关键词: 火山岩气藏, 不稳态窜流, 部分打开, 压裂井, 试井分析

Abstract: Due to the characteristics of volcanic rocks such as thick productive formations of gas reservoirs, various rock types, complicated and changeable lithologies and lithofacies, strong heterogeneity, and development of natural fractures, it is difficult to open all reservoir body by fracturing fractures during development of fractured wells. Natural fractures are dominated by vertical clinofractures and high-angle fractures, and plenty of well test data show that there are obvious characteristics of unsteady interporosity flow between media. In view of the above characteristics, considering the partially penetrating reservoir body by fracturing fractures, the matrix has been simplified to the columnar matrix evenly and alternatively distributed together with natural fractures; a well testing analysis model is established for the fractured wells partially penetrating using unsteady interporosity flow. Further, this model is solved using the point-source model, and the method of separation of variables; additionally, a chart of typical curves is drawn. The typical curve is divided into six main flow sections:well bore storage section, transition section, linear flow section, spherical flow section, unsteady interporosity flow section and boundary reflection section. The boundaries include infinite boundaries and closed boundaries, and a sensitivity analysis is carried out on the parameters such as fracture half-length. Taking a fractured well in a block of the Kelameili volcanic gas reservoir as an example, this paper analyzes the well test curve and gives well test interpretation. The results show that the horizontal permeability of the fractured well is small, the vertical permeability is particularly large, and the partially penetrating degree is relatively small, basically consistent with static and dynamic data.

Key words: volcanic gas reservoir, unsteady interporosity flow, partially penetrating, fractured well, well test analysis