Formation conditions and geological characteristics of deep giant gas provinces in the Kuqa foreland thrust belt

A series of seismic exploration technologies, such as “wide line and big combination” mountainous seismic acquisition, high steep structure pre-stack depth migration processing and deep tectonic modeling, were used to explore Kuqa deep structures. Pre-salt deep structures were preliminarily confirmed and a group of large structural traps were found. The research shows that the Kuqa foreland thrust belt is favorable for forming giant gas accumulations. Large-scale imbricated thrust systems can provide traps for large-scale oil and gas accumulation; excellent hydrocarbon source conditions and later intense charges of gas provide sufficient hydrocarbon reserves; the deep mass effective reservoir sandstone works as good reservoir volume for giant gas accumulations and thick gypsum deposits serve as good cap rocks. The geological characteristics of deep pre-salt structure giant gas accumulations typically have hydrocarbon distributions controlled by structural traps and structural gas reservoirs are dominant, reservoir properties of the deep thrust belts are generally poor, with fractures being the important controlling factor for hydrocarbon enrichment, oil and gas distribution is characterized by joint control of source and cap rock, stacking of multi-layer beds, and overall beds containing gas. Reserves are large, and single well productivity is high.