Designing Pilot Tests

Figure 38 Pilot Testing Equivalents

Figure 38 Pilot Testing Equivalents

Drilling Fluid Tests Lab
  • comparison to other products
  • temperature/contamination
  • shelf life

3. Adjustments to mud properties such as:

  • weight up/dilution
  • changing fluid loss properties
  • changing alkalinity/pH
  • treating carbonate/bicarbonate contamination
  • reducing hardness
  • adjusting MBT - clay content of the mud
  • changing oil/water ratio of oil muds
  • increasing electrical stability of oil muds

4. Study of effects of breakover, converting or displacement of muds, such as:

  • displacing water-based mud with oil-based mud or vice versa
  • converting from freshwater mud to saturated salt mud
  • breakover to lime or gyp mud
  • reducing components in mud to convert to bland coring fluid
  • treatment required to convert mud to a packer fluid

To determine how to design a pilot test or test series, look at economics and potential for problems down the road. For example, if you expect to encounter a pressured saltwater flow (16 lb/gal) with a 15 lb/gal freshwater mud at 350°F, the parameters for testing could be: (1) maximum volume of saltwater anticipated in the mud, (2) weight up to 16 lb/gal with and without contaminant, (3) effects of temperature on mud (15 and 16 lb/gal) with and without contamination, and (4) dilution and thinner treatments.

Pilot test design requires calculating amounts of materials to put into the test samples. In pilot tests, grams are equivalent to pounds and 350 cm3 is equivalent to one 42-gal oilfield barrel. Material balance equations, as developed in "Engineering, are used for pilot test design. For example, to weight the 15 lb/gal mud to 16 lb/gal without increasing the mud volume, one must calculate how much 15 lb/gal mud to dump and how much barite to add to increase density. For simpler pilot tests, such as adding only a few lb/bbl treatment, it is not necessary to account for material balance.

Note: For liquid additives, volumes (gallons, buckets, drums) must be converted into weights (pounds, grams) for pilot testing.

Rigsite pilot tests have distinct practical advantages over sending a mud into the laboratory or having a laboratory mud prepared for pilot testing. Rigsite testing allows actual material and mud to be used, which allows results to be readily available. quicker (which is usually very important), and allows rig supervisor and mud engineer to evaluate and review the pilot test results.

Laboratory pilot tests and planning are both important in preparing to drill a troublesome well. Both should be done long in advance of anticipated problems. In this case, lab pilot tests are advantageous in that they can be performed in advance, but then pilot tested again at the rigsite with the actual mud and chemicals.

Note: Protective eyewear (safety glasses or safety goggles) must be worn at all times when mixing chemicals.

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Responses

  • NOBLE
    How to test drilling additives in the lab?
    9 years ago
  • giuseppa udinesi
    How are hardness tests on drilling fluids performed?
    7 years ago
  • Marc
    How to pilot test drilling mud?
    3 years ago
  • Uwe
    How to convert sack material for pilot testing lab oilfield?
    3 years ago
  • Rita
    What is piloat of oil field test?
    2 years ago
  • biagio lombardi
    How to mike drilling fluid in lab?
    2 years ago
  • Rinaldo
    How to pilot test drilliNg fluids?
    2 years ago
  • Irene
    How to make 1 oilfield barrel of mud for testing?
    1 year ago

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