TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractOver 200 hydraulic fracturing jobs using crosslinked anhydrous methanol as fracture fluid, have been performed in Argentina since the introduction of the technology in the country in 1992. Initial development of the crosslinked methanol was intended to reduce formation damage caused by swelling clays and capillary blockage related to high fluid surface tension when stimulating gas reservoirs. This paper summarizes the basic development of the technology, presenting recent findings on lower friction pressure, proppant carrying properties, environmental concerns solutions and larger temperature range of application. It also reviews the acquired experience, focused on its application in the field with the most extensive usage in Argentina, and it includes references to the broadening of the span of applications to different gas bearing rocks, higher temperatures and deviated wells; and a brief discussion on safety and cost issues.A study of the factors influencing the gas flow initiation stress (FIS) at fracture faces after being invaded by fluid filtrate is presented, supported by laboratory tests comparing water base fluid against methanol base fluid.Finally, the influence of fluid vaporization is presented as a key mechanism unique to methanol that overcomes the effect of FIS (both at the fracture faces and in the propped fracture) in reducing effective fracture length. Methanol vaporization explains that the effective fracture lentgh will approach total propped length resulting in increased early time productivity and ultimate gas recovery.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn the last two decades, it was usual practice in the oil industry to carry out massive hydraulic fracturing works to stimulate wells with great-heighten layers of interest and/or low permeability sands.Argentina has had no opportunity so far to make a stimulation work of this type, mainly because of the absence of a layer meeting the principal characteristics needed to carry out a job of this size, considering the lack of equipment required by a service company to face the magnitude of the work in question.In the year 2000, Pan American ENERGY, a BP Amoco subsidiary, made exploratory works on a sand formation of interest that met the adequate characteristics to try and develop this kind of job. This paper shows how operator and service company designed this treatment in a team work and how this job was accomplished and came to be the largest stimulation treatment successfully done in Argentina to date. This kind of jobs can open a new way to handle tight gas zones in Argentina.