实测迟到时间法计算油气上窜速度的探讨

Calculation of oil and gas velocity with measured lag time method

以研究精确计算油气上窜速度为目的,基于对影响油气上窜速度计算值精确性的因素和国内现有"油气上窜速度计算方法"的分析,提出了计算油气上窜速度的新方法——实测迟到时间法。该方法在应用于后效气钻头下深迟到时间实测时,用电石代替有色固体材料作指示剂,其优点是以气体指示剂做气体的迟到时间,消除了用固体指示剂测迟到时间时由于重力下沉、岩屑床等因素影响造成的测定结果大于气体迟到时间的弊端,能更真实准确地获得钻头下深的气体迟到时间,同时对全烃初始峰取值时间做出了经验定义(即全烃基值2倍左右的时间点)。通过对理论迟到时间法计算油气上窜速度公式中全烃初始峰显示时间的准确确定和用实测迟到时间代替理论迟到时间,发现用实测迟到时间法计算出的油气上窜速度更符合实际。在吐哈油田12口井84次后效气录井应用表明,实测迟到时间法比理论迟到时间法计算的见油气显示时间误差可缩小25%左右。应用该方法计算过程简单、结果准确,最大限度地排除了影响计算油气上窜速度值精确性的因素,而且其迟到时间值为实际测得,故该方法可以推广应用于不同井型和不同井身结构的后效气录井作业中。

Making a study of the precise calculation of oil and gas velocity,based on analyzing the factors of influencing the calculation accuracy on oil and gas velocity and the domestic existing 'calculation method for oil and gas velocity',the authors put forward a new method to calculate oil and gas velocity-measured lag time method.When the method is applied to measure lag time of aftereffect gas that the bit runs in depth,the acetylene stones instead of colored solid materials were used as indicators,whose advantage is that gas indicator is used as gas lag time,eliminating the shortcoming of solid indicator′s lag time is bigger than gas lag time due to the factors such as gravity settling,cuttings bed,it can be more accurate to get gas lag time that bit runs in depth.At the same time,the experience definition was made to determine the time of appearing the initial peak of total hydrocarbon,namely the time point of 2times of the total hydrocarbon base value.The oil and gas velocity that is calculated by the measured lag time method is more practical through the accurate determination of the initial peak of total hydrocarbon in the formula of theoretical lag time method to calculate oil and gas velocity and using the measured lag time to replace the theoretical lag time.84 aftereffect gas logging application in 12 wells of Tuha Oilfield showed that the error of the measured lag time method is 25%less than that of the theoretical lag time method.Calculation process of the method is simple and results are more accurate,which reaches the limit of counteracting the effects on accurate calculation of oil and gas velocity,and the lag time value is actually measured,so the method can be applied in aftereffect gas logging in different well types and well bore structures.