Accurate and reliable indications of hook load and weight on bit are essential to drillers for the efficient control of ROP and hole direction. The hydraulic deadline anchor type weight indicator is a standard of the industry. A weight indicator is a relatively large analog gauge with two pointers. One pointer is main reading and second one is vernier which indicates readings in smaller units. Vernier can be set to indicate weight on the bit while drilling. Here any weight shown from zero down on Venier which is white pointer usually are Weight on bit and any weight above zero upwards is the amount of over pull above string weight when we set venier zero on actual string weight.
The Weight indicator dials are different for different number of lines reeving on Travelling Block, so it needs to be changed accordingly or else reading will be wrong.
Weight indicator are designed to work in conjunction with all industry-standard deadline anchors using either tension or compression hydraulic load cells. These load cells are sensors for weight indicator mounted on Dead Line Anchor. Indicator systems are supplied as panel-mounted as part of a driller’s console. Each system accurately senses tension in the deadline and uses this to indicate hook load and weight on bit. Many models have separate pointers for both hook load and weight on bit. In addition, integral circular hydraulic recorders are also offered on several models. It has needle-type dampers to eliminate hydraulic shock loads and extreme pointer oscillation during rough drilling or jarring operations.
Single Line Weight Indicator
The Single Line Weight indicator provides wireline service trucks with a sensitive, accurate device for measuring loads; helps prevent loss of valuable down hole tools.
Rotary Torque Indicators
The rotary torque indicator displays torque on a rugged panel or box-mounted meter calibrated in either foot pounds or metric equivalents. Installation is simple. The split core transducer is clamped around the power cable that leads to rig’s electric motor. This will enable the transducer to sense the current the motor draws, which is proportionate to that required by the rotary table, and transmit the signal to the dual output signal conditioner. The conditioner will then convert this signal to an accurate reading on the electric meter.
This dual output signal conditioner will also drive a drilling recorder or data acquisition system. It is Simple in design because there are no moving parts to wear out. Split core transducer measuring electrical current to the motor clamps around power cable. Multi-scaled meter provides readings for different gear selections.
Similarly for Chain driven rotary from Draw works, the current drawn in amperes are converted to torque in respective units. For mechanical rigs where no Electric motors are used , a different type of sensor is used to get the rotary torque.
RPM -Rotary Speed Indicator with Tacho-generator
It provides an accurate indication of rotary speed. It helps driller select optimum speed for faster penetration. The Generator can be directly coupled to any shaft turning in direct proportion to the rotary table or V-belt driven. The systems available for either panel or box- mounted meters.
TONG TORQUE: This is obtained by multiplying the pull exerted on tong by the arm length of the tong. Unit in Metric system is kg.m ( kilogram meter ) and in British system is ft.lbs ( Foot pounds ).
SPM ,Pump Speed Indicator
Measures pump speed Stroke Per Minute. The system is self powered by generator (supplied), which can operate any number of meters. It needs no outside power or batteries and generators have explosion proof ratings. the generators are easily mounted with direct connection to pump pinion shaft, piston rod oiler, or as an idler wheel to the V-belt driving the oiler. Alternatively widely used type is a electronic sensor fitted on the walls of the pump piston rod chamber and it has a rod mounted on it. Each time piston moves front , it taps on this rod which make sensor to sense one stroke and this is converted into SPM on an analogue meter or a digital counter.
Rugged E17-152 Diaphragm, Protector mounts with 2” NPT sub,hose lengths to 50 feet are standard; longer lengths available in different pressure ranges.Analog indicator can now be displayed more accurately and reliably using the Digital Gauge.
FLOW LINE SENSOR
This is to measure the return flow from the well through flow line while well is on circulation. So this gives an idea on increase or decrease of flow which indicate a kick or mud loss condition.The standard flow sensor is the potentiometer paddle type. This sensor is mounted in the return flowline between the bell nipple and the shaker as close to the bell nipple as possible. The paddle is deflected according to the rate of flow and is usually calibrated in percentage flow (100% would be full deflection of the paddle). Should mud density or viscosity change greatly, the deflection of the paddle can be adjusted (requiring re-calibration) by changing the position of a counter weight.
Pit Volume Totalizer or Mud Volume Totalizer ( PVT/MVT)
Mud Pit Level Indicator
This will measure the volume of mud in each tank and will be fed into a Mud Volume Totalizer ( MVT or PVT- Pit Volume Totalizer). The level in each tank of the active system is continuously compared to a preset value. Any change in level trips an audible alarm and is also shown on the display (analog or digital) on the Driller’s console
One of the most common indicators has a float that sends a signal indicating its position on the surface of the fluid from a base starting point.
The two types of indicators used most often are:Pneumatic or Electric
Newer Sensors are using Ultrasonic Source which reflected the surface level of the fluid in the mud pit.
Drill Watch: This is a comprehensive display & recording of rig instrumentation in one system.
- A recorder may be mechanical or electronic. A mechanical recorder is often called a Geolograph. In today’s drilling world, an accurate correlation of drilling conditions related to time is essential to efficient operations. Drilling Recorders gives duplicate 12-or 24- hour strip charts that are available in English, metric, or SI metric measurements. Recorders are available in 2- 4- 6- and 8-pen configurations. All recorders include drill string weight, penetration weight, and other parameters as follows:
Weight – This measurement is sensitive enough to detect downhole problems such as tight hole or cave-ins as they occur.
Penetration – This parameter is indicated on the English chart by a short mark for each foot drilled and a longer mark for each five feet. On metric charts, indications are at ¼ and full meters.
Rotary RPM – Indicates the revolutions per minute of the rotary table, an important function for optimum penetration.
Torque – Shows electric or hydraulic rotary torque changes during drilling that inform the driller of formation transitions, worn bit, and tight or out-of-gauge holes.
Pump Rate SPM – Permits accurate calculations of fluid volume pumped into the circulating system. Comparison of pump rate, fluid pressure, pit level, and flow could help predict kick areas for offset wells.
Stand Pipe Pressure – Provides an accurate record of fluid system pressure. Changes in pressure indicate potential washouts, kicks, plugged bits, or numerous other downhole problems.
- The standardized driller’s consoles includes single, double and triple bay arrangements. Instrumentation can be selected in a variety of configurations like gauges to measure critical rigsite weight, force, pressure and speed parameters. Advanced system displays can be offered for those requiring expanded information monitoring and analysis. At a driller’s console a driller can choose from a broad selection of gauges, controls and data acquisition devices to measure and control:
- Bit and hook weight,
- ROP and depth
- Rotary RPM and torque
- Pump pressure and speed
- Mud gain/loss and flow
- Mud temperature and density
- Total hydrocarbon gas, as well as many other important rig parameters