si4ti 1.2.0

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

We provide two build flags that let you turn on and off the timeshift (BUILD_TIMESHIFT) and impedance (BUILD_IMPEDANCE) tools. By default, both tools are built.

To build si4ti you need:

• A C++11 compatible compiler (tested on gcc)
• 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 if 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 bindings

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

Installation

Pre-built wheels are available for the following platforms for Python 3.10 up to 3.14:

• manylinux_2_28 for x86_64
• MacOS X 15.0 and newer for arm64

The pre-built wheels can be installed via pip

pip install si4ti

si4ti is compute intense and highly profits from compiler optimisation and vectorisation. Therefore, the prebuilt wheels have vectorisation enabled, but still aim for good portability. The x86_64 wheels use x86-64-v3 architecture optimisations which should be supported by Intel Haswell (released 2013), AMD Excavator, and newer CPUs, see the GCC documentation for more information and overview of microarchitecture levels on Wikipedia. The arm64 wheels are currently using the default optimisation chosen by the compiler and should be portable between all arm64 platforms.

Build from source

You can install si4ti from source via the 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 3.10 or greater including the development headers
• CMake version 3.15 or greater
• Eigen3 version 3.3.4 or greater
• OpenMP
• fftw if the bindings are built with USE_FFTW=ON

Compilation of the Python bindings via pip only builds the bindings and not the command line tools. One can specify compile options directly during the pip invocation similarly to using CMake directly. The following command builds and installs the Python bindings in test configuration with OpenMP and FFTW on MacOS from the python/ directory of the repository.

First change into the python/ directory

cd python/

and then invoke the build process via pip

OpenMP_ROOT="/opt/homebrew/opt/libomp" pip install -Ccmake.define.USE_FFTW=ON .[test]

Afterwards you can run the tests

python -m pytest --memray tests

Note, that you are expected to observe increased performance if compiling with platform specific optimisation. You can add relevant compiler flags either via the CXXFLAGS environment variable or the CMake parameter CMAKE_CXX_FLAGS (via -Ccmake.define.CMAKE_CXX_FLAGS=<flags>).

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)