Abstract
In Venezuela, Teikoku has been operating oil fields in two blocks since 1992. In the Copa Macoya gas field located East Guarico Block, Teikoku has conducted skin by-pass fracturing (hydraulic fracturing to bypass near-wellbore damage) in 2004 through 2005. Copa Macoya fields consist of lower Oligocene coastal sandstone (5-10ft) at a depth of approximately 7,000ft subsea level. According to well tests, permeability range in this reservoir from 100 to 1,000md, however skin factors show around 50 in several wells. It was considered that the reasons of high skin factors resulted from severe damages during drilling operations and/or workover operations. In order to remove these, the skin by-pass fracturing was done in two wells. These fracturing operations were successfully completed and resulted in a decrease of the skin factors to almost zero after main treatments. The design points and the results of skin by-pass fracturing operations in the high permeability reservoir are presented in this paper.
