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Stuck in the Navajo - Printable Version

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Stuck in the Navajo - samplerock - 12-10-2007 03:39 PM

Hello, We have gotton stuck in the Navajo Formation 4 times on 4 different wells now. I wanted to know if anyone else has had this happen and any opinions as to why. Its been mentioned that there may be a clay base located within the dune but I have not found any real proof anywhere and the sample returns do not have any clay but on occasion I have seen Siltstone. The samples are cruched fairly bad with the Impreg bit though that may comprimise viewing. I am located near the pinchout north east of the Moab out crop and at about 14,000+ ft. Thanks, Troy.

RE: Stuck in the Navajo - Bolen Consulting - 03-10-2010 05:45 PM

While I can make a few guesses, they would be exactly that.

I did however find this little bit of information very interesting:

The Navajo Sandstone is also well known among rockhounds for its hundreds of thousands of iron oxide concretions. They are believed to represent an extension of Hopi Native American traditions regarding ancestor worship ("moqui" translates to "the dead" in the Hopi language). Informally, they are called "Moqui marbles" after the local proposed Moqui native American tribe. Thousands of these concretions weather out of outcrops of the Navajo Sandstone within south-central and southeastern Utah within an area extending from Zion National Park eastward to Arches and Canyonland national parks. They are quite abundant within Grand Staircase-Escalante National Monument.[1][2]

The iron oxide concretions found in the Navajo Sandstone exhibit a wide variety of sizes and shapes. Their shape ranges from spheres to discs; buttons; spiked balls; cylindrical hollow pipe-like forms; and other odd shapes. Although many of these concretions are fused together like soap bubbles, many more also occur as isolated concretions, which range in diameter from the size of peas to baseballs. The surface of these spherical concretions can range from being very rough to quite smooth. Some of the concretions are grooved spheres with ridges around their circumference.[1][2]

The abundant concretions found in the Navajo Sandstone consist of sandstone cemented together by hematite (Fe2O3), and goethite (FeOOH). The iron forming these concretions came from the break down of iron-bearing silicate minerals by weathering to form iron oxide coatings on other grains. During later diagenesis of the Navajo Sandstone while deeply buried, reducing fluids, likely hydrocarbons, dissolved these coatings. When the reducing fluids containing dissolved iron mixed with oxidizing groundwater, they and the dissolved iron were oxidized. This caused the iron to precipitate out as hematite and goethite to form the innumerable concretions found in the Navajo Sandstone. These concretions are regarded as terrestrial analogues of the hematite spherules, called alternately Martian "blueberries" or more technically Martian spherules, which the Opportunity rover found at Meridiani Planum on Mars.[1][2]

RE: Stuck in the Navajo - samplerock - 03-19-2010 05:50 PM

Wow, what great information. Once I read that, I remember a location where a sand outcrop is and is loaded with Iron imbedded, just as you described. The next time we get to drill the Navaho, I'll be looking harder. Thanks for the info. Troy.