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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Center for Latin American Studies at the University of Miami is collaborating with JSTOR to digitize, preserve and extend access to Journal of Inter-American Studies.A Robert McNicoll, que me inspir6 y solicit6 este relato, fragmento de un memorial que ya se encuentra en marcha.No me referire a mis dos primeras salidas del Peru, al contar la forma como un escritor latinoamericano alcanza a defenderse de los duros embates de la fortuna, cuando su Fatum le asigna los penosos deberes de proscrito. Sin embargo, en la segunda de ellas, fui actor de ciertos pasajes nada despreciables para una novela picaresca. Con todo, a partir de la tercera salida, es que comenzaron para mi las mayores perplejidades y el ingenio se me afilo hasta el punto de convertirse en estilete, bisturl y aguja de marear, muy necesaria esta cuando la vida nos obliga a perder toda nocion del rumbo.Conviene recordar que un escritor latinoamericano es una especie social distinta a la de los escritores europeos y norteamericanos, sobre todo en lo concerniente a su manera de trabajar y de ser retribuido. Mal que mal, estos ultimos logran monetariamente algo que se acerca a lo adecuado, pero el latinoamericano, si no es periodista, esta perdido. Con la excepcion de los brasilefios y solo en cierto modo los mexicanos, argentinos, y chilenos, un escritor latinoamericano es un animal implume y bipedo que escribe con ciertas limitaciones: para que lo lean pocos, le paguen casi nada y le estimulen nadie o su propio impulso. Los libros alcanzan tiradas sencillamente ridiculas. Todavia florecen los editores que "honran" al escritor a quien imprimen, y con el dinero del "editado", es decir, a quien imprimen y no editan. Un censo de supuestos editores seria muy provechoso. Dejaria en panos menores, o mejor sin paiios, a quienes se jactan de ejercer mecenazgos que solo existen en sus calenturientas y egolatricas imaginaciones. Dicho esto, se puede entrar en materia. Cuando sali por primera vez desterrado, en febrero de 1932, yo tenia treinta y un afios de edad, era Catedratico de la Universidad de San Marcos, miembro del Congreso Constituyente del Peru y tenia publicados varios libros, entre ellos, dos volumenes de La Literatura Peruana. Habia logrado ganar algun dinero como escritor, por ser periodista y haber vendido parte de la tirada de mis libros a instituciones oficiales. Los li-1 This content downloaded from 169.229.32.138 on Fri, 9 May 2014 08:41:49 AM All use subject to JSTOR Terms and Conditions JOURNAL OF INTER-AMERICAN STUDIES breros los recibian solo a consignacion, y a veces, cuando llegaba el plazo de pagar lo consignado, pedian moratorias o ya habian cerrado la libreria. Mi experiencia, siendo de las mejores en e...

Peru has a great background in the oil industry; the first well in South America was drilled in Zorritos, located on the northwest coast of Peru, in 1863. Originally, the wells were completed in the shallower pays with cemented casing and using perforated liners in the productive areas. Production was driven by the natural energy of the reservoirs. Around 4600 wells have been drilled In Block X and, currently, there are 2021 producing wells, with an average production of 6.4 bls./day per well. Hydraulic fracturing is required to produce them economically. These works have been done since 1953, and continue up to the present applying available technical innovations. Initially, stimulations were carried out through hydraulic fracturing using diverse multifrac techniques, with crude oil as base fluid. In the 90's, oil was substituted for water as a base fluid for stimulations, to generate better fractures and increase recoveries. In spite of the maturity of Block X and the high wells density, new alternatives were searched in order to continue operating economically, considering:Re-fracturing wells, in intervals of higher pays (500–1200 ft.) with low initial fracture efficiencyUse of low cost local market sand that will allow to obtain significant savings.Reduction of polymeric load in fracturing fluids ranging 15 to 25 lb/mgal.Evaluation of new technologies (ultra light support agent and visco elastic fluids) to improve well productivity. In this paper a historical perspective as well as currently applied technologies for stimulation are reviewed, and related field results are presented. Introduction Block X operated for Petrobras EnergÍa Perú is located in Talara Basin, on the northwest coast of Peru. It is composed of 17 main fields (Fig. 1). Approximately 4600 wells have already been drilled currently, and there are 2021 producing wells, with an average production of 6.4 bopd per well. The reservoirs of Talara Basin are characterized by their low permeability ranging from 0.1 to 60 md. For that reason, hydraulic fracturing is required to be done to produce them economically. The producing formations are sandstones characterized by their heterogeneity and presence of shale. Drilling began in Block X in 1910, using percussion drilling equipment. South America's first well in Zorritos, was drilled to a final depth of 78 ft. (24 m). From 1926 on, changes in technology to rotary rigs have enabled to drill deeper and faster. Initially, wells were completed with a surface casing of around 500 ft. depth, and several sections of perforated liners (Fig.2). Driving mechanism for these wells was natural flow. From 1951 on, the wells have been completed cementing both surface (300 ft.) and production casing (5 ½" ó 4 ½"), this one up to the surface. Currently, completions are performed with 5 to 6 consecutive stages stimulation jobs, through casing; For workover jobs 3 stages hydraulic fractures through 2 7/8" ó 3 ½" tubing are needed (Fig. 3). Evolution of Stimulation Jobs SANDOIL TREATING technique, consisting in pumping a mixture of crude oil and sand, started to be used in 1953. Both fluids and proppant agent volumes were low, with figures ranging from 200 to 400 gals. and ½ lb/gal sand concentration, as well as a 2 to 4 gpm flow rate were typical. In 1956, viscous crude oil (VISOFRAC) started to be used as frac fluid in some fracturing jobs, which allowed increasing the volumes of treatments. From 1957, PERFPAC technique started to be used, which performs fracturing in stages by using nylon balls as divergent agent for temporally isolating previously fractured zones, as well as leading stimulation towards untreated formations. This technique was used in large pays, avoiding the necessity of multiple stage fractures with higher costs.