Practical Solutions for Pressure-Transient Responses of Fractured Horizontal Wells in Unconventional Shale Reservoirs

Abstract

This paper presents an analytical trilinear-flow solution to simulate the pressure-transient and production behaviors of fractured horizontal wells in unconventional shale reservoirs (Ozkan et al. 2009). The model is simple, but versatile enough to incorporate the fundamental petrophysical characteristics of shale reservoirs, including the intrinsic properties of the matrix and the natural fractures. Special characteristics of fluid exchange among various reservoir components may also be considered. Computational convenience of the trilinear-flow solution makes it a practical alternative to more rigorous but computationally intensive and time-consuming solutions. Another advantage of the trilinear-flow solution is the convenience in deriving asymptotic approximations that provide insight about potential flow regimes and the conditions leading to these flow regimes. Though linear-and bilinear-flow regimes have been noted for fractured horizontal wells in the literature on the basis of their diagnostic features, they have not been associated with particular reservoir characteristics and flow relationships. The trilinear-flow solution also provides a suitable algorithm for the regression analysis of pressure-transient tests in shale reservoirs.

A review of stimulated reservoir volume characterization for multiple fractured horizontal well in unconventional reservoirs

“…Flow regime 1 is linear flow; flow regime 2 is elliptical flow; flowregime 3 is fracture interference; and flow-regime 4 is late compound linear flow. Brown et al (2011) propose the tri-linear flow model for multi-fractured horizontal well (MFHW). It is common to regard the inner reservoir as stimulated reservoir and to characterize the permeability of the whole SRV as an equivalent permeability.…”

A multi-linear flow model for multistage fractured horizontal wells in shale reservoirs

“…According to Brown et al (2009Brown et al ( , 2011, storage effect could be taken into account with the following equation:…”

“…Brown et al (2009Brown et al ( , 2011 proposed the trilinear flow model to research the MFHW performance in unconventional gas reservoirs. In their model, pressure transient analysis was obtained.…”

“…These studies mainly focused on vertical well or horizontal well and few about the MFHW. Although Ozkan et al (2010) and Brown et al (2009) developed a trilinear flow model to simplify the complex process and get good results in unconventional gas reservoirs, desorption and adsorption mechanism, which is the key mechanism of shale gas reservoirs, was ignored. Sang et al (2014) presented a new mathematical model considering adsorption and desorption process, which made up the disadvantage of the trilinear flow model for MFHW in shale gas reservoirs.…”

An Analysis for the Influences of Fracture Network System on Multi-Stage Fractured Horizontal Well Productivity in Shale Gas Reservoirs

“…Moreover, the model assumes that linear flow is the only regime in MFH well, which is not accurate and could lead to an unconvinced result in radial or elliptic flow periods. Since the linear flow assumption is convenient for derivation and solution, the linear flow model is widely used for research on unconventional reservoir [30][31][32][33]. In fact, because of the early flow around fractures is linear, the linear flow results are in good agreement with the accurate solutions in the early period of time.…”