6 Ways Well Completions will Change in the Next 10 Years
One of the big challenges facing industry is figuring out ways to carry out well services that are common and inexpensive in conventional vertical wells, but are currently relatively difficult and expensive for horizontal wells. We are building many long wellbores but lack the appropriate tools and techniques to effectively and economically perform operations such as:
- Wellbore clean outs (solids, wax, scale, asphaltenes)
- Stimulations (placement and injection control, re-fracing, re-perforating, isolation)
- Artificial lift optimization
- Unloading water from gas wells
- Flow management to/from different zones or well segments
There are wonderful opportunities for service companies, and the industry at large to develop a range of new technologies to better manage, and optimize horizontal well productivity over the full lifecycle of the well. Let the crystal ball gazing begin!
1. Long Term Flow Control Capability
We predict most horizontal wells drilled ten years from now will have active flow control devices designed and deployed into the initial well completion. It is the only way to ensure control of well flows (both injection and production) and ensure optimized well productivity and reserve recovery over the long term.
Flow control technology is already deployed as standard operating procedure in most horizontal wells in the Middle East, where state run companies have been early adopters of this technology. Even small improvements in wellbore efficiency in these comparatively prolific reservoirs yield big bang for the buck. But in ten years, active flow control will be standard in wells everywhere.
Like many oilfield practices, designing downhole flow control into initial completions probably won’t be considered mainstream until North American operators adopt it, since more than fifty percent of all wells in the world are drilled in North America. However, we are starting to see strong interest in this technology here, and there is opportunity for impressive economies of scale in these products.
2. Redundant Completion Strategy
As horizontal wells age, they will experience the same challenges faced by aging vertical wells: scaling; waxing; solids loading; and liquid unloading to name a few. Turning the wellbore sideways does not permanently resolve any of these issues, in fact it often masks or serves to magnify the damage over time. Operators will have to remediate horizontal wells, and the only way to do that efficiently and economically is to design the initial wellbore completion with remediation in mind.
A whole new range of economical and intelligent well control, flow control, isolation and compartmentalizing devices will be deployed in wellbores to facilitate these remedial operations.
Wells will be prefabricated with enabling technologies that may not be used for the primary completion. For example, one hundred frac valves may be deployed, but only fifty will be used for initial fracturing, while fifty will be reserved for later remediation work. Some operators are already in the early stages of trialing this sort of approach.
A redundant completion strategy puts a huge premium on forward planning and the value of taking a long term view of well productivity. That will be a significant challenge for an industry which frequently focuses on near term cash requirements and short well payouts, as opposed to life-cycle returns.
3. Economic Intelligent Down Hole Tools
Current versions of electro-hydraulic completion valves for flow control have some limitations that prohibit extensive use across all sections of the industry. They are expensive. They require continuous power. The amount of cable required limits the number of devices that can possibly be installed.
Innovations are already being developed for the next generation of intelligent devices. Imagine tools that have on-board, long life batteries, and temporary power supplies that can be transported to the device with a tractor or robot. When not required, the tool may be capable of hibernation periods lasting many years.
The opportunity and challenge is to make intelligent tools vastly less expensive which will allow more of them to be deployed along the horizontal lateral so flow and pressure in different sections of a lateral can be managed discretely.
4. Artificial Lift Reaches Out
We will see new equipment developed that reliably positions the intake into artificial lift systems at the toe of the well, and/or distributes the intake into the artificial lift system along the length of the horizontal lateral. Horizontal wells are dominated by friction effects and a loss of energy in transitioning from heel to the toe. As a result the ability to mobilize fluids reduces with proximity to the toe. Having artificial lift at the heel is not enough; we need to get artificial lift technology out to the toe of the well.
5. The Golden Age of Coil Tubing
Industry’s ability to drill horizontal wells is way ahead of its ability to effectively complete them and produce them for the long term. With laterals getting longer, we predict increased use of coil tubing globally. The Golden Age of coil tubing has been predicted many times in the past but so far coil tubing has only been widely adopted in Canada and the USA. The worldwide industry’s reluctance may be set in a belief that equates ‘Endless Tubing’ to ‘Endless Trouble’.
The future for coil tubing may be different because in long laterals, we simply can’t rely on gravity to help in the way we rely on it for many operations with vertical wells. Extended reach laterals also have much greater exposure to the reservoir. Both of these factors make it very difficult to effectively place remedial stimulation chemicals, clean solids out of wellbores, or lift liquids. Circulating equipment and measurement tools are complex and expensive systems and become dramatically more costly if stuck or lost down hole.
The only reliable solution to these challenges is a robust conveyance system such as coiled tubing that allows us to not only deploy tools, but also get circulation to the toe of the well. Tractors for pulling electric line equipment into long laterals are well proven and utilized. The next significant development in this area will be coil tubing tractors (some early variants are available today) to assist in reliably getting measurement, activation and circulating equipment down to the point of interest in a horizontal lateral.
6. Better Reservoir Analysis
Historically, the desire to achieve better reservoir sweep efficiency and maximize reserve recovery was largely accomplished by either drilling more wells, or longer wells. Today, operators have many incentives to drill fewer wellbores – surface rights and land use issues, and environmental impact concerns chief among them. Those operators drilling longer laterals also face the law of diminishing returns unless every foot drilled contributes to production and profitability.
Today there is a tendency to acquire less than adequate reservoir data because it’s expensive and the focus is on making the well economic short term. Lack of adequate reservoir data can have dramatic consequences. By way of example, some studies indicate as many as fifty percent of all fractured sections in multi-stage wells are not productive, or producing sub-optimally. That’s a huge cost for little return. The results of such studies demonstrate we need to fine tune multi-stage stimulation and well completions with a focus on multi-stage productivity.
In the future, the focus will shift beyond multi-stage drilling and multistage completion to multi-stage productivity. At this time, engineers are clearly beginning to understand not all stages are productive but the language of multi-stage production doesn’t yet exist.
Broad adoption of horizontal drilling only gives industry a decade of experience. That experience has taught us that a mile long section of reservoir has more complexity than we previously assumed. We have not considered it critical to fully understand the effect of heterogeneity in the reservoir and its impact on long term productivity. It will be considered very important in future.
In conclusion, the wellbores we build ten years from now will be designed, planned, drilled and completed very different than today because engineers will focus on multi-stage production and long well life. That is a major shift in thinking that will drive:
- Better reservoir analysis
- Designs for long term flow control
- Completions with redundant tools for remedial work
- Down hole tools that are intelligent and economic
- Artificial lift at the toe of the well
- Coil tubing innovations to assist deployment and operations in horizontal wells