利用声波时差检测地层孔隙压力的新方法

分析了声波时差资料的影响因素,介绍了进行预处理的方法,并根据有效应力定理,利用声波时差资料建立了地层岩石应力-应变关系的物理模型和压力计算的力学模型。计算过程为:1.利用声波时差测出声速;2.利用声速求出有效应力;3.利用密度测井方法计算出上覆岩层压力;4根据上覆岩层压力和有效应力求出地层孔隙压力。通过在塔里木盆地的大宛齐、羊塔克等地区的应用研究表明,预测粘度高,满足工程要求。该方法与"传统方法"相比,其最大特点是不需建立趋势线,大大减少了人为因素对检测结果的影响,适用于连续和非连续沉积地层的压力评价需要。

NEW METHOD OF FORMATION PORE PRESSURE DETECTION BY INTERVAL TRANSIT TIME

This paper analyzed the factors influence interval transit time data and introduced the method of pretreatment. According to the effective stress theorem, the physical model for stress-strain relationship of formation rock and the mechanics model for pressure calculation were set up by using interval transit time data. The calculation procedures are as follows: 1. Measure sound velocity with the use of interval transit time; 2. Get effective stress by using sound velocity; 3. Calculate the overburden pressure by density logging; 4.Get formation pore pressure according to overburden pressure and effective stress. The application in Dawanqi, Yangtake area and so on in Talimu Basin showed that the method have a high prediction accuracy and can meet the engineering requirements. Compared to the conventional method, its main characteristic is that it can reduce the effect of human factors on detection results greatly without setting up trend curves. It can be applied to the pressure evaluation for successive and non-successive sedimentary formations.