unconventionals Conventional Unconventional Preferred Trap Type Structural Stratigraphic Aerial Trap Size Small Huge Geological Risk High Low Drilling Risk High Low Completion Expense Low High Critical Geologic Element Reservoir Source Table 1. Conventional Versus Unconventional Petroleum Resources. We usually find oil in a ne w place with old ideas. Sometimes, we find oil in an old place with a new idea, but we seldom find much oil in an old place with an old idea. Several times in the past we have thought that we were running out of oil, whereas actually we were only running out of ideas. New Technologies Bring Change •• Drilling and Completion Procedures •• Petroleum System Modeling – The vocabulary and concepts have shifted to the source rocks. Seems simple – it is not. •• Reservoir Scales (nanodarcies vs. millidarcies) •• TOCs, Brittleness (Poisson’s ratio, Young’s Modulus) much more laboratory focused, pressure regimes and identification •• New training is required to exploit modern resource plays Fig. 4. Ahlbrandt, Search and Discovery, 2012 This statement will ring true with many c ompanies and individuals involved with unconventional exploration in 2012. So, who said it and when? — Parke A. Dickey, University of Tulsa Petroleum geology professor, September 1958 54 years later, Professor Dickey’s statement still seems timeless. “A stratigraphic trap is one that is there bec<strong>au</strong>se of the change in the r ock character, in other words it goes from big holes to small holes, and the smaller holes, it’s harder for the oil and gas to escape from, then it seals the oil into the rock that has the larger pore space”, he noted. The development of new technologies used to recover tight gas, such as horizontal drilling and multi-stage fraccing, are also used in the recovery of tight oil, along with an ever expanding suite of new <strong>com</strong>puter technology. “We have these <strong>com</strong>puter programs that we can measure with—so we started looking at how did the source rock get buried, and when did it release its hydrocarbons, how much did it release?” Be<strong>au</strong>mont observed. (See Figure 4.) “We look in terms of total organic carbon, TOCs: how much organic carbon, and that is in a per cent. We are more laboratory focused than we used to be; we take rocks and we send them to the labs for all kinds of measurements, we never did that really, now we have 20 or 30 more measurements than before.” Fig. 5. What Is Happening Now? The Inversion of the Hydrocarbon Resource Pyramid. Ahlbrandt, Search and Discovery, 2012 | After Thomasson, 2000 Industry vocabulary and concepts have made a definite shift to source rocks Be<strong>au</strong>mont noted, leading to an inversion of the hydrocarbon resource pyramid, shifting the focus from conventionals to unconventionals (Figure 5). The US is currently producing more gas than ever, with shale now looked upon as potential reservoirs rather than seals or source rocks. As Be<strong>au</strong>mont observed, recent developments in the petroleum industry have all the characteristics of a black swan event; indeed, horizontal drilling and <strong>com</strong>pletion technology had been around for 20 years before they were utilised in tight gas recovery. For so long the shadow of peak oil has loomed large over the petroleum industry—could it be that continuing technology innovation will stimulate a new age in fossil fuel production, defying long-held wisdom? “I just wanted to show this to make the point,” Be<strong>au</strong>mont told PNR, pointing out a photo from his presentation (Figure 6). “This is a slide that somebody gave at a presentation, and it shows a tanker <strong>com</strong>ing into the US in 2001, carrying LNG, and it was <strong>com</strong>ing in— they were going to bring it in.” Fig. 6. Natural Gas Imports & Exports, 2001 (BCF). Ahlbrandt, Search and Discovery, 2012 | Source: DOE, 2002 Over a decade later, the tankers are now taking it out; the times have changed and black swans may well abound. 16 | PESA News Resources | December 2012 / January 2013
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