Abstract:

In the process of oilfield development，the water cut of crude oil increase continuously at the middle or late stage
of development. It would，on the one hand，lead to the decline of production，and on the other hand，result in the increase
in investment in oil recovery enhancement. Therefore，economic benefits of different oilfields differ widely，and it is very
important to evaluate the benefit of the oilfield with efficiency and preciseness. With cluster analysis of grey system theory，
and combined with the actual situation of oilfield development，we picked seven representative factors to do the grey clustering
analysis and research，which include: single well verified daily oil output，single well verified daily fluid production，average
water cut，geological mining speed，well working rate，effective rate for old well measures and unit production cost in six
blocks of SL oilfield. The evaluation results may provide a new method for oilfield economic benefit evaluation..

Key words: grey theory, cluster analysis, oilfield, economic benefit