GaStim Concept - A Novel Technique for Well Stimulation. Part I: Understanding the Physics

Abstract

Well stimulation for production or injection enhancement in mature fields is a key and challenging task. Loss of reservoir energy due to pressure depletion coupled with complex damage scenarios existing in adverse petro physical environments can become restrictive factors for the proper performance of conventional liquid based chemical stimulation systems. Main limitations are normally related to high interfacial tensions preventing optimal well´s clean up and cost-effective achievable penetrations. This work presents a new well stimulation concept in which the carrying system is gas instead of liquid. The overall study will be presented in 2 parts. Part I will discuss basic physical questions related to treatment durability as a function of deployment method (continuous dispersion vs liquid batch gas displacement) for at least two damage scenarios of particular interest: asphaltene deposition and condensate blockage. A basic mechanistic simulation is also presented for benefit estimations at well scale. Part II will focus on field trials design and execution using micellar and/or fluoropolymer type of chemistries that exhibited the best performance when tested under laboratory conditions. Experiments herein presented were done in formation sandstone cores simulating reservoir conditions. It is shown that natural gas when used as the carrying system to deploy conventional asphaltene dissolution and condensate removal chemistries enhances both Ko re-establishment and treatment durability as compared to equivalent liquid-based applications. Additional studies are being performed to maximize the effectiveness of the GaStim concept. Sensibilities to gas type (N2, CO2), added chemical and dosages as long as field trial documentation will be presented in part II of the present work.GaStim concept is presented as a novel chemical stimulation technique potentially allowing deeper penetrations and better chemical adsorptions. Its potential, although still not fully undiscovered, is certainly supported by higher Ko reestablishment values and longer treatment durabilities observed.

Upgrading of Extra-Heavy Crude Oils by Dispersed Injection of NiO–PdO/CeO2±δ Nanocatalyst-Based Nanofluids in the Steam

“…In this way, recently, a novel technique for well stimulation and fluid injection known as gas stimulation (GaStim) was proposed by Franco et al [28] and Restrepo et al [29]. The method consists of the dispersion of a liquid treatment on the gas stream, achieving high injection rates and liquid droplets with a smaller size, as well as increasing the invasion radius of the liquid around the injector well [29]. Restrepo et al [29] reported positive results in the first pilot test in Colombia to overcome the formation damage because of the combined effect of condensate banking and asphaltene precipitation.…”

“…The method consists of the dispersion of a liquid treatment on the gas stream, achieving high injection rates and liquid droplets with a smaller size, as well as increasing the invasion radius of the liquid around the injector well [29]. Restrepo et al [29] reported positive results in the first pilot test in Colombia to overcome the formation damage because of the combined effect of condensate banking and asphaltene precipitation. Through the injection of the treatment by means of the GaStim method, an increase of 40% in oil rate production and a decrease of 30% of the gas-oil ratio was achieved.…”

Effects of Surface Acidity and Polarity of SiO2 Nanoparticles on the Foam Stabilization Applied to Natural Gas Flooding in Tight Gas-Condensate Reservoirs

“…Because of the massive production of gases, such as methane or natural gas in the tight gas-condensated reservoirs in Colombia, the natural gas flooding with foam is a viable alternative for enhancing the recovery of oil. − Nevertheless, a significant limiting factor of foams during field applications is the fact that they are thermodynamically unstable, , hindering their long-term use . Some factors that affect the stability of the foams are the temperature, pressure, and presence of electrolytes and solid particulate material in the lamellae .…”

Injection of Nanofluids with Fluorosurfactant-Modified Nanoparticles Dispersed in a Flue Gas Stream at Very Low Concentration for Enhanced Oil Recovery (EOR) in Tight Gas–Condensate Reservoirs

“…The addition of chemicals to gas injection streams (ChEGas-EOR) has been introduced to boost the efficiency of these technologies, with positive results in oil and gas production. This method has demonstrated an ability to reduce condensate formation damage by promoting oil mobility, thereby altering reservoir wettability. , It has also provided greater durability and invasion depth of the treatments conducted for the condensate mobilization through the dispersed injection of a chemical solution in a gas stream (CO 2 , nitrogen and methane). , For example, Franco et al and Restrepo et al , reported significant oil production increases resulting from stimulation processes that occurred after the injection of a chemical liquid mix of micellar compounds based on alcohols and fluor-surfactant diluted in water and dispersed in a gas stream. ,, Nevertheless, these chemicals have failed to achieve gas-wettable systems, in addition to exhibiting low perdurability. ,,− …”

“…26,27 For example, Franco et al 28 and Restrepo et al 25,26 reported significant oil production increases resulting from stimulation processes that occurred after the injection of a chemical liquid mix of micellar compounds based on alcohols and fluor-surfactant diluted in water and dispersed in a gas stream. 24,25,28 Nevertheless, these chemicals have failed to achieve gas-wettable systems, in addition to exhibiting low perdurability. 24,25,29−33 Recently, nanoparticles have gained importance due to their exceptional properties, including small size, thermal, chemical, and mechanical stability, 34,35 and excellent performance in field applications.…”