柴达木盆地西部第三系烃源灶及其对油气聚集的控制作用

经实测数据与测井信息相关分析,建立了柴西地区烃源岩有机碳含量与电阻率和声波时差的相关关系。利用这一关系对柴西地区125口井进行了计算,获得了上、下干柴沟组4套烃源层的大量评价数据和用此数据编制的烃源灶平面分布图。综合考虑烃源岩分布面积、厚度和成熟度,柴西地区主力烃源灶为下干柴沟组,次要烃源灶为上干柴沟组。烃源灶的分布控制了柴西地区的油气聚集,已发现的油气藏大都紧邻或围绕主力烃源灶分布。根据这一规律,南乌斯东西两侧、油泉子西侧、红沟子构造带、大风山等地区可作为下步勘探的目标。

Tertiary hydrocarbon kitchen in western Qaidam basin and its control on hydrocarbon accumulation

Relational expression between TOC and resistivity and interval transit time for the source rocks in western Qaidam basin is established by the correlation analysis of measured data and logging data. Using this relational expression, calculations are performed in 125 wells in western Qaidam basin and large amount of appraisal data are achieved in the four sets of source rocks in the Upper and Lower Ganchaigou Fms. These data are used to compile the areal distribution map of source rocks. The comprehensive study of the distribution area, thickness and maturity of source rocks indicates that the Lower Ganchaigou Fm is the major hydrocarbon kitchen and the Upper Ganchaigou Fm is the less important hydrocarbon kitchen. The accumulation of hydrocarbons in western Qaidam basin is controlled by distribution of hydrocarbon kitchen, and most of oil and gas accumulations so far discovered are distributed near or around the major hydrocarbon kitchens. Based on this pattern, the western and eastern sides of Nanwus, the western side of Youquanzi, the Honggouzi structural zone and Dafengshan region can be considered to be the future exploration targets.