印尼打拉根盆地油气成藏特征与主控因素

Hydrocarbon Accumulation and Main Control Factors in Tarakan Basin, Indonesia

打拉根盆地是印度尼西亚重要的含油气盆地,油气资源丰富。盆地自陆向海划分为陆上反转构造带、陆架区伸展断裂带和深水区逆冲褶皱带,各区带油气成藏与分布特征存在差异。认为盆地油气成藏属烃源岩和输导体系联合控藏。烃源岩控制油气分布格局,中新统煤系为盆地主力烃源岩,生烃中心主体位于陆架区中部,油气主要富集在生烃中心附近的有利构造中。输导体系是不同区带油气成藏的主要控制因素,断裂和构造砂脊是陆上反转构造带油气运移的优势通道,油气主要富集在上新统与上中新统构造砂脊上的反转背斜中;生长断裂是陆架区伸展断裂带油气运移的优势通道,油气主要富集在上新统与上中新统断裂所夹持的断块上;逆冲断裂是深水区油气运移的优势通道,油气主要富集在上新统逆冲背斜中。指出陆架区伸展断裂带勘探潜力最大,深水区逆冲褶皱带勘探潜力次之,陆上反转构造带具有一定勘探潜力。

Tarakan Basin, as an important basin in Indonesia with abundant oil and gas resource, is divided into three zones from land to sea, namely inversion structure belt on land, extensive fault belt on continental shelf, and thrust belt in deep water, with respective features of hydrocarbon accumulation and distribution. It is concluded that hydrocarbon accumulation is controlled by both source rock and conduit system in Tarakan Basin. Oil and gas are mainly concentrated in favorable structures near the center of hydrocarbon generation in the shelf zone, where the Miocene coal strata is the major source rock. The conduit system is the main controlling factor for hydrocarbon accumulation in different zones. Fractures and structural sand ridges are the dominant pathway for hydrocarbon migration in the inversion structure belt, and hydrocarbons are mainly concentrated in the Pliocene and Upper Miocene structural sand ridges. The growth fault is the dominant pathway for oil and gas migration in the extended fault zone on the continental shelf, and oil and gas are mainly concentrated in the Pliocene and Upper Miocene fault blocks. Thrust faults are the dominant pathway in the thrust zone in deep water, and hydrocarbons are mainly enriched in the Pliocene thrust anticline. According to the order of exploration potential, the extensive fault belt on the continental shelf is the largest,followed by the thrust-fold belt in deep water, and the inversion structure belt on land again.