Achieving Predictable Operational Efficiencies
Philip Wade, Chief Operating Officer, Verdande Technology

As development of oil & gas reservoirs requires intensive, efficient drilling programmes, many operators are turning to 'Factory Drilling' for maximising drilling efficiencies to address wellbore-related Non-Productive Time (NPT) issues and for more optimally & faster drilled. The drive for speed is placing more stress on drilling equipment, especially downhole equipment. The article explains on predictive analytics as a solution to identify NPT issues like mud motor failure early that can help operators to minimise the risk and cost to operations and improve drilling efficiency by mitigating damage to downhole drilling equipment.

Operators are increasingly focused on maximising drilling efficiencies in land operations, and many are turning to factory drilling. While factory drilling helps isolate and address wellbore-related Non-Productive Time (NPT ) issues and allows for more optimally and faster drilled wells, the drive for speed is placing more stress on drilling equipment, especially downhole equipment. The more companies turn to factory drilling principles and the total volume of wells continues to increase, the more supply chain concerns are necessitating steps to mitigate damage to equipment. To address these issues, operators are looking for ways to reap the benefits of factory drilling while minimising the risks, and many are turning to predictive analytics as a solution.

Using predictive analytics to identify NPT issues like mud motor failure early can help operators to minimise the risk and cost to operations and improve drilling efficiency.

The Benefits of Factory Drilling
Factory drilling operations employ specialised rigs designed to maximise drilling efficiency and reduce drilling time and associated costs. These highly mobile units are optimised for rig moves and pad skidding, and are operated by experienced crews familiar with advanced automation technology.

Many oil and gas reservoirs require factory drilling to reduce the time and cost of drilling. For an oil company, Non-Productive Time (NPT) can account for USD 50,000 per incident, so while drilling efficiency delivered through factory drilling techniques is important, it is equally important to ensure that drilling operations continue uninterrupted to avoid the cost of non -productive time lapsed while operations are down.

Case Study
Factory drilling operations, for example, have reduced the average time to drill a well from 22 days to 7-9 days in Mexico. In Russia, a similar approach impacted drilling efficiency where drilling rate increased from 19 ,685 ft a month to more than 32,808 ft a month reducing time and cost. (Reference from a recent article of Drilling Contractor)

The article specified that better drilling techniques, such as factory drilling, account for significant time reduction in wells that 3 years ago might have averaged 30-35 days to drill a 10,000-ft vertical section and 10 ,000-ft horizontal lateral section and now might average 17-23 days.

Factory drilling is typically applied to high-volume operations with repeated well designs and known downhole risks where the same fit-for -purpose rigs and drilling techniques are used. One of the most significant benefits of factory drilling is that standardisation is allowing land operators to ‘engineer out’ common wellbore-related NPT issues such as twist off, differential sticking, mechanical sticking, and mud losses.

But even as wellbore-related NPT has less impact on the overall well operations’ drilling cost, operators are pushing the performance envelope across the entire drilling system, causing previously less common types of NPT issues to be the latest cost impact/performance barrier.

The Challenges of Factory Drilling
The development of many oil and gas reservoirs requires intensive, efficient drilling programmes focused on reducing time-based costs in economically marginal fields. Generally speaking, factory drilling supply chain issues with personnel and equipment, and premature equipment wear and failure thru driving equipment too hard or long to see continuous marginal improvement pose a major challenge to the equipment used in factory drilling.

While factory drilling helps isolate and address wellbore-related non -productive time (NPT) issues and allows for more optimally and faster drilled wells, the drive for speed is placing more stress on drilling equipment, especially downhole equipment. And the more companies turn to factory drilling principles and the total volume of wells continues to increase, the more supply chain issues are necessitating steps to mitigate damage to them.

One equipment-related form of NPT is wear and tear on downhole equipment, prompting the need for more robust tool sets, especially in regard to critical measurement while drilling (MWD) and mud motor systems. And of these two systems, it is mud motor damage which frequently is the limiting factor for further incremental drilling improvement in established factory drilling projects. One operator has noted that mud motor damage accounts for 35 percent of its NPT, and can cost USD 150,000 per incident.

Getting Ahead of Mud Motor Failures
By using predictive analytics such as case based reasoning (CBR), land operators can identify key indicators of potential mud motor failure early and take action before drilling operations are impacted or costly tool damage occurs.

In one mud motor damage/failure example, there are measureable early symptoms of damage sustained ahead of an outright failure that is observable using Mechanical Specific Energy (MSE), a well-established concept that links standard surface sensor measurements to downhole drilling performance. Sustained oscillation of MSE can be indicative of micro-stalling behavior down hole, which can result in pre-mature motor failure. These oscillations can be difficult to detect with the human eye but can be easily identified using properly designed and calibrated mathematical algorithms. Identification of operations currently exhibiting these symptoms enables real-time mitigation to prolong BHA life.

Companies with well-established factory drilling operations looking for continuous incremental improvement are beginning to understand the power of this approach and are leading the charge in using predictive analytics and CBR to stay ahead of downhole tool damage or outright failures, and others will need to follow suit to recognise the benefits this technology and approach provides as factory drilling becomes the prevalent drilling process or wherever downhole tool damage is the predominate NPT cost.

Using this mathematical approach with a CBR system, once the possibility of symptomatic mud motor damage has been identified, other failure modes (such as chunking, debonding, thermal fatigue, issues related to drilling fluids, or a plugged motor) can be determined and addressed before it affects operations.Using this approach, it may also be possible to link MWD tool failure to oscillating MSE, or similar damaging patterns, which then addresses another costly downhole component issue.

What Next?
There is tremendous opportunity for companies looking to break ground in shale plays if they understand the risks and how to effectively mitigate them. Many are looking at factory drilling as a way to tap into shale plays, and it is a technique that they can use successfully if they understand that continuous efficiency will require new technologies to assist in cost control and performance improvement. As they look to achieve that optimization, land operators can utilise predictive analytic technologies such as DrillEdge™ mud motor capability to monitor for the indicators of premature downhole tool damage, to quickly recognise the continuous improvement factory drilling provides to maximise their production.