Case Studies in Quantitative Flowback Analysis

Abstract

Recently, several authors have explored new methods for quantitatively analyzing multi-phase flowback data from multi-fractured horizontal wells (MFHW) to extract both fracture and reservoir parameters. These techniques provide much of the same information as long-term rate-transient analysis (RTA), although in a much shorter period of time. Flowback analysis is complicated by a rapidly changing fracture network and wellbore environment, multi-phase flow in the fractures (and possibly the reservoir), completion heterogeneity, as well as other effects which are often not present, or are ignored, when analyzing long-term (online) production data. For quantitative flowback analysis, the current authors have previously presented data-driven, pseudo-analytical methods for estimating key fracture properties (i.e. conductivity and half-length) from high-frequency, short-duration production test data. Models have been developed for both oil and gas wells representing a variety of reservoir and operating conditions. In this work, the models and procedures are extended to apply to more challenging reservoir/completion scenarios and are used in the analysis of several case studies from Canada. Each of the case studies demonstrate either the potential value add of the developed techniques, or a unique extension to the basic analysis methods. The case studies analyzed herein focus on light tight oil plays and consider layered reservoirs, multi-well flowback, and oil fracs in oil reservoirs. Further, the potential capital savings associated with conducting quantitative flowback analysis of early-time production test data is demonstrated. Each case study therefore presents a unique set of challenges that are often encountered in the real world. Numerical simulations are used to validate the sequence of flow-regimes depicted in the models. The methods presented in this paper will serve to partially satisfy the demands of industry to develop new methods for characterizing hydraulic fractures and forecasting production, particularly early in the well life. Through the use of several unique case studies, the wide-spread applicability and versatility of the techniques is demonstrated.

Mechanisms and capacity of high-pressure soaking after hydraulic fracturing in tight/shale oil reservoirs

“…On the basis of oilfield production data, the injected water was retained in the reservoir. Smaller flowback percentage of the fracturing fluid indicates a better production (Abbasi et al 2012;Williams-Kovacs et al 2015;Cao et al 2017).…”

Mathematical Modeling and Numerical Simulation of Water‐Rock Interaction in Shale Under Fracturing‐Fluid Flowback Conditions

“…The effects of free gas, permeability damage, fracture network with different geometries, conductivities and porosities, the decrease in effective fracture length, fracture compressibility, fracturing fluids energized by N 2 , condensate source and the interactions between fracture stages and wells were taken into consideration later. The proposed methods were applied in field cases for parameter inversion (Clarkson & Williams‐Kovacs, 2013a, 2013b; Williams‐kovacs & Clarkson, 2013a, 2013b, 2013c, 2014, 2015; Williams‐Kovacs et al., 2015). In the research of Dehghanpour, Abbasi, Ezulike and Zolfaghari et al., analysis methods for single water phase and for gas‐water two phase were successively proposed (Abbasi et al., 2012; Ezulike & Dehghanpour, 2014; Ezulike et al., 2014).…”

Numerical Investigation of Multistage Fractured Horizontal Wells considering Multiphase Flow and Geomechanical Effects

“…During the hydraulic fracturing process, the fracturing fluid, which is retained in the fracture network, can be produced with shale gas in the early stage of production, which decreases the fracture permeability. Many cases have been reported in field development [13]. Several researchers have established a numerical simulator to solve problems related to fluid-solid coupling from different aspects; the procedure for numerical simulation includes mathematical model establishment, model discretisation methods, and the solution of model equations.…”