小口径岩心钻探冲洗液流量计研制与应用

Development of drilling fluid flowmeter for small diameter core drilling

摘要:

小口径岩心钻探过程中，冲洗液流量监测困难。为了实时精确监测冲洗液流量，及时发现钻进过程中异常流量变化并进行调节和处理，确保钻头安全钻进，防止烧钻和埋钻等孔内事故发生，创新性地设计了一种基于浮子流量计基本结构、结合磁传导技术、可精确测量小口径冲洗液流量的流量计。分别设计了直线与环状刻度两种流量示数方案，并对直线刻度磁传导错位进行了试验，同时对浮子、锥管等主要零部件进行了参数优选试验。试验结果表明：采用8颗磁体时，主被动磁铁无错位现象；浮子直径33.8 mm、锥管两端直径52/34 mm的流量检测数据趋于线性，更适应实际需要。钻探现场应用情况表明：该冲洗液流量计具有良好的精度、灵敏度、适应性和可靠性，可实现孔内冲洗液流量的实时监测，减少孔内事故发生。

Abstract:

During small-diameter core drilling， monitoring drilling fluid flow is challenging. To enable real-time and accurate monitoring of flow rate， promptly detect abnormal flow changes during drilling， facilitate timely adjustment and handling， ensure drill bit safety， and prevent downhole accidents such as bit burning and pipe sticking， an innovative flowmeter has been designed. Based on the fundamental structure of a float flowmeter and incorporating magnetic induction technology， this flowmeter can accurately measure drilling fluid flow in small-diameter drilling. Both linear and annular scale display schemes were designed for flow indication. Tests were conducted to address magnetic misalignment in the linear scale system， and parameter optimization experiments were carried out on key components such as the float and tapered tube. The results show that when eight magnets are used， no misalignment occurs between the active and passive magnetic assemblies. The flow measurement data exhibit a highly linear trend when using a float diameter of 33.8mm and a tapered tube with end diameters of 52mm and 34mm， making it more suitable for practical applications. Field tests in drilling operations demonstrate that this drilling fluid flowmeter offers high accuracy， sensitivity， adaptability， and reliability. It enables real-time monitoring of downhole drilling fluid flow， thereby helping to reduce the occurrence of downhole accidents.