A software system that has been refined over 30 years of use at Baker Hughes, a GE company (BHGE), is being made available to industry operators and coiled tubing (CT) service providers for the first time. BHGE’s CIRCA CT simulation software offers operators data-backed solutions for challenges and projects that call for CT, enabling users to calculate potential outcomes prior to the onset of a job. The software system has been used extensively in a variety of wells and environments such as conventional and unconventional wells, on offshore and onshore projects, in horizontal and lateral wells and on deviated and S-shaped wells.

“CIRCA essentially models all CT jobs in the industry, anything from simple jobs to the more refined and complicated operations,” said Rodrigo Micheli, CT product champion for BHGE. “Some examples of those might be concentric coiled tubing or tough cleanouts, while some of the challenges seen in North America might be milling plugs, extended-reach wells or sand cleanouts.”

According to BHGE, CIRCA Pro, one of the three applications in the CIRCA suite, has been used to model, plan and execute solids transport on more than 30,000 wells to date. The software also enables CT service providers to maximize equipment performance and improve operational efficiency in well interventions.

Micheli said BHGE realized there was a need to make the CIRCA software available to the industry after receiving feedback from operators and CT service providers. BHGE said in a release that other CT simulation software systems “lacked real-world feedback and adequate support, producing inferior models that fail to adequately identify risks, especially in complex environments.”

Micheli said, “CIRCA not only offers simple CT modeling tools, but it also comes with advanced and unique calculations as well. More advanced capabilities include modeling solids transport, which predicts the behavior of solids in a well given varying fluid and gas volumes. Another is abrasive perforating and, again, concentric coiled tubing operations.”

A new way to find solutions

According to BHGE, the CIRCA system is designed to offer data-based solutions to challenges rather than companies relying on traditional methods such as experience- based decision-making. BHGE said these types of traditional decision-making methods could compromise job performance and even damage downhole equipment, particularly with the industry’s more complex wells and in wells with longer laterals and multiple stages.

“An example of that would be for sand cleanouts,” Micheli said. “Too often operators and consultants use rules of thumb. They use generalized pump rates, fluid weights and pull-out speeds because that worked the time before in a different well. But CIRCA offers an advanced solids transport model that is based not on rules of thumb but on thousands of tests and actual field evaluations to really understand the dynamics of solids moving in a wellbore as you’re pumping fluid down.”

Micheli explained that a BHGE CIRCA software client recently operating in South Texas had been using the CIRCA Pro suite modeling solids transport to model a milling and cleanout job. Rather than implementing the recommendations suggested by CIRCA, the company utilized its standard operating procedures and rules of thumb, Micheli said, to clean out the well post-fracture.

“The CT ended up getting stuck for a couple of days,” Micheli said. “Once they did a post-job analysis of [the operation], it turned out the original solids transport analysis from CIRCA was right. So essentially they were pumping too low of a pump rate and moving coil out of the hole too fast. They weren’t moving solids as fast as they needed to, and they were trying to leave the well too soon.”

According to Micheli, had the company utilized the CIRCA recommendations at the onset of the project, it potentially could have avoided the downtime.

According to BHGE, the unplanned downtime tripled the operational time. Once the mill had been freed from the well, the CT provider entered the well parameter data into the CIRCA Pro application.

“The result has been months of subsequent millout jobs with no instances of stuck CT. Further, the operator reduced costs by avoiding nonproductive time and the need for intervention/fishing to retrieve tools stuck downhole,” BHGE stated in a press release.

Software features

The CIRCA software suite includes CIRCA Complete, CIRCA Pro and CIRCA Real-Time, which Micheli said could all work in unison with each other or individually. CIRCA Complete provides tubing force analysis and wellbore hydraulics monitoring for common applications like milling, setting and retrieving tools and intervening in extended-reach wells. CIRCA Pro uses complex calculations to accurately model solids transport to surface without compromising downhole equipment in more challenging operations like abrasive perforating, cleanouts and multistage plug milling. CIRCA Real-Time optimizes jobs using live operations data inside the CT control cab, accommodating changing well conditions quickly and efficiently.

“The software delivers valuable insights [about] the subsurface such as downhole conditions, flow rates and safe operating envelopes, enabling operators to calculate outcomes with more certainty to improve planning and execution,” BHGE stated in a release.

Micheli said large operators may, for instance, use CIRCA Complete or CIRCA Pro to simulate a CT job or a larger scale plan in advance, whereas CT service providers could leverage the entire CIRCA suite.

“CT service providers can use CIRCA Complete or CIRCA Pro modeling to plan, and then they can use CIRCA Real-Time to make adjustments on the job. CIRCA Real-Time updates the initial models in the CT cabin with live data from the well site,” he said.

One of the features of the CIRCA system is its ability to replicate or even predict with a high level of accuracy key factors like surface pressures and downhole conditions.

“We’ve done a lot of work with CIRCA and conducted several matching exercises in the field, and a lot of times we’ve noticed that we’ve matched exactly what the field was applying,” Micheli said. “For example, with pump rates and fluids we’ve ended up basically matching the pressure they were seeing on the surface with a high degree of accuracy.”

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