准噶尔盆地莫西庄油田成藏模式

Hydrocarbon accumulation patterns of Moxizhuang oilfield,the Junggar Basin

毕研斌 高山林 朱允辉，庞雯 杨秋来 陈继华

摘要：在油水关系、断层发育状况和成藏背景综合分析的基础上，探讨了准噶尔盆地莫西庄油田的成藏模式。分析认为，莫西庄油田三工河组二段下亚段油砂段内油水关系正常，不存在油水关系倒置的问题，而是具有统一的油水系统。煤层发育段地震属性特征揭示，早期解释的“大”断层为煤层反射所致，三工河组不发育规模性断层，不存在“一井一藏”的断层遮挡圈闭条件。三工河组二段上亚段和下亚段具有不同的成藏条件和油气分布特征，三工河组二段上亚段油藏发育于底部的曲流河三角洲前缘水下分流河道砂体中，有利含油部位平面上呈条带状分布。三工河组二段下亚段油藏发育于辫状河三角洲分流河道砂体中，含油成片分布。综合分析认为，莫西庄油田为一受构造和沉积微相双重控制、目前仍然处于地层掀斜后动态调整分配过程中的构造-岩性油气藏，三工河组二段下亚段内部具有与上倾砂体产状一致、统一的倾斜油水界面。

Abstract: This paper discusses hydrocarbon accumulation patterns of Moxizhuang oilfield of the Junggar Basin based on a comprehensive analysis of oilwater relationship,fault occurrence and hydrocarbon accumulation background.The reservoir of J(the lower second member of the Jurassic Sangonghe Formation) in Moxizhuang oilfield has a uniform oilwater system with a normal instead of inverted oilwater relationship.Seismic attributes of intervals with welldeveloped coal beds reveals that the previously interpreted major faults are artifacts resulted from seismic reflection of the coal seams,and no large faults are developed in the Sangonghe Formation,no faultsealing trap conditions exist.Hydrocarbon accumulation conditions and distribution characteristics are different inJ (the upper second member of the Jurassic Sangonghe Formation) and Jreservoirs.The J reservoirs are developed in underwater distributary channel sandbodies of meandering river deltaic front facies,with the favorable reservoirs laterally being in strip distribution.In contrast,the J reservoirs are developed in distributary channel sandbodies of braided river delta facies,with the favorable reservoirs laterally in continuous distribution.The Moxizhuang oilfield is a structurallithologic reservoir that is controlled by both structure and sedimentary microfacies and is still in the posttilting dynamic adjusting process.There exists a uniform oilwater contact in J with occurrence the same as that of the updipping sandbody.

10.11743/ogg20110302