Integrated Pressure Transient Analysis of Hydraulically Fractured Wells in Tight Gas Condensate Reservoirs in the Sultanate of Oman

Abstract

Abstract We present an integrated approach that combines pressure transient analysis (PTA) of multiple hydraulically fractured wells and additional measurements from other disciplines to deliver consistent results of formation and fracture properties. PTA for Multi-Fractured Horizontal Wells (MFHW) has greater uncertainty than that of their vertical counterparts. Utilizing complementary characteristics and information from multiple wells reduces the non-uniqueness in parameter estimations of tight gas condensate fields. This paper features a methodology to sequentially estimate fracture conductivity, fracture height, fracture length and formation permeability for MFHWs. First, this new method separates fracture conductivity from fracture geometry using Fracture Radial formation linear (FRFL) flow regime, resulting in a significant reduction of uncertainty in fracture conductivity estimations. Then, fracture height can be estimated by analyzing the end time of FRFL flow because fracture height dictates the termination time of the FRFL flow. Using the end time of the FRFL flow to estimate fracture height is a novel technique in the industry and has significant value because a MFHW can rarely drain hydrocarbon resources beyond fracture height in tight and shale reservoirs while the fracture height is almost always an unknown. After both fracture conductivity and fracture height are determined for MFHWs, formation permeability can be estimated from bilinear flow and/or pseudo-radial flow regimes, if existing. Finally, fracture length can be estimated using the conventional approaches with much less uncertainty because the other three key parameters are known. The proposed sequential interpretation workflow and fracture height estimation will be demonstrated using field examples. The estimated results provide valuable insights into formation features, reservoir quality and completion effectiveness, which help hydraulic fracturing design, reservoir modeling and forecast, and field development optimization.