Flowback analysis (FBA) has typically been applied on a single-well basis to rapidly diagnose stimulation efficacy shortly after finishing pumping to close the diagnostic gap that exists in the early well life. Recently we have extended our FBA workflow to include SRV overlap and well interference analysis to help operators evaluate and adjust well spacing based on early-time production data. Historically, the only reliable methods available to operators early in the well life have been to apply specialized field diagnostics, such as cross-well fiber optics, however these methods are cost-prohibitive to apply to a large number of wells.
Estimating SRV overlap on a pad using FBA can be conducted in 3 easy steps:
- Conduct FBA on each individual well on a pad to estimate contacted mobile fracture volume (Figure 1a)
- Conduct FBA on rolled up pad data (“super well”) to estimate total fracture volume for the pad (Figure 1a)
- Compare sum of individual well fracture volumes with the super well (Figure 1b)
Fig. 1 – Workflow for analyzing SRV Overlap and Well Interference using FBA
Based on this analysis there are 2 possible outcomes which are described below and shown graphically in Figure 2.
- Super well frac volume is lower than sum of individual wells: SRVs are overlapping and well spacing may be too tight
- Super well frac volume is equal to the sum of individual wells: Tip to tip connection or no SRV overlap and well spacing may be too wide
Fig. 2 – Possible outcomes of FBA SRV Overlap and Well Interference Analysis
Since flowback data is gathered on the vast majority of wells, this analysis can readily be applied on every pad, providing operators with a fantastic new tool to close the diagnostic gap that exists between the pumping operation and gathering long-term (typically 1 year or more) production data.