It all begins with source water selection.
Microbes are living breathing components of our oilfield waters. Driven by survival, microbial communities naturally fluctuate. Each water will provide different nutrients and experience different environmental changes. If your water changes, so will your microbial community. Problematic microbe contamination within or near the wellbore can lead to sulfide production resulting in FeS or H2S. Take the time to care about the microbes in your frac waters by testing and treating for what is present in the fluid.
Proven Chemical Products For Hydraulic Fracturing Fluid Applications
Hydraulic fracturing utilizes large volumes of water to achieve improved hydrocarbon recovery. These fluid and proppant systems may vary in formula, but the carrier waters used will inevitably contain varying levels of microbes that have the potential to cause long term issues downhole. Many reservoirs provide conditions optimal for microbial growth, and upon introduction by fracturing operations, can contaminate the reservoir by establishing communities in the fracture networks.
The primary issues caused by a microbiologically contaminated reservoir are souring (H2S production by sulfide producing microbes) and microbiologically influenced corrosion (MIC). MIC may occur within the wellbore, or the microbes may be carried throughout an entire gathering system and into processing facilities potentially increasing corrosion risk of many assets.
In order to prevent microbial related issues, registered biocides can be applied at appropriate places in the hydraulic fracturing process to maintain microbial control. This ensures the health of the well not only during initial recovery but for the remaining production life.
Did you know?
Within the frac process it is important to select the right biocide for the job and to test the effectiveness for the duration of the frac job.
1. How long does water sit on location before pumping?
2. How long is the pumping time?
3. How long is the shut-in period?
Complete a kill study that takes into consideration:
1. Source water
2. Microbial load
3. Length of time
4. Overall desired kill
Untreated source water can contaminate the reservoir.
Not every hydraulic frac is equal but what every frac has in common is the use of water.
WHEN SELECTING YOUR SOURCE WATER, THE EVALUATION SHOULD BE INCLUSIVE OF WHAT'S IN YOUR WATER.
Every time water is used, the quality of that water degrades.
Killing it in Completions
When asked about frac kill studies, Virginia Wornstaff, CTO, responded with some words of wisdom from her extensive experience. During frac operations, frac studies are often run for the duration – often a 48 hour test. Regularly, the waters are in the reservoir for a lot longer when taking into consideration the time before load waters are fully recovered. Also, the time between frac and production facility tie in can take weeks or even months. Based on this, the selected biocide will be challenged to maintain control for this extension in time. When working with clients who get random well souring in fields with consistent frac programs and treatments, we often see the difference is in the time between frac and production activities. This extension of time creates a little incubator full of warm, stagnant, nutrient-rich conditions. Now in charge of disrupting this reservoir Petri dish, the treatment program should be adjusted to compensate for the new performance demand. Completing a three-week study or a re-inoculation procedure allows for measurement of residual biocide effects after extended periods of time. With a goal of preventing long-term contamination of the reservoir, wellhead testing 30 days after your well comes on production is going to give you the best indication of success.