«Geology, geophysics and development of oil and gas fields»

A method for determining the accuracy of measuring horizontal strains and stresses for common tectonic conditions zones

UDC: 622.276.1/.4.001.57:539.3/.6
DOI: -

Authors:

¹ PetroGM LLC, Novosibirsk, Russia

Keywords: maximum horizontal stresses, uniform tectonic conditions, assessment of horizontal stresses, poroelastic model, test for injectivity, hydraulic fracturing

Annotation:

Currently, when developing fields, in addition to geological and hydrodynamic models, geomechanical modeling is beginning to be used. The geomechanical model is used to optimize drilling, geological-technical measures (GTM) and a field development in general. This model includes mechanical properties, pressures and stresses. The stress-strain deformed state is determined by three stresses: vertical and two horizontal ones. The minimum horizontal stress (σh) is measured by direct methods. The maximum horizontal stress (σH) is calculated according to the idea of a poroelastic model of the medium, and is a function of elastic parameters, pore pressure and deformations. Depending on the tectonic state, deformation can make a significant contribution to the magnitude of the maximum horizontal stresses.

Analysis of the graphs during a single direct measurement of the minimum voltage allows accurate determination of its value. In this case, the value of the maximum horizontal stress remains unknown and can only be estimated by any other way. The article presents a method for determining the magnitude of horizontal deformations when carrying out multiple direct measurements of Sh under common tectonic (mining and geological) conditions. The strains thus obtained are then used to calculate the maximum horizontal stresses.

The method was tested on two data sets obtained from an offshore field and a field in the Western Siberia. In addition, a comparison is made with other methods for estimating the maximum horizontal stress.

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