Exercise 5 - Cement Contamination

Exercise 5 - Cement Contamination - PGE 430 Lab Exercise...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
PGE 430 Lab Exercise No. 5 To: Rig 79 Supervisor From: Student Name Re: Cement contamination of mud. Date: TA Version – memo format +0.5 point. _______________________________________________________________________ _ The mud showed an increase in rheologic properties. There was no chloride increase, but there was a large calcium increase. This was brought about by drilling cement. Recommendations and a discussion about recognizing and treating this problem follows. Recommendations: Mud flocculation resulting in an increase in rheologic properties occurred after drilling a section of cement. The problem was noticed by the increase in the rheologic properties of the mud (in fact most were so high as to be un-measurable) accompanied by a pH increase and a large increase in calcium in the mud. There are two possibilities for treatment to lower the calcium to the original level of 15 mg/l. The first is to use 804 lbs of sodium bicarbonate and the second is to use 531 lbs of SAPP. Unfortunately the rig does not have enough of either chemical on site to carry out either treatment. I recommend the following two step procedure. (1) Use all 500 lbs of SAPP in stock. This should reduce the calcium to 33.4 mg/l. (2) Use 47.6 lbs of sodium bicarbonate to lower the calcium to the original concentration. Recommendations along these lines must be shown for + 4 points. Discussion: A 9 5/8” 40 lbm/ft casing was set to a depth of 4,000 ft. (diagram attached). During cementing, the pump failed, and 500 ft. of cement was left in the casing. Consequently, the cement was drilled out to a depth of 4100 ft using a 8 ½” bit, 500 ft of 8” by 2 ¾” drill collars and 3600 ft of 4.5” 20 lbm/ft drill pipe.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/13/2012 for the course PGE 430 taught by Professor Chenevert during the Spring '06 term at University of Texas at Austin.

Page1 / 5

Exercise 5 - Cement Contamination - PGE 430 Lab Exercise...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online