隔夹层成因、特征及其对油田开发的影响——以塔中地区海相砂岩储层为例

 储层隔夹层是流体在储层中流动的重要影响因素之一。开展储层隔夹层认识和表征研究对油田中后期剩余油分布研究及开发方案的编制有着重要意义。本文针对塔里木盆地塔中地区东河砂岩段海相砂岩储层,以岩心观察为基础,分析隔夹层的成因机理,将其分为沉积作用和成岩作用形成的两大类隔夹层。从岩心井隔夹层识别入手,开展电性特征对比、物性分析资料研究,识别出泥质、钙质和物性3类隔夹层,确立了非取心井隔夹层划分识别标准。进一步探讨了隔夹层的厚度、分布范围、垂向渗透率和产状4个主要因素在油田开发中的控制作用。隔夹层对油水的封堵能力与厚度、分布范围呈明显的正相关,垂向渗透率决定着注入水向上向下的波及程度和速度,顺夹层倾向方向注水往往易形成剩余油富集区。

Origin,Characteristics and Effects on Oilfield Development of Interlayer of Shore Sandstone Reservoir in Tazhong Area

The reservoir interlayer is an important factor in the flow in the reservoir. The reservoir interlayer and the characterization of the oil field are closely related to the oil distribution remained from the mid-later period and the development of the oilfield. Based on the core observation, in view of the Tarim basin in Donghe Marine sandstone reservoir in Tazhong area, this paper analyzes the mechanism of the origin of the interlayer, which is divided into two major types, formed by deposition and diagenesis. With electrical characteristics comparisons and the data of physical properties, three types of interlayer are identified, including mud, calcium and properties, and an inter-layer identification standard of non-core wells is established. Its role in the control of the oilfield development is discussed from the aspects of the thickness, distribution, vertical permeability and the attitude of the interlayer. The sealing capacity of oil and water of the interlayer has positive relationships with its thickness and distribution. Vertical permeability decides the degree and speed of the injection water moving up and down. Water injection along the tendency direction of the interlayer is often liable to form the remaining oil-rich region.