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A valuable asset in the energy sector’s M&A activity, Dianne Ralston has played a role in several of the industry’s key mergers and joint ventures. From the formation of OneSubsea, a joint venture between Schlumberger and Cameron, to the merger between FMC Technologies and Technip, she has managed the legal side of some of the most impactful transactions in the last decade.

In her role, Ralston has also helped to shape carbon management ambitions within the oilfield services sector—a personal passion of hers.

“I am certain that the oil and gas industry will lead the way on carbon sequestration—a critical component to reach global net-zero ambitions,” Ralston said. “The reservoir knowledge of the oil and gas industry is crucial to ensure that CCS helps meet these targets.”

Joining Schlumberger

“I grew up with a perspective that the oil industry powers an important part of the economic growth engine. When I left private legal practice, I had the opportunity to join Schlumberger. I understood Schlumberger’s global reach and the important technical innovation it brought to the industry, so I felt fortunate to join the oilfield services leader. I recently returned to Schlumberger because I feel that the technology leadership that first attracted me to the company will be a significant part of the decarbonization of oil and gas production and also enable us to be a leader in energy transition as we apply technology advancements to other energy segments.”

Transitioning to C-suite roles

“While perhaps the most significant milestone for my career was the first move into the C-suite by taking the role of CLO [chief legal officer] at Weatherford, I consider returning to Schlumberger also very impactful. Coming back to Schlumberger at a crucial time in the evolution of the industry was important to help build the next generation of leaders in the company with a collaborative and empowering leadership style modeled for me by our current CEO Olivier Le Peuch. This leadership approach creates an environment where our people can innovate and take our industry forward.”

Access for all

“I am very passionate about energy access and the important role that oil and particularly gas will play for the next 20 or 30 years through the energy transition, as the most cost-effective, reliable and transportable form of energy. I recognize the important role that hydrocarbons will continue to play, particularly in the developing world, to ensure that large groups of people who still struggle for basic necessities are not left behind as the world transitions to other forms of energy.”

Be intellectually curious

“A learning mindset requires a certain humility to recognize that you can always expand your knowledge base and skill set. And I believe that a certain amount of humility, coupled with appropriate confidence in one’s skillset, are key ingredients to be an authentic servant leader.” 



  1. I was the commencement speaker at the 2022 graduation ceremony for the University of Houston School of Law.
  2. My career has taken me to every continent except Antarctica, and I continue to believe that ours is truly the most global industry.
  3. As the child of someone in the industry, I attended four different high schools in three different cities!

Click here for a full list of “25 Influential Women in Energy” honorees for 2022.

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