济阳坳陷页岩油气评价方法——以沾化凹陷罗家地区为例

Discussion on an evaluation method of shale oil and gas in Jiyang depression:a case study on Luojia area in Zhanhua sag

页岩油气是一种非常规的油气资源,陆相断陷盆地的特点决定了页岩油气勘探的复杂性,没有现成的经验可以借鉴。通过对济阳坳陷罗家地区页岩油气的剖析,初步建立了陆相断陷盆地页岩油气评价方法。通过油气地质条件分析,确定页岩油气有利区,建立目标区高频层序地层格架,明确泥页岩时空分布;根据岩石结构、构造、成分及颜色等进行泥页岩类型细分,建立岩相分类标准,利用测井资料对优质岩相进行标定、追踪和预测;以地球化学分析和生烃模拟为手段,分析有机质丰度、类型、成熟度等参数,确定页岩油气生烃地化参数标准与油气赋存特征;利用岩心观察、薄片鉴定、电镜分析、荧光观察等技术进行页岩储集空间类型、组合及发育特征研究,结合储集物性分析,进行储集性能评价;利用岩心分析、测井解释和试油试采资料,建立饱和度模型,评价可动烃含量,开展含油气性综合判识;分析产能影响因素,结合岩石可压性,预测页岩油气产能和勘探前景。综合岩相、源岩、储集性、含油气性和产能等多因素分析,将罗家地区泥页岩划分为Ⅰ类(高孔高阻类)、Ⅱ类(中孔中阻类)和Ⅲ类(低孔中阻类)3种类型,并部署了渤页平1等3口水平井。

Shale oil and gas are one of the unconventional hydrocarbon resources. Characteristics of continental rifted basins determine the complexity of the shale oil and gas exploration in such a basin and no existing experience can be used for reference. Through a study on the Luojia area in the Jiyang Depression, an evaluation method for shale oil and gas in continental rifted basins was prelimi- narily established. With which a favorable area of shale oil and gas was determined based on the analysis of petroleum geological con- ditions and a high-frequency sequence stratigraphic framework of the target area was consequently built up, where shale spatial and temporal distribution could be confirmed. A shale lithofacies classification criterion was established according to rock textures, struc- ture, composition and color, and high-quality lithofacies were demarcated, tracked and forecasted with logging data. Abundance, types and maturity of organic matter were analyzed by means of geochemical analyses and hydrocarbon generation simulation, and ge- ochemical parameter criteria for shale hydrocarbon generation and occurrence were determined as well. A model for the interpretation of reservoir logging parameters was established through studying space types, combination and evolution of shale reservoirs by means of core observation, thin-section analysis, electron microscopy and fluorescence spectrometry. The reservoir performance was evalua- ted combined with the analysis of reservoir phy＇sical properties. A saturation model was established based on core analysis, logging interpretation, and well-test and production-test data in order to evaluate movable hydrocarbon contents and carry out integrated i- dentification of oil potential. Finally, the prediction of shale oil and gas production and exploration prospects in the study area was made by analyzing influential factors of deliverability and rock compressibility. Through comprehensive evaluations on lithofacies, source rocks, accumulation quality and deliverability, shales in the Luojia area were divided into three types, i.e. type Ⅰ （high poros- ity and high resistance）, type Ⅱ（medium porosity and medium resistance） and type Ⅲ（low porosity and medium resistance）. Guided by this division, three horizontal wells including Well Boyp-1 were located.