油气上窜速度相对时间法计算公式修正

Modification of the Relative Time Method Calculation Formula for Oil and Gas Up-Channeling Velocity

为提高油气上窜速度计算的科学性和准确性,解决迟到时间法等计算结果不准甚至为负值的问题,曾研究提出了计算结果更为准确的相对时间法。但目前钻井中已广泛使用钻具止回阀,下钻过程中井内钻井液全部从环形空间上返而不进入钻具内部,导致相对时间法的计算结果不再准确。为适应新的钻井工艺,须对相对时间法的计算模型和计算公式进行修正。为此,增加了下钻深度过油气层底部的计算公式,提供了3种井身结构、12种下入深度情形的新的系列计算公式。应用实例分析表明,修正后计算公式的可靠性和适用性得到了进一步提高。

In order to ensure the scientific and accurate calculation of oil and gas up-channeling velocity and solve the problem of inaccurate or even negative calculation results in the lag time method,a relative time method with more accurate calculation results has been proposed.However,check valves have been widely used in drilling,and the drilling fluid during drilling all return from the annular space without entering the drilling tool,making the calculation result of the relative time method no longer accurate.In order to adapt to the new drilling technology,the original calculation model and formula of the relative time method should be modified.Therefore,calculation formula for drilling bit depth under the bottom of the oil and gas reservoir were added,and a new series of calculation formula for three kinds of casing programs and twelve kinds of drilling depth were provided.The real cases showed that the reliability and applicability of the revised calculation formula were further improved.