Oilfield


PQ Sodium Silicates and Potassium Silicates have proven to be cost-effective and environmentally-responsible high-performing chemicals in numerous oilfield applications, including drilling fluids, cementing and enhanced oil recovery.    

Silicate-Based Drilling Fluids
It has been known since the 1920s that water-based drilling fluids formulated with potassium or sodium silicate provide superior shale stability, regardless of shale type.  Eighty years later, silicates are still recognized as the most effective water-based shale inhibitor.  PQ silicates are non-toxic and one of the few oil field chemicals that can be beneficial to the environment both on-land and offshore. PQ’s EcoDrill® line of sodium and potassium silicate products allows for service companies to further customize the drilling fluid to maximize performance and reduce drilling fluid costs.  

Oilwell Cement
The design and placement of an effective cementing system is critical to the commercial success of every oil and gas well.  A quality cementing job not only provides a strong bond between casing and formation but also seals off the formation and protects the pipe. PQ soluble silicates allow oilwell cements to be formulated to meet these challenges.   PQ produces a wide range of both liquid and powder sodium silicates.   PQ’s proprietary process for manufacturing sodium metasilicate produces a dustless, uniformly sized powder for better dry-blending into the bulk cement. Both liquid sodium silicates and METSO® sodium metasilicates are used in this application.  

Enhanced Oil Recovery (EOR)
With oil price and demand continuing to escalate, there is greater interest in enhanced oil recovery (EOR).  An important category of EOR is Chemical Flooding.  PQ was heavily involved with the initial development work using sodium silicate for alkaline flooding and later in alkaline-surfactant-polymer flooding. The addition of diluted sodium silicate produces superior results compared to surfactants or polymers alone. 
How It Works
PQ silicates are water-based inorganic solutions of silica.  The silica is in soluble polymeric form and can add value to a drilling mud formulation by causing changes in density, ionic strength, charge, etc. that are needed for critical drilling mud functions such as:  drill-bit cooling, bit cleaning, effective cuttings removal to surface, downhole pressure control, and shale stabilization.  Likewise, the use of silicate muds offers the advantages of prevention of bit-balling, differential sticking, and loss circulation in addition to the well-known use as a corrosion inhibitor.  

Silicates are well-known as shale stabilizers providing coating and chemistry to prevent swelling and collapse in water.  PQ silicate are non-toxic and one of the few field chemicals that can be beneficial to the environment, e.g., PQ's potassium silicate is used as well in agricultural applications as a fertilizer.  

For conformance control of unwanted water and in cementing, the gelation and precipitation chemistries of silicates are exploited to give a cost- effective, durable, and high strength gel.  By controlling the type and concentration of setting agent, sodium silicate can be made to gel and set in minutes to hours.   Depending on depth of placement and desired reaction time the sodium silicate solution is formulated with an external or internal catalyst.   
 
Applications
Water-Based Drilling Fluids

Oilwell Cementing

Enhanced Oil Recovery (EOR)
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