Investigation on the asymmetric inter-fracture asynchronous huff-n-puff technology for the horizontal well group in the tight oil reservoir

Water huff-n-puff is one of the effective energy supplement methods for the development of tight oil reservoirs by horizontal wells. However, the oil production performance of water huff-n-puff severely decreases after several cycles. Available researches indicate that the inter-fracture asynchronous injection-production technology for the horizontal well is an efficient method for improving the oil production performance of water huff-n-puff. However, considering the object of the inter-fracture asynchronous huffn- puff is the single horizontal well, the study for a horizontal well group is less. Therefore, the asymmetric inter-fracture asynchronous huff-n-puff technology for the horizontal well group was investigated in this paper. The oil productions of the horizontal well group for different huff-n-puff modes were compared and analyzed first. After that, the oil recovery mechanisms of the asymmetric inter-fracture asynchronous huff-n-puff technology for the horizontal well group were revealed. Finally, the influence of operating parameters on the oil production of the horizontal well group for the asymmetric inter-fracture asynchronous huff-n-puff technology for the horizontal well group was studied by the numerical simulation method. The results show that compared with the water huff-n-puff, the accumulative oil productions for the asymmetric inter-fracture asynchronous huff-n-puff technology for the horizontal well group increased by 5134.8m3, and the increased amplitude is 36.86%. The imbibition, the inter-fracture displacement, and the inter-well displacement are the main oil recovery mechanisms of the asymmetric inter-fracture asynchronous huff-n-puff technology for the horizontal well group. The accumulative oil production of the horizontal well group for the asymmetric inter-fracture asynchronous huff-n-puff increases first, and then declines, finally tend to be stable with the increase of injection rate. Both the injection volume and the soaking time show a positive correlation with the accumulative oil production. The accumulative oil production of the horizontal well group decreases with the increase of production rate due to the aggravation of water channeling in the production stage. This work could provide certain theoretical guidance for the effective development of similar reservoirs by the horizontal well group.