Deep Learning in Salt Interpretation from R&D to Deployment: Challenges and Lessons Learned
Pandu Devarakota
1
, Apurva Gala
2
, Zhenggang Li
3
, Engin Alkan
2
, Yihua Cai
2
, John Kimbro
2
, Dean Knott
1
, Jeff Moore
1
,
Gislain Madiba
2
1
Shell Global Solutions US Inc,
2
Shell International Exploration and Production Company,
3
University of Houston
Summary
With the evolution of the deep learning eco-system
and the availability of open-source software packages
such as TensorFlow and PyTorch, creating a quick
proof-of-concept (PoC) has become a straightforward
task. However, based on our experience, we contend
that transitioning a project from PoC to Deployment is
a difficult process in which the team must
systematically consider a plethora of design and data-
centric choices, which we refer to as R&D challenges.
Some of the R&D challenges toward developing a
successful deep learning-based system in the seismic
processing domain are presented in this brief abstract.
Recommendations on how to mitigate these
challenges are discussed on a real-world example of
automating salt interpretation.
Introduction
Salt interpretation plays a critical role in velocity
model building in both exploration and development
fields. It is a time-consuming effort that requires key
domain expertise, and it is critical for imaging
complex salt formations in subsalt and pre-salt rich
prospects such as the Gulf of Mexico, Brazil, and the
North Sea prospects. Typical imaging workflow is an
iterative process in which the initial sediment only
velocity model is iteratively refined using labor
intensive salt picking and compute intensive migration
steps. Recently, many authors have used deep learning
(DL) to accelerate the salt interpretation step
demonstrating that DL can play a significant role in
model building step and can substantially reduce the
overall seismic imaging workflow cycle time (Shi
2019, Zeng 2019, Consolvo 2020, Sen 2020, Kaul
2021). Even though these findings are encouraging
and have the potential to truly transform the way both
processing and imaging workflows are performed,
deep learning has yet to be widely adopted in
production settings in the seismic processing domain.
There are numerous research and development
challenges that must be addressed in order to produce
a generalizable and acceptable solution.
In this abstract, we discuss some of those R&D
challenges towards developing a successful deep
learning-based system to automatically interpret salt
geometry, build and render velocity model to run
migration with minimal human intervention. As an
example, we focus on detecting top of salt (TOS)
which is less complex compared to other parts such as
base salt overhang (BSOH), top salt overhang (TSOH)
and finally base of salt (BOS). We first emphasize the
importance of developing systematically high-quality
large datasets and its impact on addressing
generalization issues. We then discuss why brute force
neural network search would fail and how focusing on
false positives and false negatives can help in the
development of unique approaches.
In the second part of the abstract, we shift the focus on
addressing challenges that arise during the post-
deployment phase. As it is generally known, once
these DL models are deployed, they gradually
encounter concept drift. Concept drift refers to the
deterioration of model’s inference quality as the
distribution of data on which the model was trained
begins to deviate from the data in the real-world
settings. High data variability between training and
testing is expected as the models are often trained on
legacy datasets and applied to data from new terrains
which are acquired and processed through the most
recent acquisition and processing techniques. Simple
retraining of models on new and old data is both time
consuming and it will also lead to the so-called
catastrophic forgetting, in which the trained network
loses the previously learnt knowledge. To address this
problem, we investigated a novel method based on the
sharing partial network approach (Sarwar 2020). The
key idea of partial network sharing is the unique
‘branch-and-merge’ technique, which allows the
network to learn unique knowledge from new data by
training new branch without any performance loss in
old branch (trained on original training data). The
proposed incremental learning approach is tested on a
top-salt interpretation task on field datasets from
Brazil play. We demonstrate that the incremental
training improves time/compute efficiency while
preventing the risk of concept drift (Gala 2022).
10.1190/image2022-3751725.1
Page 2989
Second International Meeting for Applied Geoscience & Energy
© 2022 Society of Exploration Geophysicists and the American Association of Petroleum Geologists
Downloaded 08/17/22 to 35.175.214.152. Redistribution subject to SEG license or copyright; see Terms of Use at http://library.seg.org/page/policies/terms
DOI:10.1190/image2022-3751725.1