Postconvention Workshops

Reservoir surveillance can provide value by improving recovery through the optimization of production and recovery, and better informed development decisions. Collaboration between operators, vendors and academia will be essential to meet surveillance needs in this low oil price environment. Also, an integrated approach drawing from a broad range of technologies including 4D seismic, 4D DAS VSP, gravity, magnetics and subsidence monitoring with PMT nodes will be needed. However, one area that remains a challenge for assessing the added value of 4D to business decisions is whether to perform a qualitative or quantitative approach given the quality of the data, type of decisions and availability of time before making a decisive action. Thus, the focus of this workshop will be on improving our ability to differentiate between the two modes of analysis by:

• defining the difference between qualitative and quantitative workflows;
• deciding when a qualitative analysis should be performed and whether it will good enough to make informed decisions;
• examining what types and data quality are required to tackle a quantitative study and investigating ways of improving or enhancing data input;
• finally, the timing of quantitative analysis - what are the benefits and impact of such work?

This workshop will facilitate an open discussion among operators, vendors and academia about their experience with qualitative versus quantitative issues, their relative merits, and potential ways forward for generating value in a fit-for-purpose flow that meets our surveillance demands in the current economic environment.

For many years, the location and origin time of microseismic events in hydraulic stimulations have been used successfully to determine the geometry of the induced fracture network which has impacted business decisions on optimum wellbore spacing, completion design, wellbore placement, etc. When using the amplitudes of the seismic signal, it is also possible to estimate the slippage movement of the event, i.e. the event’s Moment Tensor. The usefulness of the moment tensor in further characterizing future production behavior of the fracture network and its impact on business decisions has been debated throughout the industry for many years. In its three keynotes, this workshop provides an overview on the pitfalls when calculating moment tensor attributes and the arguments for and against using these attributes to estimate the production behavior of the created fracture network. This is followed by an all audience discussion on ways to clarify the apparent uncertainties and discrepancies in the interpretation of MTI attributes.

Due to the complexity of subsurface formations, physics-based modeling and inversion are increasingly supplemented by data driven approaches such as machine learning, data analytics, neural networks, and more. As sensors become smaller and cheaper, and science and technology mature, increasingly more data (including multi-physics) are collected to better understand subsurface formations. Correspondingly, the data become "big." Geophysical data sets are among the largest in science and engineering, comparable in size and complexity only to those from astronomy and particle physics. Here “big” means large quantities, multiple modalities/physics, and a range of scales. Hence, traditional physics modeling and inversion (e.g. using certain approximations to model real physics) can be complemented by data driven methods. For certain applications, data driven methods can be much less computationally demanding, faster to construct, and easier to update and maintain as new data are acquired. Major challenges exist in the systematic acquisition and processing of very large amounts of geoscience data, in their integration across modalities/physics and scales, and in their use in deriving and validating models to answer scientific questions for timely decision-making. Geophysics appears to have lagged behind other areas such as reservoir engineering, drilling and production technology in adopting data driven methods. Through a series of technical presentations and discussions, this workshop will help the SEG community understand and leverage recent developments in data analytics for a variety of data types (seismic, electromagnetic/resistivity, potential fields, etc.) and scales (reservoir and wellbore). Different workflows with fewer limitations may emerge as promising avenues to pursue in the data-rich future of geophysics.

Full Waveform Inversion (FWI) is now widely used in applications ranging from velocity model-building for imaging to assessment of drilling hazards and reservoir characterization. Nonetheless, it is still the subject of active research and development and formulations other than the now-classic approach of least-squares optimization to fit diving and refracted waves continue to be proposed as the industry becomes aware of its limitations as well as its potential.

Unsurprisingly, these limitations are often encountered in imaging domains which have proved most challenging for traditional imaging workflows, such as subsalt and onshore, due to the difficulties in, for example, assuring adequate illumination, building appropriate starting models and simulating seismic amplitudes correctly. This workshop will offer a forum to present and discuss these and other problems with FWI in such contexts, and potential solutions to them.

We therefore welcome contributions addressing or illustrating the following issues:

• What physics do we need? When is elastic simulation worth the extra cost compared to acoustic methods?
• What acquisition effort – offsets, components, sampling – is needed as a function of the depth and complexity of the target and its overburden? How accurately can we predict and plan for this? Can techniques such as interferometry be used with FWI to reduce it?
• How can data processing help, and to what extent can it compensate for deficiencies in the acquisition or the accuracy of the simulations? Is it reasonable to imagine FWI with raw data? What is the role of regularization – of both data and inversion?
• To what extent do we need to tailor workflows to fit specific problems?
• What useful information can we extract from surface wave inversion?
• Under what circumstances does FWI offer a significant uplift for reservoir characterization in 3D and 4D compared to traditional approaches?
• What are the most effective strategies for updating long-wavelength model parameter changes using the tomographic component of FWI? Are data-domain or image-domain residuals more effective?
• What is the most effective workflow combining diving-wave long-wavelength updating, tomographic FWI for deeper long-wavelength updates, and higher frequency impedance inversions to arrive at a full-bandwidth inversion solution?
• What methods or approaches help deal with non-linearity in FWI that is inherent in the inversion problem?

Potential authors may contact Paul Willamson for more information; if they wish to present a paper at the workshop they should submit a short abstract (1-4 pages). Depending on the number of abstracts submitted and accepted, the workshop may include a poster session to complement the oral presentations.

The aim of this workshop is to discuss the state of affairs and trends concerning talent, knowledge, training and recruitment issues in exploration and production of energy resources. Discussion topics will include talent shortage and retention, knowledge management, emerging professionals, and SEG training opportunities to enhance and enable member technical competencies in meeting global energy needs, in a safe and environmentally responsible fashion.

During the last 10 years, marine Controlled Source Electromagnetic (CSEM) has become increasingly established as a drilling risk reduction tool in many basins around the world. From the early days, the method has been extended to a wider range of geographic areas, geological settings and application scenarios.

The industry has been engaged with ups and downs in CSEM and marine Magnetotellurics (MT) technology development and data acquisition programs to advance the development of new integrated interpretation and the road ahead.

So far, the industry has focused the application of CSEM to de-risk deep water very high-cost drilling decisions. However, technological advances, widespread interest and continuing technology development’s effort have revealed the potential of CSEM to complement seismic for cost-efficient deep water reservoir appraisal and monitoring applications.

Recent feasibilities have shown that time-lapse CSEM data could play an important role in improving our knowledge of reservoir structure, fluid flow, and fluid saturation changes requiring less degree of repeatability when proper acquisition and advanced 3D integrated quantitative interpretation technologies are applied. It is therefore of great importance to evaluate the 4D CSEM potential, provide the step change technology development requirements for realistic deep water reservoir monitoring and contribute to build the case for industry adoption as a valuable and cost-efficient complement to 4D seismic and reservoir management and this is the main scope of this workshop.

Objectives

The distinguishing feature of this workshop is its focus on discussing how the industry perceives CSEM to add value to the reservoir characterization and production effort in the current cut back environment, and what needs to be done to maximize the value and potential of the technology to complement seismic in practical time-lapse applications when we bounce back. The benefit of the workshop is maximized by getting the operating companies to discuss their views candidly.

Target Audience

Leading Experts, Geoscientists and Exploration Managers of all E&P Companies and Practitioners in Government Agencies and Academia.

Program Overview

We invite contributions focused on:

• Seismic – CSEM time-lapse studies, applications at fluid simulator scale
• Simultaneous and cascaded seismic – CSEM joint inversion approaches and applications for reservoir characterization and monitoring
• Seismic – CSEM petrophysical joint inversion approaches and application for reservoir characterization and monitoring
• Joint inversion approaches for FWI – CSEM joint inversion requirements for time-lapse applications
• CSEM technology development requirements for time-lapse applications

Recent highly-publicized events have drawn attention to the issue of sexual harassment in the sciences, and its impact in our workplace. Conversations about sexual harassment are now occurring more broadly, including in our scientific societies, as we have witnessed multiple institutional and individual responses to often widely publicized incidences. While sexual harassment is only one barrier to the full inclusion of individuals, there remains a lack of understanding regarding the impact of sexual harassment on campuses and in our scientific workplace and best means to respond. We can take a proactive approach and work to make our home institutions more welcoming and inclusive. This workshop explores some of the barriers to inclusion, including harassment, micro-aggressions, and structural barriers; and the impacts on individuals and programs – drawing from real examples in the geosciences. The interactive workshop will present successful policies and intervention techniques—including recommended practices for institutions and individuals—to help prevent and address harassment, improve workplace climate, and make our field more inclusive for all. Elements of bystander intervention techniques will also be provided.

The impact of the Shale revolution on the oil industry is now clearly visible. Many recent oil company capital spending announcements suggest that investment in unconventional resources (UR) has gained substantial momentum. With the industry trend towards UR it is time for us to pause and discuss what the role of geophysics is in this new world. For UR plays, for a start, the reservoir structures can be relatively flat, impedance contrasts and fluid signatures can be weak, drilling is much less expensive and turnaround is quick. This raises several important and alarming questions to the seismic industry: what is the role of geophysics and what must we do now to secure and invigorate the use of geophysics in unconventional resources?

Our workshop will start with a tutorial on UR and well completions to get alignment amongst participants. We will proceed with an Executive Leadership panel discussion from various operators on the current perception and value of geophysics in UR plays. Then we will proceed to discuss the current leading edge technologies, whether we are doing the right seismic acquisition and processing for UR plays, and what the cost is. Do we need to change anything in the way we do geophysics in UR and if so what are the key changes that can add value?

The goal of this workshop is to explore these questions and help navigate a way forward for our industry in the new UR world.

Join the geoscientists who have been involved in building SEAM models, along with the teams that are using these large-scale Earth models and their simulated geophysical data in the research and development of leading edge technologies. Take the opportunity to learn about the application of advanced solutions for difficult exploration and development challenges, calibrated by using SEAM models as a realistic low-cost laboratory for testing new acquisition, processing and imaging methods, geomechanical deformations, 4D Monitoring, effect of production and injection in reservoir properties.

This workshop will facilitate in-depth discussions and the sharing of recent results and lessons learned in the advancement of emerging technologies for “Subsalt Imaging in Tertiary Basins”, for “Land Seismic Challenges”, for “Pressure Prediction and Hazard Avoidance” and for "Reservoir Monitoring”.

Researchers and geoscientists from a wide range of disciplines are expected to attend, representing a broad range of experts working on proposed technical topics. Leaders of industry and academia will discuss problems of common interest, with the objective of stimulating research and development of new complex models as well as providing industry benchmarks and an impact upon academic research and education.

We will discuss about each SEAM project and topics for future projects. From the highly successful SEAM Phase I, addressing challenges of deepwater subsalt imaging in Tertiary basins, with emphasis on the Gulf of Mexico; that gave the computational challenge in stages, starting with a purely acoustic-wave model with variable density, and proceeding through a quasi-acoustic tilted transversely isotropic (TTI) model to an isotropic elastic model. This Earth model, a realistic salt structure within a 60-block area represents a region 40 km x 35 km x 15 km in extent, with varying rock properties that produce complex imaging scenarios.

To the latest Time Lapse Pilot Project, which models 4D changes in pore pressure during a plausible production scenario. This project benefitted from the integrated work done between geoscientists and reservoir engineers. Modeling captures the evolution of pore pressure and its detectability by geophysical remote sensing during hydrocarbon production. The geologic and reservoir model chosen for the project covers an offshore region about 12.5 by 12.5 km in lateral extent and 5 km in depth and includes a series of stacked turbidite fans, part of the SEAM Phase I model of Tertiary Basins. One of the goals of the project was to advance the state of the art in realistic modeling of time-lapse studies by maintaining consistency in the representation of the underlying model in the different numerical simulations computing geophysical responses (seismic and non seismic), reservoir fluid flow, and geomechanical deformation. This is a small version of the ongoing Life of Field Project, planned to estimate the "inverse" problem of interpreting reservoir dynamics under conditions where everything about the reservoir is known. The subsalt clastic model for Life of Field is under construction and a carbonate model is under design stage. Models are resulting from an effort engaging reservoir engineers, geologists, petrophysicists, geophysicists, well-log analysts, and interpreters. Reservoir dynamics will be simulated along with the resulting well, geophysical and geomechanical responses.

SEAM Phase II, under the theme of “Land Seismic Challenges” focused on modeling land-seismic activity in a realistic way by incorporating a new set of challenges: from dealing with near-surface heterogeneity at scales from meters to kilometers, to incorporating a full range of elastic propagation physics, from surface-wave scattering and shear-wave attenuation to the general anisotropy of finely layered and fractured reservoirs. Three exploration models with corresponding classes of near-surface and subsurface features were defined. Each model has an appropriate reservoir.

The Barret model is 10 km x 10 km x 5 km and represents two types of unconventional reservoirs based on the Eagle Ford and Woodford shale plays in Texas and Oklahoma. The Arid model also cover 100 sq. km and contains features encountered in desert areas such as the Saudi Arabian Peninsula, with low-velocity surface sediments, outcropping strong refractors, buried topography, and karsts.

The Foothills model is 15 km x 12 km x 7.5 km and contains extreme topography typical of mountainous thrust zones, such as the Llanos Foothills in Colombia, with elevation differences of 500 m or more, as well as strong lateral and vertical velocity variations at scales comparable to exploration seismic wavelengths.

SEAM Pressure Prediction Project focused on“Pressure Prediction and Hazard Avoidance through Improved Seismic Imaging", evaluated and advanced on current methodologies for pre-drill pressure and hazard prediction. Industry experts prioritized current challenges in the use of seismic velocity models to construct pre-drill pore pressure forecasts for well planning. Challenges were used to design a comprehensive earth model and to simulate a benchmark data sets to be used by industry for quantifying risk and uncertainty associated with velocity models derived from current and future state-of-the-art in seismic acquisition, processing and imaging.

Invited speakers and attendees will be discussing topics such as, but not limited to Geology/Geological Modeling, Acquisition, Numerical modeling, Signal Processing, Imaging, Pressure Prediction in Complex Stress Regimes, Time Lapse (4D), Q Absorption, Reservoir Engineering, Implications of Geomechanics, Induced Seismicity, Microseismic, Scaling problems in Modeling and Simulations, Non-seismic modeling, and Modeling Carbonates.

We will embrace both theoretical and practical discussions of how model complex reservoirs to measure geophysical responses and their changes during production and injection.

In this workshop we ask what we have learned and what could be the next challenges to be modeled and simulated. Some of questions potentially addressed by workshop speakers are:

• “How does simulated data accuracy compares with real data?”
• “What is the real-world impact of geophysical and engineering reservoir modeling?
• “Where do we stand in 2017 and what are the next steps?”
• “Presence of Multiples at reservoir level. Which noise suppression technique will be appropriated to remove interbedded multiples without affecting reservoir amplitude response?
• “What are and will remain inherent limitations in modeling and simulations?
• “How Q values area changing as function of saturation and pressure?
• “What can we do with microseismic data in terms of reservoir characterization?
• “Can we integrate microseismic data into inversion workflow? What has been done so far? Which model will be the appropriate to learn more about usage of microseismic data? What has been done so far?”
• “To what degree are typical reservoir properties affected and can these changes be detected, measured, and quantified into additional valuable reservoir understandings by analyzing microseismicity indicators?”
• “What is the impact of facies complexity in carbonate models? How to model the effect of double porosity media during production?"

Advances in computational capabilities and the mathematical understanding of compressive sensing and sparse inversion have led to progress in simultaneous source technology. Simultaneous source acquisition has progressed from the more conventional slip-sweep and distance separated simultaneous sourcing methods to more flexible, but more processing-intensive, truly simultaneous sourcing methods. These technologies are advancing rapidly, providing significant improvements in cost, efficiency, and source density. There is significant motivation to continue to develop these methodologies to apply to more seismic acquisition types while maintaining or improving the quality of the resulting seismic images.

The discussions in this workshop will cover experiences with simultaneous source surveys, recommendations for obtaining safe and effective acquisitions, de-blending methods, and speculations on the directions for this technology.

Multicomponent seismic technology is typically associated with the acquisition, processing and interpretation of shear-waves (S-waves). Over 50 years our industry has been investigating S-wave applications for lithology discrimination, elastic property inversion and fracture characterization. There has been a cycle of over expectation and disappointing realization of the benefits of S-waves. Currently, a segment of our business (about 5 – 10%) is devoted to the exploitation of converted P- to S-wave (PS-waves) as the source of S-wave information. However, the recent downturn in oil prices has significantly curtailed even this small effort. One goal of this workshop is to summarize the current state of the art in multicomponent technologies, particularly as it applies to S-waves for surface and borehole environments. Another goal is to explore why S-wave applications have not grown over the years and whether they will ever provide added value for reservoir or overburden characterization. An eternal question has been, what is the best source of acquired S-waves? Conventional sources designed for P-waves have clearly driven a small market with converted PS-waves, but can S-waves that radiate from these sources also be used? For petrophysical applications, what are the challenges and benefits of joint elastic inversion for isotropic P- and S-wave impedance and density? Can we improve the inversion with orthorhombic anisotropy estimates for fracture characterization? More recent issues are, what is the role of S-waves in time lapse and/or unconventional reservoir applications to quantify reservoir brittleness, fracability (formation strength) and fracture properties: density and direction? For imaging, can S-waves provide improved resolution that benefits the near surface, the overburden at intermediate depths and at reservoir levels?

Presentations

1. Henri Houllevique, Total, “Keynote introduction”
2. Jim DiSiena, Chevron, “Historical S-wave applications and aspirations”
3. Rob Stewart, University of Houston, “Borehole seismic measurements: What can they tell us about S waves and then reservoir properties?”
4. Scott Leaney, Schlumberger, “Borehole data integration for shear-wave imaging”
5. Bob Hardage, Bureau of Economic Geology, The University of Texas at Austin, “Land based S-wave reflection seismology with P sources – does it work?”
6. Jim Gaiser, GGC, “S-waves from vector sources: making sense of radiation and scattering”
7. Peter Cary, TGS, “A Canadian perspective on shear-wave exploration”
8. Tagir Galikev, Unified Geosystems, “Multicomponent 3D-3C data acquisition, processing and characterization of unconventional reservoir in Argentina.”
9. Jim Simmons, CSM/Consultant, “Wattenberg unconventional reservoir”

Workshop format

The format will be short oral presentations followed by clarification questions and afterwards a more extensive panel discussion period with audience participation.