Leakage is one of the main causes of unproductive time in drilling operations. There is a magnesium oxide-based material designed to mitigate various degrees of leakage problems. This material is particularly effective in plugging and abandonment operations in cavernous formations, and in maintaining constant casing pressure. It is a high-strength, acid-soluble system that can be used in conventional temperature environments and replaces conventional cement plugs. The system is resistant to water-based/oil-based mud contamination.
Treatment of drilling fluids, completion fluids and workover fluids with magnesium oxide in combination with appropriate completion methods can significantly improve the removal of solids (mud cake) deposited on the well wall by borehole fluids. Magnesium oxide in completion fluid and workover fluid can keep the solution pH around 10 to avoid metal corrosion and polymer degradation.
Magnesium oxide is a new type of glue-breaker, which is inert or inactive when added to polymer/clay completion fluids, and precipitates with drilling fluids to become part of the filter cake during drilling operations. The hydrogen peroxide released by magnesium oxide in acidic solution degrades the polymer and disintegrates the filter cake. After the disintegration of the mud cake, the remaining bridging materials are removed by washing liquid flushing the mud cake disintegrated materials to improve the efficiency of gum breaking. By using the new magnesium oxide gum breaker, the filter cake removal effect can be effectively improved, and magnesium oxide can be used in drilling vertical wells, large slope wells and horizontal wells in production formations.