Fracture Imaging Pilot Designed to Compare Various Microseismic Monitoring Techniques
“Hydraulic Fracturing is an economic necessity for low permeability reservoirs. The production potential is evaluated as a function of fracture penetration and conductivity”. Highly conductive flow paths generated by fracturing some distance away from the wellbore needs to be imaged. Fracture mapping is considered as one of the key challenges for tight gas reservoir development.
Microseismic monitoring is known as a technique able to provide fracture imaging. Indeed, changes in pressure and stress induced in the formation by the hydraulic fracturing process cause small slippages to occur along preexisting fractures. These shear failures generate P- and S-waves, which can be recorded at seismic receivers.
Microseismic amplitudes are small, therefore the common technique is to run sensitive downhole tools in an offset well at small recording distances. However, availability of existing wells and the small well spacing is often a strong limiting factor to the application of this technique. Alternative solutions exist but results are as yet unclear.
For this reason, TOTAL has completed in 2008 a unique pilot experiment on the Aguada Pichana Field (Neuquen Basin, Argantina) to develop, test and validate alternative microseismic designs which can be applied to hydraulic fracture mapping for tight gas reservoir developments.
The pilot program includes microseismic monitoring from the treatment well (wire-line design), from the observation well (as reference), from dedicated shallow wells and from dense surface networks. The pilot results are going to be compared for various stages of fracs with and without proppant.
The two pilot objectives are to validate an alternative fracture imaging technique and to evaluate the potential benefits of various fracturing programs.
The paper on this unique pilot will present (1) the challenge and the objectives, (2) the monitoring networks tested, (3) the program and the frac stages performed and (4) the results focused on surface network.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009