Rock compressibility-based carbonatite stratum pore pressure calculating method

Abstract

The invention provides a rock compressibility-based carbonatite stratum pore pressure calculating method. The method comprises, according to mechanical theories on rock porous elasticity, analyzing the constitutive relation between rock compressibility and pore pressure as well as effective stress, and combining the Biot-Willis effective stress las to establish a carbonatite pore pressure predicting quantitative model for representing the relation between pore pressure and rock compressibility; performing a large amount of lithostratigraphic compressibility testing and data simulation, according to a fit quantitative relation between lithostratigraphic compressibility and effective stress as well as porosity, combining with carbonatite petrophysical simulation data to perform examination analysis of the pore pressure predicting quantitative model. Actual measurement shows that the pore pressure is high in correlation with key parameters in the pore pressure predicting quantitative model. From the perspective of petrophysics and based on the rock compressibility, the rock compressibility-based carbonatite stratum pore pressure calculating method theoretically establishes the quantitative model reflecting the pore pressure-rock compressibility constitutive relation and reduces influence of subjective cognition on pore pressure prediction.

Description

technical field [0001] The invention relates to the field of geological exploration, in particular to a method for calculating the pore pressure of carbonate formations based on the rock compressibility coefficient. Background technique [0002] Prediction of formation pore pressure is of great significance to conventional oil and gas exploration, evaluation of unconventional oil and gas sweet spots, and oil and gas development. More accurate prediction of formation pore pressure is also crucial to drilling safety and cost-effectiveness. [0003] In the past, the empirical methods that have been widely used and have good results for the prediction of formation pore pressure include: the equivalent depth method using porosity and acoustic logging data, and the Eaton (1972) formula using acoustic and resistivity logging data. Using the Fillippone (1979) formula method of seismic layer velocity, the Eberhart-Phillips model (1989) and the Bowers model (1995) by establishing the ...

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Problems solved by technology

[0005] Aiming at the problem that the current pore pressure prediction method is not suitable for complex heterogeneous carbonate formations, the present invention proposes a new pore pressure calculation method based on the rock compressibility coefficient, which solves the problem applicable to carbonate formations to a certain extent. The calculation of pore pressure is difficult due to the tight and extremely uneven lithology. Through petrophysical simulation experiments, it can be seen that the measured pore pressure has a good correlation with the key parameters in the pore pressure prediction and quantification model. This method is theoretically strong and has certain industrial applications. Value

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