Residual Damage, Its Consequences, and Remedial Measures on Post Hydrofrac Well Productivity: Learnt Lessons

Abstract

Hydraulic fracturing or hydro-frac fluids can impede well production due to the damage caused to the reservoir formation and fracture face, generated from adverse interactions with reservoir rock. Understanding the mechanisms of hydraulic fracturing, optimum treatment designs, and pumping/pressure profiles is critical for hydro-frac success. However, to realize the full potential of fracturing and the mitigation strategies for reservoir and fracture conductivity damage during and after its occurrence, fracturing must be considered during the design phase itself. This article provides a brief overview of hydro-frac techniques, including design, optimization, modeling, commonly used proppants, and fracturing fluid benefits and consequences based on critically reviewed case studies. However, the primary focus of this article is on the potential of fracture conductivity damage and the intrinsic mechanisms in hydraulic fracturing. The article presents updated information on various damage mitigation processes established through laboratory investigation and field implementation. The authors expect that the provided workflow in this article will be helpful to researchers and stimulate engineers to a great extent.

Chemical composition, particle size, and molecular weight distributions of chemically degraded guar gum solutions

“…A side effect of the chemical degradation is the formation of insoluble residues in the fracturing fluid 8 . The insoluble residue precipitates out of the initially homogenous solution, aggregates, and subsequently fouls and plugs the porous network of the fractured rock.…”

“…The insoluble residue precipitates out of the initially homogenous solution, aggregates, and subsequently fouls and plugs the porous network of the fractured rock. This mechanism is one of the causes of so‐called “formation damage,” which encompasses an array of problems such as scale formation, fines migration, proppant crushing, and so forth that arise in the well and lead to impairments in the productivity of a reservoir 7,8 . Little information is available regarding the physical or chemical properties of the insoluble guar gum residues.…”

“…4,6,7 A side effect of the chemical degradation is the formation of insoluble residues in the fracturing fluid. 8 The insoluble residue precipitates out of the initially homogenous solution, aggregates, and subsequently fouls and plugs the porous network of the fractured rock. This mechanism is one of the causes of so-called "formation damage," which encompasses an array of problems such as scale formation, fines migration, proppant crushing, and so forth that arise in the well and lead to impairments in the productivity of a reservoir.…”

“…This mechanism is one of the causes of so-called "formation damage," which encompasses an array of problems such as scale formation, fines migration, proppant crushing, and so forth that arise in the well and lead to impairments in the productivity of a reservoir. 7,8 Little information is available regarding the physical or chemical properties of the insoluble guar gum residues. This study aims to understand the source of the insoluble residue with the ultimate aim of identifying routes to reduce residue formation or otherwise mitigate the effects of the residue on well productivity.…”