Delivering A Successful Acid Fracturing Job Through Integrated GGR Analysis and Stimulation Study, Case Study of A Tight Gas-Condensate Reservoir In Central Kalimantan, Indonesia

2020 ◽  
Author(s):  
R. Rizkiaputra
Keyword(s):  
Dynamic Analysis ◽  
Reservoir Simulation ◽  
Transient Analysis ◽  
Reservoir Quality ◽  
Fracture Geometry ◽  
Central Kalimantan ◽  
Acid Fracturing ◽  
Condensate Reservoir ◽  
Acid Solubility ◽  
Geological Concept

The biggest challenge for producing a tight (<0.1 mD) gas-condensate reservoir is its low deliverability. Therefore, it is important to consider well stimulation in the field development program. There are several types of stimulation, and one of the types which has the most impact is acid fracturing. However, thorough study needs to be carried out to ensure its compatibility with the specific reservoir condition. This paper will describe in detail how the geology, geophysics and reservoir (GGR) analysis and the stimulation study play its role to create a successful acid fracturing job in Indonesia, specifically in Central Kalimantan. The study begins with the understanding of reservoir geological concept and its characterization using multiple seismic attributes and core sedimentology. This geology and geophysical (G&G) analysis is further enhanced by performing dynamic analysis such as pressure transient analysis (PTA), rate transient analysis (RTA), and flowing material balance (FMB). Following this, feasibility of acid fracturing is assessed by performing the geomechanical analysis and acid solubility test. Moreover, the fracture geometry is also simulated to make sure the resulting fracture is able to penetrate the good reservoir quality. Then, performance projection using reservoir simulation is performed to quantify the expected incremental gain from the job. The geological concept differentiates this platform carbonate into six depositional elements, in which all of the production wells are located in the Reef Complex. It is further defined using the combination of seismic attributes, petrophysical analysis, and production performance, which are able to map the reservoir quality distribution. From the dynamic analysis, it shows that each well has massive connected gas initial in place (GIIP) with several wells are having poor facies nearby that act as the barrier. The study is followed by a stimulation study which shows that the reservoir has hard rock characteristics (Young Modulus up to 3.2 million psi) and high acid solubility (up to 95%), suitable for acid fracturing job. Simulated fracture geometry shows that it could penetrate nearby poor facies and achieve the good facies target. Then, the reservoir simulation also shows that significant production gain could be obtained from the job. Following up on the encouraging result of GGR & stimulation study, the first acid fracturing campaign in this field is sanctioned and performed safely & successfully. It delivers a very encouraging result in which one of the wells shows a productivity increase of up to 200%. Production forecast shows that post-fracturing well performance could sustain the plateau rate up to two and a half years and provide an addition of 25 BSCF of proved developed producing reserves. Material enough for increasing the field profitability and optimizing future development plans. This study shows that understanding the reservoir by doing integrated GGR analysis has significant benefit to reveal the upside potential of the field. Moreover, the excellent result on acid fracturing feasibility study and fracture design prior to the job ensures that it could be performed safely, successfully, and significantly increase the well productivity.

Acid Fracturing Depleted Carbonates Improving Very Low Reservoir Quality Inside Slim Horizontal Open Hole (Russian)

2018 ◽  
Author(s):  
Amr Abd El Baky ◽  
Nawaf Al-Shuaibi ◽  
Alaa Eldine Alboueshi ◽  
Mohamed Elmofti ◽  
Ebrahim Elafify ◽  
...  
Keyword(s):  
Reservoir Quality ◽  
Acid Fracturing ◽  
Open Hole

Pressure Depletion Mapping Using Multi-Well DFITs and its Applications in Hydraulic Fracture Characterization and Permeability Estimation: Examples from Montney Formation

2021 ◽  
Author(s):  
Behjat Haghshenas ◽  
Farhad Qanbari
Keyword(s):  
Data Analysis ◽  
Surface Area ◽  
Reservoir Simulation ◽  
Production Data ◽  
Hydraulic Fractures ◽  
Fracture Geometry ◽  
Fracture Conductivity ◽  
Field Case ◽  
Pressure Depletion ◽  
Montney Formation

Abstract Recovery factor for multi-fractured horizontal wells (MFHWs) at development spacing in tight reservoirs is closely related to the effective horizontal and vertical extents of the hydraulic fractures. Direct measurement of pressure depletion away from the existing producers can be used to estimate the extent of the hydraulic fractures. Monitoring wells equipped with downhole gauges, DFITs from multiple new wells close to an existing (parent) well, and calculation of formation pressure from drilling data are among the methods used for pressure depletion mapping. This study focuses on acquisition of pressure depletion data using multi-well diagnostic fracture injection tests (DFITs), analysis of the results using reservoir simulation, and integration of the results with production data analysis of the parent well using rate-transient analysis (RTA) and reservoir simulation. In this method, DFITs are run on all the new wells close to an existing (parent) well and the data is analyzed to estimate reservoir pressure at each DFIT location. A combination of the DFIT results provides a map of pressure depletion around the existing well, while production data analysis of the parent well provides fracture conductivity and surface area and formation permeability. Furthermore, reservoir simulation is tuned such that it can also match the pressure depletion map by adjusting the system permeability and fracture geometry of the parent well. The workflow of this study was applied to two field case from Montney formation in Western Canadian Sedimentary Basin. In Field Case 1, DFIT results from nine new wells were used to map the pressure depletion away from the toe fracture of a parent well (four wells toeing toward the parent well and five wells in the same direction as the parent). RTA and reservoir simulation are used to analyze the production data of the parent well qualitatively and quantitatively. The reservoir model is then used to match the pressure depletion map and the production data of the parent well and the outputs of the model includes hydraulic fracture half-lengths on both sides of the parent well, formation permeability, fracture surface area and fracture conductivity. In Field Case 2, the production data from an existing well and DFIT result from a new well toeing toward the existing wells were incorporated into a reservoir simulation model. The model outputs include system permeability and fracture surface area. It is recommended to try the method for more cases in a specific reservoir area to get a statistical understanding of the system permeability and fracture geometry for different completion designs. This study provides a practical and cost-effective approach for pressure depletion mapping using multi-well DFITs and the analysis of the resulting data using reservoir simulation and RTA. The study also encourages the practitioners to take every opportunity to run DFITs and gather pressure data from as many well as possible with focus on child wells.

The Advantages of Having Dedicated Downhole Gauges and Wellhead Meter: A Reservoir Management Perspective from a Massive Tight Gas Reservoir in the Remote Area

2021 ◽  
Author(s):  
Ricko Rizkiaputra ◽  
Satrio Goesmiyarso ◽  
Jufenilamora Nurak ◽  
Krishna Pratama Laya ◽  
Dimmas Ramadhan ◽  
...  
Keyword(s):  
Reservoir Simulation ◽  
Transient Analysis ◽  
Management Practice ◽  
Reservoir Management ◽  
Remote Area ◽  
Tight Gas ◽  
Reservoir Properties ◽  
Gas Reservoir ◽  
Tight Gas Reservoir ◽  
Interference Test

Abstract Even though the downhole gauges and wellhead meter (wet gas meter) have been invented decades ago, having them installed in every wells are still considered as a luxury for many companies. However, does this view still reasonable for a tight gas reservoir let alone located in a remote area? This study will describe the benefit of having both equipment for reservoir management practice in one of the biggest tight gas reservoirs in Indonesia. Generally, reservoir management is an iterative process that incorporates the analysis of reservoir characterization, development plan, implementation, and monitoring. There are many analyses from the reservoir management process that can be performed using above mentioned equipment. Several analyses have been performed, such as: (i) Interference Test and Pressure Transient Analysis (PTA) after well is completed; (ii) Evolution of connected volume since early production until present day using Dynamic Material Balance (DMB); (iii) Flow regime and reservoir properties using Rate Transient Analysis (RTA); and (iv) Reservoir simulation: regular model update and project opportunity identification. In this study, the above-mentioned analyses are performed in one of the massive tight gas reservoir in Indonesia that is located in the remote area. Having a complete reservoir surveillance tools such as downhole gauges and wellhead meter on each wells is beneficial for reservoir management practice. Precious subsurface data can be obtained anytime without having to wait for equipment mobilization to location. This is critical for managing tight gas reservoir which usually demands robust subsurface data to reduce its uncertainties. There are several findings based on the above mentioned analyses, such as: (i) The interference test indicates there is reservoir connectivity among the production wells; (ii) The PTA indicates that the reservoir has tight properties, although longer buildup/observation time is still needed to better understand the reservoir characteristics in wider scale; (iii) The DMB analysis can be performed even in daily basis to provide the insight on connected gas initial in place (GIIP) evolution through time, as in this case it still shows an increasing GIIP through time which is suspected due to the transient flow regime on the wells; (iv) The RTA can also be performed in similar fashion, if it is combine with other analyses, this analysis able to provide a multi-scale reservoir properties investigation from near wellbore to far field and flow period observation (boundary observation) through time, as in this case the reservoir properties is tight and flow is still in transient period; (v) It increases robustness of reservoir simulation update since it is supported by many analyses, as such, series of hopper can be confidently presented to management, as in this case a project of well stimulation (Acid Fracturing) has been performed successfully and opportunity of further field development plan can be identified. This paper shows that, for the tight reservoir in the remote location, having each well equipped with downhole gauges and dedicated wellhead meter is significantly increasing the robustness of reservoir management process. Thus, providing economic optimization for the managed asset. Regarding the capital that is invested at the beginning, it will simply pay out quickly, looking at the time and resources that need to be spent for having equipment on site.

Modeling Acid Fracturing Treatments with Multi-Stage Alternating Injection of Pad and Acid Fluids

2021 ◽  
Author(s):  
Rencheng Dong ◽  
Mary F. Wheeler ◽  
Hang Su ◽  
Kang Ma
Keyword(s):  
Viscous Fingering ◽  
High Viscosity ◽  
Carbonate Reservoirs ◽  
Acid Etching ◽  
Fracture Geometry ◽  
Fracture Conductivity ◽  
Acid Fracturing ◽  
Fracture Surfaces ◽  
Low Viscosity ◽  
Multi Stage

Abstract Acid fracturing technique is widely applied to stimulate the productivity of carbonate reservoirs. The acid-fracture conductivity is created by non-uniform acid etching on fracture surfaces. Heterogeneous mineral distribution of carbonate reservoirs can lead to non-uniform acid etching during acid fracturing treatments. In addition, the non-uniform acid etching can be enhanced by the viscous fingering mechanism. For low-perm carbonate reservoirs, by multi-stage alternating injection of a low-viscosity acid and a high-viscosity polymer pad fluid during acid fracturing, the acid tends to form viscous fingers and etch fracture surfaces non-uniformly. To accurately predict the acid-fracture conductivity, this paper developed a 3D acid fracturing model to compute the rough acid fracture geometry induced by multi-stage alternating injection of pad and acid fluids. Based on the developed numerical simulator, we investigated the effects of viscous fingering, perforation design and stage period on the acid etching process. Compared with single-stage acid injection, multi-stage alternating injection of pad and acid fluids leads to narrower and longer acid-etched channels.

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