Multi Realization Simulation Technique Addresses Water Risk Assessment, Field Management and Field Development Plan with Optimum Recovery in a Complex Fractured Gas Condensate Reservoir
Authors: Haryanto Elin , Ben Haoua Taha , Dubois Agnes , Ghorayeb Kassem , Slimani Karim , Nacima Moussaoui , Rachida Anik , Amine Zami 
Published: February 2022

Understanding of water breakthrough risks in complex multi-layer fractured reservoir is a critical aspect in developing and maximizing recovery of gas condensate assets. An integrated study involving multiple model realizations (single porosity, dual porosity-single permeability and dual porosity-dual permeability) was conducted in order to understand various water production risk scenarios. Study resulted in an opportunity for an effective production optimization after 10 years of production history from a gas condensate field in South-East of Algeria.

In some modeling processes, the model is often built with one realization. Hence, dynamic data calibration and prediction lead to a stringent concept. Consequently, water risks are not fully assessed due to limited perspective. In this study, the dynamic modelling was enhanced with history matching regressions on multiple static model realizations resulting in a range of production forecasts. This significantly helped in understanding water production challenges in terms of breakthrough timing, water conduits and direction that was initially not obvious with a single realization concept. As a result, a better mitigation plan was devised to address those challenges.

A new approach in modeling natural fracture reservoirs was applied during the static modelling process that resulted in proper fracture distribution in 3D and enabled a static model adaptive to surveillance data hence mitigating some core data gap. The process included quantitative model property adjustment based on an integrated multidomain approach including results of a detailed pressure transient analysis across different areas of the field, borehole image interpretation, characterization of conductive fractures, incorporation of production logging data and other surveillance data sets.

A robust compositional model that allows accurate computation liquified petroleum gas and condensates recovery was implemented to improve the surveillance program and highlighting infrastructure debottlenecking requirements.

This paper presents the results from a detailed analysis of multiple water risks scenarios from a complex multi-layer fractured gas condensate reservoir and discusses its impact on optimizing the field development plan. A systematic ranking was established to compare various water mitigation solutions and production optimization opportunity based on potential gain, operational complexity, and economical due diligence. The study helped the operator and field management team to select optiaml field development plan in addition to achieving hydrocarbon production sustainability assurance resulting in a substantial incremental gas recovery.

The workflow presented in this study can be readily adopted for other gas condensate fields towards improved modeling practices in order to lay out some critical foundations prior to embarking into larger studies such as a fully integrated subsurface and surface network modelling to generate a robust production enhancement action plan.