At‑source drilling waste treatment as a lever for offshore performance
Key highlights:
- Traditional skip and ship methods are operationally dependent on weather, vessel availability and logistics, increasing risk and costs.
- At-source thermal treatment technologies enable onsite processing, recovering base oil, reducing transport needs and lowering environmental footprint.
- Case studies demonstrate potential savings of more than $18 million and a 60% cost reduction per well when using offshore processing solutions.
- Weather delays can cost more than $650,000 per day, making efficient waste management critical to minimizing downtime and expenses.
By Andrew Morris, TWMA
In today’s offshore environment, every operational decision is under increasing pressure to maximize performance while minimizing cost, with operators scrutinizing every part of their operations to find efficiencies and recover value.
A new generation of engineers and decision-makers are taking a more detailed, efficiency-led approach, challenging incumbent practices and examining how each contributes to overall performance. That means looking more closely at areas such as drilling waste management—something required on every drilling project but not always prioritized as a source of optimization.
Drilling waste management has a far greater impact on offshore performance than it’s often given credit for. When approached strategically and with the right application of technology and expertise, it can, first and foremost, improve safety. At the same time, it can significantly reduce costs versus alternatives, improve environmental performance and enhance operational efficiency.
So, what does this look like in practice? It starts with taking a realistic view of how established approaches perform and what alternatives are available.
Rethinking the default
Offshore, a typical approach to tackling drilling waste is skip and ship—collecting drill cuttings into skips on the rig before transporting them by vessel to shore for treatment and disposal. It is a well-understood solution that ensures minimum regulatory compliance, but it also introduces a number of operational considerations and dependencies.
In practice, the approach is tied to the availability of skips, cranes, vessels and suitable weather windows. Each of those factors introduces risk, therefore, where those dependencies can be reduced, so too can the handling, logistics and potential disruption that comes with them.
However, offshore operations are complex and highly case-specific. In some situations, skip and ship could be an appropriate option but, like any other part of the operation, can be optimized.
Case studies using an at-source alternative
In other cases, at-source treatment offers a practical alternative that can substantially outperform traditional approaches across safety, cost, environmental and overall operational efficiency factors.
By processing drill cuttings on site using thermal technologies, such as TWMA’s RotoMill, the need for transport is removed altogether. At the same time, base oil is recovered for reuse onsite, while treated water can be discharged and recovered solids made inert for safe overboard disposal, all within regulatory limits.
In one UK Central North Sea campaign, cuttings were treated at source during a two-well development drilling program on a jackup rig, where drilling, production and fracking operations were carried out simultaneously.
The approach resulted in:
- Recovery of about $444,000 worth of base oil;
- Eliminated more than 7,800 lifting operations; and
- Generated an overall saving in well costs of about 35%.
This was driven by the removal of skip and ship logistics, including vessel and crane activity, avoidance of about 2.5 days of weather-related downtime during winter operations and continuous offshore processing of more than 3,100 tonnes of drill cuttings with zero downtime.
These benefits are seen across both single and multi-well campaigns and in a range of operating environments.
A similar principle was applied on a project in the Middle East. On one of the UAE’s largest fields, more than 50,000 tonnes of accumulated legacy waste, including conductor drilling waste and slop waste built up over several years, were processed at source in a remote and logistically constrained operating environment.
The program resulted in:
- Elimination of more than 5,700 km of transportation;
- Significantly reduced handling and logistics requirements; and
- Reduced emissions by about 50%.
Combined with the recovery of about $1.5 million worth of base oil for reuse, this contributed to total savings of about $18.5 million.
Coupled with these substantial savings, in an environmentally conscious operating environment, reducing vessel movements is one of the most direct ways to lower the overall footprint of drilling waste management. Additionally, in the current context of rising fuel costs, reducing reliance on vessels delivers another clear operational and cost advantage.
Seeing the full cost of the well
So why is offshore processing not the default in every case? One reason is that the wider benefits are not always clear at the point of decision-making, particularly when they sit across different teams and budgets.
From a drilling perspective, the focus is on generating maximum value at the wellsite and delivering as efficiently as possible, so a simple solution such as a conveyor, a few skips and a way of getting cuttings off the rig may seem sufficient.
However, this can overlook the wider operational and commercial impact. When viewed on a total cost of ownership basis, what appears at face value to be a low-cost solution can drive additional vessel demand, increase fuel usage, and lead to more handling and higher onshore processing costs.
When brought in early, specialist drilling waste management offers a more consultative approach, bringing a full operational and commercial view that connects these factors and ensures decisions are made on the true cost of the well.
Another hidden factor is delays caused by weather. Because drilling waste must be physically moved off the rig using cranes and vessels, operations are dependent on safe operational weather conditions. A single day of delay can cost more than $650,000, and in areas such as the North Sea, particularly in winter, those are frequent. Based on a 24-hour operating day, that equates to roughly $27,000 per hour, meaning even short delays or reduced drilling rates can quickly run into six figure costs.
A total cost of ownership model is the clearest way to show this. Offshore processing solutions, such as the RotoMill, can deliver savings of up to 60% compared to traditional skip and ship methods when assessed on a like-for-like basis, using standard day rates and incorporating the full cost of installation materials and personnel, offshore equipment, operational personnel, drill cuttings processing, skip hire, transport, quayside handling and port fees.
When these factors are fully accounted for, along with base oil recovery and exposure to weather-related delays, the cost differential becomes clear. For a typical 60-day well, total costs for skip and ship can reach about $1.24 million, compared to about $510,000 for offshore processing.
Key takeaway
The scale of these savings underscores the role drilling waste management can play in overall project performance. As an unavoidable part of drilling operations, it should be approached with the same focus on efficiency and optimization applied elsewhere on the rig.
In a landscape where every element of offshore operations is under scrutiny, at‑source processing using thermal treatment technologies offers a practical pathway to reduce costs, lower emissions and deliver measurable improvements in safety and operational performance.
About the Author
Andrew Morris
Andrew Morris is TWMA's group commercial manager, a position he has held since October 2025. He has been with the company, in various management roles, since August 2016.
His previous experience includes engineering and management positions with Halliburton and Step Oiltools.
He has a bachelor's degree in mechanical engineering from Edinburgh Napier University.
Morris is currently based in Abu Dhabi, UAE.