Study on Formation Damage of Fracturing and Its Prevention through an Environmentally Friendly Method of Oxidative Stimulation in Shale Gas Reservoirs

Abstract

Large amounts of fracturing fluid remain in the reservoir after fracturing, rendering it easy to induce reservoir damage and restrict the stimulation effect. Based on the idea of less flowback of fracturing fluid and considering the characteristics of abundant organic matter and pyrite in shale gas reservoirs, an environmentally friendly method of oxidative stimulation is proposed. Through experimental verification and theoretical analysis, it is found that the oxidative stimulation method has a good application prospect in shale reservoirs. By adding an oxidant to the prefrac fluid, the oxidative stimulation can increase the porosity, enlarge the pore size, promote the imbibition capacity of the shale gas reservoir, and prevent the water trapping damage and stress-sensitive damage by reducing water saturation of the fracture and selective dissolution of the fracture surface. Since the fracturing flowback fluid faces a serious risk of environmental pollution and purification treatment due to its variety and complexity of pollutants, oxidative stimulation can prevent environmental pollution by reducing the leakage risk of the flowback fluid with a low flowback rate and continuous purification treatment of the flowback fluid, thus achieving the goal of environmentally friendly development and stimulation of shale gas reservoirs.

Nanobiocatalyst Based on Enzyme Immobilization for Mudcake Removal and Reservoir Damage Control

“…1 Due to the unique geological characteristics and harsh engineering conditions of oil and gas reservoirs, reservoir damage problems often occur during the stages of drilling and completion, oil and gas production, and enhanced oil recovery (EOR). 2 Reservoir damage can significantly reduce injection and flow capacity, hamper hydrocarbon production, and incur additional operating costs, cutting the production of the oil well. 3 The drilling operation is typically the primary cause of reservoir damage, so appropriate drilling fluids are selected to create a low-permeability sedimentary layer (mudcake) on the well wall.…”

“…Despite the significant expansion of renewable energy sources, traditional energy sources such as oil and gas continue to represent a substantial proportion of the global energy supply, accounting for over 80% . Due to the unique geological characteristics and harsh engineering conditions of oil and gas reservoirs, reservoir damage problems often occur during the stages of drilling and completion, oil and gas production, and enhanced oil recovery (EOR) . Reservoir damage can significantly reduce injection and flow capacity, hamper hydrocarbon production, and incur additional operating costs, cutting the production of the oil well .…”