Method for predicting overpressure of undercompaction and hydrocarbon generation mixed cause stratum

Abstract

The invention discloses a method for predicting overpressure of an undercompaction and hydrocarbon generation mixed formation cause, and aims to provide a method for carrying out quantitative formation pressure prediction in a development area which has two cause mechanisms of undercompaction and hydrocarbon generation at the same time and jointly causes overpressure of formation pores. Accordingto the new method, stratum TOC content pre-stack earthquake prediction is creatively correlated with hydrocarbon generation pressurization on the basis of calculating the under-compaction factor overpressure contribution by taking speed reduction as the basis by adopting the thought of quantitatively characterizing and finally stacking the under-compaction factor overpressure contribution and thehydrocarbon generation overpressure cause contribution respectively. The invention provides a new hybrid cause overpressure prediction method which is simpler, more convenient and more intuitive thanthe existing methods based on the loading / unloading theory, such as power and the like. According to the method, the risk that the prediction precision is reduced due to the fact that parameters of anunder-compaction or hydrocarbon generation prediction model are adjusted to be approximate to a mixed cause result conventionally is avoided, the complex regional parameter determination step of a power loading / unloading curve overpressure prediction method is also avoided, and a calculation result is more stable.

Description

Technical field: [0001] The invention belongs to the field of oil and gas field exploration, in particular to a method for predicting the overpressure of under-compacted and hydrocarbon-generated formations. Background technique: [0002] Abnormally high formation pressures generally exist in geologically relatively late sedimentary environments, and their development patterns are very complex in most areas. Predicting the distribution of pore pressure in underground rock formations (hereinafter referred to as formation pressure) before drilling for oil and gas exploration plays a vital role in rationally configuring the mud system to ensure drilling safety. [0003] The causes of abnormal overpressure in the formation mainly include the underpressure caused by the rapid deposition of clay minerals, the pressurization of hydrocarbon generation caused by the discharge of liquid or gaseous hydrocarbons associated with organic diagenesis, and the pressure rise caused by tectoni...

AI Technical Summary

Problems solved by technology

[0014] In order to solve the problems existing in the prior art, the present invention provides a method for predicting the overpressure of under-compacted and hydrocarbon-generated formations, which solves the problem in the prior art when the dominant factor is unknown or multiple factors cannot be ignored. Prone to problems such as parameter optimization and further improvement of speed accuracy requirements

Images