Dicationic Surfactants as an Additive in Fracturing Fluids to Mitigate Clay Swelling: A Petrophysical and Rock Mechanical Assessment

Abstract

The interactions of clays with freshwater in unconventional tight sandstones can affect the mechanical properties of the rock. The hydraulic fracturing technique is the most successful technique to produce hydrocarbons from unconventional tight sandstone formations. Knowledge of clay minerals and their chemical interactions with fracturing fluids is extremely vital in the optimal design of fracturing fluids. In this study, quaternary ammonium-based dicationic surfactants are proposed as clay swelling inhibitors in fracturing fluids to reduce the fractured face skin. For this purpose, several coreflooding and breakdown pressure experiments were conducted on the Scioto sandstone samples, and the rock mechanical properties of the flooded samples after drying were assessed. Coreflooding experiments proceeded in a way that the samples were flooded with the investigated fluid and then postflooded with deionized water (DW). Rock mechanical parameters, such as compressive strength, tensile strength, and linear elastic properties, were evaluated using unconfined compressive strength test, scratch test, indirect Brazilian disc test, and breakdown pressure test. The performance of novel synthesized surfactants was compared with commercially used clay stabilizing additives such as sodium chloride (NaCl) and potassium chloride (KCl). For comparison, base case experiments were performed with untreated samples and samples treated with DW. Scioto sandstone samples with high illite contents were used in this study. Results showed that the samples treated with conventional electrolyte solutions lost permeability up to 65% when postflooded with DW. In contrast, fracturing fluid containing surfactant solutions retained the original permeability even after being postflooded with DW. Conventional clay stabilizing additives led to the swelling of clays caused by high compression and tensile strength of the rock when tested at dry conditions. Consequently, the rock fractures at a higher breakdown pressure. However, novel dicationic surfactants do not cause any swelling, and therefore, the rock fractures at the original breakdown pressure.

Gels for Oil and Gas Industry Applications

“…The CODcr of sample was determined with potassium dichromate method according to the Chinese national standard, GB/11914-89 [69]. A certain amount of sample was added into a conical flask and oxidized by appropriate amount of potassium bichromate standard solution under the catalysis of sulfuric acid-silver sulfate solution.…”

“…Tariq et al [67][68][69] showed that the use of a solution of cationic gemini surfactants with different spacers resulted in the reduction in the breakdown pressure in unconventional tight sandstones compared to that of the deionized water, which was attributed to the clay stabilization against swelling provided by the surfactant. In addition to the lower breakdown pressure, the use of gemini surfactants allows a reduction in the volume of fluid required to fracture the formation.…”

Novel Trends in the Development of Surfactant-Based Hydraulic Fracturing Fluids: A Review

“…Tariq et al [ 67 , 68 , 69 ] showed that the use of a solution of cationic gemini surfactants with different spacers resulted in the reduction in the breakdown pressure in unconventional tight sandstones compared to that of the deionized water, which was attributed to the clay stabilization against swelling provided by the surfactant. In addition to the lower breakdown pressure, the use of gemini surfactants allows a reduction in the volume of fluid required to fracture the formation.…”

Study on the Effect of Fracturing Fluid on the Structure and Mechanical Properties of Igneous Rock

“… 22 In the oil field industry, potassium chloride (KCl) is the most commonly used clay stabilizer to prevent wellbore instability caused by swelling in sandstone upon its hydration. 23 The current use of clay stabilizers includes surfactants like quaternary ammonium-based dicationic surfactants 24 and polyoxyethylene quaternary ammonium surfactants; 25 plant extracts like okra mucus extracted from okra plants; 26 , 27 polymers; 28 and nanoparticles. 29 , 30 …”

“…The presence of clay minerals in rocks can alter the rock’s mechanical properties when interacting with fresh water . In the oil field industry, potassium chloride (KCl) is the most commonly used clay stabilizer to prevent wellbore instability caused by swelling in sandstone upon its hydration .…”