A reservoir characterization of Arab-D super-k as a discrete fracture network flow system, Ghawar Field, Saudi Arabia.

摘要

The Arab-D Formation of the Ghawar Field, Saudi Arabia, is the most prolific oil producing formation in the world, relative to both volume and productivity. Cumulative oil production from Ghawar, through 2003, exceeded 55 billion barrels, and maximum field production rate has exceeded 5.7 million barrels per day (under natural lift)---both worldwide industry records.; An important hydraulic component of this carbonate formation, "super-k," provides for anomalously high, localized, fluid conductivity, and has to date eluded simple geologic characterization.; Spatial prediction of super-k occurrence is desired for placement of water injection and oil production wells, and for improved production forecasting.; This thesis provides a new model of Arab-D super-k, comprised primarily of interwell discrete fracture networks.; The model is used to predict production performance in an 11-well study area in the Hawiyah sector of the field. Four of the wells in the study area exhibit the effects of super-k.; The principal components of the thesis, the simulation of flow in large-scale, discrete fracture systems, preceded by the mapping of geocellular models to the flow simulation model, provide for a new general approach to modeling the flow effects these highly conductive systems. This approach is immediately applicable beyond Ghawar and super-k; in general, characterization of reservoirs which are severely affected by flow in large-scale fracture systems, most notably those oil or gas developments in which the accurate prediction of water encroachment is essential to well planning or determination of economic feasibility, may benefit from this model. The model is conducive to immediate industry application, due to two key elements. First, sources, rather than discretization, are used to incorporate discrete fracture networks into the conventional, and commercial, finite difference flow simulator, without modification of the flow simulator code.; Second, a practical, stochastic discrete fracture network model serves as a tool for gradual deformation of the geocellular model in a history matching algorithm.; The super-k model was used successfully to predict production performance that is significantly affected by the presence of large-scale fracture systems, in the Ghawar study area.