Developments also under way to further increase reservoir contact, reduce interventions, and enhance monitoring & flow control capabilities
By Joanne Liou, associate editor
Compared with drilling, completion has come to account for an increasing percentage of total well costs in recent years. What are the main factors driving this cost increase?
The percentage of costs varies depending on the operating environment, reservoir type and geography. With ever-increasing water depths, more complex reservoirs and increasing stage counts in the unconventionals, I can see that completion costs have increased as a percentage of total well cost. Drilling efficiency has also improved, lowering associated costs, while the completion has become more complex.
However, our focus has been on providing technology that would ultimately lower the cost of the equivalent barrels produced while improving customers’ return on investment (ROI). One way this will be achieved is by connecting the reservoir to the completion, increasing reservoir contact through zonal isolation, monitoring the reservoir and having full flow control of the particular intervals completed.
Standardization of the completion and improving completion operational efficiency are also areas we are focusing on to improve customers’ hydrocarbon time-to-market and, ultimately, ROI.
In what ways can completions be improved to increase ultimate oil recovery?
Recovery varies significantly depending on the reservoir and the cost associated with interventions. Today we see 20% to 30% as generally accepted recovery rates for oil reservoirs. I believe a step-change in recovery can be realized by increasing reservoir contact, depending on the reservoir type. This can be achieved in different ways. In unconventional plays, it will be by placing the fracture in the right spot to maximize production and recovery and then be able to potentially and easily access the well again to re-fracture at a later stage.
We have the capability today, in complex reservoirs, to isolate or segment the reservoir into several intervals, and this could be 10, 20 intervals or even more in one well, in which pressure, temperature, flow rate and water cut can be monitored. This is a fully integrated system where each isolated interval can be controlled in real time as needed to optimize production and recovery. This will include multiple zonal isolation, monitoring and control in the motherbore and in the laterals. It allows real-time evaluation of the producing intervals and full control of the production of each interval remotely.
Open-hole sand control techniques, which is an increasing completion methodology, utilizes technology like the OptiPac Alternate Path system with internal selective in-flow control devices to enable extended-reach drilling in unconsolidated formations.
Another key area to consider is enhanced oil recovery (EOR) techniques. This needs to be approached from the field level. It’s important to have upfront reservoir modeling and simulation, followed by field trials all the way to full field implementation. Injection fluid chemistry and fluid properties are also important and require customization depending on the reservoir properties and applications.
Close collaboration between operations and domain support teams ensure correct fluid selection. Downhole permanent monitoring provides temperature, pressure and distributed temperature- sensing measurements in real time, providing information for multiphase conformance monitoring. Managed actions can then be planned to ensure optimal EOR field performance.
Schlumberger has deployed more than 8,000 permanent downhole pressure and temperature gauges in the past 20 years. WellWatcher BriteBlue harsh environment multimode fibers are the latest generation of these and are regularly deployed into thermal EOR fields to monitor well and field performance.
The key to all of these techniques is to apply domain knowledge and link the completion to the reservoir. By designing the integrated completion to allow optimum production and recovery factors, we are confident that we can essentially slow the decline curves of our customers’ reservoirs.
In the shale plays onshore, industry continues to set records with the number of fractured stages per well, but what further improvements are needed to improve the efficiency and to maximize production?
Studies have shown that today, many of the completed intervals in the shale reservoirs do not contribute to production. Domain knowledge and developing evaluation workflows to optimize hydraulic fracture placement and design can help maximize production and reduce operational cost. We have seen in recent developments where our engineered stimulation designs helped an operator, for instance, achieve a three-fold production increase with 50% less fracturing fluid.
Further to the evaluation and fracture design workflow, we are developing methods to allow for a more surgical approach to fracturing, placing the hydraulic fracture exactly where you want it with the capability to hydraulically fracture as many zones as needed with no interventions required post-fracturing. This is all done in an environmentally conscious manner with greener fluids, minimal fluid and proppant, and with a smaller wellsite footprint.
In many cases, if you go through our Mangrove engineered stimulation design in the Petrel E&P software platform with the proper data input, you can actually lower your fracture stimulation cost because you may not be fracturing as many intervals. You may not be deploying as large-scale fractures as you may have previously without that level of knowledge. Even if you are fracturing more intervals, your recovery and additional production will more than return that investment.
The impact of drilling to wells these days can sometimes be secondary to completions and/or fracturing. Why is that?
The way the well is drilled is obviously extremely important, but the completion is becoming more important as the complexity of the reservoir increases and the need to improve production and recovery factors also increases. This can be seen in unconventional plays, for instance, where stage counts have increased from typically fewer than 10 to 40 or more. As technology will allow, operators will want the ability to complete an unlimited number of stages in unconventional plays to enhance overall well performance.
Of the perforated clusters in a typical unconventional environment, less than 50% actually gets stimulated, and about 70% of the production comes from only 30% of the perforated clusters. We are working on completion technology in unconventionals to improve performance. The type of fracture applied is evolving to optimize reservoir contact while also being environmentally friendly. Acquiring proper data and developing a representative reservoir earth model leads to more effective fracture placement and design. We are developing the capabilities to essentially surgically, hydraulically fracture the reservoir interval, which is delivering the hydraulic fracture exactly where you need it in order to optimize production and recovery.
The economic demands for deepwater and other complex environments are also driving technology to be able to extract more from the reservoir. In fact, more fields are becoming economic because of completions technology.
Intelligent completions, with the capability to isolate multiple zones in the motherbore and in multilaterals with full monitoring of each interval and flow control, is finally truly enabling the smart oilfield that was originally envisioned some 15 or more years ago. This can be accomplished through the use of inductive coupling technology with a single electric control line, which minimizes wellhead penetrations. This also changes the economics by having to drill fewer wells to efficiently produce a reservoir, and these fully integrated systems will improve the efficiency and reliability of deploying the completion.
How do you define the smart oilfield and intelligent completions?
The initial concept of a smart oilfield, which I think still applies today, is being able to have visibility of your production from your reservoir, being able to have that visibility in real time, in your office and then being able to remotely act on the reservoir interval by moving a valve or impacting production from a particular interval in the reservoir. In other words, to be able to have full monitoring and control of the reservoir remotely in real time. This requires accurate and reliable sandface measurements.
For intelligent completions, we have introduced a technology called IntelliZone Compact, which is a modular zonal management system, and it is the first fully integrated intelligent flow control system for multi-zone wells. It provides an efficient, reliable and cost-effective way to control wells on land or offshore.
This has brought intelligent completions to many applications around the world where it might have been too expensive or operationally prohibitive. Intelligent completion markets traditionally had been primarily focused on key producing areas like the Middle East or the North Sea, but we have already deployed IntelliZone Compact modular multizonal management system in Europe, the Middle East, Africa and South America.
How far is industry from realizing the smart oilfield?
We have technology today to make it a reality. We have sensing technology, where in various isolated intervals throughout the reservoir we can measure pressure, temperature, flow rate and water cut, effectively acquiring wireline production logging information across each isolated section of the reservoir. This data can be communicated in real time via satellite to a customer’s office, where decisions and actions can be taken.
The key is having the proper software and applications to use the information effectively, to get the information you need in a timely fashion to make the right actions happen. By actions, I mean remotely controlling a valve to choke back or increase production from the various intervals depending on how you think it will impact the overall production from the well. It is new technology to the market, but the capabilities exist to expand the effectiveness of intelligent completions.
What have been some of the biggest technological breakthroughs in well completions over the past couple of years?
From an intelligent completion perspective, inductive coupling technology has allowed us to simplify the running of the completion and achieve full sandface monitoring and interval control. This is while minimizing the number of wellhead penetrations required, which improves overall completion efficiency and reliability. This technology is also key to enable the deployment of sensors to enhance well integrity monitoring.
In unconventional plays, our HiWAY flow-channel fracturing technique is increasing fracture conductivity and production. On average, we have seen a 20% increase in production, 40% less proppant use and 60% less water use. It introduces a new way of deploying the hydraulic fracture to create infinite conductivity channels to flow between the proppant columns to allow greater productivity while using less fluids and proppant in the process.
Microseismic technology has also played a key role in understanding the hydraulic fracture effectiveness, and it has been instrumental in optimizing fracture designs.
Degradable technology has significantly improved the efficiency of completions in unconventional plays by minimizing the number of interventions required. Swellable packers have provided a cost-effective compartmentalization of the reservoir, and it has really helped change the game in unconventionals, in sand control environments and in other more complex zonal reservoir applications.
In sand control operations, advances over the past couple of years have used shunt-tube technology to fill the voids left during gravel packing, which helps maximize their efficiency.
ResFlow inflow control devices (ICDs) create balanced flow and effective draining across the reservoir layer for optimum sweep and effective draining without premature gassing out or watering out of the well. This has proven very effective at improving ultimate recovery.
Reliability has seen a step-change in the past couple of years. One area we have focused on is debris tolerance and reliable performance of our isolation valves in difficult well conditions. The FORTRESS premium isolation valve, which isolates reservoir fluids in the lower completion and allows operators to transition to the upper completion without intervention, is designed to withstand severe debris environments and optimize the available actuation energy in a more predictable, consistent and reliable way.
It is a ball-type valve, and we have minimized the void space that may allow accumulation of debris around the ball. In addition to that, we’ve developed a debris-testing laboratory where we can pump all kinds of crud, sand, debris and metal into the valve or past the valve at various pressures and temperatures to ensure that, in these types of environments, when it’s time to activate the valve, we actually can. Testing and validation have given us the confidence to know that it will operate more effectively than previous-generation valves.
In a 2010 article in DC, we quoted a Schlumberger completions expert saying that industry will soon be capable of doing multi-zone, single-trip gravel packing in open holes. Has this been achieved?
Absolutely, open-hole gravel packing is becoming a more common completion practice worldwide. We’ve seen significant success, particularly in Southeast Asia and Latin America. The shunt-tube screen technology is the key enabler for successful single-trip, open-hole gravel pack operations.
The shunt tube diversions ensure uniform gravel pack and help prevent premature screen out and erosion hot spots; 100% gravel packing efficiency can be achieved in longer-reach wells. In-flow control devices help create a balanced flow and effective draining across the reservoir layer for optimum sweep and effective draining without premature gassing out or watering out of the well. This has also proven effective in improving ultimate recovery.
Offshore, particularly in deepwater, what are the limits of today’s completion technologies and equipment? Are there still wells that we can drill but not complete?
There are wells being drilled that challenge today’s technology. However, with proper planning and operator collaboration, technology can often be brought to market to meet increasingly challenging well environments in a reasonable time frame. We work with customers on developing technology to meet certain needs in reservoirs, like the Lower Tertiary in the GOM, well in advance of the time that the technology may be needed.
We also have R&D focused on developing and enabling technology for extreme, HPHT environments. We recently introduced to the market, for instance, the first 20,000-psi safety valve. We also have projects focusing on electronics and materials that can be used in multiple technology applications in extreme environments, which then allows for rapid adoption into new technologies that may require those types of materials.
In these extreme offshore environments, it seems a lot of completions are fit for purpose, increasing lead-time and cost. How are you balancing tailored designs and cost?
Standardization is going to be key. Pushing the envelope the way we are today will require more focus around standardization. In the majority of our current projects or collaborations, standard applications will be applicable to similar reservoir types and environments in other areas. Standardization does not necessarily mean fit-for-purpose for one reservoir or one well. Standardization becomes extremely important to our customers in a given development in order to achieve optimal operational and cost efficiency. More customers are beginning to demand more standardization, even in challenging environments. The efficiency, reliability and simplicity gains affect overall quality and safety performance, as well as their ability to optimize production and ROI.
The move toward standardization can be accomplished with functionality that can be adapted to different reservoir or field applications. Further, standardizing will certainly improve people utilization and competency.
While automation is increasingly making an impact on drilling, the completion process seems to be still highly labor intensive. Where does automation fit in with completions?
We are not at the stage where we can completely remove people at the well site. However, we are greatly reducing the number of people required to run completions by cross-training key personnel while greatly reducing the complexity and time to run completions. Minimizing the number of control lines, for instance, and using the inductive coupling technology greatly simplifies and improves the speed to run an intelligent completion.
Many of the new technologies also require less support on location compared with the previous generation. Fewer trips are required with single-trip gravel packs systems, and unconventional completions run with degradable materials, which require no interventions after the well is completed.
We are also focusing on developing the ability for real-time downhole monitoring of tool performance and functionality. Having a fully integrated standardized completion system and workflow is also key to efficiency.
We also provide remote technical support through operational support centers distributed around the globe. Manned with technical experts, these centers can monitor the operations in real time to provide technical support and improve the efficiency of running the completion.
What effects do drilling technologies such as MPD or dual-gradient drilling have on completions?
The technologies can definitely help maximize reservoir contact through extended-reach drilling and making it easier to run long sand control completions efficiently, with assurance that we get all the way to the bottom of the well. It can also help with regards to wellbore isolation by ensuring that open-hole packer sealing systems will be able to seal with proper integrity. For open-hole applications, this type of drilling technology will improve the ability, reliability and confidence that we will be able to run the completions effectively.
These drilling methodologies also help from the extreme reservoir contact perspective, particularly when you have multilaterals in the well. Some of our newer systems allow us to provide isolation of different intervals with zonal monitoring and control within the multilaterals. This also requires quality wellbores to make sure we can ensure isolation and reliability of the completion as we run these intelligent completions now in multilaterals off the motherbore.
It certainly is essential for us to work in collaboration with the drilling group to make sure we provide a total solution for customers. We need to not only integrate technology within the completion realm, but it will be important to integrate with the drilling group and other product lines to address our customers’ complete workflow.
People and the challenges of getting them trained is a huge concern on the drilling side of the industry. Is that a challenge for the completion industry? How is it being addressed?
The production market has more than doubled since 2009, which has brought on several challenges. One of the biggest is developing the human capital required to match this growth. This means more than just numbers. To meet the challenge will require having a focus on how we use our people, developing technology that will require fewer people, optimizing training and developing people who are multi-skilled. With that in mind, proper competency development and how we manage competency will also be critical.
We have successful recruitment programs that have more than doubled our new-hires over the past two years. The utilization of simulators, state-of-the-art training facilities with drilling rigs and real wells to work on also helps our young engineers to get hands-on experience while at the training schools. It is also extremely important that we recruit locally where our customers operate. We must recognize and understand fully the issues our customers face in their fields and work with them to develop long-term relationships to build for future success.
We couple that with our competency system to assess the individual’s training and proficiency, which is then certified and validated.
As the industry continues to grow, human capital development will be fundamental to our continued success as an industry.
OptiPac, WellWatcher BriteBlue, Mangrove, Petrel, IntelliZone Compact, HiWAY, ResFlow, FORTRESS are marks of Schlumberger.