基于稀疏井网条件下的古辫状河道心滩砂体估算——以苏里格气田苏X区块为例

在辫状河沉积环境中，心滩是油气储集的重要场所，如何从已钻井资料中识别心滩并进行平面组合，进而预测河道内部心滩平面展布规律，是正确认识辫状河沉积的基础。针对苏里格气田苏X区块小层划分与对比、沉积微相平面分布等精细地质研究不够深入和单井产量及最终采收率均较低等问题，基于测录井、野外露头和现代卫星图片等资料，在精细划分地层的基础上，利用单期河道砂厚中心连线法、心滩测井相分异法、心滩雷达图和心滩预测技术对研究区进行单期河道和钻遇心滩的识别与刻画、心滩雷达图的绘制以及预测心滩的刻画。结果表明：研究区盒8下1-1和盒8下1-2单层均发育3支河道；河道内心滩分别给定长厚比60∶1～80∶1、宽厚比30∶1～40∶1、长宽比2∶1～3∶1，心滩长度一般为300～1 100 m，宽度一般为150～550 m；单期河道砂厚与心滩在单一河道内发育的个数呈反比。后期加密井钻探结果显示心滩雷达图和心滩预测技术均具有较高的可信度。上述方法可提高心滩钻遇率，便于后期加密井及水平井的大规模部署，有助于提高油气采收率，为相似地层结构和井网密度的工区在研究砂体平面分布和空间叠置规律方面提供参考。

Estimating method of braided channel bar under sparse well net: a case from Su X block in Sulige Gas Field

In the braided river sedimentary environment,braided channel bars are more important reservoir sand body for oil and gas accumulation. How to identify braided channel bars by drilling well data,and then combine in plate,moreover,predict the distribution of channel bars,is the foundation for correctly understanding braided river deposits. The fine geological study of fine subzone division and correlation and sedimentary microfacies distribution in Su X block of Sulige Gas Field is insufficient,and single well yield and ultimate recovery are low. Based on the data of logging,field outcrop and modern satellite images,combined with fine stratum classification,sand thickness center line connecting method,braided bar logging phase separation method,radar map of braided bar and braided bar prediction technology,were used to identify and characterize single channel and braided bar,compile the radar map of braided bar and predict the braided bar. The results show that the layer of 1-1 and 1-2 of the lower He 8 member both developed three channels. The braided bar is given a length to thickness ratio of 60:1-80:1,a width to thickness ratio of 30:1-40:1,and a length to width ratio of 2:1-3:1, while the length is 300-1 100 m and the width is 150-550 m. The single channel sand thickness is inversely proportional to the number of braided bar. The results of infill wells show that the radar map of braided bar and prediction technology both have high credibility. The above methods can improve the drilling ratio of braided bar, provide a better condition for the arrangement of infill wells and horizontal wells and improve oil and gas recovery efficiency,and provide reference for the study of sand body distribution and space superposition in the block with similar stratum structure and well density.