低渗油藏水平井分段压裂封隔器密封结构研究

Research on Packer Sealing Structure of Open-hole Staged Fracturing of Low-permeability Reservoir

低渗油藏水平井分段压裂压缩式封隔器,由于处于高温、高压、复杂深部地层环境,胶筒组常出现坐封力低和坐封提前失效、胶筒与中心管间产生渗漏等问题,导致封隔器密封失效。提出一种十字锥形隔环与槽形胶筒组组合的新密封结构,基于ABAQUS软件分析其胶筒组沿井壁、中心管轴向接触应力,沿井壁的Mises应力分布,以及硬度、坐封力对其接触应力的影响。研究表明,新型密封结构的胶筒组与井壁、中心管接触更加充分,各胶筒接触应力显著提高且分布均匀,保证了封隔器的密封可靠性;胶筒组与井壁间的Mises应力降低,避免了胶筒组被撕裂;随着硬度、坐封力的增加,胶筒组与井壁间的接触应力增加。

Due to working in an environment of high temperature and high pressure and complex stratum,the packer rubber of open well staged fracturing of low-permeability reservoir are usually appeared with low setting force and earlier failure of setting,and leakage between rubber and center pipe,which result in packer sealing failure.A new sealing struc-ture was proposed which consisted of cross spacer ring and groove rubbers.The stress distribution of the packer was ana-lyzed by ABAQUS,including rubbers＆#39; contact stress along the well wall and center pipe,rubbers＆#39; Mises stress along the borehole wall.The effects of material hardness and packer sealing force on the contact stress of sealing structure were in-vestigated.The results show that the new sealing structure of packer realizes the full contact of the rubbers with the bore-hole wall and center pipe.The contact stress of rubber is increased significantly and its distribution is more even,which en-sures the sealing reliability of the packer.The rubbers＆#39; Mises stress along the borehole wall is reduced,which avoids the rubber torn.The contact stress between the rubbers and the borehole wall is increased with the material hardness and pack-er sealing force.