松辽盆地龙西地区泉四段砂岩岩石学特征及其对储层物性的影响

Lithology and effects of the sandstones on the hydrocarbon reservoirs in the fourth member of the Quantou Formation in western Longhupao region,Songliao Basin

松辽盆地龙西地区泉四段主要为岩屑长石砂岩和长石岩屑砂岩,成份成熟度较低,粒度较细,分选中等偏差,填隙物主要为粘土矿物和方解石。研究表明,储层物性随着石英含量的增加而变好,而随着岩屑含量的增加而变差,说明成份成熟度影响岩石的抗压性,进而影响储层的物性。泉四段砂岩中的长石主要通过钾长石的溶蚀作用改善储层物性。粒度大小和均匀程度与储层物性呈正相关关系,砂岩粒度的均匀程度也是形成低孔低渗储层的内在因素之一。

The lithic arkose and feldspathic litharenite as Quantou Formation in western Longhupao region, Songliao the main sandstone types in the fourth member of the Basin are characterized by low compositional maturity, fine grain sizes and moderate to poor sorting. The statistical data have revealed that the physical properties of the hydrocarbon reservoirs are getting better with the increase of quartz contents, and worse with the increase of lithclastic contents, indicating that the compositional maturity may have exerted an important effect on the pressure resistance, response of compression and physical properties of the hydrocarbon reservoirs. Other influencing factors for the physical properties of the hydrocarbon reservoirs include fine grain sizes, poor sorting and higher contents of interstitial materials in the sandstones from the fourth member of the Quantou Formation.