Edge Water Breakthrough in each of the major zones within Mishrif reservoir in West Qurna phase 1

Abstract

The Mishrif reservoir (Upper Cretaceous) considered the main discovered and developed
reservoir at West Qurna I field in southern Iraq and has been on production intermittently since
1999. Mishrif reservoir has been deviated into six main zones from youngest to oldest are mA,
CRI, mB1, CRII, mB2 & mC.
The West Qurna Phase I Field (WQI) has pressure depletion since production commenced in
1999. More than 450 wells penetrated Mishrif Formation, to date, almost all of the production
has been from the Mishrif formation (2180 to 2505 m true vertical depth, subsea) with minor oil
production from the Lower Cretaceous Zubair formations. Geoscientist and reservoir engineers
are looking for producing dry oil especially there are limited surface facilities at West Qurna
phase 1, for that purpose and as part of Reservoir Management, It was very important to monitor
the Formation & injection water movement across Mishrif reservoir with the time. Cased hole
logs (Saturation logs & Production logs) and Open hole logs for new drill wells are being
integrated to describe the water encroachment in Mishrif in order to Study behavior of aquifer
movement and water injection, Validate the geologic reservoir model, assess the vertical and
horizontal water sweep & enhance perforation strategies.
In West Qurna 1 (from 2010 to date) have been ran more than 500 PLTs (Production logs)
and 300 PNLs (Saturation logs) and open hole logs for new drill wells, all these logs have been
analysis and interpreted (using Geolog &Emeraude software) then were created different water
movement maps for each main productive zone mA, mB1 & mB2 in 2013, 2014 & 2016 (by
Petrel).

Different water encroachment behavior among the different zones due to heterogeneity in
reservoir rock quality, Integrating production rate allocated by zone with water encroachment
maps shows excellent relationship between production and flood front by zone, the maps showed
that quicker water movement in the Meshrif reservoir compared to the model, these maps are
using for perforation strategy, and the maps will be updated periodically every 12 months.