HUNTING OIL WITH DYNAMITE
A NEW WAY TO LOCATE OIL-WELLS
has been developed by geologists in the Gulf Coast Region, we are told by The Hercules Mixer (Wilmington, Del.), which gives credit for its facts to the Institute of Makers of Explosives.
This plan, we are told, does away with the old costly hit-and-miss drilling, and also eliminates the ancient divining-rod man. We read:
"By the new method, which is scientific and accurate, the prospector takes dynamite and detonates it on the surface of the ground. The earth-shock created is registered on seismographs placed certain distances away. In the Gulf Coast Region oil is generally found under salt dome structures located beneath the surface and it is the aim of the prospector, by means of the dynamite and seismograph, to locate these salt domes.
"This is possible because the difference in density between the salt dome and the overlying alluvial deposits is great enough to refract the shock waves when they strike the denser substance at the moment of the dynamite blast. The results recorded by the seismographs reveal the denser underlying structure and indicate accurately just where the dome is.
"The new method is an outgrowth of the experience gained during the war, when the seismograph was used to locate the enemy's hidden or camouflaged heavy artillery. The process, however, is somewhat changed; for in locating the domes where they expect to find oil, the source of the shock produced by the dynamite explosion is known.
"Over 2,000,090 pounds of dynamite have been used in oil prospecting by this method. Three oil companies used 730,000 pounds, and it seems probable that the method will spread quickly to other fields.
"It is said that already a machine has been developed that has successfully located oil structure through a limestone formation in Mexico and, if this is true, it may open a new era in oil-production from Mexican fields.
"There are different seismographs in use at this work. Some companies use one kind and some another. Their several advantages are being guarded carefully as company secrets. But broadly speaking, they all work on the same theory and they are all dependent on the detonation of dynamite on the surface for their information as to what lies beneath. The dynamite is set on by the use of electric blasting caps."
How the dynamite-seismograph method works is illustrated by the writer by the story of a recent development in the Gulf district. One of the oil companies there took over a section where there was believed to be a dome on the edge of the area. Experts in this new dynamite method were put to work in the vicinity and began their blasts and recording. They were unable at first to find any evidence of oil. However:
"After some discussion, the company decided to give them a free hand and they were allowed to go prospecting in their own way. Finally, after some dynamiting, they mapped out a section where the company did not know a dome existed. They turned in a report estimating that there was oil there at a depth of about 2,500 feet. The company, placing faith in them, began drilling to substantiate their claims. Oil was struck at 2,400 feet. And at the first three drillings they struck the dome within 100 feet of where the engineers predicted.
"In some fields the machines are used with radio and broadcasting outfits. Three of them, each loaded on a truck, are set up in triangular form within three to five miles of the shot which is in the center of the triangle, each machine registering the wavelength and making a picture of the result of the shooting. The man who sets off the blast, after making all the necessary preparations, posts the balance of the operators as to the time of shooting, and after getting all watches absolutely together by means of the radio click, the blast is pulled off to the fraction of a second."
In preparing for these shots, holes from ten to fifteen feet deep, made with a seven-inch hole-digger, are dug at the selected location. Then the hole is sprung, using from two to three cartridges. It is then loaded with dynamite, and tamped with a wooden tamping stick. These shots make a hole approximately thirty feet wide and eight feet deep, working out on a cone shape. It is afterward filled by hand. To quote further:
"In one section of the region there is a place where at least one million acres are now under survey. This large tract is laid out in sections, staked off, and complete profiles and blue-prints made of it. This makes it easier for the engineers to follow up the shooting according to the maps. After making shots, they have a complete picture of the underground strata which gives them the information as to where to drill or not to drill for oil.
Tests have proved that about 98 per cent. of all oil found in the coastal plain section is found either in a salt or sulfur dome.
"It is not known yet if this method of dynamiting to find oil can be used everywhere, but there are some who know a great deal about the method who believe that it can be adopted for all sorts of fields.
"It is perhaps impossible to estimate even roughly the millions of dollars that have been sunk in oil-shafts that never reached oil." But the discovery that dynamite and a seismograph can be used with scientific precision in the work of locating domes where oil is found is of the utmost importance to the oil industry, and if it is found capable of a wider development, may have a substantial effect on the future of the crude-oil supply and its effects be translated to the door of every automobile owner in the country."
Source: The Literary Digest for April 16, 1927
This plan, we are told, does away with the old costly hit-and-miss drilling, and also eliminates the ancient divining-rod man. We read:
"By the new method, which is scientific and accurate, the prospector takes dynamite and detonates it on the surface of the ground. The earth-shock created is registered on seismographs placed certain distances away. In the Gulf Coast Region oil is generally found under salt dome structures located beneath the surface and it is the aim of the prospector, by means of the dynamite and seismograph, to locate these salt domes.
"This is possible because the difference in density between the salt dome and the overlying alluvial deposits is great enough to refract the shock waves when they strike the denser substance at the moment of the dynamite blast. The results recorded by the seismographs reveal the denser underlying structure and indicate accurately just where the dome is.
"The new method is an outgrowth of the experience gained during the war, when the seismograph was used to locate the enemy's hidden or camouflaged heavy artillery. The process, however, is somewhat changed; for in locating the domes where they expect to find oil, the source of the shock produced by the dynamite explosion is known.
"Over 2,000,090 pounds of dynamite have been used in oil prospecting by this method. Three oil companies used 730,000 pounds, and it seems probable that the method will spread quickly to other fields.
"It is said that already a machine has been developed that has successfully located oil structure through a limestone formation in Mexico and, if this is true, it may open a new era in oil-production from Mexican fields.
"There are different seismographs in use at this work. Some companies use one kind and some another. Their several advantages are being guarded carefully as company secrets. But broadly speaking, they all work on the same theory and they are all dependent on the detonation of dynamite on the surface for their information as to what lies beneath. The dynamite is set on by the use of electric blasting caps."
How the dynamite-seismograph method works is illustrated by the writer by the story of a recent development in the Gulf district. One of the oil companies there took over a section where there was believed to be a dome on the edge of the area. Experts in this new dynamite method were put to work in the vicinity and began their blasts and recording. They were unable at first to find any evidence of oil. However:
"After some discussion, the company decided to give them a free hand and they were allowed to go prospecting in their own way. Finally, after some dynamiting, they mapped out a section where the company did not know a dome existed. They turned in a report estimating that there was oil there at a depth of about 2,500 feet. The company, placing faith in them, began drilling to substantiate their claims. Oil was struck at 2,400 feet. And at the first three drillings they struck the dome within 100 feet of where the engineers predicted.
"In some fields the machines are used with radio and broadcasting outfits. Three of them, each loaded on a truck, are set up in triangular form within three to five miles of the shot which is in the center of the triangle, each machine registering the wavelength and making a picture of the result of the shooting. The man who sets off the blast, after making all the necessary preparations, posts the balance of the operators as to the time of shooting, and after getting all watches absolutely together by means of the radio click, the blast is pulled off to the fraction of a second."
In preparing for these shots, holes from ten to fifteen feet deep, made with a seven-inch hole-digger, are dug at the selected location. Then the hole is sprung, using from two to three cartridges. It is then loaded with dynamite, and tamped with a wooden tamping stick. These shots make a hole approximately thirty feet wide and eight feet deep, working out on a cone shape. It is afterward filled by hand. To quote further:
"In one section of the region there is a place where at least one million acres are now under survey. This large tract is laid out in sections, staked off, and complete profiles and blue-prints made of it. This makes it easier for the engineers to follow up the shooting according to the maps. After making shots, they have a complete picture of the underground strata which gives them the information as to where to drill or not to drill for oil.
Tests have proved that about 98 per cent. of all oil found in the coastal plain section is found either in a salt or sulfur dome.
"It is not known yet if this method of dynamiting to find oil can be used everywhere, but there are some who know a great deal about the method who believe that it can be adopted for all sorts of fields.
"It is perhaps impossible to estimate even roughly the millions of dollars that have been sunk in oil-shafts that never reached oil." But the discovery that dynamite and a seismograph can be used with scientific precision in the work of locating domes where oil is found is of the utmost importance to the oil industry, and if it is found capable of a wider development, may have a substantial effect on the future of the crude-oil supply and its effects be translated to the door of every automobile owner in the country."
Source: The Literary Digest for April 16, 1927