si4ti 1.1.0a1

si4ti is a LGPL licensed seismic inversion tool for monitoring effects in 4D seismic from changes in acoustic properties of a reservoir.

Introduction

si4ti is a LGPL licensed seismic inversion tool for monitoring effects in 4D seismic from changes in acoustic properties of a reservoir.

Timeshift

si4ti timeshift computes the dynamic timeshift between traces of different datasets (vintages). It uses vertical and horizontal smoothing constraints, and no prior information.

Impedance

si4ti impedance uses a statistical wavelet and lateral, horizontal and 4D smoothing for computing the relative acoustic impedance of a set of vintages.

Installation

Pre-built executables for Linux can be downloaded from here.

Build from source

To build si4ti you need:

• A C++11 compatible compiler (tested on gcc and clang)
• CMake version 3.15 or greater
• Eigen3 version 3.3.4 or greater
• OpenMP
• segyio run cmake with EXPERIMENTAL=ON to get the required C++ headers
• fftw If built with USE_FFTW=True
• Boost math module version 1.76 or greater with BUILD_TIMESHIFT=ON

To build the documentation you also need:

• sphinx

To build and install si4ti run the following commands in your console:

git clone https://github.com/equinor/si4ti
mkdir si4ti/build
cd si4ti/build
cmake .. -DCMAKE_BUILD_TYPE=Release
make
make install

To build the documentation run:

cmake .. -DBUILD_DOC=TRUE
make doc

Usage

For more information on how to run the programs:

timeshift --help
impedance --help
apply-timeshift --help

Python interface

si4ti provides a Python interface for the impedance calculations. No Python interface for the timeshift is provided.

Installation

Pre-built wheels are available for the following platforms for Python 3.9 up to 3.12:

• manylinux_2_28 for x86_64
• MacOS X 14.0 and newer for arm64
• MacOS X 13.0 and newer for x86_64

The pre-built wheels can be installed via pip

pip install si4ti

Build from source

You can install si4ti via the source distribution (sdist) or the Git repository. This allows to compile the package with FFTW3 support as well as platform specific optimisation which may improve the performance.

During compilation, you need the following dependencies.

• A C++11 compatible compiler (tested on gcc and clang)
• Python 3.9 or greater including the development headers
• CMake version 3.15 or greater
• Eigen3 version 3.3.4 or greater
• OpenMP
• scikit-build-core version 0.1 or greater
• fftw with single precision (float) interface (optional)

At runtime, you additionally need

• NumPy
• xtgeo

If you want to run the tests, which is highly recommended, you also need

• pytest
• pytest-memray

One can specify compile options directly during the pip invocation. The following command builds and installs the Python interface with OpenMP and FFTW (both installed via Homebrew) from the root of the repository. It also enables platform specific optimisation (-march=native) and strict warnings (-Wall -pedantic).

pip install -Ccmake.define.CMAKE_PREFIX_PATH="/opt/homebrew/opt/libomp" \
    -Ccmake.define.USE_FFTW=ON \
    -Ccmake.define.CMAKE_CXX_FLAGS="-march=native -Wall -pedantic" \
    .

Usage

The interface is inspired by the command line interface. Please check the Python help for details. You can find the Python help via

import si4ti
help(si4ti)