WELL BORE STABILITY: CAUSES AND CONSEQUENCES IN ABU MADI FIELD, OFFSHORE NILE DELTA, EGYPT.

Abstract

Due to the location of Abu Madi gas field, where it lies on the northeastern bank of the Nile Delta, a majority of wells are being drilled deviated from shore line, as well as vertical wells to maximize the production and hydrocarbon recovery in the mature reservoirs of the study area. It is of great challenge to drill a high angle well successfully through complex structure, tectonic setting and highly stressed shale. The stratigraphic setting of the area possesses significant drilling challenges that vary widely from reactive shale to stress-related problems. The objective of this thesis is to investigate, focus and integrate drilling, geologic and petrophysical knowledge for a better understanding the geomechanics of the study area, in order to estimate pore pressure and fracture gradient, select the optimal mud weight window and to study the impact of stress orientation and magnitude, on the wellbore stability for safe drilling. Practically, the drilling events such as the stuck pipe, kick, mud losses and tight hole associated with the mud weight windows can be used for better understanding the geomechanical setting of the concerned area. Some relationships between elastic moduli and rock strength have been discussed in this study to find the most influential conditions on the formations for safe drilling and to estimate equations for these moduli in the area of study.