东濮凹陷北部沙三段裂缝发育特征及对储层影响研究

发布时间：2019-03-05 13:31

【摘要】：东濮凹陷沙三段储层中普遍发育裂缝。本文运用岩心观察、薄片鉴定、扫描电镜、物性分析等技术方法对东濮凹陷沙三段储层特征、裂缝发育特征进行了研究,统计了研究区各类型裂缝的参数特征,在此基础上,对裂缝的主控因素、成因机制及其对储层的影响进行了深入的探讨。东濮凹陷沙三段储层平均孔隙度为12.6%,平均渗透率为38.2×10-3μm2,属于低孔-特低渗储层,成岩环境复杂,成岩环境为酸-碱交替型。储层物性纵向上具有分区分带的特点,可划分出三个异常高孔隙带。平面上储层物性的分布也具有分区性,高孔区主要集中在胡状集、徐楼、濮城三个地区。研究区裂缝按规模可分为宏观裂缝和微观裂缝两大类。按成因可分为构造缝、超压缝和成岩缝三种类型。其中微观裂缝又可分为粒内缝、贴粒缝和穿粒缝。裂缝走向多呈NNE、NE,开度、密度、延伸长度等参数之间具有一定的相关性。宏观裂缝多被石膏、碳质半充填、微观裂缝有效性较好。裂缝的发育程度主要受沉积作用、构造作用、异常高压作用、成岩作用的控制。脆性颗粒含量越多、粒度越粗、层厚越薄裂缝越发育;构造缝的发育受断层控制,离断层越近裂缝越发育,断地比为10是构造缝的发育下限;盐下及盐间地层易形成异常高压带,压力系数为1.2为超压缝的发育下限。受喜山期NW-SE向拉张应力和ES向挤压应力两期构造运动的影响,构造裂缝分两期,第一期形成于沙三段末期,第二期形成于东营组末期的构造反转时期。超压裂缝形成与烃类充注和盐膏岩脱水作用有关,其形成时期为沙二段末期,与烃类充注时期相一致。成岩缝以微裂缝为主,其形成主要与压实、溶解等成岩作用有关,研究区裂缝的形成序列为:早期构造缝-压裂缝-溶解缝-超压缝-收缩缝-晚期构造缝-溶解缝-压裂缝。裂缝是该区重要的储集空间类型,裂缝发育层段的含油性普遍较好,单井的产能随裂缝发育程度的增加而提高。宏观裂缝主要起渗流作用,能很大程度提高储层渗透率。微观裂缝主要作为储集空间,增加储层孔隙度,也可以增加孔隙连通性。流体沿裂缝流动同样可形成溶蚀孔隙带,改善储层物性。
[Abstract]:Fractures are generally developed in the third member of Shahejie formation in Dongpu depression. In this paper, core observation, thin slice identification, scanning electron microscopy and physical property analysis are used to study reservoir characteristics and fracture development characteristics of the third member of Shahejie formation in Dongpu depression, and the parameter characteristics of all types of fractures in the study area are counted, on the basis of which, The main controlling factors, genetic mechanism and its influence on reservoir are discussed in this paper. The average porosity and permeability are 12.6% and 38.2 脳 10 ~ (- 3) 渭 m ~ 2, respectively. The reservoir belongs to low porosity-ultra-low permeability reservoir. The diagenetic environment is complex and acid-alkali alternate type. The reservoir physical properties have the characteristics of zonation longitudinally, and can be divided into three abnormal high porosity zones. The distribution of reservoir physical properties on the plane is also divisional, and the high porosity area is mainly concentrated in three areas: Hu-shaped formation, Xulou and Pucheng. The fractures in the study area can be divided into macro-fractures and micro-fractures according to the scale. According to the origin, they can be divided into three types: tectonic joint, overpressure joint and diagenetic fracture. The micro-cracks can be divided into intra-grain seam, grain-sticking seam and through-grain seam. There is a certain correlation between the fracture strike parameters such as NNE,NE, opening, density, extension length and so on. Macro-cracks are mostly filled with gypsum and carbonaceous half-filled, and the effectiveness of micro-cracks is better. The degree of fracture development is mainly controlled by sedimentation, tectonic process, abnormal high pressure and diagenesis. The more brittle particles are, the thicker the grain size is, the thinner the fracture is, the development of structural joint is controlled by fault, and the closer the fault is, the more the fracture develops, and the ratio of fault to ground is 10 as the lower limit of development of structural joint. The abnormal high pressure zone is easily formed in the subsalt and intersalt formations, and the pressure coefficient is 1.2 as the lower limit of the development of the overpressure fracture. Influenced by the tectonic movement of NW-SE-trending tensile stress and ES-trending compressive stress during Himalayan period, the tectonic fractures are divided into two stages, the first stage is formed at the end of the third member of the Shahejie formation, the second stage is formed at the end of the Dongying formation during the tectonic inversion period. The formation of overpressure fractures is related to hydrocarbon filling and dehydration of salt-gypsum rocks, and its formation period is at the end of the second member of the Shahejie formation, which is consistent with the hydrocarbon filling period. The diagenesis of diagenesis is mainly related to compaction, dissolution and other diagenesis. The formation sequence of fractures in the study area is as follows: early tectonic fractures-compressive fractures-dissolved joints-over-pressured joints-contraction joints-late tectonic joints-dissolved fractures-fracturing fractures. Fracture is an important type of reservoir space in this area. The oil-bearing property of fracture-developed strata is generally good, and the productivity of single well increases with the increase of fracture development degree. Macro fractures play a major role in seepage, which can greatly improve reservoir permeability. Micro fractures are mainly used as reservoir space, increase reservoir porosity, but also increase porosity connectivity. The fluid flow along the fracture can also form the dissolution pore zone and improve the physical properties of the reservoir.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

【参考文献】