Patent ID: 7476773

Claim:
A process for preparing a gas oil cut, comprising the following steps in succession: 1) in a first oligomerization reactor, catalytically oligomerizing an olefinic C 2 -C 12 hydrocarbon cut, said oligomerizing being mainly dimerization; 2) in a separation column separating a mixture of products obtained from step 1) into three cuts: a light olefinic cut containing unreacted olefinic C 4 and/or C 5 hydrocarbons with a T95 of less than 100° C., an intermediate cut of dimers having a T95 in the range 180° C. to 240° C., and a first heavy gas oil cut having a T95 of more than 220° C. and higher than the T95 of the intermediate cut; 3) in a second oligomerization reactor, catalytically oligomerizing the intermediate cut obtained from the separation column with a portion of the light olefinic C 4 -C 5 cut from said separation step in proportions such that the ratio between the intermediate cut and the light olefinic C 4 -C 5 cut is in the range of 60/40 to 80/20 by weight.