Main controlling factors and exploration direction of gas reservoir in Jialingjiang Formation, Sichuan Basin

Abstract

The Jialingjiang Formation is a traditional stratum for natural gas exploration in the Sichuan Basin, and in recent years it has been continuously discovered in northern and southwestern Sichuan, but there are still large areas of exploration blanks in the basin, which urgently needs to deepen the understanding of the natural gas accumulation law of this formation, clarify the main controlling factors of the accumulation, and then point out the exploration direction in the future. By using natural gas geochemistry and other analytical tests, combined with structural restoration, basin simulation and other technologies, based on gas source analysis, with typical gas reservoir anatomy as the core, combined with the understanding of the reservoir conditions of the Jialingjiang Formation, the main controlling factors of reservoir formation were discussed through the analysis of reservoir formation process, and the reservoir formation model was established. The results show that the natural gas of the Jialingjiang Formation is mainly cracked gas from crude oil in the lower part. The Jialingjiang Formation has good reservoir formation conditions such as multiple sets of high-quality source rocks supplying hydrocarbons, developing multiple types of carbonate reservoirs, and source-connected faults that effectively communicate gas sources. The paleostructures of the main oil generation period, the structures of the adjustment period, the source-connected faults, and the favorable reservoir types are the main controlling factors of the natural gas accumulation in the Jialingjiang Formation in the Sichuan Basin. The Jialingjiang Formation has an accumulation model of "multi-source charging to form ancient oil reservoirs, ancient oil reservoir cracking and supply gas, source-connected faults transport, and late adjustment accumulation". Based on this, it is proposed that the structural and litholo-gical composite gas reservoirs distributed in the piedmont belts of western and northern Sichuan, which are at relatively high positions during the main oil generation period and gas reservoir adjustment and accumulation period, have developed source-connecting faults, and have good preservation conditions, are the preferred exploration directions. The porous lithological gas reservoirs distributed in the structurally stable areas and syncline areas of the high and steep structural belts in eastern Sichuan are the main exploration directions in the future.

Keywords

• carbonate reservoir
• accumulation pattern
• exploration direction for natural gas
• jialingjiang formation
• triassic
• sichuan basin