Building a better shale well with biosurfactants improves production and ROI
After its Covid-induced lows of 2020, U.S. shale oil production is rebounding—with demand reaching pre-pandemic levels. In fact, energy demand, as a whole, is expected to grow 25% over the next two decades. While this demand will be met by a greater share of renewables as part of the energy transition, the need for crude oil production continues to rise, as well.
While some forecasts indicate that shale production will keep growing to meet this demand, some analysts claim the numbers are overestimated. The global oil market is currently undersupplied by roughly 1.5 MMbopd, which is contributing to a dramatic rise in oil and gas prices. This reality is opening up urgent conversations on how to produce enough oil to meet global requirements.
Over the past year, drilled-but-uncompleted (DUC) wells were a major contributor to meeting U.S. oil production needs. DUCs are attractive, due to their lower capital requirements, compared to drilling and completing new wells. In addition, production rates can be maintained through enhanced oil recovery (EOR) techniques, such as waterflooding, chemical flooding, thermal methods, and gas injection. EOR has historically been the key to maximizing oil recovery from conventional producing fields after primary production and secondary water-flooding phases are complete. But these techniques can extend production rates only so far.
In addition, many EOR techniques are typically not as effective, unproven, or not economically viable for many shale wells, due to the very low permeability of most shale formations. While shale plays will continue to be the main focus for U.S. oil production, their high initial decline rates (40%-60%) require continued drilling of new wells to maintain enough oil production to meet demand.
As operators strive to meet projected demands, they also face a $600-billion shortfall in planned investment and growing pressures to meet net-zero emissions targets. The push to reduce the carbon intensity of operations has intensified to not only remain competitive, but also receive access to capital from sustainability-minded investors. With financial restrictions and ESG pressure rising, operators need immediately implementable solutions and technologies to extend total well life cycle.
So, what can be done? One answer that is showing much promise is the use of new ESG-friendly, bio-based surfactants to build a better well from the start, Fig. 1. Operators across top U.S. basins are finding success by implementing these bio-based surfactants, or biosurfactants, in their initial well construction stages—not merely as part of a later EOR campaign. These treatments boost initial production, maintain higher production rates, and extend the total well lifecycle—resulting in low-cost, low-carbon oil.
How are biosurfactants creating such a promising future for U.S. shale? To answer this, it’s helpful to compare biosurfactants to conventional surfactants made from petroleum-based feedstocks.
Petroleum-based surfactants. Surfactants, known as surface active agents, are a class of petrochemical-based or synthetic compounds that act as foamers, emulsifiers, wetting agents, and more. They can significantly reduce surface and oil-water interfacial tension (IFT) and change surface properties of shale such as wettability. Injection of chemical surfactants can improve water imbibition, increase oil relative permeability, and reduce water blockage at the matrix-fracture interface.
In the past, petroleum-based surfactants have been used for EOR as part of chemical flooding operations, following completion of secondary recovery phases. Surfactant flooding is a well-established method with proven success over the years in maximizing oil recovery in conventional formations. However, chemical floods require high CAPEX and have technical challenges related to surfactant stability under harsh reservoir conditions, and the extensive and costly surfactant screening required for application.
Due to their favorable properties for maximizing oil recovery, surfactants were often included in hydraulic fracturing fluid systems for shale wells. During the early days of the unconventional shale development, an influx of capital allowed operators to afford the expense of building high-quality shale wells using premium proppants and surfactants to maximize production performance. Many premium surfactants were developed for hydraulic fracturing of shale wells and yielded many benefits in certain applications.
The cost and carbon reduction transition. Since the initial shale boom, the industry realized that unconventional plays were over capitalized and budgets have since been reduced. In response to these new financial restraints, chemical usage was one of the first expense categories to be reduced—with premium surfactants at the front of the line. The industry also shifted to using regionally available proppants versus premium or engineered proppants in hydraulic fracturing programs. If operators did not see immediate benefits to well productivity, many quickly reduced or eliminated premium surfactants and proppants from their programs.
In addition to their high usage cost, surfactants were also increasingly criticized for their high carbon footprint. In their search for new surfactants, some operators found microemulsion fluids to be a more sustainable alternative. However, operators had difficulty quantifying the cost and performance benefits of these fluids.
Overall, the U.S. shale industry has moved to a factory method of drilling and completing shale wells to minimize CAPEX. In the current capital restrained and ESG-pressured environment, the oil industry will rely heavily on new technologies that sustainably extend the total life cycle of the well. This begins with building a better well during hydraulic fracturing.
A new green approach. Following a review of a multitude of new technologies, industry experts identified biosurfactants as a top emerging solution to improve financial security of shale operations while meeting more stringent environmental regulations. Biosurfactants are a class of natural, bio-based surfactants comprising highly complex surface-active molecules with unmatched multifunctionality and sustainability, Fig. 2. These molecules have unique functionality and characteristics that provide mechanisms of action that surpass traditional petroleum-based and premium surfactants.
Biosurfactants reduce surface and interfacial tensions to extremely low levels, minimize fluid viscosity and have excellent wetting and dispersant properties—all of which help increase both initial and sustained production. Their unsurpassed small micelle size (< 2 nm compared to 100 nm for many traditional surfactants and 15 nm for some premium surfactants) enable them to penetrate nanopores as small as 2 nm to mobilize previously unreachable oil within the tightest shale formations. And unlike synthetic surfactants—which are often flushed out of the formation during flowback—up to 50% of the biosurfactant treatment stays in the shale reservoir and slowly desorbs over time to ensure long-term production performance.
Made from renewable raw materials, biosurfactants have a green profile that includes low toxicity, better biodegradability, and extreme stability under harsh reservoir conditions. They exhibit extremely low critical micelle concentrations (minimum effective dosage rates), making them effective at 50 times lower concentration than many traditional surfactants.
And yet, despite decades of extensive research and favorable potential, biosurfactants have not been readily adopted by the oil field. Since the 1940s, biosurfactants produced by microbes have been used in EOR applications. In this process, known as microbial enhanced oil recovery (MEOR), operators produced the biosurfactants in situ in the reservoir by injecting microbes and nutrients into oil wells. The production gains observed with these treatments were often inconsistent, and there was difficulty controlling the activity of the microbes in generating biosurfactants downhole. While a promising solution, MEOR required a revamped approach.
Oilfield adoption of biosurfactants continued to be limited by high production costs, volume limitations, scalability, and efficacy challenges over the decades. A solution was required to produce biosurfactants at larger scale, with more consistent quality and in a better controlled environment (ex situ)—and then apply them as needed in a similar method used with traditional synthetic surfactants.
Recent manufacturing advancements now enable biosurfactant development at lower costs and higher volumes, and with a near-zero carbon footprint. The new process, developed by Locus Bio-Energy Solutions (Locus BE), eliminates the use of living bacteria and nutrients in the wellbore. Biosurfactants are, instead, manufactured above-ground and formulated for a variety of oilfield applications, Fig. 3. Formulated products are sterile and do not include any nutrients or living cells.
Locus BE has reopened the surfactant market with solutions showing better performance than any previous treatments. The new biosurfactant approach has demonstrated proven results, enhancing oil recovery across major U.S. basins, including the Permian and Williston. When used in tertiary enhanced oil recovery (EOR) processes in existing wells, biosurfactants yield consistent, sustained production increases and successfully remove paraffin and asphaltene deposits from the reservoir.
Permian basin. An operator in the Delaware basin used Locus BE’s AssurEOR STIM biosurfactant treatment as part of a rigless intervention to address declining oil production in an unconventional four-well pad, while avoiding a costly full mechanical workover. A 155-day analysis showed that after just a single biosurfactant treatment, the well’s average daily oil production increased by more than 115%, with over 4,500 incremental bbl of oil produced above forecast, Fig. 4. The well also experienced a nearly 25% increase in gas production during that same period. The operator recovered treatment costs in less than four months and realized a more than 1.5x return on investment (ROI).
Williston basin. In early 2021, the North Dakota Industrial Commission unanimously approved funding to evaluate the ability of biosurfactants to sustainably increase oil mobility and production across the Williston basin. Locus BE’s AssurEOR STIM enhanced oil recovery treatments were initially used on two declining wells in the Bakken. Four months after the initial biosurfactant treatment, oil production increased by more than 70% in both wells, with a less than 40-day payback.
Appalachian basin. In early 2018, the AssurEOR biosurfactant treatment program was started on an Upper Devonian sand well in Pennsylvania. The well experienced a 140% increase in oil production 554 days after the initial treatment, with treatment costs recovered in under 50 days and higher than 3x ROI at 180 days. A second treatment in 2019 demonstrated a 320+% increase in oil production after 321 days, with treatment costs recovered in 34 days and more than 2x ROI at 180 days.
State-level regulatory bodies are acknowledging these sustained production enhancements, creating new cost-saving opportunities for operators through tax credits. The Texas Railroad Commission (Texas RRC) approved Locus BE’s biosurfactants as a tertiary enhanced oil recovery technology, qualifying users for a 50% annual severance tax credit on all oil produced on the lease over the next ten years, as long as a production increase is maintained.
In addition to improved oil recovery, biosurfactants reduce scope 1 emissions, minimize health and safety concerns, and meet or exceed ESG goals. Compared to a traditional frac in the Permian (50 stages, single well), biosurfactant stimulation of existing wells uses less than 0.1% of diesel and less than 2% of water—with only 0.01 ton of carbon per application. The treatments can help oil and gas companies achieve ESG compliance through increased production of low-carbon, low-cost barrels.
Building better shale wells with biosurfactants. Operators using biosurfactants in EOR applications have also observed production increases in adjacent, nontreated wells—demonstrating both the impact of the treatments and the importance of placement. The impressive gains in oil production realized by using biosurfactants to target specific problem areas has led to discussions on introducing them earlier in the well life cycle. Utilizing biosurfactants in frac fluids provides a cost-effective way to improve the well completion by reaching peak oil faster and sustaining higher production rates.
Implementing biosurfactants in fracs and re-fracs achieves far-field displacement from the wellbore for maximum benefits and an even larger production impact. The result is a better-designed shale well, with improved performance from the start. Their high stability and multi-functional properties enable them to outperform traditional frac surfactants at a fraction of the cost while boosting initial production, maintaining higher rates for sustained periods, and slowing declines to maximize estimated ultimate recovery (EUR).
Operators are now beginning to utilize biosurfactants during the completion of new shale wells. In initial field deployments in the Permian basin’s Wolfcamp C formation, Locus BE’s SUSTAIN treatment resulted in a 32% increase in oil production in the first 30-days and faster peak oil when compared to historical fracs using other premium surfactants. Well production was increased by more than 6,200 bbls, compared to the analog wells. The sustained production increase was achieved at 1/3 the application rate, helping to maximize EUR while delivering a greater than 3X ROI within the first 30 days.
In the Williston basin’s Bakken formation, Locus BE’s SUSTAIN treatment was used in a refracturing completion. Compared to analog refracturing completions, the operator realized a 16% increase in oil production over 75 days, with 3,500 additional barrels produced and a greater-than-4X ROI achieved.
The opportunity to build better shale wells with biosurfactants has caught the attention of many industry experts, leading to recognition that includes World Oil naming the SUSTAIN biosurfactants as a finalist for an emerging technology of the year. Discussions continue on expanding biosurfactant use in additional applications, including liquified natural gas stimulation and other areas that previously relied on surfactant use.
In today’s capital-constrained and ESG-pressured environment, EOR efforts can no longer be relied on as the primary method to higher production. The key to success starts with building a better shale well. Operators looking to cut costs and meet ESG requirements now have a new, sustainable option to maximize production from the start. The future of the shale industry may be evolving, but environmentally friendly technologies like biosurfactants can help ensure a profitable and sustainable future through the production of low-cost, low-carbon bbls of oil.
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