西昆仑山前柯东构造新生代构造变形及油气意义

Cenozoic structural deformation and hydrocarbon exploration of Kedong structure in the piedmont of western Kunlun mountain

利用高分辨率三维地震剖面、地表露头以及钻井数据分析了西昆仑山前克里阳—甫沙构造带东段柯东构造的特征,认为柯东构造为压扭构造,主要发育基底断层,表现为强烈变形的褶皱前翼和宽缓的后翼(顶部)。生长地层揭示克里阳—甫沙断层于上新世逆冲形成柯东单斜(鼻隆),具有卷入翼部旋转的变形机制;后期克里阳—甫沙断层发育突破断层将柯东单斜切割为断块,并导致地表出露一套高陡倒转的地层,这套地层卷入了侏罗系—新生界。柯东构造的深部断块构造变形较弱,使得油气藏得以保存,KD1井显示这类断块具有很好的勘探潜力。

Used high-resolution seismic data and combined with outcrop and drilling data, we analyzed structural characteristics of Ke- dong structure（the east segment of Keliyang-Fusha fault belt） in the piedmont of western Kunlun mountain, which, as a transpres sion structure, consists of mainly basement faults and shows a gently dipping backlimb（crest） and intensely-deformed forelimb. Growth strata reveal that Keliyang Fusha faults formed a monocline（nose） structure by thrust in Pliocene with the deformation of limb rotation, that is to say the Kedong structure is a basement-involved structure. Later Keliyang-Fusha faults broke through the Kedong monocline and cut it into fault blocks, resulting in a suite of steeply-reversed strata exposed to the surface, which contained Jurassic Cenozoic beds. Because deep fault blocks didn＇t suffer intense deformation, they formed good traps for hydrocarbon accu mulation. Drilling data of Well KD-1 indicated that such blocks are of good exploration potential.