Pore Pressure Lab Report

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Abstract An accurate knowledge of formation pore pressure is required for safe and economic drilling and successful and exploration and production of hydrocarbons in areas which are abnormally pressured (pressure gradients greater than 0.465 psi/ft). An accurate estimation of formation pressure and depths helps in optimum planning so that proper hole sizes, casing programs, and mud weighting schedules can be selected. Historically, techniques for measuring pore pressures and detecting the proximity of abnormal pressure formations were based on quantitative relations between various log parameters – formation resistivity or conductivity, acoustic travel time or slowness with formation effective stress. These are based on the relationship…show more content…
2000) given a suitable velocity to pore pressure transform can be established. Some examples from literature include the methods of Hottman and Johnson (1965), Pennebaker (1970), Eaton (1975) and Bowers (1995). Differences in these methods lead to a different seismic velocity to pore pressure transform. The velocity to pore pressure transform can be calibrated using an inversion of offset well data. However, seismic velocities can be influenced by changes in lithology and pore fluid content, as well as by changes in pore pressure. The resulting difference in predicted pore pressure may become significant when a pore pressure estimate is required outside the interval over which the relation is calibrated. The recent development in technology allows us to acquire both P- and S- waves in the marine environment using multi-component receivers at the seafloor. The additional information provided by the S-wave velocity helps in reducing ambiguity between variations in pore pressure and variations in lithology and fluid content. Introduction One of the biggest challenges in the deep water of the offshore drilling is the ability to accurately predict pore pressures. During exploration phase, knowledge of formation pore pressure allows the hydraulic connectivity and fluid migration pathways (Dutta, 1997) in a basin to be assessed. Thus, an increase in pore pressure below a seismic horizon may indicate the presence of a seal, while different pore pressure either side of
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