3D Model for Rock Strength In-Situ Stresses in the Khuff Formation of Ghawar Field, Methodologies Applications

摘要

Knowledge of geomechanical attributes has positive merits fordrilling in hydrocarbon formations. In the Ghawar field, theKhuff is a deep, carbonate gas-bearing formation. Severaldevelopment wells have been drilled into this formation andconventional logging data was acquired in them. Such data hasbeen exploited in generating geomechanical attributes alongthe Khuff formation in those wells. Furthermore, hard datalike minifrac tests and core mechanical properties wasavailable in some of the wells and utilized in calibrating andvalidating the computed geomechanical properties.A study was conducted to develop a 3-dimensionalcharacterization of geomechanical attributes in the Hawiyah-Khuff formation of the Ghawar field. The study wasperformed to provide a model that, together with existinggeologic models, can be used to predict regions of drillingdifficulty, provide guidance in selecting drilling bits, and helpin designing drilling mud and optimizing hydraulic fracturingjobs in the field. The study established correlations betweenthe geomechanical and the geological attributes in Hawiyah-Khuff wells. Then, these correlations were used with a preexistingHawiyah-Khuff geocellular model to map thegeomechanical attributes away from the wells in the 3DHawiyah-Khuff space. Rock strength, minimum andmaximum horizontal stresses are among the properties thatwere mapped, for the first time, in the 3D Khuff horizon.The 3-D geomechanical model is consistent with observedtrends in drilling difficulty, and with the requirements forhydraulic fracturing within the Khuff horizons. The model hasbeen used in assessing the borehole stability of deviated wellsplanned for the field. We present some illustrations andexample applications in the paper.