海上中等强度砂岩出砂预测研究
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摘要
针对中等强度砂岩岩石力学特性,采用岩石应力场与流体渗流场相耦合的方法建立了出砂预测模型,对生产过程中井壁岩石塑性区的扩展进行模拟,对出砂临界生产压差进行了计算。结果表明,非均匀地应力条件下塑性区最先在最小地应力方向出现,随着井底流压的降低,塑性逐渐扩展,并最终呈现椭圆状。由于塑性的影响井周应力发生变化,切向应力降低严重,井壁上的切向应力降为最小。井壁岩石的等效塑性应变超过0.0045,此时井壁岩石会发生大规模的脱落,造成严重出砂。实际生产表明,井底流压13MPa时,井口无出砂,计算结果与现场监测结果一致,较好地指导了现场完井防砂的选择。
According to the rock mechanic characteristics of medium strength sandstones,a sand production prediction model is established by coupling the rock stress field with the fluid seepage field.The extension of the plastic zone of the wellbore rock in the production process is simulated,and the critical production pressure difference of sand production is calculated.The results show that the plastic zone first appears in the direction of minimum in-situ stress under non-uniform in-situ stress.With the decrease of bottom hole flow pressure,the plasticity gradually expands and finally presents elliptical shape.Because of the influence of plasticity,the circumferential well stress changes,the tangential stress decreases seriously,and the tangential stress on the wellbore wall decreases to the minimum.The equivalent plastic strain of the sidewall rock exceeds 0.45%.At this time,the sidewall rock falls off on a large scale,resulting in serious sand production.The actual production shows that there is no sand production at the wellhead when the bottom hole flow pressure is 13 MPa,and the calculation results are consistent with the field monitoring results,which can better guide the selection of field completion and sand control.
According to the rock mechanic characteristics of medium strength sandstones,a sand production prediction model is established by coupling the rock stress field with the fluid seepage field.The extension of the plastic zone of the wellbore rock in the production process is simulated,and the critical production pressure difference of sand production is calculated.The results show that the plastic zone first appears in the direction of minimum in-situ stress under non-uniform in-situ stress.With the decrease of bottom hole flow pressure,the plasticity gradually expands and finally presents elliptical shape.Because of the influence of plasticity,the circumferential well stress changes,the tangential stress decreases seriously,and the tangential stress on the wellbore wall decreases to the minimum.The equivalent plastic strain of the sidewall rock exceeds 0.45%.At this time,the sidewall rock falls off on a large scale,resulting in serious sand production.The actual production shows that there is no sand production at the wellhead when the bottom hole flow pressure is 13 MPa,and the calculation results are consistent with the field monitoring results,which can better guide the selection of field completion and sand control.
引文
[1]蔚宝华,王治中,邓金根.固结砂岩气藏出砂预测方法研究[J].大庆石油地质与开发,2005,24(6):60～63.
[2] Bienawski Z T.Estimating the strength of rock materials[J].Journal of South African Inst of Min.and Metal,1974,4(8):312～320.
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[4] Geilikman M B,Dusseault M B.Fluid-saturated solid flow with propagation of a yielding front [A].Rock Mechanics Petroleum Engineering Conference[C].1994:29～31.
[5] Li X,Feng Y,Gray K E.A hydro-mechanical sand erosion model for sand production simulation [J].Journal of Petroleum Science and Engineering,2018,166:208～224.
[6] Lade P V.Rock strength criteria:the theories and the evidence[A].Brown E T.Incomprehensive rock engineering[C].New York,Pergamon:Oxford,1993:255～284.
[7] Szwedzicki T.Rock mass behaviors prior to failure [J].International journal of rock mechanics and mining sciences,2003(40):573～584.
[8] 韦立德,杨春和,徐卫亚.考虑体积塑性应变的岩石损伤本构模型研究[J].工程力学,2006,23(1):139～143.
[9] 田红,邓金根,王治中,等.定向射孔技术在适度出砂管理中的应用[J].钻采工艺,2005,28(5):35～41.
[2] Bienawski Z T.Estimating the strength of rock materials[J].Journal of South African Inst of Min.and Metal,1974,4(8):312～320.
[3] Hajiabdolmajid V R.Mobilization of strength in brittle failure of rock[D].Kingston,Canada,Queen’s University,2001.
[4] Geilikman M B,Dusseault M B.Fluid-saturated solid flow with propagation of a yielding front [A].Rock Mechanics Petroleum Engineering Conference[C].1994:29～31.
[5] Li X,Feng Y,Gray K E.A hydro-mechanical sand erosion model for sand production simulation [J].Journal of Petroleum Science and Engineering,2018,166:208～224.
[6] Lade P V.Rock strength criteria:the theories and the evidence[A].Brown E T.Incomprehensive rock engineering[C].New York,Pergamon:Oxford,1993:255～284.
[7] Szwedzicki T.Rock mass behaviors prior to failure [J].International journal of rock mechanics and mining sciences,2003(40):573～584.
[8] 韦立德,杨春和,徐卫亚.考虑体积塑性应变的岩石损伤本构模型研究[J].工程力学,2006,23(1):139～143.
[9] 田红,邓金根,王治中,等.定向射孔技术在适度出砂管理中的应用[J].钻采工艺,2005,28(5):35～41.