Optimizing operations in the Bakken basin with OLI Systems and Creedence Energy

New oil well in North Dakota

OLI can be a game changer for your business! Time and again, OLI has had the pleasure to witness clients use OLI simulation technology to transform their business. By using the intelligence and insights that simulation provides, informed decision making can translate into a more competitive position. This gives OLI clients the ability to differentiate themselves and provide added value to their clients, using the power of water chemistry simulation.

A case in point is our client, Creedence Energy Services. Based in North Dakota, USA, Creedence is an oil and gas chemical company servicing the Bakken and surrounding basins. They plan to become a leader for Bakken’s production chemical programs, and OLI simulation is now a key part of their strategy.

Creedence is using the OLI Studio: Corrosion Analyzer, to “turn the lights on” in tubing that has been plagued with corrosion issues. This opportunity results from a service that Creedence provides, to extending asset life of downhole equipment in hydrocarbon production via an Electronic Submersible Pump (ESP).

Extending the life of these pumps in the Williston Basin is a challenge. A combination of heat, the velocity of the produced fluids, abrasive particles included in production, and the corrosive fluids of Bakken/Three Forks production creates an extreme production environment. Downhole equipment risks failure due to corrosion or erosion in a time frame of 6 months or less. Scale and corrosion inhibitors are often applied; these bring with them more need for added tubing to ensure proper chemical contact to inject the chemicals at the intake of the ESP.

And failure in the tubing due to corrosion has been inevitable.

This may all be changing, thanks to Creedence and OLI. Creedence was called into one particularly difficult case: an oil well where over 100 segments of tubing were replaced in less than three months – twice. Creedence was asked to investigate. A conventional hypothesis would be carbon dioxide (CO2) driven corrosion, typical of all Bakken/Three Forks wells.

However, Creedence’s visual inspection of the failed tubing showed significant CO2 corrosion, yet the corrosion lacked the sharp edges and steep walls characteristic of this type of corrosion. In the past, similar “smoothed” CO2 corrosion was attributed to abrasion, as sand is often produced in ESP wells, which can cause a “sandblasting” effect on pipe. Smoothed pitting, atypical of normal CO2 corrosion, was also observed. This led Creedence to the question: could they be seeing oxygen-induced corrosion?

This was a step-out idea. Downhole oxygen corrosion is uncommon, as oxygen is not naturally occurring in oil producing reservoirs. However, freshwater was being used to inject corrosion control and scale control chemistries and combat salt deposition. Was the freshwater somehow exacerbating the problem?

A polarization curve, produced by the software, shows the most active corrosion will be from O2.

OLI’s Corrosion Analyzer provided Creedence with both confirmation and confidence in supporting this new understanding. Creedence modelled the introduction and mixing of the oxygen-rich freshwater with the produced fluids downhole. The software results were definitive: general corrosion rates increased 5-15 mpy on each scenario modeled. The modeled maximum pit current density increased 25-40% on models which included mixing the oxygen-rich freshwater. Lastly, the polarization curve generated by OLI’s Corrosion Analyzer showed a strong influence of oxygen-accelerated corrosion on the corrosion potential.

With the evidence provided by Corrosion Analyzer, Creedence established a trial to chemically control the oxygen concentration of the introduced freshwater.

The results have been remarkable. Since the trial, the need to replace tubing due to corrosion has plummeted. Prior to chemical control of the oxygen, the described wells would frequently require replacement of a 100 or more segments of tubing. Since chemical treatment, tubing inspections have repeatedly shown that less than 10 segments of tubing now need to be replaced due to corrosion in the same wells. What’s more, the reduced corrosion has occurred with a 100% greater exposure time than was previously possible. The life extension of the tubing is ongoing, as much of the tubing is still appropriate for use in oil and gas production.

OLI’s Corrosion Analyzer was a vital tool in diagnosing the root cause of metal loss and justifying treatment. In this particular application, Creedence’s client has already saved hundreds of thousands of dollars. This solution has been applied across 59 wells for this operator, and over 60 more planned applications. In addition, Creedence has approached other operators and trials of this new technique are pending. Upon success of the trial, similar scale-ups with other operators is expected.

This is a great success story already - and there is a new chapter underway. OLI’s AJ Gerbino and Creedence’s Eric Nelson are working together to develop guidelines, preset configuration files and case templates for an initiative we are calling “OLI for Non-Chemists.” Creedence plans to deploy OLI past their expert modelers and bring the power of OLI simulation to their technicians.

This could be your story, too!

Let us work with you to harness simulation power. Simulation has been proven time and again for its ability to help engineers and scientists cut cost and optimize physical operations. An investment in OLI provides significant rates of return to your staff in productivity and confidence gains, and to your clients in terms of optimizing operations.

Special thanks to my co-author and case study contributor

Eric Nelson of Creedence Energy Services