Differential Stuck Pipe Freeing Agents - Drilling Fluids | SLB

PIPE-LAX ENV WH

Low-toxicity, stuck-pipe spotting fluid

Schlumberger Oilfield Services

PIPE-LAX ENV WH fluid is a water-dispersible, low-toxicity spotting fluid designed to free differentially stuck pipe by penetrating between the wall cake and drillstring. It offers strong metal wetting characteristics and will act as a lubricant after it is added into the active system.

Because PIPE-LAX ENV WH additive is a single-package, liquid blend made for fast mixing, it is ideal for spotting situations.

Applications

  • Environmentally sensitive offshore and onshore wells where a low-toxicity, nonoil-based spotting fluid is specified
  • Contains no hydrocarbons, is compatible with most mud systems, and can be used either weighted or unweighted

If a density greater than 9 ppg [1.08 sg] is required, the PIPE-LAX ENV WH fluid should be weighted with M-I BAR barite, M-I WATE barite, or FER-OX weighting materials. If a density less than 9 ppg [1.08 sg] is required, PIPE-LAX ENV WH fluid should be used without dilution.

After being used as a spotting fluid, up to 3% by volume PIPE-LAX ENV WH additive can be incorporated into the active system to reduce torque and drag and to reduce the possibility of differential sticking.

Advantages

  • Effective soak solution that quickly frees differentially stuck pipe
  • Can be easily weighted with M-I BAR barite, M-I WATE barite, or FER-OX products
  • Can be incorporated into most water-based mud systems
  • Contains no hydrocarbons and is water dispersible
  • Aids in lubrication and reduces the coefficient of friction, thus improving the torque- and drag-reduction characteristics of the mud
  • Excellent stability at downhole temperatures and pressures

Mixing procedure

  1. Calculate the volume of spotting fluid required and add at least 10% to compensate for any washout. In addition, include 25 bbl [3.97 m3] to remain in the drillstring.
  2. In a clean, dry tank, mix the required amount of PIPE-LAX ENV WH fluid determined from the mixing formulation chart. When using PIPE-LAX ENV WH fluid supply adequate ventilation when opening containers and in enclosed areas. Although some separation of materials can occur in the containers, transferring the product into a pit blends the components, and product performance will not be affected.
  3. If the slurry is to be weighted, add the correct amount of M-I BAR barite, M-I WATE barite, or FER-OX weighting materials until thoroughly blended.
  4. Displace the slurry to the zone where the differential sticking is suspected. Leave 25 bbl [3.97 m3] inside the pipe to displace at an hourly rate into the openhole.
  5. Work the pipe while the spotting fluid is soaking. Pump 0.5–1 bbl [0.08–0.16 m3] every 30 min to assure fresh soak solution is being displaced into the openhole.
  6. Allow at least 24 h for the PIPE-LAX ENV WH fluid to free stuck pipe. Generally, unweighted spotting fluids are effective in a shorter period of time.

When using PIPE-LAX ENV WH fluid in deviated wells with angles greater than 35° the spotting fluid should be weighted 0.5 ppg [0.06 sg] heavier than the original fluid in the well to encourage the spotting fluid to migrate to the lower side of the hole.

Mixing formulation (per final barrel or per final cubic meter)

Density, ppg [sg] PIPE-LAX ENV WH Fluid, bbl [m3] M-I BAR Barite, lbm [kg] PIPE-LAX ENV WH Fluid, bbl [m3] FER-OX Agent, lbm [kg] PIPE-LAX ENV WH Fluid, bbl [m3] M-I WATE Barite, lbm [kg]
8.5 [1.0] 1.000 [0.16] 1.000 [0.16] 1.000 [0.16]
9.0 [1.0] 0.982 [0.155] 28 [12.7] 0.985 [0.155] 26 [11.8] 0.981 [0.155] 28 [12.7]
10.0 [1.2] 0.943 [0.15] 83 [37.6] 0.955 [0.152] 79 [35.8] 0.942 [0.15] 84 [38.1]
11.0 [1.3] 0.905 [0.145] 139 [63] 0.925 [0.147] 132 [59.9] 0.903 [0.145] 140 [63.5]
12.0 [1.4] 0.868 [0.14] 194 [88] 0.895 [0.142] 184 [83.5] 0.864 [0.14] 196 [88.9]
13.0 [1.5] 0.829 [0.13] 250 [113.4] 0.864 [0.137] 238 [108] 0.825 [0.13] 252 [114.3]
14.0 [1.6] 0.793 [0.125] 304 [137.9] 0.835 [0.133] 290 [131.5] 0.786 [0.125] 308 [139.7]
15.0 [1.8] 0.754 [0.12] 361 [163.7] 0.804 [0.128] 343 [155.6] 0.747 [0.12] 363 [164.7]
16.0 [1.9] 0.717 [0.115] 415 [188.2] 0.774 [0.123] 395 [179.2] 0.708 [0.112] 419 [190]
17.0 [2.0] 0.680 [0.11] 471 [213.6] 0.744 [0.118] 448 [203.2] 0.669 [0.106] 475 [215.5]
18.0 [2.1] 0.642 [0.10] 526 [238.6] 0.714 [0.114] 500 [226.8] 0.630 [0.10] 531 [240.9]

Higher-density PIPE-LAX ENV WH fluid formulations can develop high viscosity and become difficult to pump. Even small amounts of water contamination can aggravate this situation. For densities greater than 15.0 ppg [1.80 sg], LUBE 945 lubricant should be added to PIPE-LAX ENV WH fluid formulations to reduce the final viscosity, then weighted to achieve the desired density. Suggested dilution concentrations are as follows:

Density, ppg [sg]
LUBE 945 Lubricant, % by volume
15–16 [1.8–1.92] 5
16–17 [1.92–2.04] 10
17–18 [2.04–2.16] 15
>18 20

Limitations

  • Requires clean, dry tank for mixing
  • Water contamination results in an undesirable increase in viscosity

Toxicity and handling

Bioassay information is available upon request. Handle as an industrial chemical, wearing protective equipment and observing the precautions described in the safety data sheet.

Packaging and storage

PIPE-LAX ENV WH fluid is available in bulk or 55-galUS [208-L] drums. Store in a dry, well-ventilated area. Keep container closed. Keep away from heat, sparks and flames. Store away from incompatibles. Follow safe warehousing practices regarding palletizing, banding , shrink-wrapping, and stacking.