Research on the Sedimentary Characteristics and Oil Accumulation Laws

The key to the development of oil and gas resources in the Tamulangou Formation in the Huhehu Sag of the Hailar Basin lies in the understanding of sedimentary characteristics and the division of volcanic-sedimentary cycles. These cycles are divided into five sedimentary systems, namely alluvial fans, braided rivers, fan deltas, braided river deltas, and lacustrine systems. Based on the lithological characteristics, sedimentary structures, geometric forms, and definitions of the Huhehu Sag. The volcanic-sedimentary sequences of the Tamulangou Formation are dominated by intermediate-basic volcanic rocks and acidic volcanic rocks and they are located at the uppermost part of the Huhehu Sag. The Huhehu Sag gou Formation contains thin-bedded sedimentary rocks and locally thick-bedded sedimentary rocks, with localized development of the 148 Ma Manitu Formation volcanic-sedimentary sequence. The source rocks in the Huhehu Sag are of moderate to good quality. And the main controls on hydrocarbon accumulation are the distribution of hydrocarbon source rocks, development of fault zones, characteristics of fan deltas, and volcanic-sedimentary processes.