Controlling Circulation Losses in Open-Grade Mixes

Portugal

“We were constantly having to prepare drilling mud and were losing control of the well. Thanks to Quimacer’s treatment, we restored circulation and were able to complete the project.”

A water well drilling company in southern Portugal contacted QUIMACER while drilling a 120-meter well in an alluvial area.

The project was carried out in an area characterized by alternating layers of coarse sand, open gravel, and highly permeable strata, particularly between 40 and 70 meters.

The client was using a standard bentonite slurry, which was sufficient for relatively cohesive soils but insufficient to control fluid loss into the formation.

The project was facing delays due to excessive water consumption, the continuous preparation of slurry, and the lack of stable surface settlement.

The problem was affecting construction costs and posed a risk of collapse due to loss of hydrostatic pressure.

Problems Identified

  • Partial losses that turned into nearly total losses on the open gravel sections.
  • Difficulty maintaining hydrostatic pressure and well stability.
  • Inadequate detritus transport due to a lack of stable return flow.
  • Increased water consumption, bentonite, and mixing time.
  • Risk of entrapment due to sediment buildup from cuttings at the bottom.

Our Intervention

  • QUIMACER analyzed the type of formation and concluded that the problem was not just one of viscosity, but also of poor sealing and inadequate filtration control.
  • It was recommended to use a combined strategy: forming a cake, reducing filtration, and adding bridging material to close pores and small cavities.
  • A treatment sequence was established to avoid sudden overdosing and to prevent the sludge from becoming too heavy or difficult to pump.
  • It was recommended to check the return flow, flow rate per minute, and viscosity before continuing to drill deeper.
  • The goal was not to eliminate consumption entirely, but to restore sufficient flow and stabilize the drilling system.

Solution Implemented

  • BENTONITE QE at 25 kg/m³ as a base to enhance gel formation, stability, and suspension capacity.
  • QUIMAGEL GNT at 2 kg/m³ as a filtration control polymer to promote cake formation.
  • QUIMASEAL 1770 at 8–10 kg/m³ as a granular sealing material for leaks in gravel and small cavities.
  • QUIMASEAL FIBRAS at 3 kg/m³ to reinforce mechanical bridging in open-form construction.

Target parameters: Marsh viscosity 55–65 s, stable flow, progressive reduction in losses, and pump pressure control

Results and Improvements

Losses were reduced by more than 80% following the application of the combined treatment.

Partial circulation has been restored to a level stable enough to continue drilling.

Improved transport of detritus and reduced accumulation at the bottom of the borehole.

Water consumption reduced by more than 60% during peak periods.

Estimated operational savings of between 4,000 and 6,000 euros in supplies, water, and equipment hours.

Parameter Technical Details
Sector Water well
Soil Open gravel and coarse sand
Method Direct rotation
Critical depth 40–70 m
QC Products

BENTONITE QE, QUIMAGEL GNT, QUIMASEAL 1770, QUIMASEAL FIBERS
Recommended dosage

25 kg/m³; 2 kg/m³; 8–10 kg/m³; 3 kg/m³
Key Improvement

>, 80% reduction in losses

WHY QUIMACER?

  1. It combines chemical and physical sealing to address actual leaks.
  2. Tailor the solution to the pore size and formation type.
  3. Reduces water consumption and downtime.
  4. It allows you to continue without resorting to high-cost mechanical solutions.