High-Resolution Visualization of Flow Interference Between Frac Clusters (Part 1): Model Verification and Basic Cases
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2017, Unconventional Resources Technology Conference (URTeC). The reservoir drainage around horizontal wells is visualized at high-resolution using a newly developed analytical streamline simulator based on complex potentials. Drainage contours show the progressive oil recovery from the stimulated rock volume (SRV). The method plots streamlines, the time-of-flight for fluid to fracs, velocity contours and pressure distribution around fracked wells. Independent simulations with a commercial reservoir simulator confirm the visualizations with complex potentials are accurate, and that the latter method gives high-resolution images of the pressure and flow field around individual fracs. We show the depth of investigation reflected by pressure contour gradients is a poor indicator of drained reservoir volume. Drainage contours based on particle velocity tracking give a much clearer view of the actual region drained by a well via its fracs. First, matrix drainage by 2-frac and 3-frac clusters is studied in detail. Flow separation surfaces between 2 clustered fracs (with equal length and flux) are always straight, creating planes of symmetry between adjacent drainage regions. Clusters of 3 fracs develop curved flow separation surfaces, convex toward the inner frac. For frac spacing less than 4 times total frac length, drainage of the central region of the 3-frac clusters slows down due to flow interference, which confirms earlier findings that production gains become insignificant above certain frac length/spacing ratios. Next, the analysis shows the flow field, drainage contours, velocity contours and pressure distribution for a horizontal, synthetic well with 11 transversal, kinked fractures. The basic analysis in this paper (URTeC 2670073A, Part 1 of our study) is expanded in a companion paper (URTeC 2670073B, Part 2 of our study), which applies the methodology of flow visualization using drainage and velocity contours to a sample well from the Midland Basin, Texas.
name of conference
Unconventional Resources Technology Conference
Proceedings of the 5th Unconventional Resources Technology Conference
author list (cited authors)
Weijermars, R., van Harmelen, A., Zuo, L., Nascentes, I. A., & Yu, W.
complete list of authors
Weijermars, Ruud||van Harmelen, Arnaud||Zuo, Lihua||Nascentes, Ibere Alves||Yu, Wei