Difference in behavior of the waterflood mechanism in two typical areas of a fractured carbonate reservoir, McElroy field

The McElroy field is one of the oldest waterflood fields producing from fractured carbonate reservoirs. The field has been producing since the 1920’s and started waterflooding in the 1950’s. It is obvious that the waterflood process plays an important role in improving oil recovery. However, due to the complex fractured carbonate reservoir setting, it is a big challenge for the waterflood management to attain the ultimate oil recovery. Geologically, the field is divided into four main areas and each area behaves differently, with the waterflood process influenced by the characteristics of the fractured reservoir. Understanding the waterflood mechanism in each area will help to develop an appropriate strategic waterflood plan. This study focuses on characterizing the differences between the waterflood performance in two areas of the field, the Low Permeability Area (LKA) and the Low Pressure Area (LPA).
The study used a plentiful well database of about 680 wells within the LKA and LPA to define the contrasting waterflood performance in these areas. The main characteristics of the waterflood in the LKA and LPA to be discussed in this study consist of:
- Oil production performance
- Water production performance
- Oil recovery performance
- Waterflood management - the challenges and optimization
The main objective of the study is to define the similarities and distinctions of the waterflood mechanism performance of these two different fractured reservoir areas. This study also recommends further approaches to improve recovery efficiency in the McElroy field. The analysis can be used as a reference for waterflood design process in green or brown fields exhibiting similar conditions.