Journal of Petrochemical Universities

›› 2017, Vol. 30 ›› Issue (1): 75-81.DOI: 10.3969/j.issn.1006-396X.2017.01.015

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Characteristics of Interstitial Material in Sandy Conglomerate and Its Effects on Reservoir Porosity

  

  • Received:2016-09-23 Revised:2016-10-10 Published:2017-02-24 Online:2017-02-28

砂砾岩致密储层填隙物特征及其对孔隙的影响

王玉祥   

  1. 大庆油田有限责任公司第四采油厂地质大队,黑龙江大庆163511
  • 作者简介:王玉祥(1969-),男,工程师,从事石油地质研究;E-mail:dqytwyx@sina.com。
  • 基金资助:
    中国石油天然气股份公司重大科技专项“大庆油田原油4000万吨持续稳产关键技术研究”(2011E-1202)。

Abstract:

The successful exploration of natural gas in Shahezi formation opened the prelude for sandy conglomerate gas in faulted formation of Xujiaweizi depression in Songliao basin.Sandy conglomerateare characteristics by high interstitial fillings, complex types and various origins.The relationship between interstitial material and sandy conglomerate is unclear, which restricts the effective reservoir prediction.According to characterization of thin section, scanning electron microscope, X diffraction, physical testing, the types of interstitial fillings and the influence on sandy conglomerate reservoir are analyzed. The results show that the interstitial material types include mud matrix, volcano ash, carbonate, siliceous,clay minerals, pyrite,etc.The main interstitial fillings are mud matrix and carbonate,followed by clay minerals, silica and volcanic ash,with pyrite seldom developed.Mudmatrix and volcano ashare sedimentary fillings,silica and clay minerals are formed in the early to middle diageneticstage, and carbonate cements are mostly developed in late diagenetic stages.The relationship between interstitial fillings types and rock porosity indicates that mudmatrix plugs the pore throat and reduces original pore greatly. Siliceous cementation and chlorite cladding in the early diagenetic stage increase reservoir strength, which is conducive to the preservation of primary porosity. The volcano ash is easy to be dissolved, which is favorable for the development of secondary pores.Large poresare devided into small pores by clay mineral and a large number of micro pores are provided,so clay mineral content and the porosity are negatively correlated.Residual poresare filled by late carbonate cements,which increase the density of sandy conglomerate.

Key words: Xujiaweizi depression, Shahe formation, Tight, Sandy conglomerate gas, Reservoir, Interstitial fillings, Porosity

摘要: 徐家围子断陷沙河子组致密砂砾岩气展现出较好的勘探潜力,致密砂砾岩储层以高填隙物含量为典型特征,隙物的类型、成岩变化与储层孔隙发育密切相关。通过铸体薄片、扫描电镜、X衍射、物性测试分析,发现砂砾岩中发育泥质杂基、火山灰、碳酸盐、硅质、黏土矿物、黄铁矿等填隙物类型;填隙物中泥质杂基和碳酸盐含量最高,黏土矿物次之,硅质、火山灰发育少,黄铁矿偶尔发育;泥质杂基、火山灰为同沉积填隙物,硅质和黏土矿物多数形成于早-中成岩期,碳酸盐胶结物主要形成于成岩晚期。填隙物类型与砂砾岩孔隙度研究表明,早期硅质胶结增加了储层强度并促进了原生孔隙的保存,火山灰的溶蚀增加了孔隙空间;泥质杂其减少了原始孔隙并抑制次生溶蚀的发育,是减少砂砾岩储层孔隙度先天因素;黏土矿物破坏大孔隙的完整性,将大孔隙分割为若干微孔并提供晶间微孔,减少砂砾岩总孔隙度,但不是很显著;早期碳酸盐填隙多被溶蚀,晚期碳酸盐胶结物填充残余孔隙,导致储层进一步致密。

关键词: 徐家围子断陷, 沙河子组, 致密, 砂砾岩, 储层, 填隙物, 孔隙

Cite this article

WangYuxiang. Characteristics of Interstitial Material in Sandy Conglomerate and Its Effects on Reservoir Porosity[J]. , 2017, 30(1): 75-81.

王玉祥. 砂砾岩致密储层填隙物特征及其对孔隙的影响[J]. 石油化工高等学校学报, 2017, 30(1): 75-81.