砂质辫状河隔夹层成因及分布控制因素分析

厘清砂质辫状河隔夹层成因、掌握其分布控制因素对该类储层的开发大有裨益。以苏里格气田盒8段砂质辫状河储层为例，综合现代沉积、露头、岩心及测井等动静态资料，分析隔夹层成因特征，建立各类隔夹层测井识别模板，采用密井网多井联动、平面剖面结合的分析思路，构建各类隔夹层的三维地质模型，明确了基准面旋回、构型界面及砂体叠置样式等对隔夹层分布的控制机理。结果表明:泛滥平原、坝间泥、废弃河道、落淤层以及冲沟是构成盒8段辫状河隔夹层的主要类型。泛滥平原规模较大、分布连续，宽度为100~1 000m；单一坝间泥长宽比规律不强，宽度一般在300m以内；废弃河道样式由河道废弃方式决定，宽度为40~330m；落淤层分布受增生体大小以及落淤层发育位置决定，宽度为10~190m；冲沟分布分散，宽度一般小于100m。其中，基准面旋回升降控制隔层厚度，构型界面决定夹层分布位置及倾向倾角，砂质辫状河砂体叠置样式约束各类隔夹层比例及大小。

Genesis and distribution controlling factors of interlayers in sandy braided river: Case study of He8 section in Sulige Gasfield

Making clear distribution characteristics of the interlayer and its controlling factors are of great benefit to the development of sandy braided river reservoirs. Taking the braided river reservoir of He8 section of Sulige Gasfield as an example, the characteristics of modern sedimentary, outcrop, core and logging are combined to analyze the genetic characteristics of interlayers. The logging identification template of various interlayers is established. The three-dimensional geological model of various interlayers is constructed by using the multi-well linkage and flat-section analysis of the well network, and the distribution mechanism and controlling factors of the interlayers are defined. The results show that the floodplain, intercalation between bars, abandoned channel, falling-silt seams and chute are the main types of braided river interlayers. The floodplain has a large scale and continuous distribution with a width of 100-1 000m. The length to width ration shows irregularity in single intercalation between bars, and the width is less than 300m.The abandoned channel pattern is determined by the river disposal mode, and the width is 40-330m. The distribution of the silt layer is determined by the size of the accretion and the development position, and the width is 10-190m. The gully are of scattered distribution, and the width is generally less than 100m. The base level cycle controls the thickness of the partition. The configuration interface determines the distribution position of the interlayer and the inclination angle. The superimposed style of the braided river limited the proportion and size of the interlayer.