Abstract
Nanospheres is the conformance control technology improving the performance of water flooding in oil reservoir (Andrianov et al 2022). The pilot project has been executed in one of the light oil / tight carbonate oil fields in Block 5 in north of Oman operated by Daleel Petroleum (Daleel) by ZL EOR Chemicals (ZL).
The pilot was divided into main two stages: i) Nanospheres injection, from March 2020 to February 2021, ii) Additional monitoring period, following the injection period, from March 2021 to May 2022. The nanospheres solution has been injected in two injection wells. Special preparation and injection skid was used for injection. In total 86 tons of nanospheres were injected.
The project performance has been monitored through comprehensive surveillance program, including frequent well testing, close monitoring of water injection, pressure, emulsion, and viscosity. Technical results obtained by end of the monitoring period were positive and demonstrated the suitability of nanospheres for conformance control in carbonate fields. Cumulative oil gain achieved was around 40,000 barrels of oil at time of analysis.
The forecast was based on DCA (Decline Curve Analysis). Expected recovery in this period (combined oil rate of the three supported oil producers) without an intervention (NFA case) was 142,145 bbl. Thus, nanospheres injection added ~28% of oil gain. Overall, the project was executed successfully, safely and oil production target has been reached. This is the demonstration of technology potential in carbonate formations.
This paper is organized in the following way: Section 1 briefly introduces the reservoir and the technology; Section 2 describes experimental results, Section 3 shows injection wells selection and project design while Section 4 reviews project performance and evaluates technical results. Incremental oil gain per well was monitored closely via frequent well testing and wellhead sampling where all the three producing wells were under monitoring. Finally, Section 5 gives the project summary, lessons learnt and discusses the future expansion of the technology.
