An investigation on obtaining the minimum horizontal stress from hydraulic stress test data
W.L. Horeman (TU Delft - Technology, Policy and Management)
P.J. Vardon – Mentor (TU Delft - Geo-engineering)
A. Barnhoorn – Mentor (TU Delft - Applied Geophysics and Petrophysics)
H. Hajibeygi – Mentor (TU Delft - Reservoir Engineering)
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Abstract
Accurate estimation of the minimum horizontal stress is essential for well design, drilling safety, and predicting induced seismicity. In many regions of the Netherlands, however, only formation integrity tests (FIT) and leak-off tests (LOT) are available, raising the question of whether these drilling tests can be used to reliably infer the minimum horizontal stress. This study evaluates the reliability of stress estimation from hydraulic fracturing data, with a particular focus on the differences between fracture initiation and closure pressures.A comprehensive dataset of extended leak-off tests (XLOT), micro-fracture tests, and conventional LOT/FIT data is analysed. Multiple closure interpretation methods are compared, and their variability, bias, and applicability are quantified. In addition, initiation-based pressures are evaluated within a mechanical framework, including sensitivity analyses and stress consistency checks.The results show that closure-derived pressures provide the most reliable estimate of the minimum horizontal stress, whereas initiation-based pressures are strongly influenced by near-wellbore effects and operational conditions. Closure interpretation is inherently method-dependent, with inter-method differences up to 25~bar, significantly exceeding the repeatability within a single method. Among the evaluated techniques, the semilogarithmic derivative method demonstrates the best balance between robustness and applicability.Pressures from FIT and LOT tests often exceed closure-derived minimum horizontal stress and exhibit large variability, including non-physical results in a significant fraction of cases. While these pressures can be interpreted as upper or lower bounds within a mechanical framework, their quantitative reliability is limited. Furthermore, an offset data case study from nearby wells did not provide a reliable predictor the minimum horizontal stress.This study establishes a hierarchical interpretation framework in which closure-derived pressures form the primary estimate of the minimum horizontal stress, while initiation-based pressures provide only supplementary constraints.