Gelled Oil: New Chemistry Using Surfactants (2005)

Field Application of A Novel Viscoelastic Gelled Oil System for Sand Fill Cleanout Operations Mathew M. Samuel; Mathew M. Samuel Schlumberger Search for other works by this author on: This Site Google Scholar Hisham A. Nasr-El-Din; Hisham A. Nasr-El-Din Saudi Aramco Search for other works by this author on: This Site Google Scholar Mohamed Jemmali Mohamed Jemmali Schlumberger Search for other works by this author on: This Site Google Scholar Paper presented at the SPE International Improved Oil Recovery Conference in Asia Pacific, Kuala Lumpur, Malaysia, December 2005. Paper Number: SPE-97545-MS https://doi.org/10.2118/97545-MS Published: December 05 2005 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Samuel, Mathew M., Nasr-El-Din, Hisham A., and Mohamed Jemmali. "Field Application of A Novel Viscoelastic Gelled Oil System for Sand Fill Cleanout Operations." Paper presented at the SPE International Improved Oil Recovery Conference in Asia Pacific, Kuala Lumpur, Malaysia, December 2005. doi: https://doi.org/10.2118/97545-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE International Improved Oil Recovery Conference in Asia Pacific Search Advanced Search AbstractWater-based fluids can damage some sandstone formations due to various reasons including clay swelling, emulsions, water-block, and wettability alternations. Oil-based fluids are less damaging than water-based systems to the hydrocarbon bearing formations. Conventional gelled oils (GO) have numerous limitations; however, they are used in formations that are highly sensitive to water. Aluminum carboxylate technology has been used for several decades, aluminum phosphate ester, however, has remained the preferred gelled oil system for the last thirty years.This paper describes the development of novel surfactant-based gelled oil (S-GO). This new technology uses surfactants to develop the viscosity of diesel.Unlike conventional gelled oil systems, this gelled oil is not sensitive to the nature of base oil or additive concentrations.The S-GO system, with an order of magnitude higher low shear viscosity, has much better solids suspension characteristics. This cleaner fluid also exhibits low friction characteristics, allowing pumping at higher rates.These unique features make the new S-GO system highly attractive for fracturing, frac-packing, sand control, coiled tubing cleanouts, and as kill pills.This fluid system can be used for applications up to 300ºF.BackgroundWater-based fluids are often used in the oilfield for many applications because they are readily available, less harmful to the environment, and more cost effective than oil-based systems.However, several studies have shown that these systems can damage sandstone formations due to clay swelling, emulsion with the native crude oil, water-block, and wettability alteration.Hydrocarbon-based fluids are recommended over water-based fluids for operations in water-sensitive formations because of their less damaging nature to the hydrocarbon-bearing formation.However, they are often not the primary choice due to numerous handling limitations, lack of temperature stability, cost, dependence on the hydrocarbon source, and nature of gelation process.In the 1960s, aluminum salts of carboxylic acids [1,2] (e.g., aluminum octonate) were used to raise the viscosity of hydrocarbon-based fluids. This improved temperature stability and solids-carrying capability of these systems leading to their use in hydraulic fracturing applications.In the 1970s, aluminum carboxylate salts were replaced by aluminum phosphate ester salts.[3] This increased the temperature range in which this oil-based fluid could be used.In addition, this modification enhanced the solids transport ability of the system.Today, aluminum phosphate ester system remains the preferred method of gelling hydrocarbons for fracturing purposes. The above chemicals thicken oil by an "associative" mechanism.[4] It is suggested that the interactions between the aluminum complexes and phosphate ester molecules produce a long polymer chain as shown in Fig. 1.[5]The R groups shown in Fig. 1 are hydrocarbon chains, which are soluble in the oil to be gelled. These groups, generally containing up to 18 carbon atoms, keep the aluminum phosphate ester polymer in the hydrocarbon phase.[6]These groups have a high affinity for oils, such as kerosene and diesel that are comprised of 12- to 18- carbon (and somewhat higher) chains. Crude oils are composed of a larger number of various organic compounds and may contain paraffins and asphaltenes. Some high-molecular weight compounds, especially paraffins and asphaltenes, are not compatible with the aluminum phosphate ester gelling system. Many crude oils may be gelled using this system, however it is strongly recommended to test them prior to use in the field.The R groups can be visualized as forming an oil compatible shield around the polar core of aluminum ions.[7] Polar species (such as water, acids, bases and simple inorganic salts) are incorporated into the polar core and affect the association of the aluminum ions and phosphate ester groups. These materials can either make the gel structure more rigid or may destroy the internal gel structure completely. Keywords: drilling fluid formulation, schlumberger well service, viscosity, spe 97545, suspension characteristic, saudi arabia government, gelled oil, hydraulic fracturing, drilling fluid selection and formulation, surfactant Subjects: Drilling Fluids and Materials, Hydraulic Fracturing, Drilling fluid selection and formulation (chemistry, properties) This content is only available via PDF. 2005. Society of Petroleum Engineers You can access this article if you purchase or spend a download.