A comprehensive analysis of carbonate matrix acidizing using viscoelastic diverting acid system in a gas field

Abstract

This paper explores matrix acidizing, a method to enhance well productivity by injecting acid into the formation to dissolve damage or create flow channels. Focusing on gas well acidizing, it introduces a groundbreaking three-stage approach with hydrochloric acid (HCl) and viscoelastic diverting acid (VDA). Unlike recent research, which often overlooked specific VDA stages and favored VES or surfactant gelled systems, this study innovatively integrates VDA throughout laboratory experimentation, simulation modeling, and operational execution. The article showcases the effectiveness of HCl and VDA in dissolving reservoir materials, preventing issues like emulsion formation and iron precipitation, reducing corrosion and H2S emissions, enhancing penetration depth, fluid flow channels, and stimulating all reservoir layers. Utilizing a numerical model, it recommends an optimal acidizing method with five main acid injection stages and five VDA injection stages. The results demonstrate a notable increase of 100% in gas production, an 84% rise in gas pressure, and a reduction of BS&W from 7 to 3%. Aimed at industry professionals, this paper serves as a guide for optimizing well productivity and gas recovery processes.

A comparative study of brine solutions as completion fluids for oil and gas fields

“…In stark contrast, formation water exhibits the inverse, boasting low sulfate ion concentrations and high levels of calcium, barium, and strontium ions. The outcome of their convergence is the precipitation of compounds such as calcium sulfate, barium sulfate, and strontium sulfate salts, which manifest as undesirable sediments 4 , 45 , 50 , 51 .…”

Pore-Scale Numerical Simulation of Acid–Rock Reaction Processes in Carbonate Reservoirs

“…Acidification constitutes an essential method to enhance productivity in conventional carbonate reservoirs. − The acid system functions by dissolving formation minerals or creating new flow channels, thereby markedly improving the permeability of the wellbore region. , The chemical interaction between the acid system and rock encompasses three primary stages: (1) the transportation of reactants to the rock surface through mass transfer; (2) the reaction of acid with the rock surface; and (3) the removal of reaction products from the rock surface . The rate of acid–rock reactions is influenced by various factors, such as acid properties, injection rate, reaction temperature, and mineral composition. , Therefore, it is of great significance to study the dynamic dissolution law of acid–rock reaction by establishing a model at the pore scale …”