Abstract
A water control approach integrating log interpretation, core analysis and production history has been designed and applied to extend life of the very mature heavy oilfields of Block 1AB, located in the Peruvian Jungle. The acquisition of new data, re-processing of old data, the use of new technologies, precisely complemented, by the innovation and experience of a multidisciplinary work team have been crucial towards refining selection of zones with high water production, and stablish a new completion scheme.
It was proposed a methodology consisted of correlating neutron and production logs with core data to update the fluid saturation profile, in order to identify high water cut sands within Main Vivian and Vivian B formations. Also the technique is used to identify silt/shale beds with areal extension, separating Vivian A from B, and thin low permeability sands plugged with kaolinitc matrix within Main Vivian, which are interbedded with the productive sands; those layers are used as seal rocks when redesigning well completion.
Eleven applications in Jibarito, Jibaro and Shiviyacu oilfields were developed during 2005-2006, with successful results. Oil production was instantaneously increased in 947 BOPD, while water production was sustainably reduced in 83647 BWPD. In addition, producing cost was reduced due to lowering energy consumption by means of a reduced pumping requirement, as well as, less water injection volume; diminishing surface water treatment and mitigated environmental impacts.
