A Method for Calculating Pore Pressure in Carbonate Formation Based on Rock Compressibility Coefficient

Abstract

The present invention provides a method for calculating the pore pressure of carbonate formations based on the rock compressibility coefficient. According to the theory of rock poroelasticity, by analyzing the constitutive relationship between rock compressibility coefficient, pore pressure and effective stress, combined with Biot-Willis law of effective stress Establish a carbonate rock pore pressure prediction and quantification model that characterizes the relationship between pore pressure and rock compressibility coefficient; then through a large number of rock formation compaction coefficient tests and data simulations, according to the fitting Quantitative relationship, combined with carbonate rock physical simulation data to carry out verification and analysis of pore pressure prediction quantitative model, the measured pore pressure is well correlated with the key parameters in the pore pressure prediction quantitative model. From the perspective of rock physics and based on the rock compressibility coefficient, a quantitative model reflecting the constitutive relationship between pore pressure and rock compressibility coefficient is theoretically established, which reduces the influence of subjective knowledge 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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