Method for predicting pore pressure of regional high-pressure saltwater layer by utilizing curvature of face of geologic structure

Abstract

The invention discloses a method for predicting pore pressure of a regional high-pressure saltwater layer by utilizing a curvature of face of geologic structure. The method comprises the following steps of: determining a regional distribution regularity of salt and gypsum layers by utilizing seismic data and actual drilling logging data and constructing a contour map, constructing a regional height equation on the contour map by a harmonic trend surface method and determining the main curvature of any point constructing the region, calculating the main stress of any point, establishing a pore pressure prediction model of any point, and determining the pore pressure of the high-pressure saltwater layer. By the method, the scientific evidence for determining the safe density of drilling liquid is provided in field construction of drilling design so as to effectively prevent collapse of the well walls and avoid underground accidents.

Description

technical field [0001] The invention relates to a method for predicting the pore pressure of a regional high-pressure saline layer by using the curvature of a geological structure surface. Background technique [0002] Most of my country's oil and gas resources are concentrated in pre-salt structures, and drilling in salt rock formations is a key technical problem restricting my country's oil drilling. Because the formation is squeezed and deformed by the structure, an abnormally high-pressure brine layer is formed, and the regional distribution is irregular. During the drilling process, encounters with high-pressure brine layers often occur. When the density of the drilling fluid cannot balance the formation pressure, brine will enter The wellbore will pollute the drilling fluid, cause drilling accidents and complex situations, and bring different degrees of loss to the manpower and material resources of drilling operations. Therefore, how to predict the pore pressure of t...

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Problems solved by technology

Because the formation is squeezed and deformed by the structure, an abnormally high-pressure brine layer is formed, and the regional distribution is irregular. During the drilling process, encounters with high-pressure brine layers often occur. When the density of the drilling fluid cannot balance the formation pressure, brine will enter The wellbore pollutes the drilling fluid, causes drilling accidents and complications, and brings different degrees of loss to the manpower and material resources of the drilling operation.

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