Here’s the lowdown: Re-thinking how you perforate is a fast way to deliver immediate productivity and completions efficiency wins.
The Western Canadian Sedimentary Basin needs many different perforating approaches
The Western Canadian Sedimentary Basin (WCSB) provides a broad range of plays covering tight gas, shale and heavy oil. Each of these plays requires their own unique way to optimize the production of the hydrocarbons and this had led to all kinds of innovation over the years. Conventional oil includes light crude oil and heavy crude oil, each of which needs different development strategies. As the WCSB conventional plays mature, recent development has focused more on natural gas and oil sands.
In each of these cases, the oil and gas production comes with its own set of challenges. Hard formations can make drilling slow, whilst reduced permeabilities require stimulations such as hydraulic fracturing to achieve commercial production. Heavy oil development in very soft formation rock causes further challenges. Wellbore stability and sand management are significant issues and the highly viscous nature of the oil can make the flow regimes challenging.
What follows, is a look at three different perforating scenarios in the WCSB and at some of the new approaches which are helping deliver better production.
3 real benefits from perforating with TriStim
Increased well performance and lower operating cost by delivering better well conductivity.
Greatly enhanced tunnel geometry (bigger)
Reduction in perforation damage (cleaner)
Increased penetration (deeper)Find out more
Perforating challenges in WCSB shale formations
The Canadian shales of the WCSB are often much harder than other areas which makes them much more difficult to fracture. Additionally, some of the plays, such as the Montney and Duvernay shales, are close enough to the Canadian Rockies to be affected by stress regimes that are rarely seen in other worldwide locations and this only adds to the fracturing challenges.
In summary, the characteristics of WCSB shale plays are;
- Harder rocks
- Microscopic pore spaces
- Low pore connectivity
- Stress regimes
The specific challenges for perforating in these hard formation plays include;
- Issues around penetration
- Issues around fracture initiation
- Issues around proppant delivery
New perforating approaches that provide proven benefits
Recent experiences in the area have shown that delivering a better perforation can positively impact on production and completions efficiency.
More specifically, if treatment pressures can be reduced and pump rates improved whilst delivering higher proppant concentrations, then treatments will take less time, less horsepower and can be more productive. Couple this with the added benefit of reducing breakdown pressures and you can see significant benefits across the board.
Tier 1, together with Delphian Ballistics, have successfully deployed TriStim in a number of wells in the WCSB so as to deliver some significant increases in production beyond the typical production curves for wells in the area. Some specific benefits have included;
- Lower Breakdown Pressures, in some areas, reductions were as much as 25MPa
- Increased injectivity rates at lower pressures
- More proppant placed in zone
- Improvements in proppant concentration pumped
You can see our case study from Devon Energy deployments where some of these results are explained in a bit more detail.
The future of perforating in shale plays?
Recently, there have been some exciting experiments conducted with pumping massive amounts of sand to increase productivity: the so-called “era of the monster frack“.
Chesapeake Energy set a record with the amount of sand it used in what it called “Prop-A-Geddon” after it pumped 25,000 tons of sand down a natural gas well to deliver a cumulative production of 70%. In Western Canada, Crew Energy completed two upper Montney wells using double the normal sand loading to deliver similarly attractive results.
It may be that delivering the bigger, deeper and cleaner perforations that TriStim is capable of will enable such monster fracs to become even more effective.
2. Heavy Oil
Cold production of heavy oil has seen many different techniques attempted all of which focused on trying to exclude sand from the production stream. However the advent of PCP’s (Progressive Cavity Pumps) saw a change in production philosophy that saw the fluids being produced with sand particles deliberately left in, the result was an increased well deliverability and prolonged production life.
Perforating challenges Cold Heavy Oil Production
Traditional perforating challenges don’t exist because the creation of tunnel in soft target is much easier to achieve. But, is the tunnel structurally stable enough to promote long-term flow?
Also, the time taken to get to peak production can be an issue. Using the CHOPS methodology, the peak production is not reached for weeks or months.
New approaches that provide sand production benefits
In the application of CHOPS, can the perforation tunnel be optimized to yield better performance from the well?
The objective is to promote long-term flow by creating a cavitation effect in the tunnel by systematically failing the rock around the perforation which increases flow.
The unique geometry of the TriStim tunnel not only opens up a significant area for increased inflow but in the perforating regime incorporated in CHOPS, the TriStim tunnel is likely to respond much better to the cavitation creation desired by this perforating method.
Delivering cavitation faster
A fortuitous by-product of the TriStim process is that, in certain applications or configurations, the tunnel can be purposefully delivered in a more unstable form than the conventional tunnel.
For example, it has been recognized that the TriStim tunnel stability when deployed in horizontal wells with softer rocks, is less than its traditional counterparts. But where this is a limitation for some sand control applications, it’s exactly what’s needed for CHOPS applications.
Because of this different tunnel geometry, we anticipate that the desired cavitation might take place over shorter time. This would help to deliver peak production over much shorter timescales. Shortening operator’s ROI period in this way could deliver huge efficiency savings.
Another possible benefit is that because TriStim starts with a bigger tunnel, maybe this benefit is maintained throughout the life of the well? This could mean we also end with a bigger tunnel which, in turn, might prolong the life of the well?
Improved tunnel geometry
Read more about how TriStim is capable of delivering a different kind of tunnel geometry that has deeper penetration, increased tunnel volume whilst also being cleaner with greatly reduced perforating skin here. This bigger, deeper and cleaner geometry provides all kinds of benefits for conventional perforation.
3. Injection & Disposal Wells
The challenges of perforating for injection can initially be seen as the same for production. Perforations need to exceed the drilling damage zone, minimize the amount of perforation tunnel plugging and the amount of crushed zone. In production, the presence of a crushed zone is generally accepted to create a 20% reduction in productivity (more detail on this in our Perforator’s Guide to Formation Damage).
It actually becomes a little more complex in injection wells though, as the crushed zone not only limits the permeability driven flow regime, the fact that the sand grains are crushed and compacted results in pore throat sizes which can be significantly less than the undamaged reservoir rock. Even with good injection fluid management at surface, the potential for having particulates in the fluid can still be quite high and the risk of systematically plugging the pore throats in the crushed zone are subsequently higher than for virgin rock.
The TriStim tunnel geometry not only includes the removal of intertunnel rock matrix which increases the surface area open to injection but most importantly it removes the crushed zone. Ability to maintain injection rates at initial levels will be easier to achieve, This can reduce well reentries and workovers that might be typically required. It could also allow faster injection at lower surface pressures, reduce the time required to thermally frac a reservoir or extend the effects of that thermal fracking.
Reducing perforation skin damage
You can read more about how TriStim minimises perforation skin damage which results in better flow of hydrocarbons from the reservoir into the well here.
Flow efficiency improvements
Also, read more here about how SPE paper 174194 (‘Understanding Perforation Geometry Influence on Flow Performance Using CFD’) shows that convergent perforations can deliver improvements to flow efficiency by up to 25% and skin reduction of up to 85%.
The future of perforating in the WCSB
As a technology with one eye on the future, we have been watching with much enthusiasm the developments made by MGX and their foray into the wells business in Western Canada to produce petrolithium.
MGX hold patents to separate out the valuable minerals and salts from the brine water. One of the most valuable of these is lithium carbonate, an essential component of the batteries needed by the electric car sector.
Is the next step to look at perforating for improved Brine Production?
Find out more!
Tier 1 Energy are your local experts with the direct experience needed to help you realize the range of improvements described here.
Tier 1 Energy are your local WCSB experts
Find out more about how to deliver increased production using TriStimContact Tier 1
As a first step, you can register for a free online training course which goes into more technical detail on some of these ideas. There’s no harm in you brushing up your technical knowledge by learning more about these latest developments!
Request access to the TriStim Foundation Course
A 40 minute introduction to the TriStim Perforating System and a certificate of completion when you're done!Get trained