Method and system for predicting shale formation pressure

Abstract

The invention discloses a method and system for predicting the shale formation pressure. The method can comprise the steps that based on logging information, the clay content of shale is acquired; based on a neutron density intersection method of a dry clay framework, the first total porosity of the shale is acquired; based on acoustic logging information, a shale reservoir experience model is established, and the second total porosity of the shale is acquired; based on the first total porosity and the second total porosity, the difference value of the total porosities is acquired; based on the difference value of the total porosities and the clay content, a pressure indication value is acquired. According to the method, based on the characteristic that the porosities, gas containing performance and pressure of the shale supplement one another, by using logging methods of different measurement principles, the difference of the porosities is acquired, the difference of the gas containing performance of a shale gas reservoir is reflected, and the problem is solved that shale logging response is influenced by complex mineral components, organic matter and low porosity of the shale reservoir; the aim of using the logging information to evaluate the pressure of the shale reservoir is achieved.

Description

technical field [0001] The invention relates to the technical field of unconventional oil and gas geophysical exploration and development, and more specifically, to a method and system for predicting shale formation pressure. Background technique [0002] The practice of shale gas exploration shows that the shale gas production has an obvious positive correlation with the pressure coefficient. Overpressure or ultra-high pressure is an important feature of high production and high efficiency of shale gas wells, while high pressure and ultra-high pressure mean good preservation conditions, and high pressure is the Good gas content, especially the important feature of high free gas content. Shale reservoir pressure is not only an important indicator reflecting the preservation conditions of shale gas, but also an important parameter affecting the gas-bearing properties of shale. Shale reservoirs absorb gas and free gas under high pressure, normal pressure and underpressure cond...

AI Technical Summary

Problems solved by technology

[0004] However, the prediction accuracy of these formation pressure prediction methods in unconventional shale reservoirs is not high, and even large deviations occur

There are two main reasons for this: (1) The causes of shale reservoir pressure are different from those of conventional reservoirs. The overlying formation pressure is only one of the causes of shale formation pressure, and the more important cause is the "integrated source and reservoir of shale". "The pressure generated by the continuous hydrocarbon generation of organic matter; (2) Because the acoustic time difference (or sound velocity) of shale reservoirs is significantly affected by factors such as high clay content, high organic matter content, and extremely low porosity in shale, it is difficult to respond to acoustic logging. Easy to reflect the actual situation of shale reservoir pore space

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