利用声波时差资料研究泥岩盖层封闭能力的方法

Method for researching on mud-caprock sealing ability with the use of interval transit times

目前，盖层封闭性研究由于受并点数、取心和实验经费等因素的限制，只能用有限个实验数据来研究盖层的封闭能力，使盖层评价的准确性受到影响。本文为了获取更多的盖层封闭性信息，在分析盖层毛细管和压力封闭机理及主要影响因素的基础上，通过声波时差与泥岩排替压力、声波时差与泥岩异常孔隙流体压力之间的函数关系的确定，讨论了利用声波时差研究泥岩盖层毛细管封闭能力在剖面上和平面上的变化特征，以及压力封闭能力和其形成时期的方法，为盖层封闭性的准确评价提供了可靠依据。

Restrained by borehole number,coring,experiment cost and so on,people onlyuse limited experimental data to analyse mud-caprock sealing ability,thus greatlyinfluencing on accuracy of caprock evaluation. In order to get more informations ofcaprock sealing,we discuss how to use acoustic interval transit times to analyse thevertical and lateral variations of capillary sealing character in mud caprock,the pressure sealing ability and the formation age by analysing the capillary and pressuresealing mechanisms, and the important influence factors, and by determining thefunction relations between acoustic interval transit time and displacement pressureof mudstone, and between acoustic interval transit time and abnormal pore fluidpressure of mudstone. The method described in the paper offers the reliable basisfor accurately evaluating mud-caprock sealing ability.