Nanoparticle Application for Risk Mitigation of Condensate Blockage in the North West Sidi Ghazi Field

Abstract

Abstract Maximizing NPV by mitigating condensate blockage and restoring well productivity is challenging in rich gas condensate assets, especially when the dew-point pressure is very close to the initial reservoir pressure. Additionally, the choice of mitigation option is limited owing to the large upfront OPEX. This paper highlights the ongoing feasibility study to implement a cost-effective nanoparticle treatment for mitigating the risk of condensate blockage in the North West Sidi Ghazi (NWSG) field in Egypt. The feasibility study aims at qualifying the chemical system and pilot implementation in the NWSG field consisting of three key areas involving lab program, numerical modelling, and operational planning. Representative core and fluid samples were tested at reservoir conditions to evaluate the injectivity, durability, adsorption, and wettability alteration capability of the nanoparticles. Precise modelling of the risk of condensate blockage and treatment mechanism was performed for accurate prediction of condensate dropout and restoration of gas productivity to analyse the business viability. Operation planning focused on logistics, topside facilities and HSEQ is being carried out in preparation for pilot. Successful proof of concept of the nanoparticles showed an increase of the apparent gas permeability up to three times and the condensate permeability up to four times in a reservoir analogue system. Contact angles of up to 90° were measured for both reservoir brine and condensate, highlighting the neutral wetting nature of the chemical system. Sufficient injectivity in low permeable reservoir cores ranging up to 30 mD was demonstrated by unchanged gas permeabilities pre- and post-injection, emphasizing the suitability of the chemical system. Prediction runs from numerical simulation forecasted a reduction of well productivity of 50 to 75% already in the first year of production. The business viability was demonstrated either by significant acceleration of the production rates under similar operating constraints or by extending the plateau production over time. Additionally, the need for proper representation of the multi-phase fluid behaviour and pressure profile resulting from the high pressure drop due to condensate blockage in the first few meters around the wellbore was corroborated. Together with the chemical manufacturer, Wintershall Dea is ensuring the safe end-to-end logistics of the nanoparticles in preparation of the pilot application. Operational viability and environmental requirements of the nanoparticles is currently being evaluated. The options for condensate blockage mitigation are rather limited when it comes to minor assets, due to lower field economics. The proposed application of the nanoparticle treatment in the NWSG field focuses on long-term treatment durability, low OPEX and short pay-out times. To the best of our knowledge, no previous attempts have so far been made to mitigate condensate blockage using a solvent based wettability altering nanoparticle system for rich gas condensate assets.