夹层对SAGD开发效果影响研究

Research on the Effect of Interlayerson SAGD Development

针对油藏内部夹层影响SAGD开发效果的问题,运用分类分析、正交实验设计、数值模拟等方法,确定了夹层影响SAGD开发效果的主控因素及其影响程度。研究表明:夹层影响热连通,阻碍蒸汽腔的发育,进而降低了SAGD前期到中期采油速度;夹层与注采井的相对位置关系对SAGD生产效果影响显著;无泄流通道情况下,夹层影响SAGD开发效果的主控因素是夹层沿水平井方向发育的长度或者夹层所处位置离注汽井的距离;井间夹层长度达到水平井长度40%或注汽井上方夹层在注汽井上方3 m以内,采油速度降低40%以上。可利用直井辅助注汽的方式扩大蒸汽腔发育体积,提高SAGD采油速度。研究成果对夹层发育的超稠油油藏实施SAGD开发具有指导意义。

Due to the effect of interlayers on SAGD development,classification analysis,orthogonal experiment design,numericalsimulation and other methods wereused to determine the key controlling factors of SAGD development and their influence degrees.Research demonstrates that thermal communication and steam chamber development are affected by interlayers,which reduces oil recovery rates in the early and middle stages. SAGD development is greatly influenced by relative position between interlayer and injection- production wells. The interlayer length along horizontal wellbore direction or the distance from interlayer to steam injection well is the key controlling factor of SAGD development in case of no discharging channel. Oil recovery rate reduces to more than 40% in case of interwell interlayer length reaching 40% of horizontal well lateral length or the vertical distance from interlayer to horizontal wellbore of steam injection well is less than 3m. Steam chamber volume can be expanded by using vertical wells to assist steam injection,which can improve SAGD oil recovery rate. Research resultscan provide guidance to SAGD development of super heavy oil reservoirs with well- developed interlayers.