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Test or Not to Test: FAQ in the Waxy Oil and Low Quality Formations

Chokthanyawat, Suchart; Daungkaew, Saifon
Data Services, Schlumberger, Chatuchak, Thailand.

Well testing is one of the most effective ways for defining dynamic reservoir properties. However, a major drawback of this full scale testing method is the high cost expenditure and associated environmental impacts. Nowadays, Wireline Formation Testers are able to utilize an inflatable straddle packer system, hi-resolution pressure gauge, downhole pump, downhole fluid analyzer, and a PVT quality sampling string. This new technology can be used for conducting Interval Pressure Transient Tests (IPTT), increasing efficiency of fluid sampling, and reducing the number of well testing, especially in low permeability formations and waxy oil environments.

This paper describes a new application that has been developed to maximize the value of information and supports well test design and optimization in the early life of a field using a single well model simulation. This model can be built to capture reservoir heterogeneity by integrated with conventional well logs such as Gamma Ray, Resistivity, Neutron Porosity, Bulk Density; high resolution logs such as Nuclear Magnetic Resonance, Electrical Image Logs; as well as in-situ fluid properties from an advanced downhole fluid analyzer tool. The integration of this information will be the key to establish a link between dynamic and static reservoir properties that are leading to an improvement in reservoir understanding and provide confidence of reservoir characterization plan.

This paper uses actual field examples from the waxy oil thinly bedded reservoirs in South East Asia. Several reservoirs were already in the production phase. However, after additional reservoir information, more potential pays have been identified. Due to several challenges such as low quality formation, waxy oil, and thinly bedded, the plan to test this formation need to be justify properly. This paper presents an effective workflow that can be implemented soon after logging operations are completed. The workflow helps to determine whether the discovered prospect should be developed or abandoned through proper testing design and optimization.

 

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012