Pressure drop in the annulus is another important part of drilling hydraulic calculation and today we would like to demonstrate the equations specifically used to determine pressure loss in the annulus.
The following equations are used for calculating pressure loss in the annulus.
Today, I would like to share the great resport of the deepwater horizon – Macondo well published by the US Government. You can download the report for FREE.
Click Here to download the report => http://www.gpo.gov/fdsys/pkg/GPO-OILCOMMISSION/pdf/GPO-OILCOMMISSION.pdf
On April 20, 2010, the Macondo well blew out, costing the lives of 11 men and beginning a catastrophe that sank the Deepwater Horizon drilling rig and spilled nearly 5 million barrels of crude oil into the Gulf of Mexico. The spill disrupted an entire region’s economy, damaged fisheries and critical habitats, and brought vividly to light the risks of deepwater drilling for oil and gas — the latest frontier in the national energy supply. Soon after, President Barack Obama appointed a seven-member Commission to investigate the disaster, analyze its causes and effects, and recommend the actions necessary to minimize such risks in the future. The Commission’s report offers the American public and policymakers alike the fullest account available of what happened in the Gulf and why, and proposes actions — changes in company behavior, reform of Government oversight, and investments in research and technology — required as industry moves forward to meet the nation’s energy needs.
This article will demonstrate you how to determine hole size by fluid caliper. First of all, you need to know what is the fluid caliper is. The fluid caliper is one simple way to calculate hole diameter. The concept is based on hole volume, annular capacity, and inner capacity. You pump any substance and when you seen it on surface, you back calculate the hole size based on strokes pumped. It is quite tricky to explain so I would like you to see the example below which it will make you clear about what I say.
Assumption for the calculation: No losses
7” casing shoe is set at 5000’MD/4500’TVD
7” casing 23 ppf, ID 6.33 inch
4” drill pipe is used to drill the well and its ID is 3.34 inch.
4-3/4” drill collar is used as BHA and its ID is 2.5 inch. The length of drill collar is 500 ft.
This hole section is used water based mud and the bit size is 6-1/8”
Drill to section TD at 10,000’MD/9,000’TVD then drop carbide once TD is reached.
Pump output is 0.1 bbl/stroke.
Surface line from pumps to rig floor is 20 bbl.
Carbide is detected by a gas sensor on surface after 4,000 strokes pump.
With the given information, determine what is the hole size of the open hole section.
Learning about drilling fluids, mud pumps and conditioning equipment is required basic knowledge which personnel working on the rig must understand. In the old day, you may need to take a lot of time to learn this knowledge. Nowadays, Petroleum Extension Service publishes the book named “Drilling Fluids, Mud Pumps, and Conditioning Equipment” which will provide learners a lot of essential thing regarding drilling fluids, mud pumps and equipment. Today, I would like to review this book so you will know what inside and what you will you get from it.
What will you learn from this book?
These are brief contents which you will learn from the book.
You’ve learned about pressure loss in the drill string from the previous topic (Pressure Losses through Drill String Calculation). The general coefficient for internal diameter of pipe does not account the inside diameter of tool joint.
The general coefficient equation is shown below:
Coefficient of The Bore of Drill Pipe and Tool Joint
To get the accurate pressure loss calculation, the coefficient of a section of pipe must be accounted for both the pipe ID and the tool joint ID.
In general, each 100 ft of pipe, there is appoximately 6.7 ft of tool joint length (6.7% of total length) and 93.3 ft of drill pipe (93.3% of total length). Therefore, the general coefficient for internal diameter of pipe can be derived in to this following equation:
