Revision as of 12:26, 25 August 2026

Abstract

Deep and ultra-deep well drilling in multi-scale fractured formations frequently encounters fracture-induced lost circulation, which restricts drilling efficiency and reservoir development. To address this problem, this paper establishes a dynamic finite element numerical model based on fluid-solid coupling theory, revealing the multi-physics coupling mechanism of fracture propagation and leakage channel evolution. The model fully considers the seepage-stress coupling effect during drilling fluid circulation, and quantitatively analyzes the influences of pump rate, fluid density, fluid viscosity, fracture geometric parameters, elastic modulus, Poisson’s ratio and in-situ stress on fracture aperture and fluid loss rate. The research results show that: pump rate and fluid density are positively correlated with loss rate and fracture aperture; fluid viscosity presents two-stage regulation characteristics, which is negatively correlated with leakage parameters at the fracture initiation stage and positively correlated in steady-state leakage stage; longer fracture length increases loss rate but reduces fracture aperture; elastic modulus, Poisson’s ratio and in-situ stress mainly affect the early leakage behavior, with little influence on steady-state stage. The proposed multi-parameter coupling control model can realize dynamic prediction of multi-fracture leakage in deep wells, and provides theoretical support for on-site anti-leakage and plugging work.

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