准噶尔盆地腹部二叠系、三叠系储集层特征及烃类侵位对深部储集层物性的影响

利用薄片、扫描电镜、储集层物性、黏土矿物X衍射等资料,分析了准噶尔盆地腹部二叠系、三叠系储集层岩石学特征,进而探讨了烃类侵位对其物性的宏观影响及微观机理.大量观察与分析表明,研究区储集层以岩屑砂岩为主,具有火山岩岩屑含量高等特点,其储集物性总体具有低孔、低渗的特点,但差中有优,4000m以下深度物性明显变好.研究区深部含油储集层物性明显好于不含油储集层,深层方解石、浊沸石和自生伊利石含量随含油级别的提高呈降低趋势,说明原油的侵入在一定程度上抑制了自生矿物的形成与演化,导致深部含油储集层中自生矿物的含量减少,从而使含油储集层物性获得明显改善.图4参15

Characteristics of deep-buried fragmental reservoirs in central Junggar Basin and the effect of hydrocarbon emplacement on reservoirs'' diagenetic mineral evolution

Based on the data of thin section,scanning electron microscopy,properties of reservoirs and XRD of clay minerals,petrological characteristics of the Permian and Triassic reservoirs in central Junggar Basin were analyzed.Effects of hydrocarbon emplacement on reservoirs' diagenetic mineral evolution were carefully discussed.The results show that the reservoirs are dominated by litharenite and have a high content of volcanic cuttings.The properties of reservoirs are of low porosity and low permeability,but the properties of reservoirs below 4000m are obviously better.Properties of oil-bearing reservoirs are obviously better than that of reservoirs without oil.The contents of some diagenetic minerals such as calcite,laumontite and illite have a decreasing trend with the elevation of oil-bearing level,suggesting that the reservoirs' diagenetic mineral evolution has been restrained by hydrocarbon emplacement.Hydrocarbon emplacement plays an important role in improving the properties of deep-buried reservoirs in the basin.