Drilling Rig performance, challenges, requirements & solution to improve efficiency

A rig resembles to a factory which is manufacturing oil & gas well. Similar to a factory, a rig should have a systematic approach and plan to keep the factory running with minimum NPT.

Parameters which can be defined to evaluate performance of a machine is called efficiency. Efficiency is the ratio of the useful work performed by a machine or in a process to the total energy expended. In case of a drilling rig, the given energy is in the form of fuel, electricity, labor & time which can be equivalent to cost. Of other methods of efficiency definition, the benefit to cost ratio can be noted.

If we can find a way to exploit more from the rig in 24 hours, practically the efficiency is raised. One way to increase efficiency is to investigate deep into operation, point out and magnify hidden flat time. Flat time are the time that the rig is not operating as per program. The obvious flat time is defined as NPT and it is a loss of money to drilling contractors. NPT is usually recorded and reported to operator. However there are some tiny technical methods to increase rig efficacy by looking into hidden NPT. This includes the waste of time while tripping in cased hole due to not technically confident driller, time to rig up a cement head, time to make drill pipe stand, hook up or change an MWD Sensor, pick up drill pipe joint, makeup stand & rack back in derrick. These times are usually considered in drilling program time break down but in lots of cases with a proper management by drilling supervisor or toolpusher on the rig, the operation can be done parallel or SIMOPS. I have seen a lot of time wasted due to rig WOC, or driller is not brief about possibility of faster trip speed in cased hole, also precious time is wasted to prepare a makeup crossovers on top of each other to match the cement head thread. Although all these times are considered in the drilling program but lots of them are hidden NPT and could be done offline. That’s why the mentality have to change. To fulfill this, drilling engineers in office and experienced drilling supervisor should plan to do this SIMOPS to create a change in conventional procedures.

Performance teams usually bring in new technology, help for faster drilling and optimize operation. The concept of SIMOPS should shape up within performance team of operator or contractor and look at the procedures in a different way. Performance team along with drilling engineering team can think of many surface & downhole operation as pointed out earlier to improve rig efficiency.

To focus on the efficiency of the rigs, attention also should be given to some other subjects. There are four basic categories which can be pointed to improve rig efficiency.

  • Rig monitoring and control system
  • Rig Repair & Maintenance plan
  • Upgrading Rig by Mechanization & Automation
  • Training & upgrading Rig crew.


1- Rig monitoring and control system

The conventional rig monitoring system on drilling rigs is “drill watch”. This monitoring system usually gives the report from function and state of running machine. Usually drilling parameters can be read and monitored from this system. Due to lack of an integrated monitoring system, other rig parts have their own control panel in which the equipment operator should attend to machine is person and visit the machine for its performance. Most of the time the proper procedure for maintenance or function of the rig part is not followed by operator or mechanic, which in return will damage the equipment partially or permanently. Similar to mud logging, to monitor rig equipment like generators, water pump, traction motors & electronics, a network of sensors are hooked up to all running parts and data cables come to a junction box. The data is usually transferred from junction box to a computer with an umbilical cable. The data will be decoded from each and every sensor to show the equipment condition. With a proper software, the equipment running instruction and maintenance procedure can be valued in and it will alarm to operator the reason for maintenance on time. This intelligent software system will reduce the human error in maintenance process and R&M history of rig equipment is properly recorded.

The RMOS Rig Monitoring System on 4th Generation rigs and especially in offshore rig is piloted and currently is established in the place, which ultimately leads to lower R&M cost.


2- Rig Repair & Maintenance strategy

The cost of running a rig includes people & rig maintenance. If we can lower these cost, overall rig cost will be lowered.

Like all other functions of the rig, the rig R&M is researched and systematic approach toward implementing the R&M process on rigs has been established long back. But the problem in Iran is to start & sustain these systems. There are many R&M methods in industry which are known and selected by organizations, such as Breakdown Maintenance (BM) or Emergency Maintenance (EM), Preventive Maintenance (PM), Predictive Maintenance (PDM), Proactive Maintenance, Corrective Maintenance (CM), Total Productive Maintenance (TPM), Lean Maintenance (LM), Shut down periodic Maintenance (SDPM), Reliability Centered Maintenance (RCM), and Quick Response Maintenance ( QRM).

From all of the R&M structure above, none or just few has been poorly used in Iran drilling companies. Usually BM, CM, SDPM, QRM are utilized in Iran, and in some rare cases Predictive maintenance (PM) is followed by rig contractor. In BM, the part will not change until it breaks down and equipment stops working. In case of a top drive or draw work on a rig, this system is a disaster in which big NPT will be imposed to drilling company.  In Preventive Maintenance PM which is a proper method to be utilized by rig companies, the rig equipment & parts will be monitored, controlled, serviced, adjusted or changed  partially or completely to reduce delay or sudden broke down of the rig equipment.

The conventional method or maintenance was paper work and log book which after maintenance, the history is recorded in the log book and kept for many years. But finding the data and maintenance history was difficult in this method. Nowadays, few software are established in the market which is helping to record and promote equipment function on rigs. Iran is in early steps for developing this software, many land rig either use the log book or don’t have the maintenance history at all.

In Iran drilling industry many delays happen due to late procurement delivery. I have seen jack up rigs in Persian Gulf standby 2 weeks on fuel or 1 week standby to provide deep well sea water pump for them.

Continuous supply of parts to the rig is also a part of R&M Process. After 100 years of drilling industry in Iran, our rigs are still suffering from this issue. The pace of domestic manufacturers toward supply has been very slow and we feel the lack of spare part within the country today. Most of the time spare parts and redress kit is outsourced from the country. In many cases, due to late delivery & NPT of the rig, the quality of spare part may be sacrificed. Improper non-API parts may be installed on equipments which will in return shorten the whole equipment life. So, spare part manufactures also have to follow the standard, manufacturing procedures, and transfers of technology by means of Joint Venture with international manufactures. A good example of successful Joint Venture is Wetco-Gray with Iranian Partner which led to transfer of know-how, and by doing the right thing right, it lead to formation of WETCO Wellhead Company in Iran.

3- Upgrading Rig by Mechanization, Automation and Integration

Mechanization and automation are two options that continuously have been upgrading the rig function & its efficiency. Mechanization is considered the hardware part or mechanical interface of system while automation is the brain or software of these machines.

Most of Iranian rigs are Chinese sling shot & swing up type which are 1st of 2nd generation of land rigs. From the automation and mechanization point of view, these rigs at their best, are equipped with top drive and iron roughneck. But the industry is going toward rig automation by minimizing hand in jobs. For example they are eliminating hand of rig crew for pipe handling. From the moment the pipe arrives to rig until the pipe goes into the well, the worker wouldn’t touch the pipe. MPD system, Intelligent BOP, continues circulation system, automatized pipe handling machine, automated mud processing unit & etc. are the parts that industry is moving for.

It’s better to have new technologies as part of the rig permanently operated by trained rig crew, rather than installing an equipment then removing it from one well to another to rig it up again. Continuous circulating device, rotating head, MPD, UBD system are among the systems which can be attached to the rig.

Integration of drilling system is vital while automation. Rig parts are produced by different OEM. We should establish a system to listen to all of this different equipment language and integrate them in a common language. While automation, the rig functions should be linked with a proper integrated workflow.

The human will not be displaced by machine on high tech rigs. The human role on the rig would be more of monitoring and interfering while the equipment functioning or else, the safety of the rigs will be jeopardized. Parallel to building all these digital gadgets, the rigs should be accompanied by an analog filter so that human will decide to keep it in automated mode or manual mode.

Having said all of these about upgrading the rig, the contract model also should be modified to suit all the cost that rig owner want to invest on the rig.

4- Training & upgrading Rig crew

Optimizing total well construction crew is a goal to follow. This includes rig crew as well as service contractors who are helping in well construction, by training crew and systematic approach and procedure. The total required manpower to deliver a well can be cut by 30%.

In new R&M systems in cyber rigs, since the running condition & maintenance due is notified to the operator via a software system, Electrical Technicians (ET) are more in charge for controlling system and establishment of operational interface between mechanical and electrical parts of the rig. So, high caliber rig ET or properly trained rig worker which are multitask and are familiar to work with wired and atomized rig system are necessary.

Rig efficiency is about 75% in cases. It depends on skill & experience of personnel. Because mechanized equipment cannot operate without skilled operator. In many cases, a skilled rig worker’s decision and action can lower or increase the rig cost.

Due to lack of R&M department within contractor companies in Iran, there is no organization chart for this vital department and rigs usually are running based on effort of motorman, junior mechanic/electrician & senior mechanic/electrician with very poor support from the town. Due to no proper plan in place, rigs are usually waiting on repair or spare parts.

To conclude, the solution for promoting rig efficiency is to establish standards, procedures & systems in place for monitoring, repair, maintenance and training of rig & office crew in organizations.

Vahid Farahani

Senior Drilling Engineer

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