Production Analysis of Multi-Stage Hydraulically Fractured Horizontal Wells in Tight Gas Reservoirs

Abstract

Activities in exploitation and developing tight gas reservoirs grown tremendously in recent years. The horizontal well with multi-stage hydraulic fracture stimulation has proven to be an effective strategy of developing these unconventional resources. However, to evaluate the fracturing treatment and predict the long-term production behavior of wells in gas recovery it is important to estimate the effective half-length and spacing of created hydraulic fractures and the extent of the stimulated reservoir volume (SRV). In this paper, a simplified linear model is presented to represent the relationship between fractures and matrix rock. Four flow regimes are identified with this model which exhibits the production dynamics of multi-stage fractured horizontal wells (MFHW). Rate-normalized gas pseudopressure is derived from production data and used to interpret flow regimes with corresponding calculation equations. We illustrate the analysis procedure with two field cases from a tight gas reservoir in Northeast China. The results prove that the proposed method works well in analyzing production data from tight gas wells in their early life. The potential in further developing this technique for practical application is obvious and looks very promising.

Quantity of flowback and produced waters from unconventional oil and gas exploration

“…By examining the results from different statistical methods of decline curve development of FP water from unconventional oil and gas operations ( Figure S1, S2) we show a pattern that begins with high production rates during the first few months of production, followed by an order of magnitude reduction and flattening out of production rates over the course of production. This is consistent with observations made in previous studies (Mutalik and Joshi, 1992;Nicot et al, 2014;Wang and Zhang, 2014). In many cases, over 50% of the FP water is generated within the first year of an unconventional well, with a majority of that FP water composed of hypersaline formation water (Figs 3 and 4).…”

“…There are a number of ways to analyze and quantify production data on a basin-wide scale (Arps, 1945;Bai et al, 2013;Ilk et al, 2008;Jackson et al, 2014;Kondash and Vengosh, 2015;Lutz et al, 2013;Mutalik and Joshi, 1992;Nicot et al, 2014;Valko, 2009;Valko and Lee, 2010;Wang and Zhang, 2014). Several studies have shown estimated ultimate recovery of oil, natural gas, and FP water values similar to the results generated in this study, mostly agreeing with the reported median FP production values (Nicot and Scanlon, 2012;Nicot et al, 2014;Scanlon et al, 2014a).…”

“…Decline curves were first used by Arps (1945) to estimate ultimate recovery of currently producing conventional wells using limited data from initial production. Since then, varying empirical and theoretical methods have emerged attempting to estimate ultimate recovery of oil, natural gas, and FP water (Arps, 1945;Bai et al, 2013;Ilk et al, 2008;Jackson et al, 2014;Mutalik and Joshi, 1992;Valko and Lee, 2010;Wang and Zhang, 2014). We used data provided by DrillingInfo to generate decline curves for both oil and gas production from unconventional oil and gas wells ( Figure S1), and similarly FP water generation ( Figure S2).…”

“…When a well is hydraulically fractured, it is done so in stages, with each stage being plugged, while the next is being drilled and fractured (Mohammad et al, 2014;Wang and Zhang, 2014). This creates an increase in pressure and a backup of both fluids and gas, while further stages are drilled.…”

Graphic Template Establishment and Productivity Evaluation Model of Post-Fracturing Based on the Fluctuation Pattern of G-Function Curve

“…In 2000, the G-function formulation was modified by R. Henry Jacot and Bruce R. Meyer [16] and the natural development factor β was proposed to quantitatively characterize the communication between natural fractures and induced fractures. In subsequent studies, different scholars [17][18][19][20][21][22][23][24][25] have successively developed G-function plates applicable to volcanic reservoirs based on construction curve pressure drop analyses and used G-function fluctuation characteristics to evaluate the complexity of the fractures. In 2022, Xiao Yang [26] analyzed the fracture morphology of the reservoir based on G-functions using pressure drop data after the fracture pump stoppage, which was subsequently verified using microseismic data.…”