InvaShield

Controlling Seepage Losses, Inhibiting Fracture Propagation and Restricting Pressure Transmission into the Formation can Mitigate major Drilling Challenges. InvaShield is a blend of plant based Organic Fibers and is Thermally Stable up to 350oF. InvaShield’s ability to form Flexible Deformable Virtually Impermeable Plugs within the Fracture addresses Seepage Losses, Inhibits Fracture Propagation as well as Prevents Pressure Transmission to the Formation, thereby greatly Reducing the Mechanical Instability challenges faced.

InvaShield Advantages:

  • Environmentally friendly
  • Powdered material for ease of mixing
  • Forms aggregates of various lengths eliminating the need to match PSD to pore throat dimensions.
  • Does not degrade over time and circulation
  • Protects mechanically weak formations
  • Increases fracture formation pressures, lending itself well to increasing LOT/Fracture Gradient etc.
  • Prevents induced losses
  • Minimises Differential Sticking
  • Minimises fluid transmission to the formation, making it an ideal choice for weak/sub-hydrostatic reservoir drilling

A Near Instantaneous thin and very Low Permeability Barrier is Formed on the Wellbore interface. This barrier Prevents the Transmission of Fluid Pressure into the Formation via Microfractures, Natural or Induced. The retention of fluid column pressure within the well bore results in the following:

  • The wellbore is competent to maintain an overbalance thereby preventing cavings and instability in mechanically unstable formations with micro-fractures or bedding planes. This ability to restrict transmission of pressure from the wellbore to the formation also minimises the risk and incidents of differential sticking.
  • Induced fractures in mechanically weak rocks is inhibited as pressure transmission to the formation is prevented, thereby ensuring fractures do not propagate. This in turn minimises the risk of induced losses when drilling overbalanced or within narrow ECD windows. Typically fracture initiation pressures are raised, widening the mud weight window.
  • InvaShield creates a very thin cake near the wellbore but is not a bridging particle. This ensures extremely low formation damage due to minimal fluid invasion into the formation. Being very close to the surface as well as not plugging the pore throats, filter cake clean up and flowback is very easy.

InvaShield dosage is typically between 6 – 10 ppb. Formation of aggregates of various lengths allows InvaShield to be applied as a Fluid Invasion Restrictor over a Wide Range of Permeabilities. InvaShield would typically perform in formations with fractures in the range of 100-250 microns. 

Case Histories

  1. The North-eastern part of India is a tectonically active area, the lithology mostly being shale with the pay zone being fractured granitic basement, having sandstone intercalations. A major operator has drilled approximately 90 wells in this area using the Non-Invasive Fluid additive (predominantly in the payzone). The advantages seen included ability to keep the hole open and stable for longer periods vis-à-vis offset wells, in severe cases there were prolonged fishing operations undertaken and the wells were still stable. In a particular case the wellbore was found to be capable of holding 3000+psi over the predicted hydrostatic window and not exhibit instability. Flow back from the wells was also easier and with higher yield. The wells came online even with only a single application of the compressor, evidencing very low lift off pressures required to clean out the low invasion fluid.
  2. The East Coast of India can be said to be predominantly Shale and Sandstone with Clay streaks. A major operator has used the additive in this area with noted success. The main advantages brought were pushing the limits of the mud weight window with enhanced wellbore stability. The operator has also used the additive in Deep Water wells. Major advantages seen are fewer differential sticking issues, smooth wellbore, huge reduction in seepage losses. These led to fewer complications and faster drilling. The operator has drilled nearly 21 wells in this area using this additive (predominantly in the payzone).
  3. Western offshore and North-western onshore in India can be considered to comprise of Shale/Carbonate alternations, Shale/Sandstone alternations and Shale/Claystone alternations. The major issues faced are narrow mud weight windows and wellbore instability issues brought about by different permeability/porosity regimes being encountered in the same section. A major operator has drilled nearly 75+ wells in this area using this additive (predominantly in the payzone). Definite improvements seen have been reduction in seepage losses, less stuck pipe, improved mud weight windows, smoother wellbores, easier running casing etc. In some cases, reduction of time spent due to drilling complications have been reduced by as much as 35-40%. The operator has also run this additive with SOBM’s, evidencing its compatibility with both WBM and SOBM.
Product Data Sheet
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