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MARA-STIM PROCESS |
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Any conventional deep penetrating or big hole shaped charge can be utilized with the STIMGUN™ assembly. A special KISS™charge has also been developed for use in soft formations. A larger diameter hold is produced with penetration designed just to "KISS" the formation after passing through the cement sheath. The perforating gun is detonated by conventional, electric line, or tubing conveyed firing techniques.
When the shaped charge is detonated, the propellant sleeve is ignited within an instant, producing a burst of high pressure gas. The high pressure gas enters the perforation and breaks through any damage around the tunnel, creating fractures. In hard rock, fractures are estimated to extend as much as three to six feet from the wellbore.
When the gas pressure in the wellbore dissipates, gas in the formation is surged into the wellbore, carrying damaging fines away from the formation. Mara-Stim(SM) is a service mark, and STIMGUN™ is a trade mark of Marathon Oil Company. http://www.marathon.com |
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CYLINDRICAL SLEEVE |
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The STIMGUN™ assembly used in the Mara-Stim process employs a cylindrical sleeve of gas generating propellant that is simply slid in place over the outside of conventional hollow steel carrier perforating guns. It can be run on wireline or in a tubing conveyed configuration. |
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The propellant is ignited by the pressure and shock wave of the shaped charges as they penetrate the gun, casing and formation. The propellant sleeve, on initial inspection, would appear similar to a piece of PVC pipe held in position by slightly larger end subs on the carrier. |
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The technical design, of the propellant sleeves, is complex, which insures a consistent ignition and burn rate. |
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CASE HISTORIES
Permian Basin Field Tests Of Propellant-Assisted Perforating
The use of a new
propellant-assisted perforating technology will be discussed. Two cases, one producing well and one injection well, are reviewed to illustrate successful and unsuccessful results in the Howard Glasscock Field of Howard County, Texas.
View STIMGUN™ demonstration movie in Quicktime (8.9 MB) -
Click Here to Download
HDSR - Owen High Speed Data Recorder
Click Here for More Info
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PRESSURE RESPONSE - Fast Gauge Data from the StimGun™ Assembly
The ultra-fast recorder monitors the pressure response of the perforating event and propellant burn. The data can be compared to a computer model for validation of the model and to estimate rock properties. In at least some wells, the fracture gradient can be estimated from this data. One of the most important use of the ultra-fast pressure gauge data is to determine proper execution of the job. It is possible to see the perforating event, the propellant ignition, and the rate and magnitude of the propellant burn. This data has led to the successful development of the tools and procedures currently being employed. The ultra-fast recorder has the capability to measure 100,000 g's of shock load. This recorder, developed specifically for these oilfield applications, came from military technology. Pressure, acceleration, and strain data can all be obtained.
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