Mud motor failure downhole may be happened from time to time. The questions that are usually raised are things like “How do I know if the mud motor fails down hole?” and “What indications will I see that this has happened?” etc. Due to this, I would like to share my personal experience regarding mud motor failure and its symptoms.…
Added by Rachain Jetjongjit on May 7, 2012 at 1:30am —
Drilling waste minimization is a method to reduce any waste generated from drilling operation. The ideal goal of it is to generate zero residue requiring final disposals. People have developed technologies for two main reasons which are project cost reduction and environmental protection.
Typically, the drilling waste minimization starts with reducing amount of drilling waste, recycling and recovering waste… Continue
Added by Rachain Jetjongjit on April 22, 2012 at 10:30pm —
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… Continue
Added by Rachain Jetjongjit on March 13, 2012 at 10:30pm —
I’ve got an email asking me about how to figure out the total bit revolution (RPM) at down hole when the mud motor is used in the drill string and rotating at surface is also conducted.
There are two components contributing in the total… Continue
Added by Rachain Jetjongjit on February 6, 2012 at 7:00am —
Cutting slip velocity
is velocity of cutting that naturally falls down due to its density. In order to effectively clean the hole, effect of mud flow upward direction and mud properties must be greater than cutting slip velocity (settling tendency of cuttings).
Otherwise, cutting will fall down and create cutting… Continue
Added by Rachain Jetjongjit on September 2, 2011 at 10:00am —
increases over depth (the more a well is drilled, the more overburden stress will be seen). When mud weight is not enough to support the overburden, the stress from the overburden will create shale fractures which will fall down into the wellbore. Finally, shale fractures will pack the wellbore and cause a stuck pipe incident,
(Mud weight is high enough to overcome overburden stress.)…
Added by Rachain Jetjongjit on August 12, 2011 at 9:30am —
Pore pressure in shale is more than hydrostatic pressure; however the well does not flow because shale is in permeable. While drilling through pressured shale formation, pressure in shale causes fractures of shale due to stress crack.
Shale finally falls into the well and results in stuck pipe
Added by Rachain Jetjongjit on August 11, 2011 at 8:30am —
I update some useful drilling formulas into the drilling formulas spread sheet called version 1.1.
Please feel free to download.
Added by Rachain Jetjongjit on May 17, 2011 at 10:00pm —
Cement volume calculation is based on annular capacity multiplied by length of cement as per cement program.
This topic will demonstrate you how to determine cement volume as per specification and displace volume. After reading and understanding the concept, you will be able to apply to your cement job.
The knowledge required:… Continue
Added by Rachain Jetjongjit on May 16, 2011 at 9:30pm —
Kill Weight Mud or Kill Drilling Fluid Density is the mud weight required to balance formation pressure. The kill weight mud may be pumped into the well at different time depending on kill methods (Driller’s method
, Wait and Weight,
Bull head, etc). …
Added by Rachain Jetjongjit on May 15, 2011 at 10:00pm —
Drilling mud has several important functions and one of them is hole cleaning which I will discuss today. Transporting cutting from the wellbore is fundamental part of drilling operation and you will not be able to successfully drill the well if you do not pay attention to this basic concept.
Nowadays people have more focusing on new technology about drilling mud and try to improve drilling fluid properties to achieve hole cleaning because many wells drilled in the world are more… Continue
Added by Rachain Jetjongjit on April 24, 2011 at 10:00pm —
This is an electronic version (Excel sheet) of trip sheet from drilling formulas blog. The trip sheet can be used for both trip in hole and trip out of hole.
Please check out this link below to download.
1. When you open the file, you will see the screen like this.
2. First of all, you need to input pipe… Continue
Added by Rachain Jetjongjit on April 24, 2011 at 10:00pm —
pH is a value representing the hydrogen ion concentration in liquid. We use it to indicate acidity or alkalinity of drilling mud especially water base mud. Let’s talk about general of the pH. The pH is presented in a numerical value (0-14) which means an inverse measurement of hydrogen concentration in the fluid.
The pH formula is listed below;…
Added by Rachain Jetjongjit on April 14, 2011 at 9:00am —
Total Flow Area (TFA) is summation of nozzle areas which fluid can pass through. When you consider about the TFA, you need to count all nozzles that you have in a bit or a reamer.
Basically, you can determine flow area with a simple circle area formula.
in square inch…
Added by Rachain Jetjongjit on March 23, 2011 at 9:30pm —
I got a question about how an anticline gas cap can create the abnormal pressure. The anticline with gas cap can be the potential high pressurized zone.
Because of reservoir connectivity between fluid underneath gas and gas reservoir, it can generate abnormal pressure. This example below demonstrates you how this situation could… Continue
Added by Rachain Jetjongjit on February 1, 2011 at 9:30am —
The solid content in the drilling mud has several operational impacts on drilling operation as listed below;
Equivalent Circulating Density (ECD)
– The ECD will be higher if the solid content increases, regardless of whether High Gravity Solid (HGS) or Low Gravity Solid (LGS). As you may know, excessive ECD will lead to formation fracture and a loss circulation issue.…
Added by Rachain Jetjongjit on January 16, 2011 at 9:00pm —
I got the question from my friend, Nien, asking me about directional drilling calculation and the question is shown below:
Wellplanner is planning to design a deep kick-off well with a build section to by pass a salt dome section. He intends to achieve a horizontal departure of 1500 ft at the with the TVD at the target point to be 10,000 ft. Calculate the measure depth and build up rate.
Added by Rachain Jetjongjit on January 11, 2011 at 9:00pm —
Solid content is a fraction total solid in drilling mud, and it always increases while drilling ahead because of drilling solid (cuttings), mud chemical additives and weighting material. When we talk about the solid content, we always mean soluble and insoluble solid content in the drilling fluid system.
There are three types of solid contents as listed below;
- Soluble material such as salt
Added by Rachain Jetjongjit on January 10, 2011 at 8:30pm —
Newtonian fluid model is the simplest rheological model. Let’s describe in the mathematical way, a relationship between shear stress (lb/100 ft2) and shear rate (1/sec), named a consistency curve, is a straight line which passes through the original (see the figure below).…
Added by Rachain Jetjongjit on December 20, 2010 at 1:30am —
The gel strength is the shear stress of drilling mud that is measured at low shear rate after the drilling mud is static for a certain period of time. The gel strength is one of the important drilling fluid properties because it demonstrates the ability of the drilling mud to suspend drill solids and weighting material when circulation is ceased.
How can we get… Continue
Added by Rachain Jetjongjit on December 12, 2010 at 11:30pm —