Main Controlling Factors for the High Production of Tectono-Stratigraphic Reservoirs in Continental Down-Faulted Basin

Huoduomoer structural zone is one of the most favorable oil and gas accumulation zones in Beier depression of Hailaer basin. However, the exploration in this zone has experienced a long and tortuous process, and the exploration is almost stagnant until the natural production capacity of well x1 has obtained daily output of 472m 3 , which has achieved a major breakthrough in the exploration of tectono-stratigraphic and stratigraphic unconformity reservoirs in this structural zone. Based on the comprehensive study of the subdivided layers of the structural belt, this paper holds that the Nantun Formation suffered from long-term denudation after deposition, the Nantun Formation at the high part of the uplift belt was denuded completely, and the remaining Nantun Formation at the periclinal area was the main target layer for exploration. Based on the analysis of the main controlling factors of hydrocarbon accumulation, it is considered that feldspar lithic sandstone and lithic sandstone mainly developed in the subaqueous distributary channel deposition of braided river delta front are easy to be leached and eroded, forming high-quality reservoir with secondary porosity near the unconformity surface, and the multi-direction oil and gas migration system is the key to the oil and gas accumulation; the stable and thick mudstone deposition in the large section provides a good sealing condition for traps.