Eni using lean well design, near-balance drilling, dual-casing technologies to ensure well integrity, improve pressure management in complex wells
By Jerry Greenberg, contributing editor
Angelo Calderoni is senior vice president, drilling & completion, for Eni’s E&P Division.
What are some of the main drilling issues facing the industry?
Besides the “business as usual” of efficiency and effectiveness targets, HSE is becoming the key metric to measure the health of drilling operations. Macondo has taught us a hard lesson: A big incident may jeopardize the survival of any operator. Granted a strong commitment to HSE, the industry keeps moving toward more and more challenging operating scenarios such as deepwater, ultra-deepwater, HPHT, remote locations and unconventional resources.
Has the Macondo blowout affected the way Eni conducts E&P operations in other regions of the world?
Macondo has affected the whole industry and moreover the overall public opinion. To this extent, the Gulf of Mexico blowout has affected the way Eni conducts its operations simply because we have to follow more stringent regulations, even though Eni’s procedures are traditionally conservative and its operational focus is primarily on conventional and low-risk assets.
For those wells that we deem critical, such as high-pressure, high-temperature, deepwater, etc, we closely follow the operations using a real-time drilling center located in San Donato Milanese, where the more appropriate and high-level competencies are available to support the operations run worldwide in our business units. We have further strengthened our vision that safety and performance has to go hand in hand. Eventually, safety is performance.
How are Eni in particular and the industry generally responding to these issues?
Eni’s drilling operations have historically focused on incident prevention. This has been achieved by addressing safety aspects through the well cycle, starting from the design phase. For example, Eni extensively applies its proprietary reduced-clearance well design – extreme lean profile, or x-lp, to ensure enhanced well integrity.
The x-lp is a new well profile consisting of a drastic reduction of the borehole size without affecting the diameter of the production casing and tubing size. In this case, the clearance value between casing and borehole remains constant at about 1.5 in. from surface to the bottom of the well.
Besides better cementing jobs, this allows for overall better hole quality and potentially more contingency casings per well. Moreover, drilling smaller holes permits improving drilling efficiency, thus reducing drilling time by 30% on average, with less impact on the environment thanks to the reduced volume of rock to be drilled.
The reduced-clearance x-lp is Eni’s standard for complex wells and, since 2010, is being applied in Kashagan development wells.
Also, the development of proprietary drilling technologies aimed at maintaining continuous mud circulation has demonstrated to be a key factor for safety and well control enhancement. The Eni near-balance drilling technology (e-nbd), based on the proprietary continuous circulation system, the Eni circulation device (e-cd), allows us to control and stabilize bottomhole pressure into small operating windows within narrow pressure margins, for example, in HPHT and deep offshore wells, by maintaining continuous mud circulation in the well.
With dozens of applications in the last five years, this technology is becoming another Eni standard for complex wells and a perfect companion to the reduced-clearance well design.
The availability of these technologies will have an impact on the way we drill our wells, just like it was when the top drive or the automatic steering drilling systems became available. Eni wants to continue to be part of this change, playing an active role in the technology development.
Eni is also working at developing additional and independent safety barriers in drilling operations on top of the conventional ones, such as blowout preventer and drilling mud.
In general, we are not only willing to take the best technology available in the market but also push the envelope by investing some capital expenditures on selected developments. Our 2010 R&D spending totaled more than US$358 million (€268 million).
It’s worth noting that two key safety-enhancing technologies have been field-tested in wells in Italy and Kazakhstan during 2011. In early 2011 we field-tested in Italy’s Val d’Agri field a new-to-the-industry downhole blowout preventer close to the bit aimed at containing influx into the well. This is a first successful attempt to have available an additional, independent dynamic barrier while drilling. In November 2011 a surface-controlled casing valve, to provide an additional static barrier in the well, was successfully deployed in a Kashagan development well. The last two examples prove our effort in working toward safer drilling operations.
Safety leadership is extremely important for Eni. This is ensured not only by technologies but by a wise blend of technologies, competence – for example, our people – and processes. Key positions of critical operations are usually assigned to Eni personnel rather than external consultants who may lack specific company culture. The best technical competence is usually deployed to ensure the most effective monitoring and control of critical operations. Insourcing rather than outsourcing is key for Eni to keep inside ownership and responsibility.
To capture the experience and lessons learned through years of technology application in the field, we have developed basic rules that we call the “10 golden rules for Eni drilling operations” that were broadly distributed within our drilling community. These practical and simple rules are just an example of how to preserve and spread the company’s professional culture.
In the post-Macondo world, the industry in general has reacted in a pretty fast and effective way by appointing several focus groups and by raising attention, especially on oil spill remediation. Regulators want to know the “what if’s” in case of potential disasters. The industry is reinforcing existing tools, for example, by increasing the number of available BOP rams or by developing well capping and containment equipment. Of course, as a diligent operator we are already cooperating on safety issues with other operators and regulators to keep raising the bar of drilling safety.
What technologies is Eni using in its global E&P efforts to meet the challenges you noted earlier?
Technologies that are able to raise the safety standard are a priority for Eni. I mentioned earlier the additional independent safety barriers and the continuous circulating systems. I would mention another Eni proprietary technology specifically developed for deep offshore scenarios, the deepwater dual casing technology (e-dwdc). This technology is applied while drilling the riserless phases in deep offshore wells, where the application of automatic drilling tools permits the drilling and running of the conductor pipe and surface casing strings in one single phase, thus dramatically reducing the time necessary to complete the riserless phases. The technology, which has been successfully applied in 20 wells so far, presents other important advantages relevant to safety because of the perfect verticality and stick-up of the subsea wellhead and the improved cementing operations.
Another recent initiative we are working on is an ultra-deepwater lean well project, based on the use of reduced diameter and weight equipment compared with current standards for deep and ultra-deepwater drilling. In the past, the industry has seen an increase in dimension, complexity and cost of offshore rigs and related equipment. Our vision is to reap benefits by downsizing the supply chain – riser, BOP and wellhead.
The benefits would be twofold. Current deepwater rigs could extend their operational capabilities to ultra-deepwater applications, and, given the same operating capabilities, future-generation rigs could have a leaner design compared with current rigs. It would mean more exploration and development opportunities at a lesser risk, which is driven by complexity, weight and cost.
Does Eni in particular and the industry generally rely on service companies to develop the technologies you need?
Eni relies on a 360° approach. Service companies are very important because they are the ultimate tool we have in our hands to develop ideas to the marketplace. Above all we are looking at good ideas to be developed. Wherever a good idea is generated, we are willing to transform it into an opportunity. Sources of good ideas are academia, internal expertise and, of course, service companies. We own quite a number of proprietary drilling technologies that are the result of this approach. Of course, we understand this is far from panacea; different companies may rely on different strategies to feed their technology needs.
What are some technologies or solutions to drilling and completion challenges that you wish you had but are not yet available to the industry?
There are several “dreams” we own. Probably the most ambitious is full drilling automation. But we know some dreams can become reality. For example, we started in the early ’90s the funding of the R&D project that developed the first automated steering tools, including the rotary steerable system and straight-hole drilling system, which are now applied worldwide in the oil industry. It’s a standard that changed the way of drilling complex wells, and a dream come true.
Are there any other issues or challenges facing Eni or the industry?
At Eni we are stepping into a growing drilling activity scenario. This is a challenge because it will be necessary to ensure that we have available internal and external competencies at the highest level. It is important that a best-in-class criteria is followed for the selection of the service and drilling contractors. Our approach is don’t look at service cost but at the overall well cost. We believe this ensures the right quality level is in place, especially in the challenges we mentioned above, within a continuous improvement process.
x-lp, e-nbd, e-cd and e-dwdc are trademarks of Eni.