Mud density
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This document summarizes a student's fluid mechanics lab experiment on measuring mud density. The aim was to learn how to use a mud balance apparatus to measure the density of drilling mud and see how density changes with the addition of barite. The student first prepared a bentonite mud and measured its density. Barite was then added to increase the mud density, which was remeasured. Understanding mud density is important for maintaining proper hydrostatic pressure to prevent fluid influx from formations during drilling.
Mud density
- 1. KOYA UNIVERSITY FACULTY OF ENGINEERING SCHOOL OF PETROLEUM AND CHEMICAL FLUID MECHANIC LAB NAME OF EXPEREMENT: Mud Density NAME OF STUDENT: Kamal Abdurahman Group: B SUPERVISED BY: Mr.Pshtiwan Jaf
- 2. Aim of experiment: 1.To know how to use mud balance apparatus. 2.To know the change in density after adding barite by using water. 3.To recalculate the density of the mud which is given.
- 3. Introduction Density or weight of a given volume of liquid is determined by using a mud balance. The arm is graduated and permits accurate measurements to within +- 0.1 pounds per gallon or +- 0.01 specific gravity. The mud balance is constructed so that the fixed volume cup at one end is balanced by a fixed counterweight at the opposite end, with a sliding weight rider free to move along on the beam indicates when the system is in balance.
- 4. Theory The density of the drilling fluid must be controlled to provide adequate hydrostatic head to prevent influx of formation fluid, but not so high as to cause loss of circulation or adversely affect the drilling rate and damaging the formation. Normal pressure gradiant by water is equal to(0.433 psi/ft) and equal to 433 psi/1000 ft. A mud balance,also known as a mud scale is adevice used to measure the density(weight) of drilling fluid,cement or any type of liquid or slurry. There is no reliable visual method of determining the density of drilling mud, the mud balance is the most reliable and simple way of making the determination.
- 5. Apparatus of experiment The instrument consists of a constant volume cup with a lever arm and rider calibrated to read directly the density of the fluid in PPG(water 8.33),pcf(water 62.4),specific gravity (water=1) and pressure gradient in psi.
- 6. Calibration 1.Remove the lid from the cup ,and completely fill the cup with water. 2.Replace the lid and wipe dry. 3.Replace the balance arm on the base with knife-edge resting on the fulcrum. 4.The level via l should be centered when the rider set on 8.33ppg.If not, add to or remove shot from the well in the end of the beam.
- 7. Procedure 1.Remove the lid from the cup, and completely fill the cup with the mud to be tested. 2.Replace the lid and rotate until firmly seated, making sure some muds expelled through the hole in the cup. 3.Wash or wipe the mud from the outside of the cup. 4.Place the balance arm on the base,with the knife-edge resting on the fulcrum. 5.Move the rider until the graduated arm is level,as indicated by the level vial on the beam. 6.Noted down the mud temperature corresponding to density. 7-after we are prepared bentonite mud we put in this mud barite(weight 25.8463gm) and after that we are rerecorded the density of the new mud by mud balance.
- 8. Mud Preparation V1 W1 + V2 W2 + ….. = Vf Wf V1 + V2 + …… = Vf Where: V1 : Volume of the first material to be mixed. V2 : Volume of the second material to be mixed. Vf : Total volume of the mud. W1 : Density of first material. W2 : Density of second material. W3 : Density of the mud.
- 9. Discussion -We must be clean all the device before our works because if they are dirty ,they will be cause error in our experiment. -If the water is not clean(dirty)to prepare this mud we have some error to equilibrium this balance,you must balanced this mud balance with the water(standard solution)in first stage and after that you balanced the bentonite mud with respect to density of the water and we put this mud (barite) to increase the density of the mud (to controlled the formation). -In this experiment we want to recalculate the density of the mud,first we weight 17.041gm of the bentonite in the weight balance and mixed it with 493.19cc of water,then we put it in the mixture tool,in fact we could not make the mud balance our bentonite in the lab was bad ,so our result was mistaked. -If the mud was mixed didn't bad,we must find the mud density by the mud balance. After the mixture we must weight 25.8463gm of
- 10. barite and put in to the mixture of the bentonite and water(mud) in the mixture tool,after this mixture we find its density by the mud balance too.From that we know the difference between both density. Q/Why are we increase density of this mud? A/In this test we are weightining this mud by adding the barite(high density) to increase the density of mud(bentonite mud) ,the useful of this increasing mud to contolling the adequate hydrostatic head to prevent in flux of formation fluids .
- 11. Pressure Ph = MW × TVD × 0.052 Pr = 0.433 × TVD Pf = fracture gradient x TVD Where: – Ph: is mud hydrostatic pressure in psi. – Pr: is reservoir pressure in psi. – Pf : is fracture pressure in psi – TVD: is true vertical depth in ft. – MW: is mud weight (density) in ppg. – 0.433: is fresh water pressure gradient in psi/ft.
- 12. Pressures • To avoid the risk of kick (blowout), hydrostatic pressure should be greater than the formation (reservoir) pressure. • To avoid the risk of formation fracturing (fluid losses), hydrostatic pressure should be less than the fracture pressure. Pr < Ph < Pf
- 13. The Standard one of This Test