A油田花岗岩潜山裂缝型储层分类评价方法

Reservoir Classification and Evaluation Method of the Granite Buried Hill in the A Oil Field

摘要: A油田是以中生界花岗岩侵入体为主要岩性的潜山油气藏，储集空间类型包括裂缝和孔隙，具有双重孔隙介质特征。受构造运动和风化作用的双重影响，潜山纵向上具有明显分带性，自上而下依次为极强风化带、强风化带、次风化带和弱风化带，顶部局部发育坡积砂。研究证明储层储集空间类型的发育很大程度上受潜山分带的控制，自上而下依次为孔隙型、裂缝–孔隙型、孔隙–裂缝型和裂缝型，各风化带横向分布相对稳定，呈现“似层状”的储层分布模式。其中，强风化带储集空间类型为裂缝–孔隙型、孔隙–裂缝型，是主要的产层段。以物性分析数据为基础，综合测井解释、FMI、压汞实验等资料将潜山储层分为I、II、III、IV类，优选深、浅侧向电阻率曲线、中子曲线以及密度曲线等能敏感反映不同类别储层差异的曲线，建立了中子–电阻、中子–密度交会图版，基于潜山分层模式，结合交会图版，对潜山储层进行划分和识别，取得了较好的效果。

Abstract: A oilfield is a buried hill reservoir and the main lithology is the Mesozoic granite intrusion. The reservoir space types include pore, fracture and have the characteristics of dual porosity media. Influenced by tectonic movement and weathering, the vertical reservoir has obvious zoning fea-tures. From top to bottom in turn for highly weathered zone, strong weathered zone, weathered zone and weak weathered zone, and on the top of the buried hill is the diluvial sand. Studies prove that reservoir space types of the reservoir development are largely controlled by buried hill zone, from top to bottom in turn for pore type, fracture-pore type, pore type and fracture type, the transverse distribution of the weathered zone is relative stability, and presents the characteristic of “layer” model of reservoir distribution. The reservoir space types of strongly weathered zone are fracture-pore type; pore-fracture type is the main reservoir section. On the basis of petrophysical analysis data and comprehensive logging interpretation and FMI, mercury injection experiment and data, the buried hill reservoir is divided into Class I, II, III, IV, optimizing deep and shallow lateral resistivity curve, neutron and density curve which can reflect the different types of reservoir sensitivity difference curve, establishing the neutron-resistance and neutron-density intersection chart. Based on the buried hill layered model, combining with the SEC chart, the reservoir is classified and evaluated, good results have been achieved.