Technical Advancement of Carbonate Acid Stimulation Injection

Abstract

Formation damage is the impairment of permeability of rocks inside a petroleum reservoir. This occurs during drilling, production, stimulation and enhanced oil recovery operations, by various mechanisms such as chemical, mechanical, biological and thermal. Near wellbore formation damages have a great impact on productivity of the damaged formation. Acidizing is a stimulation method to remove the effect of near wellbore damage through reacting with damaging materials or the formation rocks (carbonate or sandstone rocks) to restore or improve permeability around the wellbore. Several experiments are conducted to study the effect of temperature and acid concentration combined on the efficiency of matrix acidizing. Three different concentrations scenarios of hydrochloric acid (3%, 15%, and 28%) and 4 different temperatures scenarios (25 °C, 35 °C, 70 °C, and 100 °C) were tested to investigate pore-enlargement success effect on permeability. The purpose of this experiment is to introduce the concept of optimized temperature augmented with optimized acid concentration in carbonate matrix acidulation. Morphology of pore geometry and area measurement software is used. New Advancement in imaging that captured pore area enlargement as big-data necessarily for artificial intelligence modeling. Captured pores before treatment and captured pores after thermal-HCL acid treatment have demonstrated that image processing of the actual acidized rock data can select the optimized recipe concentration of acid that will increase permeability, hence recovery. The results show that matrix acidizing is an effective method to improve permeability and enhance production, as it demonstrates that using less acid concentration with the optimized temperature can result in a favorable and satisfying outcomes.

Results of Laboratory Studies of Acid Treatment of Low-Permeability Rock Cores

“…Near wellbore formation damages have a great impact on productivity of the damaged formation. Combined skin factor approach, which takes into account the complexity of near wellbore damage zone and its modification during acid stimulation is presented by authors of [18][19][20][21]. Combined skin factor is introduced that takes into account the present damage subzones with different permeability, perforation channels, wormholes, relative permeability and viscosities of pumped fluids and their changes during acidizing process.…”

Influence of Geological and Technological Parameters on Effectiveness of Hydrochloric Acid Treatment of Carbonate Reservoirs

“…To enhance the effectiveness of the hydrochloric acid effect on reservoir, a large number of modifications of acid compositions (AC) are being currently developed, contributing to the individual nature of the process of the treatment of productive sediments near wellbore [7][8][9]. To exercise a competent approach to the design of hydrochloric acid treatment, physical and chemical properties of formation fluids, lithologic and mineralogical composition, type of rock paleolithic facies and pressure-temperature conditions will be taken into account [10].…”