High Quality Images while Drilling

Abstract

Abstract Drilling highly deviated wells in heavily fractured and complex heterogeneous carbonate formations is a challenging process that requires a real time monitoring and utilizing an MWD and LWD technology. Currently PDO is developing X field and drilling horizontal wells for gas in A formation in which the reservoir compromises a heterogeneous vuggy limestone and fractures network that is distributed all over the field. The challenge faced during drilling is the total drilling mud losses due to presence of major fractures, consequently those fractures represent a threat for early water break through and shortening the life of the well. PDO has utilized the Ultra high resolution LWD resistivity images in several wells to tackle this problem, which successfully helped to identify the fractures zones that contributed to the drilling mud losses and design completion to isolate those fractures zones. As well as selecting a proper perforation zones away from the fractures. Having different depths of investigation can help to analyses invasion, provide inputs for petrophysical formation evaluation and to differentiate between features that appears near wellbore or deep in the formation. After drilling, memory data which has better sampling and data density was processed and quick geological interpretation was performed, The interpretation included complete structural borehole features identification such as (Structural dip computation by picking bed boundaries intersected while drilling), Detailed fractures characterization. To identify type of fractures(conductive, resistive), morphology and geometry of each fractures (continuous, discontinuous) and fractures density and distribution along the logged interval. Minor sub-seismic faults were also identified from the images. The geological interpretation of the high resolution resistivity images revealed the presence of a few major conductive fractures that were possibly enhanced by drilling and a large number of partial discontinuous conductive and resistive fractures.