damage evolution and the seepage-stress coupling is established. Meanwhile, the damage evolution equation which is based on equivalent plastic strain and the permeability evolution equation of shale are proposed in this paper. The physical model of borehole rock for a well in China western oilfield is set up to analyze the distribution of damage, permeability, stress, plastic strain and displacement. In the calculation process, the influence of rock damage to elastic modulus, cohesion and permeability is involved by writing a subroutine for ABAQUS. The results show that the rock damage evolution has a significant effect to the plastic strain and stress in plastic zone. Different drilling fluid density will produce different damage in its value, range and type. This study improves the theory of mechanical mechanism of borehole collapse and fracture, and provides a reference for the further research of seepage-stress-chemical-damage coupling of wall rock.
Authors and Affiliations
Xiaofeng Ran, Yuezhi Wang, Shanpo Jia
Multiple crack propagation by DBEM in a riveted butt-joint: a simplified bidimensional approach
A Multi-Site Damage (MSD) crack growth simulation is presented, carried out by means of Dual Boundary Element Method (DBEM), in a two-dimensional analysis of a cracked butt-joint made of aluminium 2024 T3. An equ...
Application of the Moment Of Inertia method to the Critical-Plane Approach
The Moment-Of-Inertia (MOI) method has been proposed by the authors to solve some of the shortcomings of convex-enclosure methods, when they are used to calculate path-equivalent ranges and mean components of comp...
Valutazione della capacità di rientro alla base di un elicottero in presenza di danno balistico ad un albero di trasmissione della linea rotore di coda
Nella progettazione di un elicottero militare, destinato ad operare a bassa quota e in ambiente ostile, il danneggiamento di componenti critici, conseguente ad impatto balistico, riveste un ruolo primario nella valutazio...
Evaluation of the increased load bearing capacity of steel beams strengthened with pre-stressed FRP laminates
We analyse the problem of a simply supported steel beam subjected to uniformly distributed load, strengthened with a pre-stressed fibre-reinforced polymer (FRP) laminate. We assume that the laminate is first put i...
Simulazione della propagazione di difetti a fatica mediante il modello di zona coesiva
Le giunzioni incollate guadagnano sempre più mercato, nel campo delle costruzioni in genere, dove è necessario un alleggerimento delle strutture. Nel caso di geometrie di giunto semplici il dimensionamento avviene attrav...