Exploration and Practice of CO2 Huff-N-Puff Combined CO2 Flooding in Shale Oil Well Cluster Group

Abstract

Shale oil production wells in Dagang Oilfield in China are put into production by means of horizontal well and segmented multi-cluster massive volume fracturing. The production characteristics are that the output is high in the initial phase of production, the output decreases rapidly with the continuous production, and there are no effective measures to increase production. There is an urgent need for stimulation technology to improve the recovery of shale reservoir. In the field of oilfield development, CO2 has multiple advantages such as easy injection, viscosity reduction and energy increase. For the shale oil well cluster group with good inter well connectivity, the author designs an implementation mode of “CO2 huff-n-puff combined CO2 flooding” to improve shale oil production. This implementation mode can play the dual role of CO2 huffn- puff combined CO2 flooding and CO2 drive to realize the efficient production increase of shale oil well group. After two phases of implementation of the test well group, the cumulative oil increase of the well group has reached 3864 tons, and the comprehensive oil change rate has reached 1:1.22, which has achieved good stimulation effect. This implementation method can effectively improve the production of shale oil reservoirs and provide a new technical measure for improving production and efficiency of similar shale reservoirs.