Evolution of Stimulation Jobs, Block X, Talara Basin, Peru

摘要

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 riven 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: 1. Re-fracturing wells, in intervals of higher pays (500-1200 ft.) with low initial fracture efficiency 2. Use of low cost local market sand that will allow to obtain significant savings. 3. Reduction of polymeric load in fracturing fluids ranging 15 to 25 lb/mgal. 4. Evaluation of new technologies (ultra light support agent and visco elastic fluids) to improve well productivity. I n this paper a historical perspective as well as currently applied technologies for stimulation are reviewed, and related field results are presented.