Integrated Asset Modeling: An Approach to Long-Term Production Planning
Authors: Carpenter Chris 
Published: January 2017

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 176322, “Samarang Integrated Operations: Integrated Asset Modeling— An Innovative Approach for Long-Term Production Planning Focused on Enhanced Oil Recovery,” by W. Sifuentes and J. Moreno, Schlumberger; P. Kumaran and R. Hamdan, Petronas; M. Muhamed Salim, M. Mohd. Som, H.W. Lee, A. Ahmad, N. Pangereyeva, S.S. Biniwale, N.J. Rodriguez, J.T. Nitura, R. Alia, O.A. Talabi, and V. Halabe, Schlumberger; and S. Pedraza, SPE, prepared for the 2015 SPE Asia Pacific Oil and Gas Conference and Exhibition, Bali, Indonesia, 20–22 October. The paper has not been peer reviewed.

With declining trends in production and dwindling reserves for a 35-year-old offshore field, the Samarang Redevelopment Project was initiated with a vision toward implementing integrated operations as an asset-management decision-support tool. To realize expected reserves and optimize the production, an integrated-asset-model (IAM) concept is introduced with state-of-the-art modeling techniques to treat the asset as a whole unit rather than as isolated silos, which had been the traditional approach.

Introduction

The Samarang field is located in Subblock 6S-18 northwest of Labuan in eastern Baram Delta province. The production history of the field, first discovered and developed in the 1970s, is discussed in detail in the complete paper.

A full-field review was carried out from 2004 to 2007 with the objective of identifying redevelopment opportunities. A field-development plan (FDP) was then established before an alliance was signed in 2010 to redevelop the field. The redevelopment team has drilled more than 17 infill wells, obtained new 3D- seismic data, carried out several studies including fine tuning of the enhanced-oil-recovery (EOR) development plan, and executed an extensive program of production enhancement and surveillance activities to boost the field production. This has given the team further insight into the Samarang field potential as well as the untapped near-field potential.

The proposed EOR process is gas-assisted simultaneous water-and-gas (GASWAG) injection. This process consists of simultaneously injecting water updip in the gas cap and gas downdip in water-swept zones. The numerical reservoir-simulation model is the primary tool used for the EOR evaluations, optimizations, and forecasts. Implementation of the EOR scheme requires strategically positioning infill and injection wells. The recovery mechanisms targeted by this EOR scheme include

Displacing attic oil back to existing well completions

Sweeping the remaining oil toward new wells

Repressuring the compartments

Improving vertical sweep by using assistance gravity segregation

Reducing residual oil in water by injecting gas in water-swept layers

Traditionally, planning, forecasting, and optimization have been performed by the conventional approach of considering the reservoir, surface-network, and process-system models as being relatively isolated from one another. In this regard, many simplifications were taking place to translate the shared production limits, and account for surface backpressures, for each of the isolated models. These simplifications have negatively influenced production forecast for long-term predictions. The objective is to use an IAM approach to analyze and improve the production process for long-term planning.