Integrated Modeling of the El Furrial Field Asset Applying Risk and Uncertainty Analysis for the Decision Making

Abstract

The El Furrial field is one most important hydrocarbon giants of Venezuela.It's located at the north of the Monagas State and it handles approximated 45 %of the production of this area. It was discovered in 1986 and itscharacteristic makes it unique. The strategy of development has been supportedby the combined injection of miscible gas and water; this has allowedmaintaining the production plateau of 400 MBPD of 28 ° API oil. Atranscendental advance in the characterization of the field was done with a newdynamic model called V9, what promoted the evaluation of new developmentscenario. This paper presents one of the first integrated development plan built byPDVSA; focus on the Integrated Modeling of the Asset, considering risk anduncertainty analysis in the decision taking. The project was developed under aphilosophy of collaborative work and changing the way of thinking fromdeterministic to probabilistic.The Project was executed by amultidisciplinary team integrated by personnel of the core areas of the asset, creating a milestone in the traditional way of working. This integrationallowed evaluation through statistic and expert interview, the uncertaintiesassociated to the variables involved in the evaluated scenarios. Huge reductionof capital expenses related with the grow of facilities were obtain due to theestimation of production profiles based on risk and uncertainty analysis. As aresult of this analysis a decision matrix was built, with the recovery factor, investment, qualitative risk factor, and economic indexes, which were evaluatedto decide the optimum development plan. Introduction The El Furrial Field is located in the Monagas State, at 25 Km of MaturinCity (Figure 1), at the area corresponding to the West Venezuela's Basin (SubBasin of Maturin). It was discovered in February 1986, by the FUL 1X well, representing at the time, the most important discovery made in Venezuela andone of the largest worldwide. This field has two producing formations: Naricual and Los JabillosFormations. One important characteristic of the reservoirs is that they arevolumetric, and produce by rock and fluid expansion. At the beginning, the field produced naturally; however, high-pressuredecline observed by the end of 1992 justified a water injection process to beimplanted in Naricual Formation, and in 1997 in Los Jabillos Formation.Subsequent reservoir studies led to identify opportunities to increase therecovery factor through gas injection. Therefore, in 1998 a miscible gasinjection process was implemented in Naricual. Currently, a combined process ofwater and miscible gas injection1 supports the exploitation plan of the field, maintaining a Production Plateau of 400.000 BOPD. A huge advance in the reservoir characterization has impulsed the evaluationof new development scenarios in order to increase the recovery factor of thefield by means of a new development plan. Due to the complexity and size of the actors involved in the implementationof the new exploitation plan, the development plan was selected following aninnovative methodology (Integrated Asset Modeling) in order to reduce decisiontime and better take account for associated risks. Definition and Philosophy of the Process. The Integrated Asset Modeling (IAM), is a way of working that integrates allthe core disciplines of the asset in order to generate and/or update theIntegrated Exploitation Plan from the business point of view (Figure 2). Bymeans of IAM, professionals working in different activities are temporallydetached, in order to conform an extended multidisciplinary work team. The dayto day work of IAM is constantly enriched by experience exchanges betweenprofessionals belonging to different technical and administrative departments.This is very helpful when it comes to identify and quantify risk anduncertainties associated to every factor involved. The use of this methodology allowed the reduction of technical analysistime, focusing only on the key factors. Additionally, as people from differentsection worked togeter in order to select the optimum exploitation plan, implementation time is considerably reduced.