摘要
煤层气地层中的陷落柱不利于煤层气的保存,又易引起井壁垮塌,影响钻井工程质量,尤其是水平井。陷落柱的存在严重制约了煤层气开发效率,因此准确判断尤其重要。以沁南东三维区为例,根据陷落柱在地震剖面上的特征,优选了分频相干、形态指数、方差体等地震属性,准确地预测了该区陷落柱的平面分布规律。与常规地震剖面圈定的30个直径100~300m陷落柱相比,应用分频相干、形态指数、方差体等属性技术,圈定直径20~0m的陷落柱达40个,修正了陷落柱的大小及形态。本区的精细解释结果为井位部署,尤其是水平井位部署提供了技术保障。在全区的200口开发井中,由于避开了陷落柱,使低效井比例由前期的28%降低到10%,有效提高了水平井质量及单井日产气量。
The subsided column in strata is disadvantageous to CBM accumulation and easy to cause well collapse, impacting drilling quality, especially in horizontal well. It is seriously constraining CBM exploitation efficiency, thus accurate judgment of its existence is particularly important. Taking the 3D seismic prospecting area in southeastern Qinshui Basin as an example, based on subsided column features on seismic section, have optimized seismic attributes of frequency division coherent, morphology index, variance cube, etc. , and accurately predicted planar distribution of subsided columns in the area. Comparing with conventional seismic section have delinea- ted 30 subsided columns with diameter 100 - 300m, while through this technology delineated 40 subsided columns with diameter 20 80m, and corrected their sizes and shapes. The precise interpretation in the area has provided technical support for well location de- ployment, especially for horizontal wells. Since subsided column avoiding has made proportion of inefficient well lowered down from previous 28% to 10%, thus effectively improved horizontal well quality and single well daily output.
出处
《中国煤炭地质》
2017年第5期69-74,共6页
Coal Geology of China
基金
中国石油重大科技专项"煤层气地球物理综合评价技术研究"(编号:2013E-2202)资助
关键词
陷落柱
分频相干
形态指数
方差体
沁南东三维区
subsided column
frequency division coherent
morphology index
variance cube
southeastern Qinshui Basin 3D seismic prospecting area
