穆格莱德盆地凯康坳陷西斜坡地层剥蚀与埋藏史研究

Study on denudation and burial history of the strata in the west slope of Kaikang Depression,Muglad Basin

为深入了解穆格莱德盆地凯康坳陷西斜坡地区地层沉积和埋藏史情况,根据回剥法改进的"刘景彦模型",消除多剥蚀面盆地内上覆地层压实作用影响,并利用声波时差计算各剥蚀面剥蚀厚度,在综合分析地层残余厚度与剥蚀厚度的基础上恢复了研究区埋藏史.结果表明:①Baraka与Amal间剥蚀厚度最大,Abu Gabra与Bentiu间剥蚀厚度最小;②斜坡西部与南部剥蚀量大,东部与北部小;③受区域构造运动和沉降速率影响,北部地区沉降速度和沉积速率小,地层埋藏较浅,断层规模小,密度大,发育大量小型断块圈闭;④南部地区沉降速度和沉积速率较高,各组地层埋藏较深,烃源岩进入生油窗时间更早,大型同生断层发育,多见大型断块和断鼻圈闭,石油地质条件优于北部地区.

To better understand the formation sedimentation and burial history in the studied area,the denudation thickness on every denudation surfaces are calculated based on interval transit time and the improved 'Liu Jingyan Model',and the impact of compaction of upper strata on the denudation thickness is eliminated in calculating.The results show that: 1)the formation denudation thickness between Baraka and Amal is the largest and the formation denudation thickness between Abu Gabra and Bentiu is the smallest;2)the formation denudation thickness in the western and southern parts of the slope is larger than that in the eastern and northern parts of it;3)in the northern part of the slope,controlled by regional tectonic movement,sedimentation and deposition rates of the strata is lower,the size of the faults and the burial depth of the strata are less than in the southern part,the density of strata is great and a lot of small fault block traps are developed;4)in the southern part of the slope,sedimentation and deposition rates of the strata is higher,the burial depth of the strata are greater than in the southern part,large contemporaneous faults,large fault traps or fault nose traps are developed,so the petroleum geological conditions are better than in the northern part of the slope.