特低渗透砂岩油藏自发渗吸-水驱原油动用规律研究  

Investigation on law of oil production by spontaneous imbibition and water flooding in ultra-low permeability sandstone reservoirs

作　　者：陈辉 CHEN Hui(Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying City,Shandong Province,257015,China)

机构地区：[1]中国石化胜利油田分公司勘探开发研究院,山东东营257015

出　　处：《油气地质与采收率》2025年第2期94-103,共10页Petroleum Geology and Recovery Efficiency

基　　金：中国石化科技攻关项目“特低渗透油藏未开发储量效益开发关键技术”(P24021)。

摘　　要：压驱注水技术解决了胜利油田特低渗透砂岩油藏“注不进、采不出”的问题,但压驱的焖井和水驱过程中油水置换规律以及各尺度孔隙中原油动用规律尚不明确。针对上述问题,以东营凹陷特低渗透砂岩油藏为研究对象,开展自发渗吸实验和水驱实验,采用高温高压核磁共振仪研究自发渗吸和水驱过程中油水分布演化特征。结果表明:东营凹陷特低渗透砂岩饱和油T2谱主要分为单峰和双峰,其中双峰又分为左峰高和右峰高2类。T2谱呈单峰分布、孔隙结构呈网状分布的砂岩,通过焖井过程中的自发渗吸可以大幅度动用孔隙中的油相;对于T2谱呈双峰分布、孔隙结构呈树枝状分布的砂岩,自发渗吸后仍有大量油相未被充分动用,通过水驱可进一步提高采出程度。自发渗吸更多动用的是微孔和中孔中的油相,而大孔中油相的采出程度对采收率的贡献较小。自发渗吸后转水驱,采出程度可进一步提高,此时更多的是动用大孔和中孔的油相,而微孔中的油相采出程度则较低。Pressure drive-based water injection technology has solved the problem of“no injection and no production”in ultra-low permeability sandstone reservoirs in Shengli Oilfield,but the law of oil-water displacement and the percentage of oil production in pores at different scales in the process of pressure drive-based shut-in and water flooding are still unclear.In order to solve the above problems,spontaneous imbibition and water flooding experiments were carried out in the ultra-low permeability sandstone reservoirs in Dongying Sag,and the evolution characteristics of oil-water distribution during imbibition and water flooding were studied by high temperature and high pressure nuclear magnetic resonance(NMR).The results show that the T2 spectrum of saturated oil in ultra-low permeability sandstone in Dongying Sag is mainly divided into single peak and double peak,and the double peaks are further divided into left peak height and right peak height.The most oil phase in the pores of the sandstones with an unimodal T2 spectrum and network pore structure can be produced through spontaneous imbibition during shut-in.For sandstones with a bimodal T2 spectrum and dendritic pore structures,a large amount of oil phase is still unproduced after spontaneous imbibition,and the oil recovery can be further improved by water flooding.The oil in micropores and mesopores can be produced through spontaneous imbibition,but the contribution of oil recovery in macropores to total oil recovery is less.When spontaneous imbibition is followed by water flooding,the recovery is further improved,and more oil in macropores and mesopores is produced,but the oil in micropores is less produced.

关 键 词：核磁共振 特低渗透砂岩油藏 自发渗吸 水驱 提高采收率 

分 类 号：TE312[石油与天然气工程—油气田开发工程]