致密砂岩油气储层储集性能量化表征及其有效性评价

The tight sandstone oil and gas have become the preferred field in unconventional petroleum exploration and developmentin our country, due to its abundantreserves and high credibility of the recoverable resources. Reservoir is the soul of the tight sandstone oil and gas exploration and development, therefore, the quantitative characterization of reservoirs porosity, permeability and pore-throat structure, the genetic mechanism and evolution of densification and the distribution of high quality effective reservoirs have become the research hotspots and difficulties. Taking the tight sandstone oil and gas reservoirs in Ordos basin, Junggar basin, Bohai bay basin, and Songliao basin as the research objects, the research thinking of “characterizingphenomenon, exploring the nature and summarizing the rules”will beadopted. Based on the deposition model and diagenesis model, this project will establish the quantitative characterization model of rock fabric in tight sandstone oil and gas reservoirs. Then based on the quantitative characterization model of rock fabric， combining the study on the characterization parameters of pore-throat structure, characterization model of reservoir porosity-permeability and microscopic pore-throat stucture in tight sandstoneoil and gas reservoirswill be established.Based on the recovery of reservoir physical parameters constrained by rock fabric and diagenesis evolution, the genetic mechanism of densification of tight sandstone reservoirs and its evolution model will be established. Based on the calculation of the effective exploitation lower limit of physical parameters of the tight sandstone oil and gas reservoirs, the method of classifying and evaluating the effectiveness of tight sandstone oil and gas reservoirs will be built, and the distribution of high quality effective reservoirs will be summarized. These results will provide theoretical basis and technical support to the exploration and development of terrestrial tight sandstone oil and gas.

致密砂岩油气储量丰富、可采资源量可信度高，已成为我国非常规油气勘探开发的首选领域。致密砂岩油气勘探开发的灵魂是储层，储层物性及孔喉结构量化表征、致密化成因及其演化、优质有效储层分布规律已成为研究热点和难点。本项目以鄂尔多斯盆地、准噶尔盆地、渤海湾盆地、松辽盆地等致密砂岩油气储层为研究对象，遵循“现象表征-本质探索-规律总结”的研究思路，以沉积模型和成岩模型为基础，建立致密砂岩油气储层岩石组构量化表征模型；以岩石组构量化表征模型为基础，结合储层微观孔喉结构特征表征参数探讨，建立致密砂岩油气储层孔渗和微观孔喉结构表征模型；以岩石组构和成岩演化约束下储层物性参数演化恢复为基础，建立致密砂岩油气储层致密化成因及演化模式；以致密砂岩油气储层有效开发物性下限计算为基础，建立致密砂岩油气储层有效性分类评价方法，总结优质有效储层分布规律。研究成果将为陆相致密砂岩油气勘探开发提供理论依据和技术支撑。

致密砂岩油气勘探开发的灵魂是储层，储集性能量化表征、致密化机理及有效储层分布规律已成为研究热点和难点。本项目以准噶尔盆地、松辽盆地及渤海湾盆地等致密砂岩油气储层为研究对象，开展了储集性能量化表征及其有效性评价研究。致密砂岩储层发育纳米级孔喉系统，平均孔隙半径分布范围为128.97μm-152.31μm，平均喉道半径分布范围为0.197μm-0.869μm。沉积成岩综合相对致密砂岩储层品质指数（RQI）具有较好的约束，以沉积成岩综合相为基础，根据其良好的测井响应特征，建立了储层储集性能表征参数的分布图版，进而对致密砂岩储层储集性能进行量化表征。根据储层成岩特征及作用机理，结合地质历史时期物性演化可知，对于不同研究区，压实作用均是储层致密化的主导因素，而胶结作用最终决定了储层致密化的形成。根据胶结作用发生时间与油气充注的关系，本次研究共划分了“先致密，后成藏”、“先成藏，后致密”与“边成藏，边致密”三种典型的致密砂岩油气藏。其中，“先致密，后成藏”型致密砂岩油气藏，储层经历压实作用之后，一般发生了先于油气充注的早期胶结作用；“先成藏，后致密”型致密砂岩油气藏，储层经历压实作用之后，物性仍然较好，油气充注发生于胶结作用之前；“边成藏，边致密”型致密砂岩油气藏，储层经历了压实作用之后，物性接近致密，随后胶结作用与油气充注过程伴随。对于 “先致密，后成藏”型致密砂岩，孔喉结构及其配置关系控制油气能否进入储层，而润湿性改变则影响油气在储层中如何聚集；对于“先成藏，后致密”致密砂岩，成储过程主要受油气的选择性富集控制，与储层致密前的物性、成岩过程、油气充注之间存在密切关系。以致密砂岩油气储层有效开发物性下限计算为基础，基于有效储层控制因素分析，以渗透率差值为母因子，借助灰色关联分析，开展储层综合评价分类，进行了“地质甜点”评价；以致密油储层产能为基础，以试油日产液量为评价参数，以产能控制因素为约束，采用灰色关联的方法，进行了“经济甜点”评价。