斜井测井声波检测孔隙压力校正方法研究

RESEARCH ON PORE PRESSURE DETECTION USING DEVIATED WELL ACOUSTIC WAVES

针对斜井地层压力检测中的重要因素——泥页岩声波各向异性,提出测井声波各向异性因子计算模型及斜井测井声波校正方法,并利用其进行斜井地层压力计算。首先,在大量分析国内外实验数据和理论分析的基础上,提出泥页岩在地层应力条件下声波各向异性因子的线性-指数计算模型,指出声波各向异性因子的大小与泥页岩中泥质含量呈正相关关系,得到声波各向异性因子的计算模型;然后,在Hornby B.E.椭圆方程理论基础上,进行斜井声波数据校正;最后,对某油田一口大斜度井,利用其测井声波数据,进行地层孔隙压力检测。结果表明:校正后,部分井段测井声波校正量高达20%,地层压力计算精度平均提高了10%。与传统方法相比,该模型计算简捷,且考虑了泥质含量、地应力对泥页岩声波各向异性因子影响,斜井地层压力计算精度得到提高。

For the acoustic wave anisotropy in mud shale is one of the important factors in deviated well formation pressure calculation,a model of calculating the Thomsen parameter and a method of correcting the logging acoustic wave were proposed to calculate the deviated well pore pressure. Firstly,the linear-exponential calculation model of acoustic wave anisotropy parameter under the condition of mud shale in- situ stress was proposed and the positive correlation relationship with the shale content was analyzed. On the basis of these relationships,the calculation model of acoustic wave anisotropy parameter was built.Then,deviated well logging sonic data was corrected based on the Hornby 's elliptic equation theory. Finally,the methods were applied successfully in a deviated well,its formation pore pressure was calculated with using sonic log data by Eaton and Bowers model. The results showed that the correcting value could reach as much as 20% in some part of the well section and formation pore pressure calculation accuracy improve 10% on the average. Compared to the traditional methods,the calculation of this model is very simple,and the influence of shale content and terrestrial stress on acoustic wave anisotropy parameter is also considered. As a result of this,the formation pore pressure of deviated well is calculated more accurately.