Conventional oil and gas discoveries are becoming rarer, and increasing the need to develop unconventional tight resources. Understanding the complex mineralogy, variable rock fabric, and mechanical properties poses the greatest challenge in finding and producing these resources. Once the reservoir is properly understood, appropriate drilling, completion, and production strategies can be applied to successfully convert it into economic reserves. The key challenges in unconventional and tight gas plays are the understanding where, over vast geographical areas the regions of the reservoir with the highest combination of Reservoir Quality-RQ and Completions Quality-CQ are located. In many North American plays, the sweet spots were found only through extensive drilling of hundreds-and even thousands-of wells. In Egypt, operators need to find the sweet spots much faster than a trial-and-error approach. To do that, understanding reservoir heterogeneity is paramount.
Two vertical wells were drilled in Western Desert of Egypt in appraisal program for collecting the required data to explore one of the unconventional reservoirs discovered recently. Reservoir is planned to be appraised and developed with the help of multi-stage horizontal wells. Laboratory testing, which included scanning electron microscopy and X-ray diffraction were conducted to determine mineralogy and potential damage mechanisms. Fracturing fluid chemistry was tested and optimized using core plugs. Geomechanical rock properties derived from advanced petrophysical analysis of newly acquired high-definition triple-combo full-wave sonic logs and core samples were combined with geological parameters and potential treating schedules to develop sophisticated fracture simulation models. These models were then refined with in-situ reservoir data obtained from Mini Fall-Off (MFO) analyses to derive the final fracturing treatment design. The stimulation model was built using a three-dimensional (3D) geological model with multidisciplinary inputs, including formation properties, in-situ stresses, and completion parameters.
This paper describes the workflows followed with the heterogeneity analysis to study the data collected from these two vertical wells. Petrophysical and mechanical properties were used to describe RQ and CQ vertically across the reservoir to select the target layers. The main objective of the study is to plan approaching horizontal wells' lateral placement for the best performing fracturing completions across these target layers identified with the help of integrated advanced workflows.
