应用断层古滑距、滑动速率法研究苏丹Muglad盆地凯康坳陷生长断层活动,定量表征早白垩世、晚白垩世、古近纪新近纪三幕构造旋回断陷期断层生长及活动强度的差异性.结果表明控凹断层为多期、多段式生长连锁模式;控构造带断层为初期生长连锁,后期简单生长模式;控圈闭断层表现为简单生长模式.早白垩世断陷期控凹断层分段生长影响烃源岩分布,断-拗构造旋回造成砂泥岩沉积显著分异,形成下、中、上部多套储盖组合.油气的聚集层位及分布规律受圈闭类型、断层在Darfur群油气大规模运移期活动强度、Nayil组Tendi组破坏期活动强度3方面因素控制,构造转换带横向背斜以及地垒型、反向断块型等古构造可形成早期残留油气藏或浅层次生油气藏,顺向断块不利于成藏.Darfur群与Nayil组—Tendi组滑移速率之比可以代表早期油气聚集与后期油藏破坏能力的相对大小,与单条断层伴生构造圈闭的油气纵向层位聚集状态有对应关系.凯康槽东侧为高产油气聚集带,隆起带以下组合白垩系成藏为主,断阶带上、中、下组合均能成藏;凯康槽西侧斜坡带和断阶带成藏条件差,隆起带北部成藏条件一般,多层系成藏但产量不高,隆起带南部成藏条件好于北部但以下组合白垩系成藏为主;坳陷带内断层晚期活动强烈,可形成次生油气藏.%In this study,ancient fault sliding distance and sliding rate were used in a quantitative study on growth faults in the Kaikang Sag,Muglad Basin,Sudan to quantify variations in fault growth rates and activity intensities in three different rifting phases,i.e.,the Early Cretaceous,Late Cretaceous,and Paleogene to Neogene.The results showed that the controlling sag faults developed in a linked multi-phase multi-section fashion,the controlling structural belts faults underwent linked growth at the beginning and simple growth later,whereas the controlling traps faults experienced simple growth throughout.Fault activities in the Early Cretaceous controlled the distribution of source rocks,while the three rifting-sag structural cycles led to differentiation of sand and shale,forming the upper,middle and lower reservoir-seal assemblages.Hydrocarbon accumulation was controlled by three main factors:trap type,fault movement intensity in the Darfur group as source rock entered into oil-generating peak,and fault movement intensity in the Nayil-Tendi formations when paleo-oil reservoir could be destroyed and readjusted.Transverse anticline in structural transform zone,horst,and antithetic fault block were favorable structures for paleoreservoir or shallow secondary oil reservoir formations,whereas consequent fault block was not favorable.The results also showed that the fault activity ratios of the Darfur group to Nayil-Tendi formations can be used to measure the relative capability of hydrocarbon accumulation in the early period vs.oil reservoir destruction in the late period.This relative capacity,based on actual drilling data,is related to the accumulation layers in the following way:the eastern limb of the Kaikang trough hosts a prolific oil and gas accumulation zone,where under the uplift zone hydrocarbons mainly accumulated in the lower reservoir-seal assemblage of the Cretaceous system,forming deposits throughout the eastern fault slope zone.In contrast,accumulation condition in the western limb of the Kaikang trough is poor in its slope and fault step zones,where the northern uplift developed multiple accumulation layers but low production,while the southern uplift faired better with accumulation mainly in the lower reservoir-seal assemblage of the Cretaceous system;in the depression zone,secondary oil reservoir might be formed due to strong fault movement in the late period.
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