弓形缺失水平井井孔声场数值模拟  

Numerical Simulation of Borehole Acoustic Field in Horizontal Well with Missing Arch

作　　者：谢丹艳[1] 张宏兵[1] 孙树林[1] 

机构地区：[1]河海大学地球科学与工程学院,江苏南京210098

出　　处：《测井技术》2015年第2期150-154,共5页Well Logging Technology

摘　　要：针对水平井中可能存在的水泥环上层弓形缺失,通过建立不同弓形缺失高度、弓形缺失部分为混浆等模型,利用交错网格有限差分法求解应力—速度的一阶偏微分方程组,实现水平井弓形缺失复杂井孔声场的数值模拟。模拟结果显示,弓形缺失的弓高影响声场首波幅度和旅行时间,弓高低于水泥环厚度30mm首波为第Ⅱ界面特征波,高于30mm首波为套管波;弓形缺失部分为混浆对声场波幅和首波旅行时间影响不是特别明显,但是与内部为水的声场相比,首波幅度明显减小;当水泥环存在弓形缺失时,靠近缺失部位的接收器接收到的首波幅度明显减小,首波旅行时间则明显增大,依此可以判断缺失方位。For existing bow missing of cement layer in horizontal wells, we establish the models of different bow missing heights, bow missing parts mixing, and use the three-dimensional finite difference method to solve the stress-speed first-order partial differential equations, to achieve complex borehole acoustic field simulation in bow missing horizontal wells. Simulation results showed that： First, bow missing height affected the first wave amplitude and travel time. Bow height was less than 30 mm which was the cement thickness, and the first wave was two interface characteristics wave, else the first wave was casing wave; Second, bow missing mixing minimal affected the first wave amplitude and travel time, but compared with the sound field which the interior was water, first wave amplitude significantly reduced; Last, when bow missing existed in cement, the first wave amplitude that was received by the receptor which was close to the missing parts was significantly reduced, but the first wave travel time that was received by the receptor which was close to the missing parts was significantly increased. Based on this, we can determine the missing orientation.

关 键 词：水平井 弓形缺失 混浆 三维有限差分法 数值模拟 

分 类 号：P631.84[天文地球—地质矿产勘探]