Sedimentation, stratigraphy, and petroleum potential of Krishna-Godavari basin, East Coast of India
Sedimentation, stratigraphy, and petroleum potential of Krishna-Godavari basin, East Coast of India
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DOI：
10.1306/8626ccdf-173b-11d7-8645000102c1865d
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发表时间：
2001-09
期刊：
影响因子：
3.5
通讯作者：
G. Rao
中科院分区：
文献类型：
--
作者：
G. Rao
克里希纳-戈达瓦里盆地位于印度东部被动大陆边缘中部。盆地构造格局为东北—西南走向。上白垩统沉积岩的暴露将盆地边缘划分为西北方向，西北-东南走向的普拉纳希塔-戈达瓦里地堑毗邻盆地。该盆地含有厚层沉积物，具有多个沉积旋回，其年龄范围从晚石炭世到全新世。自晚白垩世以来，一个具有厚泥质相的主要三角洲一直向海进积，是碳氢化合物勘探目标。磁力和重力数据预测了盆地结构，随后通过多道地震调查得到证实。该盆地被断控山脊划分为多个子盆地。次盆地沉积物堆积厚度超过5公里。在基底山脊上方，发现了薄薄的沉积物。直到侏罗纪时期，沉积物才沉积在裂谷和地形低地。该层序完全被下白垩统海侵沉积楔所覆盖。后来，持续的三角洲进积成为盆地沉积的特征。这个已探明的含油盆地面积约为 45,000 平方公里，潜在的储层年龄从二叠纪到上新世不等。在 160 多个结构中钻探了 350 多口井，发现了 42 个含油气结构。从二叠纪-石炭纪到早中新世的层序中已知良好的烃源岩。由于储层砂体横向变化有限，了解不同层序的地层和沉积亚环境对于破译储层砂体的有利区位至关重要。倾斜断层、生长断层和相关的翻转背斜提供了构造圈闭。 （第1624页开始）
The Krishna-Godavari basin is located in the central part of the eastern passive continental margin of India. The structural grain of the basin is northeast-southwest. Exposures of Upper Cretaceous sedimentary rocks demarcate the basin margin toward the north west, where the northwest-southeast-trending Pranahita-Godavari graben abuts the basin. The basin contains thick sequences of sediments with several cycles of deposition ranging in age from Late Carboniferous to Holocene. A major delta with a thick, argillaceous facies that has prograded seaward since the Late Cretaceous is a hydrocarbon exploration target. Magnetic and gravity data predicted the basin architecture, which was subsequently confirmed by a multichannel seismic sur vey. The basin is divided into subbasins by fault-controlled ridges. Sediments accumulated in subbasins more than 5 km thick. Above the basement ridges, thin sediments are found. Until the Jurassic period, sediments were deposited in the rift valley and in topo graphic lows. This sequence is completely overlain by a Lower Cretaceous, transgressive sedimentary wedge. Later, continued delta progradation characterized basin sedimentation. With an areal extent of approximately 45,000 km2, this proven petroliferous basin has potential reservoirs ranging in age from the Permian to the Pliocene. Exploratory drilling of more than 350 wells in more than 160 structures has resulted in the discovery of 42 oil and gas bearing structures. Good source rocks are known from sequences ranging in age from Permian-Carboniferous to early Miocene. Because the reservoir sand bodies have limited lateral variation, understanding the stratigraphy and depositional sub environments in different sequences is essential to decipher the favorable locales for reservoir sands. Tilted fault blocks, growth faults, and related rollover anticlines provide the structural traps. (Begin page 1624)