致密砂岩微-纳米孔喉体系中油赋存特征和可动性研究

The growing energy demand with continuously increasing consumption of conventional oil and gas resources has driven a new wave of exploration for oil and gas. In addition to exploration for conventional petroleum, unconventional oil and gas are attracting increasing attention, especially the exploration and development of tight oil with a great exploration potenital will give a release to the confused situtation. However, the micro- nanometers scaled pore system is the tight oil reservoir, which caused a major diffenece on the oil charging process from that of conventional oil. Whether oil can be flow or not? the onset condition of it, the storage state and the flow characteristics are unclear, which blocks the process of tight oil explaration and development. In this applicaton, we decide to use the conventioanl experiments (XRD, porosity and permeability measurements) and unconventional methods (rate-controlled mercury penetration, NMR, ESEM, CT-Scanning and displacement system of oil & gas experiments) to study the state of tight oil and retention space; the mobility oil saturations, oil distritution ranges in the micro- nanemeters scaled pore system; the tight oil charging process. In aim to reveal, (1) the storage state of tight oil and the onset pressure condition of oil flow; (2) mobility oil saturations and oil distribution ranges in the micro- nanemeters scaled pore system; (3) the plates of properties of tight sand for oil charging. This research will help much for revealing the tight oil storage mechanism and its formation mechanism.

随着社会发展对能源需求的日益增加和常规油气资源开发的逐渐枯竭，油气供需矛盾凸显。发展我国非常规油气资源，尤其是具有巨大资源潜力的致密油的勘探开发，是缓解这一矛盾的重要举措。然而储集在微-纳米孔喉体系中的致密油的赋存状态、赋存孔径、是否可动，以及流动规律方面的研究还十分薄弱，影响了致密油的勘探开发。本申请综合利用非常规测试手段（恒速亚汞、高压压汞、N2低压吸附、核磁共振、环境扫描、CT扫描及充注成藏物理模拟等实验）和常规测试手段（XRD、物性测试），重点开展微-纳米孔喉体系中油的赋存特征、可动流体饱和度与可动流体分布孔径范围、以及致密油充注成藏物理模拟研究，达到揭示致密油的赋存状态和可动的启动压力条件、确定可动流体分布孔径范围与相对贡献、建立致密油成藏物性下限图版的目的。这一研究对于完善致密油赋存机理和成藏机制内容方面有重要科学意义。

微-纳米孔喉体系中油的赋存状态、赋存孔径、可动性，以及流动规律一直制约着致密油的勘探开发。基于我国典型盆地致密储层的物性、孔喉结构、油气显示与产能等资料，确定了我国典型盆地的成储下限和分级评价标准。在分级评价标准的基础上，开展不同级别的致密岩石非常规测试手段（恒速压汞、高压压汞、低温N2吸附、核磁共振、扫描电镜、CT扫描）、常规测试手段（XRD、物性测试）及充注模拟实验，并取得以下重要成果：1）依据水膜厚度法厘定理论下限、经验统计法厘定成藏下限、试油产能法厘定工业下限、力学平衡法厘定致密储层上限，结合孔喉结构法建立分级界限，建立了一套致密储层成储下限和分级评价研究方法；2）基于ESEM、FE-SEM、铸体薄片镜下观察、结合高压压汞、恒速压汞、低温氮气吸附和核磁共振等实验手段方法，形成了一套全方位、多角度、多尺度的致密储层孔隙结构表征技术手段，揭示了齐家-龙虎泡地区高台子油层各小层不同沉积相储层储集空间类型和微观孔喉结构特征；3）基于自主研发了核磁-驱替联用装置，物理模拟了松辽盆地高台子、三塘湖条湖组、芦草沟组致密油充注过程，揭示了致密砂岩微-纳米孔喉体系中油赋存状态、可动的启动压力条件，建立了致密油充注模式；结合微纳米CT、Qemscan等实验手段，建立致密储层三维数字岩心，采用格子玻尔兹曼方法模拟了致密油的充注过程，模拟了致密油的充注过程，考察了不同模拟因素（充注速率、润湿性、充注动力、裂缝）对充注中油赋存状态、可动的启动压力条件的影响；4)采用核磁离心、驱替以及渗吸三种手段研究了齐家-龙虎泡地区致密储层流体的可动性，对比了不同方法表征致密储层流体的可动性差异，揭示了高台子致密储层中流体可动性的主控因素；5)致密油高产和分布受控于超压、储层质量及岩石的润湿性。超压、强充注是致密油高效聚集的先决条件，优质储层是致密油高效聚集的前提保障，岩石润湿性对致密储层含油饱和度有重要的影响