Managing Frac Driven Interactions (FDI’s)
The maturing of unconventional field development has led to a shift in the focus of microseismic monitoring activities. The emphasis of monitoring has become more one of understanding the interaction between completed wells as development proceeds and less on the optimization of the frac program for single wells or even pad. This shift has been the result of the increased interaction between primary (sometimes called parent) and secondary (sometimes called child) wells as stage and well spacing have been reduced in modern field development programs.
Fracture Driven Interactions (sometimes called frac hits) are common in unconventional reservoir development accomplished with closely spaced and often stacked horizontal wells. Production of earlier (parent) wells will create a zone of reduced pore pressure or “pressure sink” in the zone of depletion with a concurrent change in the geomechanical properties of the reservoir rock. Subsequent completions on nearby secondary (child) wells have been observed to preferentially “grow” towards these pressure sinks (see diagram). Such a deflection of the stimulation can compromise the stimulated volume of the secondary well(s) (their SRV) and affect the production of the primary well.
The documented effects of these FDI’s run from minor to major as follows:
- Temporary loss of production
- Permanent loss of production
- Poor SRV development in child well leading to lower than expected production
- Wellbore damage by mechanical distortion of the casing
- Complete loss of well by shearing off the well
The goal of microseismic monitoring is to provide a description of the FDI’s that are taking place as evidenced by the microseismic event patterns that are captured. An analysis of the data is done in a timely fashion to provide guidance that will allow the operator to avoid the negative effects of FDI’s as listed above. This may involve documenting the progress of SRV growth and the effectiveness of pressure sink mitigation tactics being deployed by the operator. It may also involve when faults appropriately aligned with respect to regional stresses are present, monitoring in real-time detects reactivation of faults that can lead to wellbore damage and even loss.
The goals of monitoring can be summarized as follows:
- Stimulation mapping to support custom treatment design and adjustment of injection rates, fluid volume, and proppant volume.
- Ensure the “template” drainage volume and ultimate recovery is met for every well but avoids overspending by over stimulation.
- Allow for timely tuning the frac parameters as one observes changes in the reservoir response to stimulation.
- Allow for a timely response to the unexpected whether mechanical or geological.
MSI has monitored more than 47,000 frac stages since 2005. We have the experience to make sure your job goes as planned and every well gets “cooked just right”!
To learn more about Frac Driven Interaction, please contact MicroSeismic.