Simulated Investigation in Wormhole Expansion Law of Gelling Acid Etching and Its Influencing Factors in Deep Carbonate Reservoirs

Abstract

Acidizing with gelling acid is the key technology in developing a carbonate reservoir successfully. It is difficult for the laboratory to carry out the radial displacement experiment with a large rock core. It is necessary to establish the gelling acid wormhole expansion model under the radial conditions, simulate the gelling acid wormhole expansion law under the radial conditions, optimize the construction parameters, and provide the basis for the optimal design of carbonate reservoir matrix acidizing. The research objective is to simulate the gelling acid etching wormhole expansion in a deep carbonate reservoir and make clear its influencing factors, which are helpful for reservoir stimulation. The mathematical model of gelling acid wormhole expansion was established, considering the influence of pore microscopic characteristics on acid flow and acid rock reaction. The simulation results indicated that viscosity, surface reaction rate, and hydrogen ion diffusion coefficient have different effects on gelling acid etching wormhole. The spatial distribution of pores determines the trend of gelling acid solution and thus the shape of the armhole. Perforation completion has a significant impact on the expansion of gelling acid etching wormhole. The wormhole extends forward along the perforation hole, and perforation increases the length of the wormhole. This wormhole expansion law is very suitable in situations where a deep carbonate reservoir is needed for gelling acid fracturing.

Acid Fracturing Technology and Effect Evaluation of Carbonate Horizontal Well in Fuman Oilfield

“…At present, the buried depth of the reservoir on the South Bank of Tahe River generally exceeds 7500 m, the formation temperature exceeds 160℃, the porosity is 0.4%-4.6%, and the permeability heterogeneity is strong. Deep carbonate reservoir has complex geological conditions and strong heterogeneity [1][2][3]. Based on the existing materials and previous research results, in this paper, through the fitting of fracture static pressure and fracture conductivity curve, the reservoir seepage characteristics are analyzed, the reservoir seepage characteristics were analyzed by using fracture static pressure fitting and fracture conductivity curve [4][5][6][7].…”

Quantitative evaluation of acid flow behavior in fractures and optimization of design parameters based on acid wormhole filtration losses

“…Katene et al 41 identifies and describes important processes occurring during proppant embedment, hydraulic fracturing, laboratory testing of fracture conductivity, as well as modeling of proppant embedment. Wang et al 42 established an expansion model for gelling acid wormholes under radial conditions, enabling simulation of their expansion characteristics. This research optimized construction parameters and provided the basis for optimal design of carbonate reservoir matrix acidizing.…”