This is one of excellent training video demonstrating the drilling process from start at surface casing to completing of the well in less than 7 minutes. This would be a good tool to teach people about drilling in our oil and gas industry. We also provide video transcription in order to help learners understand the content easily. If you love this content, please feel free to share with your friends.
In order to properly design a completion, reservoir rock and fluid properties must be carefully taken into account because they directly influence on equipment selection. Reservoir properties (rock and fluid properties) which must be considered are as follows;
Permeability (k)
Low permeability formation may require fracturing operation to enhance production. The completion for tight formations must be able to withstand pumping pressure and allow fracking fluid and proppant to flow through.
Formation Strength
Unconsolidated formations are required to complete a well with a sand control completion; thus, a well can be produced without any damage to downhole and surface equipment.
Formation Pressure
Reservoir pressure directly affects the pressure rating on all completions because all components must be able to work under reservoir condition. What’s more, formation pressure will affect how much flow of the well can produce.
Formation Temperature
High reservoir temperature will quickly degrade some components, especially elastomer, and this will result in well integrity issues due to pressure leakage. This is one of the critical concerns in selecting the right equipment to work under high temperature conditions. Continue reading
Perforation is a special operation to crease an efficient communication path between a wellbore and a reservoir by creating tunnels. The effective paths allow reservoir fluid to flow into the well with minimum pressure loss (less skin as much as possible).
Perforation (Courtesy of Schlumberger)
The process of perforation involves lowering a perforating gun into a wellbore to a planned depth and energizing the gun to be safely fired. When perforating a well, shape charges are fired and then energy from the explosion will create tunnels through casing, and cement and then into a reservoir. Length and diameter of perforation hole are dependent on the objectives which will be discussed later. Figure 1 shows the cross sectional of perforation.
Figure 1 – Perforation Cross Section Ref:http://www.angelfire.com/wy/lisadenke/pictures/assorted_facts_pics/HES_perfs.gif
When tubing is freely suspended, it can be buckled by an upward force applied at the bottom of tubing. A section of tubing exposed to compression force will have a chance of being buckled. However, a part which is under tension will not face a buckle issue.
The neutral point is the boundary below which buckling can possibly be occurred and above which buckling will not happen.
Figure 1 – Wellbore Diagram with Tubing Buckling Due to Compression Force
Difference in temperature causes steel to contract or expand. If tubing is free to move, length of the tubing will be either longer or shorter due to thermal expansion. On the other hand, if the tubing is not free to move, there will be a change in axial force due to the temperature effect.
Figure 1 illustrates an increase in length due to heat and Figure 2 demonstrates a decrease in length because of cooling.
Figure 1 – Tubing Lengthen by Temperature Increase
Figure 2 – Tubing Shorten by Temperature Decrease
