冀中坳陷饶阳凹陷中深层有效碎屑岩储集层发育机理研究

发布时间：2018-11-10 12:20

【摘要】：饶阳凹陷是中国重要的油气生产基地,其中深层沙河街组碎屑岩层系更是当前油气勘探的热点。但沙河街组储集层埋深大,成岩演化过程复杂,油气勘探理论尚不完善。因此针对饶阳凹陷储层发育机理,尤其是致密背景下优质储层发育机理及分布规律的研究,对于饶阳凹陷的中深层勘探具有实际参考价值。本文基于钻井、录井、岩心、薄片以及前人的研究成果,探讨了层序地层格架下沙河街组优质储层的发育模式,建立了一套适用于研究区的测井成岩相识别标准,揭示了优质储层的发育机理与主控因素。研究结果表明饶阳凹陷沙河街组三段整体上为1个二级层序,可进一步细分出3个三级层序,每一个完整的三级层序均发育低位、湖侵和高位体系域。层序界面控制了界面之下砂体的溶蚀作用和碳酸盐胶结作用,但并未构成流体运移的优势通道,从而促进界面之上砂体的溶蚀作用。低位体系域砂泥混杂,抗压实能力差,原生孔隙不易保存,且早期碳酸盐胶结物易从过饱和的碱性水体中沉淀。湖侵体系域砂岩粒度细,但分选较好,早成岩阶段原生孔隙可得到一定保存,且与烃源岩直接接触,易于接受有机酸溶蚀形成次生孔隙。高位体系域砂岩颗粒较粗、分选好,沉积物抗压实能力强,埋藏相对较浅,原生孔隙容易保存,且受上覆层序界面影响,在成岩早期接受大气淡水淋滤形成次生孔隙,加之后期有机酸的充注可进一步促进其溶蚀,因而储层质量最好。建立了不同体系域砂岩经历的同生成岩、早成岩和中成岩阶段的成岩演化模式,指出了层序地层格架内的成岩作用特征,可实现优质储层的对比追踪。此外,砂岩储层成岩作用和成岩相特征的研究表明沙三段砂岩储层经历了压实、胶结、溶蚀和破裂等成岩作用,现今正处于中成岩A期。根据成岩作用类型、强度和成岩矿物等,储层成岩相被划分为压实致密、粘土矿物充填、碳酸盐岩胶结、不稳定组分溶蚀和中等压实弱胶结5种成岩相类型。建立了各成岩相的测井识别标准,实现了单井纵向上成岩相的识别与划分,明确了中等压实弱胶结相和不稳定组分溶蚀相为两种建设型成岩相。中等压实弱胶结相发育层段,一般表现为低GR、中—高声波时差的特征,电阻率变化范围较大。而不稳定组分溶蚀相则表现为低GR和电阻率变化范围大的特征,其声波时差值一般表现为中等。阐明了饶阳凹陷中深层异常高孔储层的成因机理,指出高成份和结构成熟度、早期油气充注、孔隙流体超压发育及溶蚀作用是优质储层发育的主要控制因素。
[Abstract]:Raoyang sag is an important oil and gas production base in China. However, the reservoir depth of Shahejie formation is large, the diagenetic evolution process is complicated, and the oil and gas exploration theory is not perfect. Therefore, the study on the mechanism of reservoir development, especially the development mechanism and distribution of high-quality reservoirs in Raoyang sag, has practical reference value for the exploration of middle and deep layers in Raoyang sag. Based on drilling, logging, core, thin slice and previous research results, this paper discusses the development model of high quality reservoir of Xiasha River formation in sequence stratigraphic framework, and sets up a set of criteria for identifying diagenetic facies of logging in the study area. The development mechanism and main controlling factors of high quality reservoir are revealed. The results show that the third member of Shahejie formation in Raoyang sag is a second-order sequence, which can be further subdivided into three third-order sequences, each of which is low, lacustrine transgressive and high-level system tracts. The sequence interface controls the dissolution of sand bodies and carbonate cementation under the interface, but does not constitute a dominant channel for fluid migration, thus promoting the dissolution of sand bodies above the interface. The sand and mud of low system tract are mixed, the compaction ability is poor, the primary pore is not easy to be preserved, and the early carbonate cementation is easy to precipitate from the supersaturated alkaline water. The granularity of the sandstone in the lacustrine transgressive system tract is fine, but the separation is good. The primary pores can be preserved in the early diagenetic stage, and they are in direct contact with the source rock, so it is easy to accept organic acid dissolution to form secondary pores. In the upper system tract, the sandstone grains are coarse and well sorted, the sediments have strong compaction resistance, relatively shallow burial, easy preservation of primary pores, and influenced by the upper layer sequence interface, the secondary pores are formed in the early diagenetic stage by atmospheric fresh water leaching. In addition, the late filling of organic acid can further promote its dissolution, so the reservoir quality is the best. The diagenetic evolution models of syngenic, early and middle diagenetic stages of sandstone in different system tracts are established, and the diagenesis characteristics in sequence stratigraphic framework are pointed out, which can realize the correlation and tracing of high quality reservoirs. In addition, the study of diagenesis and diagenetic facies of sandstone reservoir shows that the sandstone reservoir of formation 3 has undergone diagenesis, such as compaction, cementation, dissolution and fracture, and is now in stage A of middle diagenesis. According to diagenesis types, strength and diagenetic minerals, diagenetic facies are divided into five diagenetic facies: compaction, clay mineral filling, carbonate rock cementation, unstable component dissolution and medium compaction weak cementation. The logging identification standard of each diagenetic facies is established, and the diagenetic facies in single well are identified and divided. It is clear that the medium compacted weak cemented facies and the unstable component dissolution facies are two constructive diagenetic facies. The middle compacted weakly cemented phase developed layer is generally characterized by a low GR, medium to high acoustic time difference and a large range of resistivity changes. The unstable component corrosion phase is characterized by low GR and wide range of resistivity variation, and the acoustic time difference is generally medium. The genetic mechanism of abnormal high porosity reservoir in middle and deep depth in Raoyang sag is expounded. It is pointed out that high composition and structural maturity, early oil and gas filling, overpressure development of pore fluid and dissolution are the main controlling factors for the development of high quality reservoir.
【学位授予单位】：中国石油大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P618.13

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