Polymer Flood Pilot to Recover Heavy Oil Using Heated Water

Abstract

The Days Chapel area of the Slocum oilfield was investigated as a target for conducting a polymer flood using heated water. The crude oil in the Carrizo zone of the Slocum oilfield is a heavy oil with an API gravity of about 19 degrees and a viscosity of about 1000 cp. The Carrizo formation is a shallow sand with high porosity and permeability. A new well was drilled for the purpose of obtaining log and core data needed to characterize the target area. Simulations using these data were used to assess its potential in this area of the field. Polymer flooding using heated water is significantly more complicated than conventional polymer flooding with respect to the surface facilities, the design and prediction of the flood, the operation of the flood, and the reservoir performance. One of the most important variables is the temperature of the heated water. Higher temperature results in lower oil viscosity, but it also results in higher heat losses from the wellbores and reservoir, and higher energy costs to heat the injected polymer solution. Injection and production rates are also key variables. Another important design variable is the duration of hot water injection before starting hot polymer flooding. Preliminary results indicate this innovative approach to polymer flooding of heavy oil zones is promising and should be evaluated in other heavy oil reservoirs.