地层变形的流固耦合数值模拟

Numerical Simulation of Stratum Deformation Based on Fluid-structure Interaction

石油开采当中,地层变形往往是造成套管损坏的首要因素,而开发过程中例如高压注水采油在很大程度上造成了地层的变形。本文针对石油工程中高压注水采油引起的地层变形,运用有限元软件ADINA建立了七井点流固耦合数值模拟模型,具体描述了高压注采过程中地层的变形情况,并对其计算结果进行了研究分析,结果表明,高压注水采油易使井壁处地层应力集中、岩层滑移与膨胀变形、储油地层凹陷等,且与较大孔隙度油层相比,低孔隙度油层高压注采时的孔隙压力与流体流速增加幅度要更大,以上结论为预防和减少流固耦合作用下地层变形造成的影响等提供了理论依据。

Stratum deformation is one of the major reasons to cause casing damage in petroleum exploitation,and some exploitation methods such as the high-pressure water injection oil recovery promotes the deformation of strata significantly. In this paper,the finite element software ADINA is used to establish a seven-points well fluid-structure interaction numerical simulation model in the light of the deformation of strata which results from high-pressure water injection oil recovery in petroleum engineering,and the process of stratum deformation in high-pressure injection is described in detail,then the calculation results are studied and analyzed. The results show that the high-pressure water injection is apt to make the wellbore formation stress concentrated,and make the rock sliding,expanding and the stratum sunken and so on. In addition,the increment of pore pressure and fluid flow velocity in low porosity reservoirs are more than that in large porosity ones. The above conclusions provide theoretical basis for preventing and reducing the influence caused by stratum deformation in fluid-structure interaction.