土库曼斯坦阿姆河右岸卡洛夫—牛津阶储层流体包裹体特征及成藏期

Fluid inclusion characteristics and hydrocarbon accumulation period of Callovian-Oxfordian reservoir on the right bank of Amu Darya, Turkmenistan

基于阿姆河右岸中部中上侏罗统卡洛夫—牛津阶碳酸盐岩储层流体包裹体的镜下观察、均一温度测定,结合烃源岩生排烃史、地层埋藏史、热史及构造演化史,恢复阿姆河右岸中部油气藏的成藏过程。结果表明:第一期为早白垩世阿尔必期(120~105 Ma),穆尔加勃坳陷的中下侏罗统烃源岩进入生烃门限,早白垩世晚期,生成的油气沿不整合面及查尔朱基底断裂运移至桑迪克雷隆起的碳酸盐岩礁滩体而聚集成藏,对应的包裹体为赋存于二世代方解石胶结物的、具有定向排列的叶黄色荧光包裹体;第二期为晚白垩世土伦期(75~65 Ma),盆地东南部中下侏罗统生成的凝析气继续充注桑迪克雷隆起的圈闭,中下侏罗统达到生烃高峰,生成的油气开始充注中部油气藏,对应的包裹体为赋存于半自形晶簇状及自形连晶状方解石胶结物的、略具有定向性的绿色荧光包裹体;第三期为晚渐新世—中新世(30~20 Ma),在穆尔加勃坳陷的油气持续充注的背景下,烃源岩对中部油气藏的充注强度不断增加,并在喜山期构造挤压的影响下,对古油气藏进行调整定形,对应的包裹体为与大量气体包裹体共生的杂乱无章的蓝色荧光包裹体。

There are abundant subsalt oil and gas resources on the right bank of Amu Darya.By means of microscopic observation and homogeneous temperature measurement of fluid inclusions in Middle-Upper Jurassic Callovian-Oxfordian carbonate reservoirs in the middle region,combined with source rocks generation and expulsion history,burial history,thermal history and tectonic evolution history.The hydrocarbon accumulation process in the middle part has been restored.Base on the analysis,conclusions are as follows:firstly,the Middle-Lower Jurassic source rocks in the Murgab Depression enter the hydrocarbon generation threshold during Early Cretaceous Albian.And the generated hydrocarbon migrated along the unconformity surface and the Chadzhou basement fault to the carbonate reef-beach bodies and accumulated in the Sandykly Uplift during Late Cretaceous(120~105 Ma).The corresponding inclusions are yellow fluorescent inclusions with directional arrangement in the second generation calcite cement.Secondly,during the Late Cretaceous Turonian,the condensate gas generated by the Middle-Lower Jurassic in the southeast of the basin continued to charge traps in Sandykly Uplift.And the Middle-Lower Jurassic in the middle of the right bank reached the peak of hydrocarbon generation,whose oil and gas began to charge the middle reservoir(75~65 Ma).The corresponding inclusions are green fluorescent inclusions which are slightly directional in the semi idiomorphic crystal cluster and idiomorphic crystal stock calcite cements.And thirdly,during the Late Oligocene-Miocene,under the background of the continuous charging of oil and gas from the Murgab Depression,the charge intensity of the source rocks on the right bank to the middle reservoir increased continuously(30~20 Ma).And under the influence of Himalayan tectonic compression,the paleo-reservoirs were adjusted to shape.The corresponding inclusions are disordered blue fluorescent inclusions symbiotic with a large number of gas inclusions.