Khelil Kartobi

Applying a New Systematic and Dynamic UBD Procedures Prevented Formation Damage, Wellbore collapse and Improved Oil production

The Hassi Massoud oil field is the largest of its kind in Algeria. The reservoir was discovered in 1956 and produces from a Cambrian-age at approximately 3400 meters depth. It produces 45°API oil from a thick Cambro-Ordovician sandstone formation. This sandstone is extremely hard, abrasive and slow to drill. The reservoir is naturally fractured in some parts. Fractures are either open or plugged with materials such as shale, silica, anhydrite, pyrite and bitumen. Porosity is ranging from 6 to 12%. Generally, the permeability is low with a range of less than 1 to more than 100 md in open-fractures layers.

Identification and Characterization of Producing Fractures in Naturally Fractured Reservoirs Using PIWD

Underbalanced drilling provides an unprecedented opportunity to examine a reservoir as it is being drilled. With proper data acquisition and engineering interpretation, underbalanced drilling allows us to measure and calculate the Productivity Index while Drilling – PIWD. This data helps us locate and identify geologic anomalies such as fractures, tight zones, pinch outs, discontinuities, and water zones. A better understanding of the fracture networks and their impact on the production is critical to optimize infill drilling and produce the remaining reserves in any reservoir. Also, PIWD graph is a good indicator of reservoir productivity characterization. The real time data obtained using this graph can clearly show what kind of reservoir is being drilled and what kind of production can be expected.