羌塘盆地油气勘探前景展望

矿物组成及其微观特征对研究油气藏的沉积环境、岩石骨架及储集空间等方面具有重要意义。本文利用高光谱扫描和扫描电镜矿物组成定量分析技术(QEMSCAN)，对羌塘盆地二叠系龙格组碳酸盐岩岩心样品的矿物组成、含量及其空间分布规律等进行研究，为羌塘盆地古生代碳酸盐储层油气藏评价提供矿物组成和微观特征方面的依据。结果表明：龙格组岩性以微晶灰岩和粒屑灰岩为主，矿物组成主要为方解石和白云石，两者含量之和普遍大于90%，其次为石英及少量的黏土矿物和长石。矿物组成具有明显纵向分段特征：上段方解石和白云石含量均较高；中段白云石含量较高，且白云化程度较为强烈，孔隙度和渗透率均有所下降；下段以方解石为主。黏土矿物特征分析显示，龙格组地层经历了复杂的沉积-成岩作用和后期热扰动作用及流体作用，这对该地区油气运移及保存有较强的影响。

Oil and gas prospect for exploration in Qiangtang Basin

Mineral composition and its microscopic characteristics are of great significance to the study of sedimentary environment, rock framework and reservoir space of oil and gas reservoirs.To investigate the mineral composition, content and spatial distribution of carbonate core samples of the Permian Longge Formation and provide the basis for oil and gas evaluation of the Paleozoic carbonate reservoirs in Qiangtang Basin.The sample was analyzed by hyperspectral scanning and QEMSCAN.The Longge Formation is dominated by microcrystalline limestone and granulated limestone, and the minerals are mainly calcite and dolomite, the contents of which are generally greater than 90%, followed by quartz and a minor clay mineral and feldspar. The mineral composition has obvious characteristics of longitudinal segmentation. The contents of calcite and dolomite are higher in the upper section. The content of dolomite in the middle section is higher, and the degree of dolomization is relatively strong. The porosity and permeability of this section have decreased. The lower section is mainly composed of calcite. In addition, the analysis of clay mineral characteristics shows that the Longge Formation has experienced complex sedimentary-diagenesis and late thermal disturbance and fluid replacement, which has a strong impact on oil and gas migration and preservation in this area.Hyperspectral scanning technology can be used to quickly and efficiently interpret large-scale mineral features. QEMSCAN enables more precise and quantitative analysis of mineral microscopic features. The Longge Formation is dominated by carbonate and obviously affected by diagenesis and the local dolomization is strong. The oil and gas conditions in this formation are poor.