Abstract

Rubiales and Quifa fields are major heavy oilfields (oil gravity ranges from 11.3 to 14.4 °API) in Colombia with a current oil production of more than 264 MSTB and an oil viscosity range from 370 to 730 cP. Horizontal well technology used to drill through unconsolidated sandstones with an active and strong aquifer, under primary depletion, has been used to develop this field. Since 2006, 1,019 horizontal producer wells have been completed using slotted liners (conventional completion) because of the low cost and effectiveness in controlling the coarse-grained sand formation and low fines production.

The high water production rate from the beginning of the operation in the horizontal wells is the primary problem in these fields because of the high cost of produced water treatment and other factors. In formations in which high permeability, high oil viscosity, and strong aquifers are combined, early water influx can result. Water production is predictably associated with the oil production; however, one of the major challenges is to delay the water production for as long as possible. Currently, a large number of wells are closed in that have reached economic limits, primarily caused by high water cuts.

An autonomous inflow control device (AICD) was placed in each screen joint to balance the production influx profile across the entire lateral length and to compensate for the permeability variation and therefore the productivity of each zone.

In late 2012, a new technology project was designed and implemented as a pilot to help address the described issues in horizontal wells. AICDs would be used to maintain equilibrium of produced fluids along the horizontal section of the well, ultimately delaying water coning. After the first pilot is completed, a technical analysis could be conducted, based on the results obtained, and, if possible, the AICD technology could be implemented in additional prospect wells. The AICD pilot was implemented in geological conditions more adverse than wells previously completed with conventional completions and still other wells previously completed with passive but non-autonomous inflow control device (ICD) completions; the pilot will be evaluated with horizontal wells of the area. The main purpose of this paper is to provide details about the selection process, design, and evaluation results for the use of the AICDs in horizontal wells in both heavy oil fields.

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