Integration of 4D Seismic Data for Improved Reservoir Management and Development Decisions in the Dan Field

Since 4D seismic is considered a key surveillance technology to produce the remaining oil of the mature Dan field in a cost efficient manner, a third monitor survey over the Dan field has been acquired in 2016. 4D seismic in the Danish Underground Consortium (DUC) proved to be very useful to identify, mature and de-risk infill drilling, redevelopment as well as well- and reservoir management (WRM) opportunities. The observed 4D signal in the chalk reservoirs is strong and clearly correlates with production effects. The resolution is good enough to monitor the performance of individual wells and even specific completion zones along the long horizontal well tracks. Water swept zones are often characterized by an acoustic impedance (AI) increase due to the replacement of oil with water. The resulting hardening signal can be used to track the water sweep and identify pockets of remaining oil.

In this presentation we will discuss how 4D seismic is integrated in the asset team and impacts business decisions in a mature field. We will compare drilling results with 4D predictions, show how 4D seismic is used to identify and mature well intervention opportunities and discuss some interpretation challenges.