Abstract One of the difficulties in present methods for using surfactants to improve waterflood efficiency is that their movement through the rock is slow relative to the rate of water movement. As a result, these agents do not remain at the flood front. In addition, the bank of connate water ahead of the flood front prevents the surfactants from reaching the oil-water interface. The present invention overcomes this difficulty by injecting gas in proper volume to move through the injected and connate water bank to the oil-water interface, carrying the surfactant with it. This gas purging method is also considered to be of value in collecting and producing dispersed oil associated with and left by other surfactants, wetting agents and oil solvents. The present invention relates to a method for the recovery of oil from underground deposits thereof. More particularly, it is concerned with an improved waterflooding technique for oil recovery.
The process of claim 1 wherein said gas is dissolved in the floodwater at a pressure greater than the reservoir pressure so that said gas comes out of solution within the reservoir as small dispersed bubbles.
Claim 2
Dependent Claim
13 words
forming bubbles in said flood water by contacting the latter with a gas,
Claim 3
Dependent Claim
36 words
continuing the introduction of said gas into said reservoir to transport said bubbles through said flood water to said producing well whereby said surfactant collects on said bubbles and is carried thereon to said interface, and
Claim 4
Dependent Claim
32 words
The process of claim 1 in which the surfactant is a glycol ether consisting of a two to six mol ethylene oxide adduct of a six to eight carbon atom aliphatic alcohol.
Claim 5
Dependent Claim
15 words
The process of claim 1 in which the surfactant employed is a ditertiary acetylenic glycol.