井径扩大率对岩屑迟到时间的影响校正

The correction for the influence of hole diameter enlarging rate on cutting lag time.

岩屑迟到时间理论计算公式是录井现场常用的公式,因其中井径常用钻头直径代替而忽略了井径扩大率,导致计算结果偏小。在对岩屑迟到时间的概念、理论计算公式及其影响因素进行分析的基础上,以中原油田东濮地区30口井的井径扩大率的统计分析为依据,引入了采用井径扩大系数消除由于井眼不规则而引起的理论计算迟到时间不够准确的校正方法。6口井的实例对比表明,采用校正方法计算出的迟到时间更为准确,对应的录井深度与测井深度值更为接近。

The theoretic computation formula for cutting lag time is commonly used on mud logging wellsite,and the computation result is lower than the real lag time as the hole diameter in the formula is often replaced by bit diameter and the hole diameter enlargement is neglected.On the basis of analyzing the concept,theoretic computation formula and its influence factors on the cutting lag time,taking the statistic analysis of hole diameter enlargement rate from 30 wells in Dongpu area of Zhongyuan Oilfield as the basis,the paper introduced the correction method for incorrect theoretic computation due to the irregular hole with the hole diameter enlargement factor.It was showed by practice in 6 wells that the lag time calculated by the corrected method was more accurate and closer to the corresponding mud logging and wireline logging depth.