Physical Properties of Mud
Introduction to Petroleum Engineering
Dr. Shirish Patil
Petroleum Engineering Department
University of Alaska Fairbanks
Drilling fluid (mud) is a mixture of water or oil, or emulsion base , clay, weighing material and some chemicals. The combination of mud may vary according to the changes in formation. Drilling fluid plays essential role in drilling process. For this experiment we used a 2000 mL sample of mud with 12 lb/gal density where 6 lb/bbl bentonite. This experiment was performed by using the Marsh Funnel method, pH meter and strips with weighing material barite to determine drilling mud characterizations.
Drilling mud is a chemical mixture used while drilling a well for several purposes. The mud is circulated down the drill pipe, out through the drill bit, across the rock face being drilled, then back to the surface carrying debris from the bottom of the well. The mud is then cleaned, tested, and re-used in the well on a continuous basis. Drilling mud has several important functions: 1. Assists in making hole by:
a) Removal of cuttings, the removal of cuttings from the face of the well bore is still one of the most important functions of drilling fluids. Fluid flowing from the bit nozzles exerts a jetting action that keeps the face of the hole and edge of the bit clear of cuttings. b) Power transmission to bit nozzles or turbines;
c) Cooling and lubrication of bit and drill string, considerable heat is generated by friction in the bit and where drill string is in contact-with the formation or casing. There is little chance for this heat to be conducted away by the formation; therefore, the circulating fluid must remove it. 2. Assists in hole preservation by:
a) Support of bore hole wall;
b) Containment of formation fluids;
3. Supports the weight of pipe and casing;
4. Serves as a medium for formation logging;
In this experiment, we determined pH balance of mud, its density and flow rate by using the Marsh funnel, pHydrion paper test-strips, and Baroid mud balance to determine its density. Materials
Baroid Mud Balance
pH Meter and Strips
1. A solution of 200 mL drilling fluid was used with 12 lb/gal density and 6 lb/bbl bentonite where barite as a weighting agent. We filled a funnel with 946 mL 70°F (± 5°F) water. Then we recorded time of the outflow of 946 mL of water, it has to take about 26 (± ½ ) seconds. Fill the upright funnel with prepared mud sample and cover the orifice with a finger and pour the freshly collected mud sample through the screen into a dry, clean Marsh funnel until the mud level reaches the bottom of the screen (1500 ml). 2. After that by using a finger as a stopper, it was immediately removed from the outlet and the time required was recorded for the mud to fill the receiving container to the one-quart level. 3. For the calculation of mud density, a 500cc sample was separated from the mud sample and placed on the mud balance. 4. For determination of pH balance of the mud, a strip of PHydrion paper was placed into the mud and remained there the color stabilized, it took about 2 minutes. 5. Flow time was recorded as 40.8 seconds.
6. The experimental calculation of mud density was 9.0 lbs/gal. 7. The experimental calculation pH balance of the sample was 6.5.
Prepared mud fluid
Experimental mud fluid
In this experiment we calculated the viscosity of the drilling fluid (using Marsh Funnel), as well as mud density and checked its pH balance. Funnel method used widely because of its easiness and handiness. It helps to determine the viscosity of drilling mud and its changing...
References: Contents from Lab Handout
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