VisiTrak超深电阻率探测工具和多边界反演新技术在地质导向中的应用

Application of VisiTrak Ultra-Deep Resistivity Detection Tool and New Multi-Boundary Inversion Technology in Geosteering

VisiTrak超深电阻率探测工具是一种基于电磁波传播的随钻测量工具,具有深度探测性能,但若要借助其获得井眼轨迹与地层界面之间关系、地层电性参数变化等指标,需要以反演技术作为支撑。提出一种多边界反演新技术,引入一个可以由用户嵌入地质知识和参数范围的先验模型,推演得到等价模型,并以此为基础计算层状模型的电磁场,递进获取井眼轨迹与地层接触面轴向之间的接触关系,用以指导地质导向。将多边界反演新技术融合于VisiTrak超深电阻率探测工具的测量过程,开发多边界反演软件,在X油田中进行应用实践。反演成果显示,该方法具备高达30 m的超深探测能力,能够提前探测到远处高阻抗界面信息,指导油藏地质研究人员及随钻跟踪人员提前了解储层的构造位置,对地质导向工作的平稳高效开展起到了推动作用。

The VisiTrak ultra-deep resistivity detection tool is an MWD tool based on electromagnetic wave propagation,which has depth detection performance.However,to obtain the relationship of borehole trajectory and formation interface and the change of formation electrical parameters,inversion technology is needed as a support.A new multi-boundary inversion technology is proposed,which introduces a prior model which can be embedded with geological knowledge and parameter range by users,and deduces an equivalent model.Based on the equivalent model,the electromagnetic field of layered model is calculated,and the contact relationship between borehole trajectory and axial direction of formation contact surface is obtained progressively,so as to guide geological guidance.The new multi-boundary inversion technology is integrated into the measurement process of VisiTrak ultra-deep resistivity detection tool,and the multi-boundary inversion software is developed and applied in X oilfield.Inversion results show that this method has the ultra-deep detection capability of up to 30 m,can detect the distant high impedance interface information in advance,guide reservoir geological researchers and tracking personnel while drilling to know the structural position of the reservoir in advance,and promote the smooth and efficient development of geosteering work.