This article demonstrates how to design the well trajectory in J-shape from the surface location to the required target depth (TD).
The surface location coordinate of Well-A is 6,543,065.00N 416,695.00E and the target is located at 6,542,213.00N 415,456.00E and the UTM zone is 31N.
Kick off depth = 4,200’MD/4,200’TVD
Planned build up rate = 2 degree/100 ft
Well profile = J-profile (build and hold)
The surface location coordinate of Well-A is 6,543,065.00N 416,695.00E and the target is located at 6,542,213.00N 415,456.00E and the UTM zone is 31N. Therefore, the surface and the target for Well-A can be illustrated is Figure 1. Continue reading →
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.
Nowadays, many wells required complex well trajectory plans in order to reach reservoir sections and some of complicated well paths (Figure 1) cannot be drilled with either rotary drilling assemblies or mud motors. In order to achieve the drilling goal, rotary steerable tools are usually selected.
Figure 1 – Complex Well Paths
While the precise mechanics might vary, each rotary steerable tool uses much the same approach. Running the rotary steerable immediately above the bit serves as a sort of replacement for a near bit stab (NB stab). Most tools use three blades close to the drill bit, which act as stablizers and move in and out. While the tool turns, the blade which is turning in the opposite direction pushes against the side of the hole, giving the necessary side force to create a curved hole while drilling.
When using a steerable motor, the adjustment of the well path a series of slide drilling and rotary drilling doesn’t give a clean smooth edge, but rather creates a hole with multiple sharp edges, and straight sections between them. A rotary steerable tool, on the other hand, does give a smooth curved hole. This makes the wellbore more stable, and less resistant when tripping in and out of the hole. With higher inclinations, a smooth curve makes for an easier job of running casing or logging tools. Continue reading →
Rotary drilling assemblies can typically control a directional of a well by having proper stabilizer placement. With this kind of drilling assembly, only inclination can be controlled and a well cannot be directionally oriented to required direction. In this article, it briefly describe how stabilizer placement can affect the well direction.
Rotary Build Assembly (Fulcrum Assembly)
When a drill collar is supported at both ends but not held vertically, its own weight causes it to sag in the middle. This phenomenon is used in rotary drilling assemblies to create the necessary side force at the bit to alter the angle (Figure 1).
A positive displacement motor (PDM) is one of the most popular tool for drilling a directional well. It works by boring downwards and pumping mud through the motor itself. As shown in figure 1, the bottom section of the motor has an adjustable bend housing.
Figure 1 – Positive Displacement Motor (Courtesy of Schlumberger)
Before the motor is run into the hole, a set-up process needs to be carried out
The bend will be adjusted according to the directional performance that the motor needs to achieve. This bend is only very slight, usually being under 2°.
The motor is hooked up to navigational tools, which are then calibrated, in order for the driller to see where the bend is pointing when drilling. These tools are known as measurement while drilling, or MWD, and are described in detail later in this document.
The other parts of the system will be adjusted to account for the required directional performance- the severity of this will depend on the drill design.