大安油田扶余油层裂缝发育特征研究

发布时间：2018-06-30 18:11

本文选题：大安油田 + 微裂缝　；参考：《东北石油大学》2015年硕士论文

【摘要】：大安油田区域构造位置位于松辽盆地中央坳陷区大安-红岗阶地二级构造带中。目的层为下白垩统泉头组扶余油层,是典型的低渗透砂岩油田。储层物性差,非均质性强,裂缝发育复杂,对油气的分布和渗流起决定性作用。因此,研究该油田裂缝发育规律对油田开发方案设计及开发效果分析具有重要的指导意义。论文获得的主要认识:(1)研究区储层物性总体特征表现为:储层物性较差,主要为特低孔-超低孔、超低渗-致密储层。研究表明孔喉半径对渗透率具有明显的控制作用,孔隙大小与渗透率相关性较好,分选性、连通性与孔渗关系复杂。大安油田扶余油层主要发育成岩裂缝和局部构造裂缝,裂缝规模上主要为微观裂缝。从地质分类角度看,研究区内发育的裂缝主要为层间/层理缝、粒内缝、粒缘缝和局部构造缝;规模分类上主要发育的是微观裂缝。(2)裂缝主要受三方面因素控制:断裂对物性的影响可能更多的体现在裂缝分布方面,而对孔隙的影响不大;沉积环境是决定储层物性的前提条件,不同沉积微相的岩性、物性不同,造成不同沉积微相力学性质不同,从而导致裂缝发育程度存在明显差异;成岩作用对于储层裂缝后期改善具有很大影响,扶余油层局部抬升剥蚀,酸性氧化的地表水加剧了成岩溶蚀作用。(3)研究区发育典型致密储层,含有典型致密油,准连续分布,甜点富集,含油丰度低且分布复杂。根据岩心资料与录井资料对岩心的含油级别进行划分,分为五个级别,分别为含油、油浸、油斑、油迹与荧光。储层渗流能力随可动流体饱和度的增加而增加,通过研究建立了可动流体饱和度与孔隙度、渗透率的回归关系,定量地评价储层可动流体饱和度及渗流能力大小,其中裂缝可以有效改善储层渗流能力。(4)无论是构造缝还是非构造缝,它们对致密砂岩储层的储集性能都有着很大的改善作用,都可以作为油气的储集空间和运移通道。裂缝可以明显提高储层渗透率,沟通原有储层孔隙,储层质量得到良好的改善。当烃类在运移过程中受到泥岩遮挡时,随着压力增大泥岩段聚集而产生裂缝,烃类通过泥岩裂缝排出,泥岩内部压力释放后微裂缝闭合,微裂缝可以有效运移油气。
[Abstract]:The regional tectonic location of Da'an Oilfield is located in the secondary tectonic belt of the Da'an-Honggang terrace in the central depression of Songliao Basin. The target formation is a typical low permeability sandstone oil field, which is a Fuyu reservoir of Quantou formation of Lower Cretaceous. The reservoir has poor physical property, strong heterogeneity and complex fracture development, which plays a decisive role in the distribution and seepage of oil and gas. Therefore, the study of fracture development in this oilfield is of great significance to the design of oilfield development scheme and the analysis of development effect. The main conclusions obtained in this paper are as follows: (1) the general characteristics of reservoir physical properties in the study area are as follows: the reservoir physical properties are poor, mainly ultralow porosity and ultra-low permeability tight reservoir. The results show that the radius of pore throat has obvious control effect on permeability, the correlation between pore size and permeability is good, and the relationship between porosity and permeability is complex. Diagenetic fracture and local structural fracture are mainly developed in Fuyu reservoir of Da'an Oilfield, and the fracture scale is mainly micro fracture. From the perspective of geological classification, the fractures developed in the study area are mainly interlayer / bedding fractures, intragranular fractures, grain margin fractures and local structural fractures. (2) fractures are mainly controlled by three factors: the effect of fracture on physical properties may be more reflected in the distribution of fractures, but the effect on pores is not; Sedimentary environment is the precondition to determine reservoir physical properties. The lithology and physical properties of different sedimentary microfacies make the mechanical properties of different sedimentary microfacies different, resulting in obvious difference of fracture development degree. Diagenesis has a great influence on the improvement of reservoir fracture in the later stage. The partial uplift and denudation of Fuyu oil layer and acidic oxidized surface water aggravate diagenetic dissolution. (3) typical dense reservoir is developed in the study area, which contains typical dense oil and is quasi-continuous distribution. Rich dessert, low oil abundance and complex distribution. According to the core data and logging data, the oil-bearing grade of the core is divided into five grades, namely, oil bearing, oil immersion, oil spot, oil trace and fluorescence. The percolation capacity of reservoir increases with the increase of movable fluid saturation. The regression relationship between movable fluid saturation and porosity and permeability is established, and the reservoir movable fluid saturation and percolation capacity are quantitatively evaluated. Fractures can effectively improve the percolation ability of reservoir. (4) both structural fractures and non-structural fractures can improve the reservoir performance of tight sandstone reservoir greatly and can be used as reservoir space and migration channel of oil and gas. Fracture can obviously improve reservoir permeability, communicate with original reservoir porosity, and improve reservoir quality well. When hydrocarbon is blocked by mudstone in the process of migration, cracks are produced with increasing pressure of mudstone section, hydrocarbon is expelled through mudstone fracture, micro-fracture is closed after release of internal pressure of mudstone, and micro-fracture can effectively migrate oil and gas.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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