Can we establish presence of hydrocarbons in a petroleum prospect before drilling a well down to the prospect?
Existing petroleum exploration techniques of geochemical and geophysical surveys, analyses, correlations and interpretations lead an exploration geologist/geophysicist to identify and define a potential prospect of oil and/or gas. There is no sure way to confirm the presence of oil and/or gas in the prospect other than drilling a well. Drilling is an expensive undertaking and over 70% of the time it leads to a dry hole. This raises the cost of finding undiscovered oil and gas which adds to energy challenges the world faces today. There is a possibility of using breakthroughs in science and technology to create new windows of information for finding an answer to this question before drilling the well and thus reducing the chances of drilling dry holes. One possible area for a new window could be the use of unfiltered satellite data for multiple indicaters of oil and gas. Has anyone some thoughts and knowledge about any such breakthrough in petroleum exploration.
I agree that petroleum prospects are deep down the sequence of rocks and water and and that it would be physically difficult for the sensors to penetrate that depth. I alluded to the possibility of surface indications relating to the presence of a pool of hydrocarbons at some depths.
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We do use quite a few tools to establish a higher probability of hydrocarbons before drilling, but drilling is the only way to arrive at the final truth. (by the way, I don’t think your 70% failure number is wildly incorrect for exploration wells.) When oil was easier to find, often the indicator that was used was the oil seeping to the surface. Also consider that dry holes are not always wasted money. They are expensive sources of data, but are often the most reliable data that leads to later discoveries. Most companies actually include dry holes into drilling plans, as they have all seen the examples where one company walked away and the next one made a major discovery using the information from the first dry hole.
Seismic data has reached a point that certain indicators are likely to be caused by the presence of hydrocarbons. Geometric patterns in the seismic data, and processing to isolate frequency responses of sound to lower density gas concentrations are used commonly. There are advances being made in seismic techniques, such as using multi component seismic acquisition, and processing to determine things like fracture orientation.
Geochemical surveys are something I think is underutilized in the industry today, especially surface biogeochemical surveys that can detect natural gas and oil that slowly escapes upward from oil and gas reservoirs. These are not new, but are improving.
A decade ago Texaco announced that they had created a new airborne petroleum detection instrument called a hyperspectral airborne imaging spectrometer that they were patenting. It was such a big advance they were planning to spin it off as a separate company. About that time Chevron came along and bought out Texaco and I never heard what happened to TEEMS. To me, it was an impressive way of gathering vast amounts of data more quickly than doing it by hand on the surface, but seemed likely to have equally impressive errors. It was expected to provide structural mapping, outcrop lithology, identification of hydrocarbon seeps, and could be used for drill-site planning and seismic program planning. It probably had more useful applications in environmental studies and oil spill tracking however. While Texaco presented it as a revolutionary new tool for hydrocarbon exploration, most of the data it was obtaining can be obtained by boots on the ground.
http://www.eomonline.com/Common/Archives/1996may/96may_prelat.html
As for satellite data, there is probably little that a satellite can detect other than hydrocarbon seeps, that is not already available from airborne surveys. Airborne surveys are used for mapping geomagnetic data, gravity, and structural geology, and have been for many decades. NASA’s ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) has been used to map oil seeps on the surface of the ground or at sea. However, these seeps are not often unknown, and are of such a scale that they would be hard to miss by anyone on the ground. The real problem with satellite data is that there are no direct indicators of hydrocarbons on the surface of the planet, so even if it is utilized, it still takes a drill bit to confirm the discovery.
http://gis.esri.com/library/userconf/proc03/p0868.pdf
Also see "satellite systems commonly used in basin-scale applications"
http://aapg.confex.com/aapg/2006am/techprogram/A102760.htm
why dont we use hydrogen. there are cheap ways of converting water that can be hooked up to existing engines. and the only wast is water. then we can tell the middle east to f off
I don’t have a good answer to the main question, but I must address the previous responder’s advocacy of hydrogen. In the first place, hydrogen is not cheap; it is made from natural gas, and has much less energy than the original gas. (Hydrogen can also be made by elecrolyzing water, but that is even more expensive because so much electricity is required.) Secondly, hydrogen is a pain to transport: it likes to seep into the tiny cracks between steel crystals, which embrittles the steel and weakens it. (You can deal with this by lining your pipes with plastic, but that’s a nuisance.) Thirdly, hydrogen is a pain to deliver: if delivered as a liquid, it is the second coldest substance there is, and special materials, not embrittled by such cold temperatures, are required to handle it. If delivered as a gas, extremely high pressures (5000 - 10000 PSI) are needed. Fourthly, hydrogen is not dense: to have a useful quantity of it, you need a large tank: a standard gas cylinder (about five feet high) holds only the equivalent of a half gallon of gasoline. My advice: if you hear that a car maker is spending money on hydrogen, short the stock.
at the moment, there aren’t any ways of indirectly establishing the presence (or quantity) of hydrocarbons in a prospect. the only way to verify its presence at this time is to actually drill to it. however, prospecting methods have been refined such that a lot of wells that would have been drilled in the early days are not being drilled, which saves some money. however, those that are being drilled are still expensive.
your mention of remote-sensing techniques is not really very practical as most prospects are located beneath kilometers of not only earth and rock, but water as well. there are no techniques of overcoming this hurdle which is practicable at this time.
use hydrogen
Don’t know if you’re going to get a lot of geophysicists on Yahoo answers…they’re probably too busy spending their raises.
I’m not sure where your 70% failure rate comes from.
First, most wells are not dry, and the success rate has improved drastically over time. Check out this pdf from the dept. of energy:
http://www.eia.doe.gov/emeu/mer/pdf/pages/sec5_4.pdf
If you note, in 1973, 10,000 of 27,000 wells were dry holes (63% success rate) and in 2003, only 3,700 of 30,700 wells were dry (88% success rate).
Also, wells often encounter hydrocarbons (technical success) but are not commercial either because of the low reserve size or because their isn’t adequate infrastructure nearby (often the case in deepwater exploration).
Trends in seismology that I’m aware of tend to be on 4-D (monitoring the reservoir as it produces) and deeper targets (like 30,000′ wells in the US Gulf shelf) http://www.searchanddiscovery.net/documents/2006/06024hardage04_gc/index.htm
Yes, there are several methods for the "surface detection" of hydrocarbons. However, they cannot discriminate between just a little bit or a major deposit.
Part of this is because the migration of hydrocarbons is not a "straight up" process. The molecules are deflected by the dip of the strata, lithologic changes in the strata, faulting, etc. so the surface indications may not be centered over the hydrocarbons accumulation at depth.
Also, the surface methods cannot discriminate the depth. Does an indication of mean there are a lot of hydrocarbons at a great depth? Or does the same indication mean there’s just a small amout very shallow?
As you said in your question: the only way to know is to drill it!