Plenary sessions at the SEG had a distinctly ‘green’ flavor this year with a special session on geophysics and water resources and a presentation from Eric Barron of the National Center for Atmospheric Research on the ‘Changing debate on climate change.’ Barron’s thesis is that the notion that increases in greenhouse gas (GHG) promote warming is now ‘incontrovertible.’ On this point, there is ‘no argument.’ The real debate is a) how much warming comes from anthropogenic CO2 and b) how fast and c) how significant its impact will be. a) and b) ‘will be matters of debate for a long time,’ so decision makers focus on c), a political, not a scientific question that is ‘tied to your own sense of values and risk.’
Something of a consensus emerged from a recent White House meeting of experts. GHG is increasing from oil, coal and other sources. Our planet has warmed by 0.6°C in a century. ‘Warming is real and there is no ‘magic bullet’ to fix this, draw down will take centuries.’ Modeling with and without anthropogenic CO2, adding in solar effects and aerosols and ‘you’ve nailed it for the last century.’ But the future is harder. There is uncertainty of between 1 and 6 degrees in the models leading to a huge range of predictions. Predictions can be divided into what is ‘virtually certain’ to what is speculative. It is ‘virtually certain’ that the stratosphere will cool and ‘very probable’ that surface temperatures will increase by from 0.5 to 2°C by 2050 and by 2.5°C by the end of the century. This ‘remarkable consensus’ includes the skeptics and forecasts a rise that is from 3 to 9 times that of the previous century.
Global precipitation will increase, sea ice will retreat in the Northern hemisphere and the Arctic will warm from the albedo effect. It is ‘very probable’ that sea level will rise 5 to 40 cm by 2050. Different models of the continental US out to 2100 show from ‘not much change’ to up to 8°C. ‘How can we believe such differing models?’ Similar wide divergence comes from predictions of precipitation. Predictions of the granularity that is of interest – i.e. for hurricane frequency or for Las Vegas’ water resources ‘won’t be known for decades.’ Even if warming eliminates the forests of Georgia, our grandchildren will never have seen them and may look at the new grasslands and say ‘how fine’. Heat waves and vector borne diseases are more serious if uncertain threats. But these are amenable to public health infrastructure improvement as the 1,000 fold difference in the incidence of dengue fever on either side of the US/Mexico border shows. There will be ‘different outcomes for rich and poor countries.’ Other model predictions for the US include a dwindling snow pack in the Rockies—bad for skiers and water managers. According to a US Navy model, the Arctic will be a theatre of operations by 2020 and ‘we need to start building icebreakers now!’ Warming is a ‘given,’ its impact is uncertain. Although we don’t know if there will be more hurricanes, we are pretty sure that it will be dry in Denver. Wealthy nations can manage some effects, others will be more exposed. Surprisingly the SEG offered no opportunity for questions at this well attended talk!
Shiv Dasgupta (Saudi Aramco) described a daring experiment performed by Saudi Aramco’s EXPEC R&D center to test passive seismics for production monitoring. Aramco expects that ‘real time’ geophysics will contribute to production enhancement. Forward modeling of a water flood does not tell us where attic oil is left. Only geophysics can image the interwell space, prevent water breakthrough and introduce some determinism into the stochastics. Techniques include 4D seismics, microseismics, EM borehole and surface, electroseismic and micro gravity and satellite/inSAR. Dasgupta showed passive seismic hypocenters at the Arab-D reservoir. These were calibrated by stopping injection for a month – then restarting injection at very high rate. This gave ‘pretty conclusive results’ and suggested that water is going along a fracture trending right into an older dry hole. The challenge for the ‘intelligent’ field and recovery optimization is integration. Permanent geophysics will create a paradigm shift.
The Forum Session on ‘Managing groundwater resources’ was judged slightly off-topic for the SEG by the Forum chair, but it was interesting in that water is experiencing its own ‘peak,’ analogous to oil and gas, and also because of the showcasing of Schlumberger’s new Water Services division. Dave White (Schlumberger Water Services) claimed that aquifers are harder to model than oilfields because of recharge and environmental coupling. Geophysics plays a significant role in monitoring and enabling subsurface engineered solutions. Models do help in aquifer storage and recovery (ASR). ASR is used for strategic reserves and peak shaving. In the Middle East, one country has created a 30 day supply ASR to mitigate desalination plant failure by storage in a 100m deep aquifer. This involved time domain EM, nuclear magnetic resonance, well logs, magnetic resonance (CMR tool) and core data to determine permeability. The study was unusual in that high end oil and gas technology was applied to a water study. White concluded that oilfield technology including geophysics can be applied to the water business if costs can be managed.
The SEG was a platform for Repsol along with partner IBM to roll-out of its US ‘Kaleidoscope’ high-end, GPU-based seismic processing project. We covered this in last month’s Journal, but a talk from Repsol’s Francisco Ortigosa underlined the potential impact of ubiquitous HPC in oil and gas. Ortigosa is an evangelist for compute intensive reverse time migration (RTM) the only technique that accurately images complex salt structures of the deepwater Gulf of Mexcio. Repsol’s Kaleidoscope supercomputer gets around 120 TFLOPS out of 8 racks using the IBM QS20/QS21. By 2013, ‘all companies will have petascale computing’ and this will change the game for seismic processing. A decision tree was used to analyze the value of information of RTM processing. With today’s ‘astronomical’ drilling costs and reduced computing costs, the time for RTM is now. Ortigosa predicts that soon (maybe by 2010), seismic imaging will all be done inside oil companies.
Svein Ellingsrud (EMGS) thinks that controlled source electro magnetic prospection (CSEM) a.k.a. sea bed logging, has also evolved to ‘commodity’ status. Today there are ‘5-6 vessels operating’ and over 400 surveys to date, a $200 million world market. More growth is possible, but this requires more ‘acceptance.’ Will CSEM be as big as marine seismics? ‘We can only speculate*.’ Computer power is ‘up to it’ but again, this is ‘dependent on market acceptance.’ In the next 5 years we will see stronger sources (20,000 amps or more) and perhaps towed streamer acquisition is a possibility.
Alan Huffmann’s (Fusion Petroleum Technologies) geomechanics paper started off with a slide of a burning oil rig, Huffmann observed that ‘even infill drilling can give unpleasant surprises’ and pressure prediction can have a ‘large HSE impact.’ Pore pressure prediction is about a holistic model of the basin’s history. Pressure regimes start as ‘normal,’ in an open, drained system. Then compaction disequilibrium comes into play in a shale dominated system. Rocks stop fluids escaping and water begins to carry load – generating ‘undercompaction’ and higher porosity than expected. Most deepwater systems fall into this category. Worse surprises come from ‘unloading’ systems such as clay diagenisis, aquathermal and hydrocarbon maturation.
Schlumberger and Hess offered a geomechanical tour de force, integrating results from Schlumberger’s ‘Visage’ modeler with Petrel and Eclipse in a study of well stability and caprock integrity. Seismic inversion, core data, drilling and well test data were used to extract a stress field forward model this throughout the life of the field. 4D seismic data was used to ‘close the loop’ and monitor depletion induced fracture strain. This correctly predicted a well failure after about a month of production.
* This suggestion has been made before (OITJ October 2004). Subsequent slow progress with the technology suggests this is unlikely, a view apparently shared by the investment community!
This report is an extract from The Data Room’s Technology Watch report of the SEG—more from tw@oilit.com.
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