Presented in The 5th ITB International Geothermal Workshop Thursday, March 31, 2016 ON THE FEASIBILITY OF GEOTHERMAL HEAT PRODUCTION FROM A HOT SEDIMENTARY AQUIFER: A CASE STUDY OF THE JABABEKA DISTRICT, WEST JAVA | Nurita Putri Hardiani, Setya Drana Harry Putra Geothermal Program of Institut Teknologi Bandung HOT SEDIMENTARY AQUIFER

Introduction Geothermal play types, literature reviews, purpose of study, study area

2 TYPES OF GEOTHERMAL SYSTEM

2 GEOTHERMAL PLAYS IN GEOLOGIC SETTING Geothermal Plays Convection-dominated geothermal plays Conduction-dominated geothermal plays Play: Groups of prospect that resemble each other closely geologically, allowing world-wide analog comparison. Geologist‘s attempt to recognize patterns in heat charge system, permeability structure and fluid type related to a specific geologic setting

2 CONVECTION DOMINATED SYSTEMS e.g. Volcanic-Hydrothermal Type

2 CONDUCTION DOMINATED SYSTEMS e.g. Sedimentary Basin-Hosted A – Geothermal plays above 3 km depth with temperature suitable for district heating, B – Deep geothermal plays below 3 km depth suitable for heating and electricity, C – Very deep geothermal plays below 4 km depth as potential HDR systems.

A Hot Sedimentary Aquifer (HSA) system is a type of geothermal play of choice to consider in an area with no known recent volcanism and/or that hosts an extensive and deep sedimentary basin. Such a play makes use of the hot water contained within a confined sedimentary aquifer layer, which is often deeper than 1 km beneath the surface (Ungemach, 2005). In addition, it has been shown that many oil reservoirs as well as sedimentary aquifers carry high inherent natural porosity and permeability (Allis and Kirby, 2013) which have made the exploitation of HSA system seem even more appealing. HOT SEDIMENTARY AQUIIFER TERMINOLOGY

Country Estimated Geothermal Potential (GW) HydrothermalEGS/HDR/HSA Australia Canada510 Chile16- China6.7- Indonesia*28.8-?? Japan Korea-0.2 Mexico8.0- New Zealand5.0- The Philippines4.3- United States36.415,915 Estimated geothermal resource potential, the APEC Region *Geological Agency (2012). Geothermal Area Distribution Map and Its Potential in Indonesia. December 2012

1 DISCUSSION Any Potential Hot Sedimentary Aquifer in North West Java Basin?

2 LITERATURE REVIEWS In evaluating the feasibility of a HSA play, a number of authors have utilized several different methods: Pluymaekers et al. (2012) - employ a “static” approach, i.e. they first determine potential aquifers based on depth and temperature criteria, and subsequently run a sequence of geothermal aquifer characterization process. Wellmann et al. (2010) - utilize a dynamic reservoir simulation procedure based on a constructed 3-D geological model of a sedimentary basin to determine its subsurface fluid- and heat-flow fields. Poulsen et al, (2015) - a prediction of the aquifer’s production profile sensitivities to various physical and production parameters

2 AIMS OF STUDY The purposes of this study are of the following: To carry out a procedure for a Hot Sedimentary Aquifer reservoir characterization, combining aspects of the aforementioned references, i.e. an integration of dynamic reservoir simulation, sensitivity study and theoretical recovery estimation represented by the production profile. To apply the proposed approach to a potential Hot Sedimentary Aquifer that presumbaly underlies the Jababeka Area.

2 THE STUDY AREA: JABABEKA DISTRICT, WEST JAVA The region is a part of the Bekasi regency, West Java.

2 JABABEKA AREA The first modern eco-industrial estate, as well as the most successful ( The many industrial activities make a good potential for the development and application of government supply-independent power generation and utilization. Situated on a sedimentary basin with high heat-flow density and subsurface temperatures, leading to a potential Hot Sedimentary Aquifer play (see PT LAPI ITB, 2014; Putra, 2015).

Methods Model domain, model and numerical modeling parameters

THE SUBSURFACE FORMATION LAYER IN THE VICINITY OF JABABEKA (10X10 KM²) Basement Lower Cibulakan Upper Cibulakan Jatibarang Parigi Cisubuh

2 THE MODEL DOMAIN (SIMPLIFIED, 5 KM X 5 KM )

2 THE MODEL PARAMETERS Case 1 Production rate (m³/h) Case 2 Re-injection temperature (ºC) Case 3 Reservoir thickness (m) Case 4 Reservoir permeability (1e-12m²) Case 5 Well Spacing (m) Case 6 Confining Beds Thermal Conductivity (W/mK) A7528 ª 100 ª 5E ª B150 ª E-14 ª 1200 ª 2.5 C E ª Denotes reference parameter values (i.e parameter values when other parameters are being varied)

2 NUMERICAL MODELING PARAMETERS Boundary ConditionsTop: 120ºC | Side: No-Flow, Heat-insulated Hydraulic Parameters Numerical Discretization Integrated Finite-Difference with rectangular blocks (equivalent to node-centered Finite- Difference scheme)

Results Sensitivity Analyses

2 THE SENSITIVITY ANALYSIS

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