Successfull Pilot Waterflood to Determine Connectivity of Reservoir Sand in W3 Layer North Niru Structure Limau Field

Abstract

North Niru Structure is located in the working area of PT. PERTAMINA EP ASSET 2. which is in the south Sumatera province, was found in 2006 with the first well is NR-01. starting October 2006 production by natural flow with initial oil production is 678 BOPD with 0% watercut, it has a good permeability with a range value of 200-500 md, and viscosity 0.94 cp, initial pressure 1698 Psi and saturation pressure 1580 psi.

After the discovery of the NR-01 well, massive drilling was performed on the northern Niru structure, peak production layer W3 north Niru is 5,573 bopd in June 2010. Production by pleatau obtained until the year 2013 and then decline production significantly, its happened because reservoir pressure is only 835 psi below bubble point pressure. previously W3 Niru structure has not been inject by water, this is because there is little uniqueness, although the value of good permeability and pressure is low but the injectivity test showed the results of low injectivity rate.

Hydraulic fracturing stimulation of 2 injection wells resulted in a very large injection rate of about 7,000 Bwpd with wellhead pressure only 100 psi, after injection lasted for 2 months there was a significant increase in the watercut of the monitor well, by 2017 pilot waterflood with peripheral pattern with previous data, pilot waterflood planning with peripheral pattern there are 4 injection wells and 8 production wells. For this pilot will not do hydraulic fracturing to increase well injectivity and do different things with hydrofluoric acid over displace Stimulation, the result got good injectivity 1500 bwpd with 200 psi well head pressure, surveillance monitoring was performed on both production and injection wells and one monitor well showed good results with a increase in DFL and a decrease in watercut in less than 2 months.

this paper will describe the steps that have been done from the evaluation of production data, selection of injection well criteria and how to monitor the survillance until the success of the pilot waterflood.