Exploration discoveries and implications of well Zheng 10 in the Zhengshacun area of the Junggar Basin

The expansion toward deep-to-ultra-deep oil and gas exploration is strategically vital for reserve growth and production addition in the Junggar Basin. Well Zheng 10 drilled in the Zhengshacun area in the hinterland of the Junggar Basin underscores the significant potential of the basin’s central part for ultra-deep oil and gas exploration. This study first presents the characteristics of hydrocarbon reservoirs in the area, emphasizing the elements of pertroleum system, such as source rocks, reservoirs, and migration pathways, that contribute to hydrocarbon accumulation. Accordingly, it identifies the determinants of hydrocarbon accumulation in the area and establishes the hydrocarbon accumulation mode. Furthermore, this study presents the implications of these factors for deep-to-ultra-deep oil and gas exploration in the area. The results reveal three major factors influencing the hydrocarbon accumulation therein: (1) A mechanism driven by low geothermal gradients and overpressure for hydrocarbon-generating evolution. This mechanism extends the oil window and elevates the transformation ratio, thereby significantly enriching hydrocarbon resources; (2) A four element (including low geothermal gradient, overpressure, chlorite coating, and zeolite dissolution) -controlled reservoir formation. This pattern redefines the lower depth limit for the development of conventional clastic reservoirs, thus broadening the scope for hydrocarbon exploration. (3) A migration mechanism governed by both faults and overpressure. This mechanism provides high-energy pathways for hydrocarbon migration and determines the vertical differential hydrocarbon migration, thus ensuring efficient hydrocarbon charging in ultra-deep reservoirs. By integrating superimposed factors including ultra-deep source rock evolution, pressure changes, tectonic shifts, diagenetic sequences, and hydrocarbon accumulation periods, we establish a hydrocarbon accumulation mode for the study area. This mode incorporates the temperature-pressure control over hydrocarbon-generating evolution, four element-controlled reservoir formation, and hydrocarbon migration governed by both faults and overpressure. This study aims to provide theoretical guidance and a scientific basis for new exploratory well emplacement and the delineation of potential new play fairways in the area.