Fracture Face Damage—It Matters

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe poorer-than-expected performance of some fracturing treatments has been an issue for decades. Considerable effort has been devoted to improved modeling of fracturing treatments so that improved expectations can be provided. Fracturing fluids have been modified to enhance cleanup. Proppant conductivity studies have lead to a better understanding of fracture performance. Yet, there are still many treatments, particularly in low-permeability gas wells, that defy efforts to clean up quickly and to produce at the expected rates. This paper revisits the question of whether fracture face damage is an issue in the subsequent performance of a gas well. It will be demonstrated that the landmark paper by Holditch 1 has been misquoted for 25 years. A numerical simulator has recently been written that has reproduced the earlier work, but also expands on it by demonstrating the physical mechanisms by which fracture face damage can reduce gas production and accelerate water production. The simulator includes relative permeability curves for both gas and water, and capillary pressure functions. The role of Laplace pressure, or capillary pressure, will be highlighted in the explanation of how fracture face damage can cause significant loss in well productivity. In addition, the role of relative permeability to gas will be highlighted as to how it ultimately leads to decreased gas production and increased water production when the fracture face is damaged.

Simulation of Fracturing Induced Formation Damage and Gas Production from Fractured Wells in Tight Gas Reservoirs

“…Like the studies in the literature (see, Gdanski et al 2005;Barati et al 2008), the results show that it has a significant impact only when the absolute permeability is reduced by more than 99% in a depth of several to several tens centimetres, which seems improbable if the fracturing fluid is correctly selected.…”

“…Fracturing fluid induced formation damage has been studied in the literature (see, for example, Holditch, 1979;Friedel, 2004;Gdanski et al 2005Gdanski et al , 2006Shaoul et al 2007;Lolon et al 2007; Barati et al 2008;Wang et al 2009). Here, we use a mathematical model based on the polymer flow with a near-well fine grid system for the formation damage simulation of hydraulic fractures.…”

First Field Application in Canada of Carbon Dioxide Separation for Hydraulic Fracture Flow Back Operations

“…Fracture face damage due to phase trapping has been documented as a 'real' phenomenon which may greatly reduce the performance of hydraulic fractures (Cramer 2005, Gdanski 2005.…”

Effect of gel damage on fracture fluid cleanup and long-term recovery in tight gas reservoirs

“…However, his model did not consider capillary forces in the reservoir, closure stress effects, or damage in the fracture or the formation surrounding the fracture. Recently Gdanski et al (2005) simulated fracture face damage by clay swelling and concluded that fracture face permeability damage of 90% or higher can cause a major increase in water production and reduction in gas production. Cinco-Ley and Samaniego (1981) provided a relationship for estimating the effect of fracture face skin on well productivity.…”