塔河油田、普光气田碳酸盐岩储层特征对比研究

中国海相碳酸盐岩油气勘探相继发现了以塔里木盆地塔河油田、四川盆地普光气田为代表的一批大中型油气田。本文系统对比了塔河油田、普光气田碳酸盐岩储层基本特征、成岩作用和控制因素。礁滩型储层一般物性较好,储集类型为孔隙型或裂缝-孔隙型,非均质性弱;风化壳岩溶型储层一般物性较差,储集类型多样,非均质性极强。白云石化是超深层（〉6000m）碳酸盐岩储层形成的重要机制,白云岩较灰岩储层平均孔隙度可提高3．5％～4．0％。硫酸盐热化学还原（TSR）反应主要是对储层进行强烈改造,改善程度并不大。沉积相、构造作用对不同类型储层的影响程度、影响方式不尽一致：对于风化壳岩溶型储层,沉积相的影响主要体现在对岩石可溶性、透水性的控制上,在岩石可溶、透水的基础上构造作用控制了储层的发育范围及程度;礁滩型储层受沉积相的严格控制,构造作用形成的裂缝对储层物性有明显改善。

CARBONATE RESERVOIR COMPARISON BETWEEN TAHE OIL FIELD AND PUGUANG GAS FIELD

Great breakthroughs have been made in China＇s carbonate rocks exploration for oil and gas in recent years with the discoveries of such large-scale oil and gas fields as Tahe oilfield and Puguang gasfield. Basic features of reservoirs, diagenesis, and controlling factors of Tahe oilfield and Puguang gasfield are discussed and compared systemically in this paper. Reef （shoal） reservoirs on the platform margin are usually in good quality as porous or fractured-porous reservoir type with low heterogeneity. Weathering crust karst reservoirs are usually in bad quality, as pore-hole-fracture complex reservoir type with high heterogeneity. Dolomitization is an important mechanism for the forming of super-deep （ 〉 6000 m） carbonate reservoirs, resulting an average porosity increase of 3.5 -4.0 %. Thermochemical sulfate reduction （TSR） reactor plays an active role in alteration of reservoir, but it may not meliorate reservoir properties greatly. Tectonism and depositional facies are the main factors controlling the reservoir physical properties of Tahe oil field and Puguang gas field. Depositional facies controlled reservoir quality by affecting rock solubility and water permeability in weathering crust karst reservoir, or by affecting lithology and physical properties in reef （shoal） reservoir on the platform margin. Teetonism controlled the distribution and intensity of weathering crust karst reservoir, while multi-stage structural fractures improved the reservoir physical properties of reef （shoal） reservoir on the platform margin.