- Copyright © 2004 Society of Exploration Geophysicists
BP's recent drilling results in the Akhen gas field, offshore Egypt, provide an excellent case study into the challenges of drilling and developing the pre-Pliocene in the Nile Delta. The challenges are significant and include Pliocene overpressure cells, variable thickness and rugosity of Miocene aged anhydrite, deep and complex structural elements, and seismic quality challenges. However, the reservoirs in the pre-Pliocene are known to contain very condensate-rich gas with high reservoir pressures and significant exploration potential, making this basin and this play a significant asset in BP's global portfolio.
The Akhen Field is located within the Ras El Bar concession in approximately 100 m of water (Figure 1). The field actually lies on the western flank of the much larger Temsah-Akhen structure, which is over 40 km in length. Currently producing fields on the structure include Akhen and Temsah Northwest. The eastern end of the structure contains the yet to be developed Temsah Field (Figure 2). The primary production interval in these fields comes from Serravallian (Miocene) aged reservoirs at depths ranging from 3.5 to 4.5 km. The fields are jointly operated and owned by BP and ENI.
This paper will present a short retrospective of the drilling results of the West Akhen-2 well, illustrating how subtle changes in seismic migration velocities can have a significant impact on well placement. Of particular interest is the application of tomographic velocity estimation that allowed us to gain a much …