There are many factors which can affect the drilling performance starting from the drilling rig itself, down hole equipment, running parameters, formation type and many other issues. Understanding the entire drilling system can lead to provide guidelines and procedures to identify and manage the effecting drilling parameters which can result to improve overall drilling performance and reduce the drilling costs.
The drilling bit is among the master pieces in the drilling system which has to be planned, prepared, followed during operations and evaluated after operations to gather maximum of information in order to optimize next runs and operations.
Identifying and understanding of the limitations of the rig equipment help to get the maximum and minimum parameters variables that are available for the operations.
Solid control equipment
Poor solid control equipment can cause many problems:
- Bad functioning of the shakers can affect the cutting removal from the mud system which can lead to the limitation of the penetration rate.
- If solids are not removed effectively from the drilling mud, the drilling fluids can become very erosive which reduce the bit and down hole tool life resulting in shorter run lengths.
For these issues the shakers have to be checked. The vibrations have to be tested and adjusted to its working standards. The screens and mesh size have to be appropriate to the drilled formations.
Mud pump
The mud pumps drive the drilling fluids around the drilling system. According to the section depth and the bit hydraulics, the mud pump liner sizes have to be chosen to deliver the accurate flow rate required for the operations and resist to the pressure which can be reached when getting to the total depth of the section.
The drilling fluids have to be well conditioned for many reasons as balancing formation pressure, inhibiting shale reaction, transporting cutting to the surface, cleaning and cooling the bit.
Lost circulation material
Lost circulation material are used to cure the down hole losses which can be faced while drilling operations. They come in various sizes, fine medium and coarse. They are pumped in the well bore with different concentration according to the rate of losses. Pumping this type of products has to be well planned to avoid plugging the drilling bit which can lead pulling it out of the hole.
Surface gauges
Surface parameters gauges are the tools to gather information, monitoring and evaluate situation and react during the operations. Keeping these gauges in good condition is a crucial issue.
Bottom hole assembly (BHA) evaluation
BHA effects directly the drilling performance. Fitting the BHA with downhole motors (PDM or Turbine) can increase significantly the rate of penetration. Stabilizers and their positions in the BHA can adjust the tendencies of the BHA (dropping, building or maintaining). Rotary steerable motors can provide improved directional control while drilling extended reach wells or when the differential sticking will be a problematic.
Choosing the turbine or Low torque-high speed motor can be crucial to avoid premature damage to the drill bit. It can reduce the bit life and the run lengths due to the high revolution per minute delivered by such equipment.
Stabilizers can affect the tendencies of the BHA and the weight transmitted to the drill bit. Stabilizers can hang up leading to difficulties to reach the bottom of the open hole which can affect the gauge of the bit.
Evaluating Previous Bit Run
Evaluating the bit runs can help to improve the next runs and consequently drilling performance. Analyzing the bit dull grading and bit photos help to gather maximum information about the faced problems and hole conditions. For example if the previous bit is a PDC type and pulled with severe damage, roller cone bit with junk basket has to be run. PDC are not recommended for long reaming intervals or cleaning out junks.
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