Rule Based Vs Physics-Based Well Engineering

Traditional Well Engineering is synonymous with wiper trips, limited well path of 2 degrees/100 ft, not setting casing in sand, identifying the risks avoid, etc. In this paradigm, the best well is the well with the least failure or non-productive time, irrespective of how long it took to drill.

A well is considered a "technical success" if it is delivered irrespective of whether it produced oil/gas optimally or not.

The best well engineer for the job is the one who has mastered these rules and has the highest years of experience having learned and applied them. And experienced well engineers often referred to younger colleagues trained on physics-based methods, as "theoretical" or "computer-Based" well engineers mockingly.

Drilling in the '90s

Approaching the millennium, some super majors started to realize the efficiency of cash use was more important than 'technical success' in well delivery. They began to recruit bright and high-capacity university graduates, to be trained in physics-based well engineering, with very mixed successes. The implementation lacked the right expertise resources, well engineers continued to be trained in the old. No surprise that in the operating units located in Africa, Middle East and Asia, it is hard to find well engineers not trained in the old rule-based well engineering. This explains the huge discrepancies in well delivery efficiency between the USA and Nigeria, for example. a 10,000 ft well in the USA will drill in 10 days, while same takes average of 83 days in Nigeria.

Modern Physics-Based Well Engineering

Modern well engineering is targeted at preserving wellbore and overall Well Integrity. Prior to drilling, a model of the well is built using all available data, and applying physics and modern engineering principles such rock failure mechanics, fluid mechanics, drill string dynamics, etc, and integrating these with the offset wells data with the help of the emerging field of applied data analytics. Well construction then involves dynamically monitoring the actual well progress against the predicted performance. The results have been overwhelmingly huge cost savings such as reported by my friend Tayo Ajimoko in World Oil magazine (https://www.worldoil.com/magazine/2007/july-2007/features/technical-limit-thinking-produces-steep-learning-curve/#:~:text=The%20technical%20limit%20is)

How do we re-orient the mindset of the old-fashioned rule-based experienced well engineers, who are todays's decision makers, to accept, and not stifle a physics based approach?

Costs of Rule-Based Well Engineering

1. A recent land well operation encountered huge surface losses to the extent of causing broaching. The obvious answer was to pump cement and abandon the well as all available lost circulation materials have proved fruitless. However, we revisited the model of Wellbore integrity and discovered room that can be exploited. This resulted in drilling a long 8000 ft 12 1/4" open hole for the 9 5/8" casing. Not only was the well program successfully recovered with minimal lost time, the cost of building a new slot/location was successfully averted.Estimated saving: $4 million
2. A Middle East land well needed re-entry and sidetrack into a new objective. The options were to either apply the 2 degrees/100 ft limitation and drill a long 4000 ft open hole which will pass through a know 0.95 psi/ft high pressure reservoir. Or, implement a physics-based short-radius drilling requiring 4o degrees/100 ft. A huge debate arose but the value of the latter was a saving of 90 days drilling time worth $12.6 m. Hence the physics based approach was approved by management.Estimated saving: $13 million

Conclusion

No doubt, the science based well engineering is the future of well engineering. The challenges are:

• How do we re-orient the mindset of the old-fashioned rule-based experienced well engineers, who are todays's decision makers, to accept, and not stifle a physics based approach?
• Where do we find the experts to implement and/or train well engineers in the physics-based methods?
• How do we convince operator managements, who often only understand the old rule-based methods, that the cost savings from physics-based well engineering actually results in value to the field development, in terms of faster well delivery, reducing formation damage, increases productivity of the well, etc. and not just a "theoretical" to "computer" well engineering?