Martin Wells - Early Cretaceous deltaic deposits of the Main Pay Reservoir, Zubair Formation, SE Iraq: Depositional controls on reservoir performance
12:00pm - 1:00pm /
Friday 24th February 2017
/ Venue: Jane Herdman Lecture Theatre Jane Herdman Building
Type: Seminar /
Category: Department
- 0151 795 0619
- Jamie Hughes
Add this event to my calendar
Click on "Create a calendar file" and your browser will download a .ics file for this event.
Microsoft Outlook: Download the file, double-click it to open it in Outlook, then click on "Save & Close" to save it to your calendar. If that doesn't work go into Outlook, click on the File tab, then on Open & Export, then Open Calendar. Select your .ics file then click on "Save & Close".
Google Calendar: download the file, then go into your calendar. On the left where it says "Other calendars" click on the arrow icon and then click on Import calendar. Click on Browse and select the .ics file, then click on Import.
Apple Calendar: The file may open automatically with an option to save it to your calendar. If not, download the file, then you can either drag it to Calendar or import the file by going to File >Import > Import and choosing the .ics file.
The Early Cretaceous (Barremian-Aptian) Main Pay Member of the Zubair Formation is the main producing reservoir in the supergiant Rumaila oil field in southeast Iraq, one of the world’s largest oil fields. Whilst the field has been on production for c.60 years, significant resources remain. Key to their economic development is an improved understanding of the geological controls on reservoir performance and how this impacts reservoir management decisions. This has been achieved through an integrated study of numerous static and dynamic datasets.
The Zubair Formation was deposited by fluvial-dominated, tide-influenced deltas during a period of enhanced sediment supply from the hinterland. Several scales of geological heterogeneity exist, each exerting a strong control on reservoir performance. At the coarsest scale the reservoir is layered, with layers defined by mudstones deposited above widespread flooding surfaces. These mudstones cause multiple moved oil water contacts and hold back significant pressure. Their identification and correlation enables the development of a perforation strategy where each reservoir flow unit is completed separately, avoiding cross-flow and lost production. Between the flooding mudstones an array of paralic depositional elements was deposited as the delta system repeatedly advanced and retreated. The type, geometry and connectivity of these depositional elements define the reservoir architecture, which controls large-scale sweep efficiency and the habitat of remaining hydrocarbons. An improved understanding of these elements and their control on sweep has facilitated a successful infill drilling campaign. Finally, many of the reservoir sandstone types contain numerous fine-scale geological heterogeneities which exert a control on small-scale sweep efficiency. An improved understanding at this detailed level is important for determining expected recovery factors and future water-handling capacity requirements.
The Zubair Formation was deposited by fluvial-dominated, tide-influenced deltas during a period of enhanced sediment supply from the hinterland. Several scales of geological heterogeneity exist, each exerting a strong control on reservoir performance. At the coarsest scale the reservoir is layered, with layers defined by mudstones deposited above widespread flooding surfaces. These mudstones cause multiple moved oil water contacts and hold back significant pressure. Their identification and correlation enables the development of a perforation strategy where each reservoir flow unit is completed separately, avoiding cross-flow and lost production. Between the flooding mudstones an array of paralic depositional elements was deposited as the delta system repeatedly advanced and retreated. The type, geometry and connectivity of these depositional elements define the reservoir architecture, which controls large-scale sweep efficiency and the habitat of remaining hydrocarbons. An improved understanding of these elements and their control on sweep has facilitated a successful infill drilling campaign. Finally, many of the reservoir sandstone types contain numerous fine-scale geological heterogeneities which exert a control on small-scale sweep efficiency. An improved understanding at this detailed level is important for determining expected recovery factors and future water-handling capacity requirements.