Technology of Nitrogen increase formation energy

Introduction

During the process of oil production, the formation energy will continuous decline with fluid extraction, which will lead to production rate decreasing. However, some reservoirs are not suitable for water flooding due to reservoir space features, reservoir heterogeneity and water sensitivity. To this kind of reservoirs, high pressure nitrogen injected into the formation is alternative to improve the well productivity.

Technical principles

Compressed nitrogen injected into the formation quickly buildups the formation energy, displace the residual oil in the reservoir, and realize well stimulation.

A) To replenish formation energy and increase displacement pressure;

B) To replace the residual oil in the attic space of reservoirs

C) To displace residual oil in microfractrures or microporous throat.

Suitable reservoirs

A) Reservoirs with natural depletion and depleted formation energy, and unsuitable for water injection;

B) Carbonate reservoirs;

C) Sealing fault-block sandstone reservoirs and subtle reservoirs.