摘要
选取大庆油田“中342 检21井”泥岩岩心,对其进行浸水实验,用伯格模型来描述其流变特性,在此基础上建立了泥岩粘弹性本构方程.依据线性粘弹性问题的对应原理和套管外挤力弹性解,得到套管外挤力粘弹性问题的解.对岩样的实验数据进行拟合,确定了泥岩流变特征参数,计算出随时间变化的泥岩层套管外挤力.计算结果揭示了大庆油田套管蠕变挤毁机理,还可看出泥岩的水化程度只改变蠕变速度,使套管所受外挤力变化速率加快,并不改变最终外挤力的大小.
Submerging tests for a set of mudstone samples from Well zhong342-inspection21 were performed. The results demonstrate that the rheological property of mudstone can be described well with the Burgs model and the viscoelastic constitutive equation is proposed. Based on the corresponding principle of linear viscoelastic problem and the elastic solution of external squeeze pressure on casing, the solution to the viscoelastic problem of external squeeze pressure on casing is obtained. The rheological property parameters of mudstone are determined by fitting the test data. The variation of external squeeze pressure on casing in mudstone zone with time has been calculated. The results reveal the collapse mechanism of casing creep in Daqing Oilfield. The degree of hydration of mudstone only changes creep rate and accelerates the variation rate of external squeeze pressure on casing.
基金
中国石油天然气股份有限公司科技攻关项目(020115-1)
关键词
套管损坏
泥岩
粘弹性
本构方程
受力计算
casing damage
mudstone
viscoelastic
constitutive equation
calculation of pressure on casing
