Abstract:

The low-grade heavy oil reservoir in the Gudao oilfield is a typical double-low unit.  The present recovery percent of reserves is 5.5％, and the oil production rate is only 0.36％. Exploitation is difficult because of poor reservoir development and fluid properties. Due to the serious problems of high-pressure steam injection, poor steam injection effect and low-cycle oil production in the reservoir developing, the study to improve heavy oil properties through injecting CO2, oil-soluble viscosity reducer, and  both was carried out. In field application, combined with the geological characteristics of reservoirs, different chemical compound huffing and puffing technology were applied in wells of different development characteristics. It achieved obvious  effects of oil incremental.

Key words:  Gudao oilfield, low-grade heavy oil reservoir, CO2, oil-soluble viscosity reducer, chemical compound huffing and puffing technology