准噶尔盆地玛湖凹陷西斜坡百口泉组砂砾岩储层成岩作用及对储集性能的影响

发布时间：2018-10-11 13:32

【摘要】：砂砾岩作为重要油气储层类型之一,以非均质性显著、易受成岩作用影响为特征,因而分析其成岩作用及对储集性能的影响是储层研究的关键。文章在准噶尔盆地西北缘玛湖凹陷地区,以最近勘探取得重大突破的西斜坡艾湖油田下三叠统百口泉组(T1b)缓坡扇三角洲砂砾岩储层为例,研究了成岩作用类型及对储集能力的影响。结果表明,研究区砂砾岩主要发育了四种成岩作用类型:压实、交代(碎屑长石的钠长石化和蒙皂石的伊利石化)、溶蚀(钾长石和方解石等)和胶结(方解石、高岭石和少量绿泥石)。它们对储集性能的影响差异显著。压实作用显著破坏了颗粒间的原生孔隙,降低了储层物性;矿物交代总体对储层物性影响有限;相比而言,在断裂沟通含烃流体促进下,钾长石等矿物的溶解在扇三角洲前缘的水下河道与颗粒流沉积等具有较好初始物性的砂砾岩,形成了次生孔隙发育带,显著改善了砂砾岩的储集性能;胶结作用不利于砂砾岩成岩中晚期孔隙的保存,特别是高岭石和方解石的局部富集导致了低渗透层的形成。据此,发现研究区不同段的储层发育有明显差异,由下至上百一段在油源断裂附近发育优质储层;百二段在油源断裂的上倾位置发育优质-较好储层;而百三段研究区储层几乎不发育。
[Abstract]:As one of the important oil and gas reservoir types, sandy gravel is characterized by remarkable heterogeneity and easy to be influenced by diagenesis. Therefore, the analysis of diagenesis and its influence on reservoir performance is the key to reservoir research. In the Mahu sag area of the northwestern margin of Junggar Basin, this paper takes the lower Triassic Baikouquan formation (T1b) mild-slope fan delta sandy gravel reservoir as an example, which has recently made a major breakthrough in exploration. The types of diagenesis and its influence on reservoir capacity are studied. The results show that there are four types of diagenesis: compaction, metasomatism (albite of clastic feldspar and Illite of montmorillonite), dissolution (potash feldspar, calcite, etc.) and cementation (calcite, etc.). Kaolinite and a small amount of chlorite There are significant differences in their effects on reservoir performance. Compaction significantly destroys primary pores between particles and reduces reservoir physical properties; mineral metasomatism as a whole has a limited effect on reservoir physical properties; comparatively speaking, when faults communicate with hydrocarbon bearing fluids, The dissolution of potassium feldspar and other minerals in the subaqueous channel and grain flow deposition in the front of the fan delta, which have better initial physical properties, formed the secondary pore development zone, and improved the reservoir performance of the sandy gravel. The cementation is not conducive to the preservation of pores in the late diagenetic period of sandy gravel, especially the local enrichment of kaolinite and calcite, which leads to the formation of low permeability layers. On this basis, it is found that there are obvious differences in the development of reservoirs in different sections of the study area, from the bottom to hundreds of segments developing high quality reservoirs near the oil-source faults, and the Baier member develops high-quality and better reservoirs at the upward dip of the oil-source faults. The reservoir in the study area of the third member is almost undeveloped.
【作者单位】：中国石油新疆油田分公司实验检测研究院;南京大学地球科学与工程学院;
【基金】：国家科技重大专项(2016ZX05001-005)
【分类号】：P618.13

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