Skin by-pass fracturing in Venezuela

Abstract

In Venezuela, Teikoku has been operating oil fi elds in two blocks since 1992. In the Copa Macoya gas fi eld located East Guarico Block, Teikoku has conducted skin bypass fracturing hydraulic fracturing to bypass near-wellbore damage in 2004 through 2005. Copa Macoya fi elds 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 bypass 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 bypass fracturing operations in the high permeability reservoir are presented in this paper.