CAJ | 학술논문

针对水平井井壁围岩应力随井壁渗流压力变化的问题，考虑井内流体渗滤造成井壁岩石孔隙压力和孔隙度变化，推导孔隙度与井内流体压力和渗滤半径的理论关系，建立考虑孔隙压力变化的井壁围岩应力计算模型。应用模型计算表明：孔隙压力变化对井壁上径向、周向和轴向应力大小影响明显，渗滤带内随着距井眼中心距离增加，孔隙压力逐渐趋于地层初始压力，考虑和不考虑孔隙压力变化计算得到的径向、周向和轴向应力差值逐渐减小，在渗滤边界处考虑和不考虑孔隙压力变化计算得到的各向应力数值相等。
침대수평정정벽위암응력수정벽삼류압력변화적문제，고필정내류체삼려조성정벽암석공극압력화공극도변화，추도공극도여정내류체압력화삼려반경적이론관계，건립고필공극압력변화적정벽위암응력계산모형。응용모형계산표명：공극압력변화대정벽상경향、주향화축향응력대소영향명현，삼려대내수착거정안중심거리증가，공극압력축점추우지층초시압력，고필화불고필공극압력변화계산득도적경향、주향화축향응력차치축점감소，재삼려변계처고필화불고필공극압력변화계산득도적각향응력수치상등。
In view of the problem that borehole surrounding rock stress changes with well-wall seepage pressure in the horizontal well,we took changes of the pore pressure and porosity caused by borehole fluid percolation into consideration,de-duced a theoretical relationship among porosity,borehole fluid pressure,and percolation radius,and established a calculating model for sidewall surrounding rock stress considering the pore pressure change.Calculation results show that the pore pres-sure change has obvious effect on the radial,circumferential and axial stress of the sidewall.In the percolation region,with the increase of distance from the center of the borehole,the formation pore pressure approaches to original formation pressure,and difference value between radial stress,circumferential and axial stress with and without pore pressure change gradually de-creases.And stress values in all direction with and without pore pressure change are equal at the percolation border.