If you've wondered about mature fields in our current environment here's a very preliminary list of some of the ways technology is being used to revitalize mature fields.
New technology continues to be a game-changer in mature fields, where unconventionals are blended with conventional targets to make highly economic "hybrid" fields.
Refracs and new types of enhanced oil recovery (waterfloods, CO2 floods), along with new uses of analytics, passive seismic, imaging and chemicals, is allowing producers to extract another 10 — 25% out of old producing zones and fields.
The success triggers a question: How many of the early shale plays that never performed very well could be revisited with new technology, and made to produce quite well? Finding the "botched" shale plays is one of the hottest new activities in an oil industry that is starting to get its legs back under itself after three years of difficulties.
A revisited shale play, combined with vertical multiple pay zones is the ideal configuration. Even though it is something that everyone is looking for, and each well has been evaluated many times, each well deserves a new look, particularly at each iteration or step change of new technology.
Bringing Together Geology, Engineering, Chemistry and More
Restoring the Drive / Sweeping the Oil: New Waterfloods
New waterflood techniques that utilize different oil field chemicals, that both change the surface chemistry (surfactants) and the salinity can make all the difference. Companies such as eSal (http://esalinity.com/) have been designing injection fluids that can help improve the sweep. In addition, some companies such as Midcon have been utilizing surfactants to improve the results of their waterfloods and to improve the ultimate recoverable reserves by up to 15%.
Unclogging the Wells: Conquering Paraffin and Asphaltenes
New technologies that heat up pipes, maintain the bottomhole pressure, and heat up reservoir fluids are being implemented in wells with heavy oil or which tend to have problems with paraffin or other precipitates.
Dewatering: Residual Oil Zones (Permian Basin)
In some formations, the oil saturation is very low. The problem is compounded by low reservoir pressure. However, there is oil trapped in the formation — usually oil that was left behind as it migrated through sometime after its formation in the "kitchen" and updip through migration pathways to a trap. Now, new techniques are being applied to pump the water from the zone, and to inject surfactants so that the gas and oil molecules begin to flow. The longer the formation is produced, the results. It's a matter of patience and not being dismayed by unsettlingly low production numbers. Wells in the Permian have been known to go from 1 barrel of oil per day to 30 or 40, and to maintain production at that rate for years.
Improving the Recovery in Horizontal, Multi-Stage Wells: ReFracks
Decline curves are steep and the drainage radius tends to be confined to narrow induced fracture networks. If the well is re-fracked after 24 months or so, then adjoining fracture networks can be induced, which can lead to as much as 40% new oil production. The costs are relatively low, and the infrastructure is already in place.
Radial Refracs? Building in the Multilateral with a Refrac Plan
For carbonates that are very heterogeneous, radial multilaterals are being implemented, particularly in plays where drainage in a 640-acre section could be difficult to achieve, given permeability barriers. If refracs can be done quickly, then a planned and staged refract program could be carried out in each of the "spokes" of the wheel (or claws of the chicken foot) for a 10-year productive life (rather than the typical 18 — 24 months of flush production in a traditional single horizontal well.
Getting the Stranded Pay: In-Field Drilling with Laterals and Horizontals
SandRidge and other companies are employing new drilling techniques to boost production. They are using what is referred to as a "multi-lateral" — a vertical well that has multiple horizontals that splay out from a single pipe. It is a technique modified from offshore drilling and it allows more coverage in the zone of interest. They are also drilling three separate horizontal wells from a single vertical. Thus, they can drain an entire section from a single well bore.
Replacing Equipment Based on a Good Fit with the Producing Formation
The pump is rusty. The gas compressors leak. Just replace them. It's that easy, right? Actually, it is important to understand the formation and the producing zone and to match pump with pay zone. One has to understand the geomechanics, the lithology, the integrity of the rock, and more.
Lean Operations / Factory Drilling with a Lean Manufacturing Mindset
Efficiency has come to the oil industry, and "factory drilling" has been improved with the use of advanced analytics which allow better reservoir modeling and simulation.
Don't miss — Big Data / Deep Learning
Familiar Formations, New Approaches
Here are just two examples in North America, but what is happening there applies throughout the world.
DON'T MISS AAPG PLAYMAKER FORUM / MAY 11
Hunton Lime / West Edmond Field, Oklahoma:
Gastar made headlines when they entered the Oklahoma STACK (Sooner Trend Anadarko Canadian Kingfisher) play and started producing the Hunton in ways it had never been produced before. They also targeted the Meramec, Oswego, Osage, and Woodford, but it was the Hunton that really gave people pause. They operated wells in the West Edmond Hunton Lime with 256 Lower Hunton and 235 Upper Hunton, with an average of 6,000 ft laterals. The peak wells averaged 646 Boe/d (88% oil) (Gastar website / http://gastar.com). After 90 days, they were still averaging around 330 Boe/d. What made this different? Instead of simply drilling at the unconformity, Gastar decided to drill along the unconformity surface, at the zone of maximum enrichment.
Wolfcamp Shale / Midland Basin, Texas:
When the USGS announced estimates of 20 billion bbls of oil in the Midland Basin, the already hot Permian Basin heated to a boil. But, what made the Wolfcamp shale attractive in a way it had never been before? The answer had to do with new technologies that made the oil technically recoverable. New approaches to reservoir characterization, identifying landing zones, proppant, hydraulic fracturing, frac design, frac spacing, make the difference.
As new techniques are tried, new roads open for more step-changes and efficiencies. There will also be new discoveries based on what we learn from the mature fields. This is an exciting time to be in the oil industry with emerging technologies. The more one can envision, plan, model, and test, the more breakthroughs are made possible.
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