The Formation Testing SIG (FTSIG) strives to advance formation pressure and sampling methods and knowledge (est. December 2010)

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Webinar Series December 7th 8:00-9:00 a.m.
Presentation 1: 08:00 AM

Formation Testing in a Challenging Environment of Balanced Reservoir Condition and Complex Reservoir Fluid
Speaker: Vinay Mishra

Abstract : Reservoir dynamic testing for rock and fluid properties is a common practice in hydrocarbon fields. Most of the tests involve typical reservoir fluid and rock properties and are performed using well established tools and methodologies. But testing becomes challenging if the reservoir pressure and fluid exhibit non-standard characteristics, such as balanced reservoir, fluid density much higher than water density 1.00 g/cc. A customized methodology and an innovative approach are needed to test such reservoirs successfully and efficiently.
This presentation is a case study of a multi-well campaign from a major US onshore field, where a multi-layered reservoir was evaluated for potential water disposal operations. An advanced wireline formation testing (WFT) tool with oval probe, high-rate downhole pumps and latest in situ fluid characterization sensors was used for the given objectives. Several unexpected reservoir responses were observed which, if not resolved with innovative approaches, could have jeopardized the success of the campaign. Most of the reservoir layers were underbalanced, resulting in classic a no seal signature during pressure testing. The fluid pump-outs also exhibited similar appearance of a no seal because of the flowing pressures as well as the flowing fluid indicating mud or high-density fluid flow (in situ density ranged from 1.00 to 1.30 g/cc).
A wide range of techniques were applied to ensure that the formation test results are valid. The in-situ fluid density sensor indicated a presence of complex fluid in the reservoir. Multiple reservoir layers were successfully evaluated via measuring rock mobilities and identifying downhole fluids. The fluids were generally water with varying salinities. The in situ optical sensor data was used to determine variations in pumped water fluid salinities. The customized testing program allowed capturing of representative low-contaminated samples from a record number of stations (21) with a high efficiency (in less than 36 hours).
This case study from a water disposal project would highlight interpretation methodology to quality control (QC) and validate formation testing data in a balanced reservoir condition and non-typical reservoir fluids. New technology tools such as oval probe, high-rate pumps and downhole fluid sensors along with innovations of using optical spectrum for water salinity determination will be discussed.

Presentation 2: 08:30 AM

The Benefits of Integrated Reservoir Pressure Test Analysis
Presenters: Tim Salter

Abstract: As reservoir modelling techniques and our ability to handle uncertainty become ever more powerful there is sometimes the need to step-back and ensure that our underlying reservoir concepts are as valid as possible. Formation pressure test datasets are wonderful information that often remain under interpreted as differing technicians each extract only what they may need. It is suggested that the Geologist must own the interpretation of such data and be encouraged to explore and explain even the smallest pressure differentials as there is often a story to be told. This is a reminder to move beyond first-pass, best fit lines of fluid gradient remember the many scales of  reservoir heterogeneity that may be revealed.

Tim Slater A reservoir geologist with 30 years’ hands-on experience of subsurface studies across a wide variety of assets in Europe, Middle East, and S. E. Asia. Originally a sedimentologist with an appreciation for detailed reservoir characterisation, now acting as a global advisor for Baker Hughes in reservoir modelling across conventional oil/gas and energy transition projects.

Steering Committee:

  Some general SIG activities anticipated:
- SIG related meetings, workshops, short courses, and sessions at general/annual meetings
- Maintain contacts with other professional societies that are also concerned with formation testing
- Web-based information exchange, perhaps including posting of papers, experts list, question area
- Provide leadership for technical standardization activities or QA/QC related with pressure measurements or fluid sample acquisition

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