Combining Acid- and Hydraulic-Fracturing Technologies Is the Key to Successfully Stimulating the Orito Formation Rafael Rozo; Rafael Rozo Petrominerales Search for other works by this author on: This Site Google Scholar Javier Paez; Javier Paez Petrominerales Search for other works by this author on: This Site Google Scholar Alberto Mendoza; Alberto Mendoza Ecopetrol Search for other works by this author on: This Site Google Scholar Arthur Milne; Arthur Milne Schlumberger Search for other works by this author on: This Site Google Scholar Diego Soler Diego Soler Schlumberger Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Hydraulic Fracturing Technology Conference, College Station, Texas, U.S.A., January 2007. Paper Number: SPE-104610-MS https://doi.org/10.2118/104610-MS Published: January 29 2007 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Rozo, Rafael, Paez, Javier, Mendoza, Alberto, Milne, Arthur, and Diego Soler. "Combining Acid- and Hydraulic-Fracturing Technologies Is the Key to Successfully Stimulating the Orito Formation." Paper presented at the SPE Hydraulic Fracturing Technology Conference, College Station, Texas, U.S.A., January 2007. doi: https://doi.org/10.2118/104610-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Hydraulic Fracturing Technology Conference and Exhibition Search Advanced Search Abstract The Orito field in the south of Colombia was initially put on production in 1969 and has produced continuously since then. The most prolific reservoir, is the Caballos Formation, a thick (250 ft avg.) laminated sandstone located at a depth of 6100 to 7500 ft that has produced (30 to 45 °API crude) for over 35 years, with production peaking at 66,000 BOPD. The permeability varies from 20 to 200 mD with streaks exceeding one Darcy. At different times in the past, attempts were made to hydraulically fracture one or more of the sands, using a variety of different (water- and oil-based) fluids. However, many of the wells indicated positive skin factors following the fracture treatments, irrespective of the fluid system used. In at least one case, a well stopped producing after being treated.A core study revealed that despite the relatively low clay content in the formation the critical velocity was less than one cc/min. Moreover, the retained matrix permeability after performing a static leakoff test (500-psi differential for 30 minutes) was less than 5%, regardless of the fluid used. From this testing it was concluded that the reduction in the permeability was due to the mechanical plugging of the kaolinite or disrupted mica in the pore throats. This reduction in the matrix permeability creating a very high fracture face skin that would account for the higher skin factors following fracture treatments.To eliminate the fracture face skin created during the fracture treatment a new treatment incorporating a pre-pad of acid viscosified with a solids free visco-elastic surfactant was developed. By incorporating this stage into the fracturing treatments, the retained matrix permeability was increased to +/- 30%, resulting in a negligible fracture face skin. The productivity of fracturing treatments performed using this technique resulted in negative skin factors and production ratios that exceeded expectations. Keywords: flow in porous media, static leakoff test, hydraulic fracturing, acid system, Caballo formation, core flow test, Fluid Dynamics, acid, fracture treatment, reservoir Subjects: Drilling Fluids and Materials, Hydraulic Fracturing, Reservoir Fluid Dynamics, Drilling fluid selection and formulation (chemistry, properties), Fracturing materials (fluids, proppant), Flow in porous media Copyright 2007, Society of Petroleum Engineers You can access this article if you purchase or spend a download.