贝尔凹陷潜山储层的地球物理响应特征及勘探方向

Geophysical response characteristics and exploration trend for buried-hill reservoir in Beier Depression

本文综合利用地质、地震、测井资料,分析了贝尔凹陷的构造演化和基岩潜山的储层特征及其地球物理响应,结果表明:①贝尔凹陷基岩潜山的形成伴随伸展断陷盆地的三个演化过程,即初始裂陷(铜钵庙组)、快速断陷(南屯组)和断拗转换(大磨拐河组),形成了高陡断块型、宽缓背斜型、断阶型和孤立残丘型等四种潜山类型。②潜山储层类型主要有风化溶蚀型和构造裂缝型两类,其中风化壳的地震波组外部轮廓表现为透镜体、内部为弱反射特征;基岩潜山的裂缝类型主要有高角度、低角度和网格状等,其中高角度平行裂缝使双侧向测井响应幅度呈现正幅度差,低角度裂缝呈现负幅度差,网状裂缝的双侧向测井响应特征受两组平行裂缝的倾角和夹角的影响。③苏德尔特南部高陡断块型潜山及霍德莫尔和巴彦塔拉宽缓背斜型潜山带是下一步的有利勘探目标。

By integration of geological,seismic and well logging data,the tectonic evolution for Beier Depression,the reservoir characteristics and geophysical response of basement buried-hill were analyzed in this paper.The analysis results brought the following conclusions:The formation of the basement buried hill accompanies the 3 evolution processes of the extensional rift basin,that is,the initial rifting stage (Tongbomiao Formation) stage,the fast faulting (Nantun Formation) stage,fault-depression conversion (Damoguaihe Formation) stage,so the 4 buried hill types,high and steep fault block type,wide-gentle anticline type,fault terrace type and isolated hammock type,were formed. The reservoir types of buried hill include the two types,the weathering erosion and structural fracture.The seismic wave group of weathering crust look like a lens outside,and there exists the weak reflection inside. The main fractures of the basement buried-hill are high angle,low angle,grids and so on. The high angle parallel fractures cause positive scope difference in the dual-lateral data,and the low angle fractures causes negative scope difference. The well logging response characteristics were affected by the dip and the included angle of the two sets of parallel fractures. The high and steep fault block buried-hill in the south of Sudeerte,the wide-gentle anticline buried-hils in Huodemoer and Bayantala will be the favorite exploration targets for the next step.