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Question
QUESTION: I'm trying to.get my salt water to break. It is full of really fine silt and my centrifuge won't fling the silt out. So what do you think I should do?

ANSWER: Josh,
Are your discharges going through a de-silter before being fed into the centrifuge? If not, that is what I suggest. A centrifuge will clean very efficiently but if used as the first stage will sometimes clog. If you are going through a hydrocyclone as the first stage it should be a de-silter, 8 or 10 4" cones, rather than a de-sander, 2- 8" cones, because the smaller cones handle fine, low gravity solids better than the larger de-sander cones. If you have neither at your project site a complete mud cleaner with both size hydro-cyclones discharging into a very fine mesh vibrating screen cleaner which discharges into the centrifuge supply tank should do it. I dislike direct recommendations but SWACO, part of Schlumberger, has good equipment and a good site to determine which you need and if the equipment is needed for only a short time, there are rental skid mount units that have their own power supply.

---------- FOLLOW-UP ----------

QUESTION: My water.runs over a shaker then into a flock tank then into the centrifuge.  So I still don't understand with my equipment how to get the silt out of the salt water.

Answer
Hi Josh,
I'm sorry there was some delay in answering, my wife really felt that she deserved my un-divided attention for her birthday, I realize you have an urgent problem.

What you have going on is insufficient retention time for the silt to settle. Recall that a drilling rigs shakers discharge into a sand trap and then the sand trap discharges into a de-gasser/de-silter tank. The sand is heavy and will settle quickly to the bottom of the sand trap. The lighter silt takes longer to settle and is either separated mechanically or, as is sometimes done in Austin Chalk formation horizontal wells, is allowed to flow through tanks that have longitudinal dividers. This gives the fluid time to move slowly through the tank while the silt settles. The less agitation and the smoother the movement, the faster the settling rate (this is why the Mississippi River is muddy).

Catch some of your water in a clear glass and let it sit still and time how long it takes for half of the silt to settle. This will be the heaviest material and should be enough to allow the centrifuge to remove the lighter material. If you cannot set up a tank to tank feed before entering the centrifuge then, as I see it, you only other option is to use hydrocyclone de-silters.

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Carl Alexander

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READ THIS! Do NOT ask me questions about LEASING, MINERAL RIGHTS, ROYALTIES, POOLING, etc. I am not qualified to give accurate answers on these subjects. If you DO ask, I will NOT answer! I CAN help you understand the technology and equipment involved in drilling oil and gas wells on land or offshore and the production process after the well is drilled. I prepare the programs for the rigs that get oil and gas out of the ground and direct activities on the drill rig so questions concerning the engineering process and preparing drill sites and roads or marine transport are welcome, those concerning the legal process less so. I work with wells on land or offshore, U.S.A. or other countries. I can also answer environmental, regulatory and safety practices questions.

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35 years working in the 'Patch' all over the world. I have drilled for oil & gas on land and water in the U.S.A, Brazil, Guatemala, Nigeria, South Africa, Angola, Tunisia, England, British North Sea, Iran, Oman, Pakistan, Vietnam, Philippines. I have drilled in water depths up to 2000 meters and on land in desert and artic conditions. Some were in countries where environmental and safety concerns were non-existent and others when they were primary. I have certification for well control/blowout prevention, have attended water/helicopter/boat survival school and am certified for spill cleanup. I am currently working as a consultant for drilling projects and spend half my working time at the drill site and half in my office and most of my "off time" traveling between the two.

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Society of Petroleum Engineers

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BA/BS - Petroleum Engineer

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