分砂层地质曲率分析在裂缝预测中的应用

APPLICATION OF SINGLE SANDLAYER GEOLOGIC CURVATURE ANALYSIS TO FRACTURE PREDICTION

胡宗全 廖红伟 刘人和

HU Zong-quan LIAO Hong-wei LIU Ren-he

中国石化, 勘探开发研究院, 北京, 100083 2. 西北大学, 地质系, 陕西, 西安, 710069 3. 中国石油, 勘探开发研究院, 廊坊分院, 河北, 廊坊, 065007

Research Institute of Exploration and Production, SINOPEC, Beijing 100083, China 2. Department of Geology, Northwest University, Xi'an, Shanxi 710069, China 3. Langfang Branch, Research Institute of Petroleum Exploration and Development, CNPC, Langfang, Hebei 065007, China

曲率分析是裂缝分布预测中的传统方法,并在长期的应用过程中被逐步改进.研究中使用的地质曲率就是一种新的地质层面曲率算法,该方法兼具数学上的严密性和地质上的实际意义.文中研究的地质对象是侏罗系某组的3个横向分布稳定的砂层.该地区以前的研究是运用整个组的顶面构造图来研究裂缝的分布规律,对构造与裂缝分布之间的内在关系仅停留在简单的和定性的认识上.为了搞清构造对裂缝分布的控制作用,作者通过三维地震精细解释各砂层顶面的构造图,用改进的地质曲率算法计算各砂层的顶面地质曲率,并运用地质曲率值作为裂缝预测参数.研究结果表明,各砂层的地质曲率分布规律和数值高低之间均存在显著差异,各层之间的曲率数值总体差异与各层之间的产能总体差异具有很好的匹配关系,各砂层在各井点处的自然产能高低与曲率值高低具有较好的统计相关关系.同时,曲率分析证实了研究区内构造复合关系的存在.研究发现,构造的叠合部位往往是裂缝的发育区.这些结论的得出对裂缝的钻前预测是十分有意义的.

As a traditional fracture-predicting method,curvature analysis was gradually improved in the long period of application. The geologic curvature used in this paper is a new kind of curvature-calculating method for geologic layers,which processes strictness in mathematics and practical significance in geology. The geologic targets of this research are three sandlayers with stable distribution laterally in a certain Jurassic formation. The previous research of this area investigated fracture distribution rules by the supersurface structural map of the overall formation;only a series of simple and qualitative conclusions were obtained about the relation between structure and fracture distribution. To reveal the controlling effect of structure upon fracture distribution,the structural map of each sandlayer supersurface was interpreted accurately with three-dimensional seismic data,the supersurface geologic curvature of each sandlayer was calculated with the new improved geologic curvature-calculating method,and the geologic curvature values were used as fracture-predicting parameters. Research outputs indicate that there are apparent differences between the distribution rules and values of geologic curvature for each sandlayer,the overall difference among the curvature values of each sandlayer has a very good matching relation with the overall difference among the production capacity of each sandlayer,and fine statistical relation exists between the natural production capacity and geologic curvature value of each well point in each sandlayer. Curvature analysis proved the existence of compound structures in the study area,and revealed that fractures often develop in the superimposed of structures. All this conclusions are of significance for fracture prediction before drilling.

https://doi.org/10.11781/sysydz200205450