井斜角对裂缝特征参数统计的影响及其意义
Impact of Wellbore Inclination Angle on the Statistics of Fracture Characteristic Parameters and Its Significance
赵中平1
作者信息
- 1. 西北大学大陆动力学国家重点实验室/地质学系，西安 710069
- 折叠
摘要
井轨迹对裂缝钻遇率有重要的影响。以某裂缝性碳酸盐岩油藏为例，利用100余口井的 FMI 资料按照小斜度井(包括直井)和大斜度井(包括水平井)分组分别统计裂缝的平均倾角、裂缝密度参数，并与不考虑井斜角利用所有 FMI 资料统计的结果相互对比，以分析井斜角对裂缝倾角、裂缝密度参数统计的影响。结果表明，按小斜度井钻遇裂缝统计的裂缝平均倾角和裂缝密度均明显低于按大斜度井和所有井未分组钻遇裂缝的统计结果；因此，小斜度井钻遇高角度裂缝的几率明显低于大斜度井。这一结论具有三方面的意义：对于本文中某裂缝性碳酸盐岩油藏，目前主要为直井和小斜度井钻遇的GH层，应部署水平井进一步评价其油气勘探潜力；为更准确地统计高角度裂缝性储层的裂缝倾角并客观地评价裂缝密度，应尽量利用井轨迹垂直于裂缝走向和主要裂缝面的水平井钻遇的裂缝来分析统计；对于同类高角度裂缝性油藏的勘探评价和开发，应尽量采用大斜度井和水平井并确保井轨迹垂直于主要裂缝面。
Abstract
Well trajectory has important impact on the drilling encounter ration of fractures.In order to study the influence of wellbore inclination angle on the statistics of fracture characteristic parameters, over 100 wells with FMI data are grouped into wells with small inclination angle (including vertical wells)and wells with large inclination angle (including horizontal wells).The author carried out the statistics of average fracture dip and fracture intensity by using FMI data of the two grouped wells respectively,and compared the results with the statistics derived from all ungrouped wells.It shows that the average fracture dip and fracture intensity are both smaller than the statistic results from the wells with large inclination angle and ungrouped wells.So,the drilling encounter ration of fractures for wells with small inclination angle is obviously smaller than the one for wells with large inclination angle. This conclusion is of significance in three aspects,first,for the G H layer of the fractured carbonate reservoir described,wells with large inclination angle should be drilled in order to further evaluate the oil exploration potential.Secondly,only the drilling and well data from the wells which are nearly perpendicular to the fracture surface should be used if we want to get accurately statistics of fracture inclination angle and a more objective evaluation of fracture density.In addition,for the exploration and development of the same high angle fractured reservoirs,it strongly suggests that slant wells with large inclination angle should be used.
关键词
井斜角/裂缝倾角/裂缝密度/裂缝性储层/碳酸盐岩/油藏Key words
wellbore inclination angle/fracture dip/fracture intensity/fractured reservoirs/carbonatite rocks/oil reservoir引用本文复制引用
基金项目
国家科技重大专项(2011ZX05023001002)
出版年
2014
NETL
NSTL
维普
万方数据