The drilling console contains the analog and digital gauges used to monitor the key parameters required for efficient drilling and effective well control. It also has four chart recorders for monitoring pit level, drill pipe, penetration rate and casing pressures.
A detailed description of the various components of the Drillers Console is as follows:
- Weight Indicator: A large-scale face indicator calibrated to 500,00 lbs. The second dial with expanded sensitivity is utilized to indicate weight-on-bit. Operator can zero set second dial.
- Weight-On-Bit: Digital readout of actual weight-on-bit.
- Rotary Torque: A circular 4″ face gauge that measures rotary torque with a scale of 0 to 1,000 amps.
- Tong Torque: A circular 4″ face gauge that measures make up or break out torque.
- Return Mud Flow: A circular 6″ face gauge that measures the return in the flow line from the well with a scale of 0 to 100%. It consists of high and low set controls with 2 visual alarm indicators, a level adjust and a power on/off switch.
- Rotary Speed (rpm): A circular 4″ gauge that measures the rotary rpm with a scale of 0 to 300 rpm.
- Mud Pump 1 (spm): A circular 4″ gauge that measures the pump stroke per minute scaled for 0 to 200 spm.
- Low Pressure Select: A Circular 4″ gauge that can be selected to measure casing pressure or drillpipe pressure, scaled at 0 to 1500 psi.
- Mud Pump 2 (spm): A circular 4″ gauge which measures the pump strokes per minute, scaled at 0 to 200 spm.
- Stroke Counter: A digital readout of total elapsed strokes with reset and run/hold control.
- Drillpipe Pressure: A circular 6″ gauge that measures drillpipe pressure. Scales are combined in psi and kg/cm². These scales are 0 to 5000 psi and 0 to 350 kg/cm².
- Mud Weight Indicator: A digital indicator that measures return mud weight.
- Casing Pressure: A circular 6″ gauge that measures casing pressure. Scales are combined in psi and kg/cm². These scale are 0 to 5,000 psi and 0 to 350 kg/cm².
- Deviation Mud Volume: A circular 6″ gauge that measures the increase or decrease in mud volume. It consists of high and low level set controls with two visual alarms.
- Mud Volume Totalizer: A circular 6″ gauge that measures the total mud in the system with a scale of 0 to 1,000. A power on/off switch and four mud tank switches are provided so the student can add or subtract mud from the system.
Note: For mud volume Totalizer to become operational, the on/off
switch must be in the “ON” position.
- Stand Tally: A digital readout that displays the total number of stands in the hole.
Note: Each stand is equal to 90 feet.
- Stand Tally Control: A one-turn control that will allow the student to decrease the number of stands in the hole.
Note: When participating in well control exercises with bit on bottom, this control must be in the fully clockwise direction to indicate bit on bottom.
- Chart Recorder: There are four two-pen chart recorders that can be used for a permanent performance record.
- Trip Tank: 4″ circular gauge that measures the total number of barrels of mud in the trip tank.
- Stripping Tank/Trip Tank: A two-position switch that allows the student to select either the stripping tank or trip tank.
- Stroke Counter: A digital readout of total pump strokes.
Note: Cement pump strokes will be read on this digital readout.
- Trip Tank Pump: A push button illuminated switch that allows the student to enter mud into the hole. This switch will become illuminated when stands are removed from the hole.
- On/Off Switch: A switch allowing the geolograph to be turned on or off.
This section provides additional thoughts and considerations concerning solids-control equipment. The practical operational guidelines for equipment discussed here may not apply to all drilling applications. These guidelines (in italics) were developed as part of API RP 13C. The discussion beneath each captures some of the comments by committee members as they debated the guideline before approval.
Continue reading “Solids-control equipment guidelines – Surface Systems”
2. Auxiliary tank system-Trip Tank
A trip tank should also be a component of the tank system. This tank should have a well-calibrated, liquid-level gauge to measure the volume of drilling fluid entering or leaving the tank. The volume of fluid that replaces the volume of drill string is normally monitored on trips to make certain that formation fluids are not entering the well bore. When one barrel of steel (drill string) is removed from the borehole, one barrel of drilling fluid should replace it to maintain a constant liquid level in the well bore. If the drill string volume is not replaced, the liquid level may drop low enough to permit formation fluid to enter the well bore due to the drop in hydrostatic pressure. This is known as a kick. Fluid may be returned to the trip tank during the trip into the well. The excess fluid from the trip tank should be returned to the active system across the shale shakers. Large solids can come out of the well and plug the hydrocyclones if this drilling fluid bypasses the shakers.
The addition of trip tanks to drilling rigs significantly reduces the number of induced well kicks. The obsolete or old-system drillers filled the hole with drilling fluid with the rig pumps by counting the mud pump strokes (the volume was calculated for the displacement of the drill pipe pulled). The problem here was that a certain pump efficiency was estimated in these calculations. If the mud pump was not as efficient as estimated, slowly but surely the height of the column of drilling fluid filling the hole decreased. This caused a decrease in hydrostatic head, and if formation pressures were greater than the hydrostatic head of the drilling fluid, a kick would occur.
Another common way to induce a kick was to continue filling the hole with the same number of strokes used for the drill pipe even when reaching the heavy-weight drill pipe or drill collars were pulled. Both the heavy-weight drill pipe and the drill collars have more displacement per stand than the drill pipe; therefore a reduction in the height of the column of drilling fluid in the well bore would occur and problems would result.
3. SLUG TANK
A slug tank or pit is typically a small 20- to 50-barrel compartment within the suction section. This compartment is isolated from the active system and is available for small volumes of specialized fluid. Some drilling-fluid systems may have more than one of these small compartments. They are manifolded to a mixing hopper so that solids and chemicals may be added and are used to create heavier slurry to be displaced partway down the drill pipe before trips. This prevents drilling fluid inside the pipe from splashing on the rig floor during trips. These compartments are also used to mix and spot various pills, or slurries, in a well bore. The main pump suction must be manifolded to the slug pit(s).
Proper agitation is needed for this tank because there will be many different types of slurries mixed during drilling operations. Some will be easy to mix, while others will take a lot of energy to mix properly. The addition of a mud gun or guns would be beneficial in mixing various pills as well as keeping solids from settling in the bottom or corners of this tank.
4. RESERVE TANK(S)
The reserve tank(s) are for storage of excess drilling fluid, base fluids, or premixed drilling fluid for future mixing/additions. It could even be a completely different type of mud system for displacing the existing drilling fluid.
Land drilling rigs do not have reserve tanks in their systems. Extra tanks are rented as needed for their operation. These tanks are typically called fractionalization (frac) tanks.
Marine drilling rigs incorporate reserve or storage tanks in their design. The volume and number of these tanks depend on the space available and the available deck load capabilities of the rig. If more storage volume is required for marine drilling rigs, extra storage tanks can sometimes be installed on deck depending on space and deck load availability.
The type of drilling fluid stored in the reserve tanks will dictate whether it needs to be agitated. Since the type of fluids stored will vary, adequate agitation should be available if required.