Insight into selection of appropriate formulation for colloidal gas aphron (CGA)-based drilling fluids

Mohsen Pasdar,Mohammad Hossein Ghazanfari,Mohammad Soleymani,Ezatallah Kazemzadeh,Ehsan Kamari

doi:10.1007/s12182-020-00435-z

Mohsen Pasdar, Mohammad Hossein Ghazanfari + Show 3 more

Open Access

https://doi.org/10.1007/s12182-020-00435-z

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Abstract

Application of light-weight drilling fluids is essential to develop depleted hydrocarbon reservoirs. Recently, colloidal gas aphron (CGA)-based fluids have been introduced for such applications due to their ability in controlling fluid losses. In this work, a comprehensive experimental study was performed to choose the best formulation for CGA fluids by implementing static stability tests, rheological behavior measurements, and bubble size analyses of CGAs. Xanthan gum polymer and sodium dodecyl benzene sulfonate (SDBS), an anionic surfactant, and cetyl trimethyl ammonium bromide (CTAB), a cationic surfactant, were utilized to prepare CGAs. For the range of experiments conducted, the performance of CGA fluids prepared with SDBS was improved by increasing the polymer and surfactant concentrations. However, for CTAB, it was improved by an increase in the polymer concentration and a decrease in the surfactant concentration. The formation of white, long hair-like precipitates observed at high levels of CTAB caused CGA fluid to become rapidly unstable. Also, it was observed that the size of CGAs was significantly influenced by the polymer and surfactant concentrations. The most stable bubbles were formed at 6.86 g/L of polymer concentration. The results of this study provide insights into appropriate formulation for CGA-based fluids which could be potentially applicable in drilling operations.

Highlights

Colloidal gas aphron (CGA)-based fluids were successfully used in the petroleum industry to drill through depleted oil and gas reservoirs and low-pressure formations (Brookey 1998; Ivan et al 2001; Kinchen et al 2001; MacPhail et al 2008; Ramirez et al 2002)
Aphrons are comprised of a spherical core of air and a protective multilayer film. This film, which is the key to maintaining bubble stability, enables the aphrons to function as a stable drilling fluid
A comprehensive experimental study was conducted to choose the appropriate formulation for colloidal gas aphron (CGA)-based fluids using static stability tests, rheological behavior measurements, and bubble size analyses of CGAs simultaneously

Summary

Introduction

Colloidal gas aphron (CGA)-based fluids were successfully used in the petroleum industry to drill through depleted oil and gas reservoirs and low-pressure formations (Brookey 1998; Ivan et al 2001; Kinchen et al 2001; MacPhail et al 2008; Ramirez et al 2002). Aphrons were first introduced as unique microbubbles with unusual characteristics (Sebba 1987). This tri-layer film is composed of an inner surfactant layer enveloped by a viscous water lamella, which is overlaid with a surfactant bilayer that provides rigidity and low permeability to the whole structure

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