Analyzing Underperformance of Tortuous Horizontal Wells: Validation With Field Data
- Murat Kerem (Shell Intl. E&P BV) | Michael Proot (Shell Global Solutions International B.V.) | Pieter Oudeman (Shell Intl. E&P BV)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- November 2008
- Document Type
- Journal Paper
- 431 - 438
- 2008. Society of Petroleum Engineers
- 1.14.1 Casing Design, 4.1.2 Separation and Treating, 4.3.4 Scale, 5.5 Reservoir Simulation, 5.6.11 Reservoir monitoring with permanent sensors, 1.6 Drilling Operations, 5.3.2 Multiphase Flow, 4.1.5 Processing Equipment, 4.2 Pipelines, Flowlines and Risers, 5.6.8 Well Performance Monitoring, Inflow Performance, 2.7.1 Completion Fluids, 1.11 Drilling Fluids and Materials, 2.3 Completion Monitoring Systems/Intelligent Wells, 5.4.2 Gas Injection Methods, 4.3.1 Hydrates, 2 Well Completion, 3 Production and Well Operations, 2.4.3 Sand/Solids Control, 5.1.1 Exploration, Development, Structural Geology, 5.6.4 Drillstem/Well Testing, 3.1.6 Gas Lift
- smart completion, inflow performance
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This paper presents the results of a project that was initiated to analyze the inflow performance and inflow distribution of one smart and two problematic conventional, long, and tortuous horizontal wells in Brunei.
Following a detailed hydraulic analysis of these wells, a good match with field measurements was obtained. Simulation results show that the problems in the conventional wells were not as severe as those interpreted from the measurements of distributed temperature sensing systems (DTSs). It is also demonstrated that the compartmentalized completion with inflow control valves (ICVs) in the smart well has added value, because the well would not be producing from over half of the reservoir section without the smart completion.
Brunei Shell Petroleum (BSP) is a keen implementer of wells with sophisticated trajectories for achieving maximum reservoir exposure. The aim is to drain oil from stacked sand bodies that cannot be produced economically via separate dedicated wells. These wells have long reservoir sections of up to 3 km with undulations of up to 40 m. Some of them are equipped with distributed temperature-sensing technology for monitoring the inflow distribution, and some have smart completions to control inflow from different reservoir sections and to assist with well cleanup. Interpretation of the DTS traces indicated inflow-performance problems in the long conventional producers, whereas the smart wells were observed to be flowing over at approximately their full length. Inadequate well cleanup was thought to be the primary cause of the problematic inflow performance of the conventional wells. A detailed hydraulic analysis of two problematic conventional wells and one smart well was requested by BSP to understand the inflow problems in the conventional producers and to confirm the justification for smart completions.
Because the initial kickoff and cleanup are highly transient processes (Mantecon et al. 2004), a transient multiphase-flow simulator was used for modelling. The wells were simulated from initial startup until early in their production life, which included mud removal and stabilized wellbore flow. In both of the conventional wells, calculated flow rates and pressures agreed with the available well test measurements. Simulation results have shown longer producing intervals than those derived from the DTS traces. The main reason for this could be that the limited flow coming from the toe section in a horizontal well causes a minor temperature disturbance, which can be overlooked easily in the DTS traces (Ouyang and Belanger 2006). Good results from the initial calculations, gave enough confidence to continue with the smart well; a more-complicated case from the modelling point of view.
Because the smart well had not been tested in the early stages of production, only the recorded pressures from the permanent downhole pressure gauge (DHPG) were used to validate the model. Calculated flowing bottomhole pressures (FBHPs) agreed with the measurements. Simulations have shown that the smart completion gives an opportunity to produce the well over the full length. A sensitivity analysis was performed by removing the smart completion from the model. Results justified the smart completion because the well would be producing from only half of the reservoir section if it were completed conventionally.
Results of this work have provided enough confidence to use the same modelling approach in design and operation of future wells with complicated trajectories and architecture. This modelling approach could also be of value for a more-adequate interpretation of DTS measurements and better understanding of how the smart completion helps to increase the producing interval over a long well section.
|File Size||2 MB||Number of Pages||8|
Mantecon, J.C., Andersen, I., Freeman, D., and Adams, M. 2004. Impact of Dynamic Simulation onEstablishing Watercut Limits for Well Kick-off. Paper SPE 88543 presentedat the SPE Asia Pacific Oil and Gas Conference and Exhibition, Perth,Australia, 18-20 October. doi: 10.2118/88543-MS.
OLGA2000 user manual. 2005. Kjeller, Norway: SPT Group.
Ouyang, L.-B. and Belanger, D. 2006. Flow Profiling by DistributedTemperature Sensor (DTS) System--Expectation and Reality. SPEPO21(1): 269-281. SPE-90541-PA. doi: 10.2118/90541-PA.