Fractional Dimension Rate Transient Analysis (FD-RTA): A Key to
Unconventional Wells and Complex Fracture Networks
Jorge A Acuña
J Acuna Consulting, LLC.

Abstract:
Unconventional wells show features that make them very difficult to characterize. One of them is the “transitional” flow regime that lasts months to years and is different from known flow regimes such as linear or boundary dominated flow. Fractional Dimension RTA (FD-RTA) is based on work on fractals and fractional dimension systems from the late 80’s and early 90’s. These principles were significantly expanded with innovative elements, rigorous solutions, modeling techniques, and adapted to the geometry of unconventional wells. The result is FD-RTA, a new technique to analyze and understand fracture networks ranging from complex ones with rock fragments of many different sizes to simple ones with equally spaced fractures. This lecture explains the evolution of these ideas and the power of the fractional dimension approach to explain “transitional” flow regimes as the result of fracture complexity. In this new approach, known flow regimes such as radial or linear flow are only special cases of a single general transient solution. The approach can be easily converted to a numerical model and explains several previously unexplained features, such as rapidly increasing gas-oil-ratio, apparent fracture closure with time, etc. The power of FD-RTA is demonstrated by applying it to parent-child well interference. I would like the members to take away the idea that basic methods for pressure and rate transient analysis can explain previously unexplained features of unconventional well behavior but only when the correct model for fracture geometry is considered.

Biography:
Dr. Jorge Acuna graduated from USC in 1993, where he worked on transient behavior of fractal networks of fractures. He joined Chevron (then Unocal) in 1996. He became a leading expert in geothermal modeling and reservoir engineering. He started work in unconventional pressure and rate transient analysis in 2012 and developed Fractional Dimension RTA between 2016 and 2020. The method was published and implemented in commercial software. He retired from Chevron in 2022 to start his own consulting firm J. Acuna Consulting. He has authored more than 30 papers, regularly reviews SPE papers and has participated as session chair in SPE conferences.

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Join us this Halloween season for our SPE Denver YP Halloween Party! Registration will include drinks, appetizers, and darts! Don’t forget to wear your best costume!

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SPE Membership is hosting its inaugural Pickleball Tournament on November 1st. Come enjoy drinks and pickle with fellow oilfield professionals at 3rd Shot Pickleball from 3pm-7pm. Team themes are encouraged, and prizes will be awarded for the top (and not-so-skilled) picklers.

Paddles and Pickleballs will be provided to players who register!

3rd Shot Pickleball

3545 Wadsworth Blvd, Wheat Ridge, CO 80033

Ticket options:

• Team Ticket – $70
• Single – $35 (will be added to a team on arrival)

Sponsorship options: Each Sponsor will have a team registered as well.

• Presenting sponsor (1) – $3,000

• • Includes name & logo on large, printed brackets. Also includes a court named after the sponsor, the courts will be referred to by the sponsor through the entirety of the tournament to help players find their matches.

• Court Sponsor (3) – $1,500

• • Each court sponsor will have a court named after them. The courts will be referred to by the sponsor through the entirety of the tournament to help players find their matches.

• Drinks sponsor (1) – $1,000

• • Sponsor of drinks (bar on-site) for the event. Each player receives two

• Food sponsor (1) – $1,000

• • Sponsor of food (pizza and snacks available)

• Ball sponsor (logo on custom pickleballs, must be ordered by October 11th) – $1,000

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SPE YP is hosting a lunch and learn on November 7th! Lunch will be sponsored by ChampionX and the venue will be sponsored by Liberty Energy!

Abstract:

Automation has been used for many years now as a means for oil and gas operators to optimize sucker rod pump wells. Traditional automation for rod pump wells involved operating the well at a fixed speed and idling the well based on a preprogramed time (time clocks) or fillage (pump off control). However, utilizing a Variable Frequency Drive (VFD)is a more sophisticated method to allow operators to increase their runtime by detecting when there is less fluid to produce and slowing the unit down, accordingly. Although utilizing a VFD can provide significant improvements in production and failure reduction, in some cases operators are not able to realize the full advantage of their rod pump wells with VFDs because the VFD setpoints are not optimized. Optimizing VFD setpoints is not necessarily challenging, but in many cases requires many iterations of user intervention which takes time, and with the ever-changing nature of some reservoirs, that job may never be complete for a given well. However, utilizing a host software with algorithms developed by industry experts, VFD setpoint optimization can be done autonomously. Using domain-specific algorithms, the host software can detect deficiencies in VFD operations and iterate through setpoint changes to determine the optimal setpoints. Utilizing host software, the algorithms can constantly check to make sure that the setpoints are keeping the well running optimally, even when reservoir conditions change. By identifying issues like excessive cycling, lost production, unnecessary speed changes, and poor pump fillage, the algorithms implement changes that improve the performance of the well and help operators leverage the full capabilities of their VFD.

About our Speaker:

Ian has an undergraduate degree in petroleum engineering and a master’s degree in mechanical engineering. He joined the Theta/ChampionX team (formerly Dover and then Apergy before ChampionX) back in 2016 as an artificial lift engineer. He also was the support team manager and product line manager before starting a new role managing the customer success team.

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SPE YP is host a happy hour on November 7th sponsored by ChampionX!

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