Study on the limit of ineffective cycle control in Lamadian Oilfield in the late period of ultra-high water cut

Development Program Room, Geological Research Institute, No.6 Oil Production Plant, Daqing Oilfield, Heilongjiang, 163318, China

Corresponding author’s e-mail: lihui23@petrochina.com.cn

Abstract

The ineffective circulation in Lamadian oilfield is mainly banded ineffective circulation and dendritic ineffective circulation, and the ratio of ineffective circulation to the total well production is mostly concentrated below 40%. Therefore, this paper first divides the levels of ineffective circulation and simulates the proportion of liquid production in different levels of ineffective circulation to get the limits of ineffective circulation management. The results showed that the invalidation index R < 0.2 was a fourth-grade invalidation cycle, 0.2≤R < 0.3 was a third-grade invalidation cycle, 0.3≤R < 0.4 was a second-grade invalidation cycle, and R≥0.4 was a first-grade invalidation cycle. The reduction of water injection in the planar heterogeneous layer will lead to the decrease of cumulative oil production, and the discrimination index R is small, and the reduction range is almost unchanged. When the discriminant index R is above 0.4, the reduction of cumulative oil production increases significantly.