渤海湾盆地牛东1超深潜山高温油气藏的发现及其意义

Niudong 1 ultra-deep and ultra-high temperature subtle buried hill field in Bohai Bay Basin: Discovery and significance

冀中坳陷霸县凹陷牛东1井在蓟县系雾迷山组获得了石油642.9 m3/d、天然气56.3×104 m3/d的特高产油气流,从而发现了渤海湾盆地乃至中国东部目前埋深最大、温度最高的潜山油气藏。牛东1井钻探揭示,油气藏底部深度已达6 027 m仍未见油水界面,温度已达201℃。该潜山油气藏的发现经历了初战失利、再战搁浅、重燃希望、重大突破4个阶段30余年的探索,高精度二次三维地震勘探及抗高温深度体积酸压改造为其圈闭发现和获得高产提供了关键技术支持。该超深潜山油气藏高产富集的主要因素:①深层沙四段—孔店组发育巨厚优质高成熟烃源岩,油气源充足;②潜山储集物性好,基本不受埋深的影响;③成藏条件匹配好,具有圈闭早形成并被烃源岩包围,以及油气早充注、持续充注、高压充注的成藏优势。牛东1潜山油气藏的发现对于推动渤海湾盆地超深层潜山油气勘探具有重要的里程碑意义。

Niudong 1 Well,which recorded a prolific oil flow of 642.9 m3/d and gas flow of 56.3×104m3/d,discovered a buried hill field in the Baxian Depression,Jizhong Sub-basin,Bohai Bay Basin.The reservoir of this field is the deepest and its temperature is the highest in the Bohai Bay Basin or even in East China.The well has a total depth of 6 027 m at which the reservoir is saturated with oil and oil-water contact is not found.Its bottom hole temperature is up to 201℃.The exploration of this field has experienced 4 stages： Initial failure,suspension of renewed exploration,regained hope and great breakthrough,which last over 30 years.High resolution repeated 3D seismic prospecting and hydro-fracturing with high temperature-resistant acid played vital roles in finding the buried hill trap and obtaining prolific oil and gas flows.The hydrocarbon richness and prolific production rate of this field are attributed to the following three main factors.①Thick excellent highly matured source rocks are developed in the deeply buried from Sha 4 Member to Kongdian Formation so that abundant hydrocarbons could be generated.②Reservoirs of the buried hill field possess good petrophysical properties,which are generally not affected by the burial depth.③The buried hill trap was formed early and characterized by early charging,sustained charging and overpressured charging.The good matching of timing of hydrocarbon charging and trap formation favored the hydrocarbon accumulation and entrapment.The discovery of Niudong 1 Well is of milestone significance in promoting exploration of ultra-deep buried hill fields in the Bohai Bay Basin.