投球调剖工艺技术研究

Studies on Technology of Water Injectivity Profile Modification by Using Rigid Plastic Balls as Perforation Closer

简介了注水井投球调剖机理,即在注水井吸水量大的层段,与注入水同步流动的、直径略大于炮眼直接的均质刚性塑料球,在注水压差作用下靠贴压实在炮眼上,将炮眼堵住,使注入水流向并进入其他层段。简介了调剖球的制造和物性。叙述了在模拟实验中得到的稳态条件下调剖球在注入管内受力情况和炮眼附近的流动场。介绍了投球调剖工艺,包括停注后重新开始注水时使调剖球复位的方法;调剖球的用量根据动态仿真模拟软件计算结果选定。本工艺已在中原7个区块的18口注水井应用,效果良好。介绍了在一口封隔器失效注水井上投球调剖的效果:注水压力由11MPa上升至16MPa,吸水曲线斜率增大,启动压力上升4.1MPa,对应油井(1口)产油量增加,含水下降。本工艺的优点有:工艺简单,安全,可靠,不动管柱,工作量小,不使用化学剂,费用低。图2参3。

The mechanisms involved in water injectivity profile modification (IPM) by using plastic balls as perforation closer are introduced concisely: the homogeneous rigid plastic balls of diameter larger than that of perforations flow synchronously with the injected water and approach to and are squeezed on the entrance of perforations in high water absorption zones (HWAZs) under the water injection pressure thus plug them and divert the water stream to other zones. The manufacture and physical characteristics of the balls are described briefly. The forces applied to the balls in stead state flow in the downhole pipeline and the flow field near a perforation entrance are presented on the basis of simulation experiments. The technology of performing IPM by this method includes the way of ball reenclose in the case of starting water injection after a shutdown period and the determination of the amount of balls needed by using a dynamic simulating modelling software. This technology has been put into use in 18 water injection wells in 7 districts of Zhongyuan with good results. In a water injection well with paker failured application of plastic balls to enclose the perforation in HWAZs leads to increase in injection pressure from 11 to 16 MPa and in startup pressure by 4.1 MPa, to raise of water absorption curve slope and to enhancement in oil productivity and water cut reduction in the connected well. The technology of IPM is featured by simplicity, safety, reliability, no need to move pipe strings, less labor, lower job cost, and no use of chemicals.