CAJ | 학술논문

古城墟隆起奥陶系海相碳酸盐岩地层近年来相继发现了一些出油气井，已经成为塔里木盆地的重点勘探目标区。目前已证实古城墟隆起存在奥陶系一间房组顶部灰岩与鹰山组内幕灰质白云岩两套含油气层系。奥陶系主要为正常压力、高温的干气气藏，但顺南1井一间房组顶部的原油属低硫、低蜡轻质油，表现出典型的凝析油特征。综合油气性质、生物标志化合物特征及烃包裹体发育特征，认为该区主要存在两期油气充注过程：第一期油气充注发生在加里东晚期-海西早期，以来自寒武系-下奥陶统烃源岩的原油为主；第二期油气充注发生在喜马拉雅期，以寒武系过成熟的干气为主，气侵改造导致该区以纯气藏和凝析气藏为主。古城墟隆起已钻井均见到不同级别的油气显示，并且不含水，初步研究认为优质的碳酸盐岩储层是油气成藏的最关键因素，同时北东向断裂对油气成藏有重要影响。
고성허륭기오도계해상탄산염암지층근년래상계발현료일사출유기정，이경성위탑리목분지적중점감탐목표구。목전이증실고성허륭기존재오도계일간방조정부회암여응산조내막회질백운암량투함유기층계。오도계주요위정상압력、고온적간기기장，단순남1정일간방조정부적원유속저류、저사경질유，표현출전형적응석유특정。종합유기성질、생물표지화합물특정급경포과체발육특정，인위해구주요존재량기유기충주과정：제일기유기충주발생재가리동만기-해서조기，이래자한무계-하오도통경원암적원유위주；제이기유기충주발생재희마랍아기，이한무계과성숙적간기위주，기침개조도치해구이순기장화응석기장위주。고성허륭기이찬정균견도불동급별적유기현시，병차불함수，초보연구인위우질적탄산염암저층시유기성장적최관건인소，동시북동향단렬대유기성장유중요영향。
Guchengxu Uplift in which commercial oil and gas have been drilled out in Ordovician marine carbonate rocks in some wells in recent years has become one of the exploration focus areas in Tarim basin. Two series of Ordovician hydrocarbon-bearing reservoirs have b een confirmed to be present in Guchengxu Uplift, one is the limestone at the top of Ordovician Yijianfang Formation and the other is the limy dolostone of internal Ordovician Yingshan Formation. The hydrocarbon is present mostly in dry-gas state with normal pressure and high temperature in Ordovician reservoirs but exceptionally, light oil with low content of sulfur and wax which is characteristic of condensate oil are drilled out in the top of Yijianfang Formation in Well SN-1. Combined with the analysis of hydrocarbon property, biomarkers and hydrocarbon inclusion characteristics, it is suggested that two periods of hydrocarbon emplacement experienced in this uplift. Emplacing oil derived from the Cambrian to lower Ordovician source rocks in the first period of emplacement that occurred during the late Caledonian to Early Hercynian movements, and emplacing over-mature dry gas were dominated in the second period of emplacement that occurred during Himalayan movement. The following gas emplacement resulted in forming pure gas or condensate gas reservoirs. Different ranks of oil/gas shows are present in the drilled wells in Guchengxu Uplift, and specially all of oil and gas yielded are with no water. It is generally considered that high-quality carbonate reservoirs are the key for hydrocarbon accumulation and the developing NE-trending faults play an important role in hydrocarbon accumulation.