| المستخلص: |
Pore pressures in most deep sedimentary formations are not hydrostatic; instead they are overpressured and elevated even to more than double of the hydrostatic pressure. If the abnormal pressures are not accurately predicted prior to drilling, catastrophic incidents, such as well blowouts and mud volcanoes, may take place. Fracture gradient prediction methods are reviewed, and the minimum and maximum fracture pressures are proposed. The commonly used empirical methods for abnormal pore pressure prediction are well logs. The purpose of this project is to develop a pore pressure and fracture pressure prediction strategy for North Gailo oil field which is situated in the eastern portion of the Sirt Basin, and applying the proposed model to design a drilling model of a development well in the formation. To achieve this offset well data from three wells in the pool which are 6J9, 6J10 and 6J12, respectively will be reviewed, analyzed and predict an analytical model. The final pore and fracture pressures model developed will be helpful for future development in the pool when they are drilling new development wells. In this study an analytical method is used to predict the pore pressure and fracture pressure model, here the all raw data collected will be transformed into a form where interpretations can be made. Using the real-time drilling data the model is verified. Eaton’s sonic and resistivity methods are then adapted using depth-dependent normal compaction equations for pore pressure prediction in subsurface formations, the adapted methods provide a much easier way to handle normal compaction trend lines. In addition to the empirical methods, the theoretical pore pressure modeling is the fundamental to understand the mechanism of the abnormal pressure generation. When the pore pressure model is finalized that will be used to design the surface casing of a development well in the formation. As well as, the fracture pressure and pore pressure model can be used for future development of the North Gailo field.
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