The following Water Based Mud Testing Procedures are according to approved ANSI/ API RP 13B-1. ( Download Now PDF API RP 13B-1) . In this article we will provide all the procedures for all the mud tests related to WBM including physical properties and chemical properties. But first before going in depth on our subject, let’s have a look on Safety Precautions While Mud Testing
Water Based Mud Testing Procedures For Physical Properties
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These test procedures are for both Water-based mud and oil-based mud so we will add it here and in the article of oil-based mud testing procedures.
Water Based Mud Testing Procedures For Chemical Properties
pH In drilling fluid is one of the major drilling fluid properties for monitoring as it affects clay interactions, corrosion processes and solubility of certain chemicals. We can determine drilling fluid pH using pH Meter or pH Strips, as follows. Accordingly, we will explain the steps of PH in drilling fluid testing procedures.
The alkalinity test is one of the important Water Based Mud testing procedures as alkalinity affects the performance of some treating additives in the water-based fluid, especially if they require alkaline conditions for better performance. Sodium or Potassium Hydroxide normally provides the hydroxyl ions (OH–) for calibrating the pH of water-based fluids . However, carbonate (CO3 2–) and bicarbonate (HCO3 –) ions also increase fluid alkalinity, along with formation contaminants (e.g. H2 S or CO2 gas).
We can define Water “hardness” as water that contains dissolved Calcium and Magnesium salts, which in high concentrations will decrease the performance of Bentonite and polymers ( check also How to Design Polymer Mud), which will result in consuming large amounts. In this article you shall learn the water based mud testing procedures for Total Hardness as Calcium & Calcium and Magnesium Ion Content
The water-based fluid may have chlorides from the base fluid (e.g. Sodium or Potassium Chloride), or may pick up chlorides while drilling. The application of Chloride Test is determining any changes in water-based mud salinity. As an increase or reduction in salinity will indicate salt or water contamination. So It is important to have chlorides in drilling mud.
We use this Clay Content test in drilling mud for estimating the Cation Exchange Capacity (CEC), which estimates the reactive clays in the drilling fluid system. This article handles the Methylene Blue Test For clay content in both drilling fluid and shale samples.
It is essential to do Potassium ion concentration monitoring for Water Based Fluid systems that utilize Potassium as Shale Inhibition agent as it will deplete once it is adsorbed into shales. Monitoring Depletion and Maintaining effective inhibition levels are essential in the drilling fluid system. So you can easily estimate Potassium ion concentration by adding excess Sodium Perchlorate to a certain volume of mud filtrate to precipitate out Potassium Perchlorate. In this article, you shall learn how to measure, calibrate & calculate Potassium Ion & KCL In Drilling Fluid.
In general, Mud engineers utilize Glycol in KCl-Polymer fluid systems as it improves Shale Inhibition . In addition to that, Glycol will be lost through adsorption on exposed shale formations in the wellbore and on the cuttings. Also, it is important to understand that the glycol depletion rate is a function of drilling Penetration Rate (ROP) and Cuttings size. Based on above, Mud engineers always keep an eye on the glycol concentration in drilling fluid. In this article, you will be able to understand the equipment and the steps for such test.