By: Saad Ibrahim, P. Eng (Nov. 3, 2021)
Have you ever asked any of the following questions, and received this answer from your boss: We are not in the business of science!!
- I need to cut a core to understand reservoir heterogeneity
- I need to obtain relative permeability data to design my waterflood project
- I need to conduct a pressure survey to evaluate the performance of my field
If you received the answer “We are not in the business of science!!” here is an interesting case study you should provide:
An eighteen (18) stage frac was performed on a cased/cemented Hz well which was significantly under-performing relative to all the offset Hz wells. Therefore, a flow/build-up test was conducted to diagnose the production problem. The buildup test data could not be matched with the Model “Multi-stage Frac Hz Well (MFHW), which was a surprise. The data pressure could only be matched by a vertical well model!! Fortunately, a micro-seismic survey was conducted during the frac job, which explained the cause of the problem. Apparently, a poor cementing of the casing was evident, as a result, most of the frac fluids of 16 stages channeled behind the casing & activated a fault located close to the heel of the Hz heel.
As a result, only two frac stages close to the heel of the Hz well were successful. Therefore, the well Hz acted as a vertical.
Conclusion: without applying “science“ and investing $$ for a micro-seismic survey and a well test, the mystery of the well’s poor performance could not be recognized
The lateral cement needed to be repaired and then refraced.
Expected well performance was restored.