Society of Petroleum Engineers
Distinguished Lecturer 2004-05 Lecture Season

Hydraulic Fracture Design, Treatment and Optimization:
Lessons Learn’t from Case Studies
Usman Ahmed
Schlumberger

Usman Ahmed

Abstract:
A number of studies have documented that the demand for oil and gas is expected to grow at a rate of 2.5% and 3.2% per year, respectively, for the next 10 years. Such a growth cannot be addressed only through new discoveries. An area that can significantly address this demand is the application of technological advances made in the area of hydraulic fracturing of formations in particular those in mature and brown fields. Typically, hydraulic fracturing has been applied to relatively low permeability formations. With the advent of technological developments in equipment and pumping materials high permeability formations can now be effectively hydraulically fractured

A recent review on Hydraulic Fracturing Survey of Industry Practices suggests that two-thirds of the treatment in the U.S. fail to reach the optimized well productivity goals. Careful review of the data show that the primary reasons for such failure include gross assumptions made in the understanding of the reservoir parameters and thereby resulting in inefficient fracture design, improper post-fracture analysis techniques and in certain cases the use of inappropriate analytical and numerical models. Review of hydraulic fracture treatments in various other parts of the world also show similar discouraging news.

The news does get better. A series of case studies performed in various parts of the world reveal that the aspects that cause the failures are the same items when paid attention to can provide great dividends and pave the road to treatment improvement and optimization. Key to a successful treatment starts with a design based on clear understanding of the reservoir properties impacting production following fracturing. Proper treatment implementation is another key element. Use of real time monitoring of bottom-hole pressures to the use of passive seismic / tiltmeter technology can have significant effect. It is rare that we know the growth of hydraulic fracture away from the well bore and as such post-treatment evaluation is critical to treatment optimization. The important point to recognize is the need for a closed-loop workflow applied on a field wide basis and not necessarily on every well.

We use field case study examples to show how improved identification of productive intervals, improved fit-for-purpose stimulation design, clearer understanding of the results by comparing it to predicted values lead to reduced cycle time and also the reduction of the cost per hydrocarbon unit.
Biography:
Mr. Usman Ahmed is currently the Schlumberger Global Business Manager for Mature Fields and Carbonates based in Houston, Texas. Prior to this assignment he has held various technical and management positions within Schlumberger in the U.S. and overseas. Prior to joining Schlumberger, Mr. Ahmed worked for an oil and gas operator and a research organization. He has authored / co-authored over forty publications and two patents in the areas of well stimulation, formation evaluation, rock mechanics and field development He is currently chairman of the SPE Eastern Hemisphere Forum implementation committee and also member of the overall SPE forum committee. Mr. Ahmed holds B.S and M.S. degrees from Texas A&M University, both in Petroleum Engineering.

LASPE Forum Committee:
Maryam Davari, 213-225-5900x209, mkashfi@breitburn.com
Brandy Fellers, 562-624-3237 brandy_fellers@oxy.com
Rick Finken 562-570-3961, richard_finken@longbeach.gov