Exploiting Oil from Thin Pay Zones and Inaccessible Areas of Lower Burgan Sabiriyah, North Kuwait
Khan, Ali N.
Field Development, Kuwait Oil Company, Ahmadi, Kuwait.
The Sabiriyah field located in northern Kuwait is consisted of three productive formations; lower Burgan sandstone, upper Burgan sandstone and Mauddud Limestone. The sandstone reservoir in the lower Burgan formation is one of the major sources of Kuwait oil's production. It consists of good quality reservoir-sandstone. It can be divided into lower massive sand and upper sand shale intercalations (layered Lower Burgan). As many as eleven depositional packages representing specific depositional settings have been identified. These sand units have a fundamental influence on fluid movement during the course of production from a reservoir.
Since the inception of the field this reservoir has been primary contributor towards oil production. One of the ways to step up production of oil from Sabiriyah field it was thought to look into the possibility to go for horizontal/high angle wells in Lower Burgan Reservoir. A feasibility study was carried out which was concluded with positive results. It was decided to go and explore the possibilities to access areas where placement of vertical well was not accessible: because of surface congestion, oil lakes and thin poor quality of sand.
As on date major portion of the remaining reserves for Lower Burgan lies in upper part (Layered Lower Burgan): LBLCOAL-1, LBLCOAL_2, LBM-2 and LBM-04. Accordingly three areas were targeted- in and around GC-23, oil lake area and area of thin poor sand quality. Three wells A, B and C were worked out and released for drilling. All these three wells have been successfully drilled and completed as oil producer.
The experience gained and the lesson learned during firming up the locations, drilling and completion of first ever drilled horizontal well in Layered Lower Burgan of North Kuwait is being discussed here. The main results and mile stones achieved along with way forward are as follows:
These wells on completion have collectively produced ~14000 BOPD almost four times of the rate of vertical wells in these areas.
For the first time in Kuwait a thin pay: 5 to 7 feet was drilled through (NCW) and has been successfully completed as oil producer.
It also opens up opportunity to access thin pays which otherwise would have not been economically viable by vertical wells.
Possibility of using Inflow Control device (ICD) for water controlled production is being worked out.
AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012