Yuan Bin, Yang Shuo, Xu Bihua, Zeng Shunpeng, Li Pingchuan
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China.
School of Petroleum and Natural Gas Engineering, Chongqing University of Science and Technology, Chongqing 401331, China.
ACS Omega. 2022 Oct 19;7(43):38796-38810. doi: 10.1021/acsomega.2c04463. eCollection 2022 Nov 1.
An excellent flushing efficiency evaluation device is indispensable for studying the cementing flushing fluid. However, the existing flushing efficiency evaluation device cannot simulate the formation and flushing process of the downhole mud cake. Therefore, this paper proposes a novel flushing efficiency evaluation device that can simulate the formation and flushing of downhole mud cakes. The rotational speed of the device during flushing and the rotor's diameter is deduced based on the principle of equal wall shear rate. The evaluation device and method can be used to quantitatively evaluate the flushing efficiency of the flushing liquid on the mud cake under high temperatures and high pressures. This device analyzed the effects of the annular gap, temperature, construction displacement, and flushing fluids on flushing efficiency. The results show that the smaller the annular gap, the higher the temperature, the larger the displacement, the higher the scouring efficiency, and the higher the shear bond strength. Fiber flushing has the dual function of mechanical and chemical flushing, so its flushing efficiency is 14.75% higher than that of heavy flushing fluid at 10 min. The surfactant in the emulsified rinse leads to a sudden increase in rinse efficiency in the middle and late stages. The reduced flushing efficiency of the flushing fluid is due to the reduced ζ potential.
对于研究固井冲洗液而言，一种出色的冲洗效率评估装置必不可少。然而，现有的冲洗效率评估装置无法模拟井下泥饼的形成及冲洗过程。因此，本文提出了一种新型冲洗效率评估装置，该装置能够模拟井下泥饼的形成与冲洗过程。基于等壁面剪切速率原理，推导了冲洗过程中装置的转速以及转子直径。该评估装置及方法可用于定量评估高温高压条件下冲洗液对泥饼的冲洗效率。此装置分析了环空间隙、温度、施工排量和冲洗液对冲洗效率的影响。结果表明，环空间隙越小、温度越高、排量越大，冲刷效率越高，剪切粘结强度也越高。纤维冲洗具有机械冲洗和化学冲洗的双重作用，因此在10分钟时其冲洗效率比重冲洗液高14.75%。乳化冲洗液中的表面活性剂导致冲洗效率在中后期突然升高。冲洗液冲洗效率降低是由于ζ电位降低所致。
