塔里木盆地塔中5 井下奥陶统隐藻类生物礁

塔里木盆地塔中地区下奥陶统主要为一套海相碳酸盐岩。塔中5 井所钻遇的下奥陶统自上而下可分为四个岩性段, 即:灰岩段、角砾白云岩段, 上白云岩段和下白云岩段, 其中第二岩性段(角砾白云岩段)由隐藻类粘结形成的叠层石、凝块石、层纹石和核形石组成的隐藻类生物礁, 其中,叠层石和凝块石具抗浪组构。该礁经历了一个礁基形成期、三个礁生长期和二个间歇期,生长期表现为礁前亚相和礁核亚相交互发育。隐藻类生物礁具一定的储集能力, 钻井中有活跃的油气显示。

LOWER ORDOVICIAN CRYPTO ALGAE ORGANIC REEF IN WELL TZ5 IN TARIM BASIN

The Lower Ordovician in Tazhong area is dominated by marine carbonate. The Lower Ordovician penetrated by Well TZ5 can be divided into four lithologic members, i.e. limestone, brecciated dolomite, upper and lower dolomite, among which the brecciated dolomite member is a crypto algae reef composed of stromatolite, lamellar stone, oncolite etc formed by crypto algae bonding, stromatolite has wave resistant structure. The crypto algae organic reef underwent one reef base forming stage, three reef growing stages and two intermission, fore reef and reef core subfacies alternatively appeared in the reef growing stage. Active oil/gas show in drilling indicates that the crypto algae organic reef has fair storage capability.