Feature Article: Evolving technology is a key driver of performance in modern gas wells: a look at the Montney Formation, one of North America’s biggest gas resources
Release date: 2018-04-25
Two things determine how much oil or gas a well will produce: the quality of the reservoir the well is drilled into, and the technology applied to the well. Thus, one way to get better results from new wells is to find better reservoirs to drill. This is why companies drill their best prospects first, and why it becomes harder over time to find high quality reservoirs. The other way to improve the performance from new wells is to improve the technology applied to them. In particular, horizontal drilling and multi-stage hydraulic fracturing have continually improved after being widely deployed in Canada and the United States around 2007. In general, the performance of new wells has continued to improve since then.Footnote 1
Source and Description
Source: IHS-Performance Evaluator for well locations and the Atlas of the Western Canada Sedimentary Basin for the location of the Montney Formation.
Description: This map shows the location of the Montney Formation in a belt 200 km wide that stretches near Edson and Hinton, Alberta, in the southeast to near Fort Nelson, British Columbia, in the far northwest. The map also shows the location of Montney wells drilled since 2005, which are largely located on the Montney’s south and western sides.
The Montney Formation is located in western Canada and has an area of 130 000 km², about the size of New Brunswick and Nova Scotia combined. The Montney has the potential to produce a total of 449 trillion cubic feet (Tcf) of natural gas with modern technology, making it one of the biggest gas resources in North America.Footnote 2
However, only a small part of that large area is currently being developed. The large majority of the gas is found in only 35 000 km² on the Montney’s west side. Of this, “core” areas of 25 000 km² are of the most interest to gas producers. Core areas are developed first because they tend to have the best reservoir quality and can produce the most gas.Footnote 3 Meanwhile, non-core areas are usually avoided at first, because reservoir quality is often lower and wells drilled there typically perform worse.
The figure below shows monthly gas productionFootnote 4 from average Montney Formation gas wells drilled from 2001 to 2017. The large majority of Montney wells were drilled in core areas over this time. Each well shows the same trend: gas production quickly ramps up for the first 1 to 3 months before peaking, after which production begins a steep decline followed by a more gradual decline. This “decline curve” shape is not only typical for Montney Formation gas wells, but wells in almost all formations that produce tight gas and tight oil (including shale gas and shale oil).
Source and Description
Source: IHS-Performance Evaluator
Description: This graph shows the average, monthly production for gas wells drilled in the Montney Formation from 2001 to 2017. Production from wells drilled from 2001 to 2006 peaks at about 0.8 million cubic feet per day (MMcf/d) in its 2nd or 3rd month before declining to about 0.2 MMcf/d after 60 months. Production from wells drilled in 2007 peaks at 1.3 MMcf/d in its 2nd month before declining to 0.3 MMcf/d after 60 months. Well performance improves over time such that production from wells drilled in 2012 peaks at 2.6 MMcf/d in their 4th month before declining to 0.7 MMcf/d in 60 months. Production from wells drilled from 2013 to 2017 peaks at 2.9 MMcf/d, 3.0 million cubic per day, 3.2 MMcf/d, 3.8 MMcf/d, and 3.9 MMcf/d within their first 4 months of production, respectively, though 60 months of production data are not yet available to compare to.
This figure shows that technology has helped newer wells outperform older wells. Peak production rates were 0.9 million cubic feet of gas per day (MMcf/d) for wells drilled in 2005, but more than quadrupled to almost 4 MMcf/d for wells drilled in 2017. After 5 years of production, newer wells continue to have higher rates of production. A well drilled in 2005 typically flowed 0.2 MMcf/d after 5 years while a well drilled in 2012 flowed 0.7 MMcf/d. Wells drilled after 2012, which do not yet have 5 years of available production data, could have higher 5-year production rates as well.
The total amount of gas Montney wells will produce over their lifetimes is also expected to increase for newer wells. Better performing wells have a higher “estimated ultimate recoveries”, or EURs.Footnote 5 Montney gas wells drilled in 2005 are each expected to product a total of 1.8 billion cubic feet (Bcf) of gas, but improving technology since then means that wells drilled in 2016 are each expected to produce a total of 7.2 Bcf of gas, 4 times the 2005 value.
Source and Description
Source: EURs: NEB analysis of IHS-Performance Evaluator data, Fracture stages: IHS Performance Evaluator data
Description: This graph shows the estimated ultimate recoveries of natural gas as based on the average Montney gas wells. Montney gas wells drilled in 2006 are expected to recover less than 2 billion cubic feet (Bcf) of gas. Montney wells drilled after 2006 are expected to recover an escalating amount of gas, with 7.2 Bcf for wells drilled in 2016.
This graph shows the average number of fracture stages applied to Montney Formation wells. The number of fracture stages has increased from about 9 in Montney gas wells drilled from 2006 to 2009 to 32 in wells drilled in 2017.
Increasing well performance of newer wells in the Montney Formation is consistent with companies continuing to drill high-quality reservoirs in their core areas while technology continues to improve. Much of this improvement is likely from increasing the number of fracture stagesFootnote 6 and the lengths of wells. As a result, each well is in contact with a larger volume of fractured rock and can flow more gas.
Because of the large size of the Montney’s core area, companies will likely take many years to fully drill areas with the best reservoirs before they start drilling areas with lower reservoir quality. Therefore, it is likely that Montney well performance will continue rising as technology continues to evolve.
Well performance in other plays could evolve differently, however. Generally, the larger a play’s core area, the more potential it has for well performance to continue growing over time.Footnote 7 However, oil and gas plays with smaller core areas have greater potential for their high quality reservoir to be drilled up more quickly, meaning producers would have to start drilling lower quality rock sooner rather than later. Well performance in plays where drilling is moving from core areas to non-core areas could evolve in three ways:
- Improving technology could possibly outpace declining reservoir quality and the performance of new wells could continue to increase.
- Improving technology could keep pace with declining reservoir quality and the performance of new wells could be the same as older wells.
- Improving technology may not be able to keep pace with declining reservoir quality and the performance of new wells could start falling compared to older wells.
Changing well performance in different western Canadian plays will be explored in future Market Snapshots.
A quick guide to some oil-and-gas lingo
As in most industries, oil and gas professionals use jargon for very technical concepts.
Formation: A layer of rock with similar characteristics over a wide geographic area. In the Western Canada Sedimentary Basin, formations vary from a few metres to hundreds of metres thick.
Reservoir: Rock with oil and gas in its pores. Tight reservoirs need to be hydraulically fractured so oil and gas can escape from those pores and flow into a well.
Play: A formation or group of formations containing reservoirs with similar characteristics. The Montney tight-gas play, for example, refers to locations where the Montney Formation is being horizontally drilled and hydraulically fractured to produce gas.
Core area: A core area is where a play has the best reservoir quality.
Horizontal drilling: When a well is drilled vertically into a reservoir before the drill bit is steered sideways, creating a “horizontal leg” often a few kilometres long in the reservoir.
Hydraulic fracturing, or fracking: When water or other fluid is pumped down a well at pressures high enough to crack a reservoir, creating a network of fractures through which oil and/or gas in the reservoir can flow into the well. Multi-stage hydraulic fracturing occurs when several points in a well are hydraulically fractured, typically along a horizontal leg in a horizontal well.
Estimated ultimate recovery, or EUR: The total amount of oil and/or gas that a well is expected to produce over its lifetime.
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