Middle-deep layers in western South China Sea are distributed with reservoirs of strong heterogeneity and low permeability,complex sedimentary bodies like (fan) delta and water channels-submarine fans,complex temperature and pressure fields featured by high-temperature with normal pressure and high temperature with overpressure,etc.,as well as multi-stage hydrocarbon charging and actions by fluids like CO2 and meteoric fresh water,which bring challenges to the evaluation and prediction of reservoirs.In this paper,on the basis of the reservoir evolution and formation mechanism under complex sedimentary-diagenetic fields,features of lithofacies-reservoir facies of different and same sedimentary bodies have been depicted,features of regional sedimentary and diagenetic fields classified,the relationship between lithofacies,pore evolution while diagenesis,and fluid charging by oil and gas,etc.,clarified,the main factors of reservoir physical properties and genetic mechanism of effective reservoirs determined,the prediction model for reservoir physical properties with consideration of effects of various sedimentary bodies,temperature and pressure fields,and fluids built,favorable reservoir distribution delimited according to integrated main controlling factors of reservoirs,and physical features of favorable areas predicted.As a result,a series of technologies for the evaluation and prediction of favorable reservoirs in complex sedimentary and diagenetic fields have been formed,including the fine characterization of lithofacies and pore throat structure,quantitative recovery of pore evolution and prediction of reservoir physical properties in critical time points,quantitative evaluation of diagenetic-reservoir facies and prediction of favorable reservoirs.The series of technologies have been applied to the Miocene gravity-flow sedimentary channel-submarine fans and high-temperature and overpressure fields in the Yinggegai-Qingdongnan basins,which has pointed the way forward for the reservoir evaluation and discovery of deep commercial effective gas reservoirs;during their application in the (fan) delta and high temperature and normal pressure reservoirs in the Eocene Liushagang Formation of Wushi sag in Beibuwan basin,favorable zones have been successfully acquired and breakthroughs in commercial oil layers and deep exploration obtained.%南海西部海域中深层存在强非均质性和低渗储层,(扇)三角洲和水道-海底扇等复杂沉积体,高温常压和高温超压等复杂温压场,多期烃类充注及CO2、大气淡水等流体作用,给储层评价及预测带来了挑战.本文围绕复杂沉积-成岩场背景下储层演化与形成机制,通过刻画不同或相同沉积体储层岩相-储集相特征,划分区域沉积与成岩场特征,明确不同地质条件下岩相、成岩孔隙演化及其与油气等流体充注关系,确定储层物性主控因素与有效储层成因机制,建立不同沉积体、温压场、流体影响的储层物性预测模型,叠合成储主控因素圈定有利储层分布,预测有利区物性特征,形成了复杂沉积成岩场有利储层评价预测技术序列,包括岩相-孔喉结构精细表征技术、孔隙演化定量恢复及关键时刻储层物性预测技术、成岩-储集相定量评价及有利储层预测技术.该技术序列应用于莺歌海-琼东南盆地中新统重力流沉积水道-海底扇、高温超压领域,指导了储层评价及深层商业有效气藏发现;应用于北部湾盆地乌石凹陷始新统流沙港组(扇)三角洲、高温常压储层领域,成功评价了有利区带,钻探获得商业油层与深层领域性突破.
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