Formation Testing SIG (FTSIG) was established in December 2010 to advance formation pressure and sampling knowledge

Christine Ehlig-Economides, University of Houston Dept. of Petroleum Engineering

Distinctions and differences between MiniFrac, DFIT and MicroFrac

Tests designed to provide reservoir and geomechanical parameters needed for hydraulic fracture design include minifrac, diagnostic fracture injection test (DFIT), and microfrac. The minifrac and DFIT are typically associated with fracture injection testing performed during the completion of the well and frequently used prior to hydraulic fracture completions in cased hole environments. MicroFrac is associated with wireline formation testing in openhole environments using much lower injection flow rates, volumes and shorter testing times. This presentation will illustrate with data the differences between these tests and which parameters each test can reveal. It will also explore ways that modern technologies might improve on traditional testing approaches.

Oliver Mullins, Schlumberger

Connectivity analysis in a large reservoir by integrating concepts in petroleum systems, reservoir fluid geodynamics and structural geodynamics

The Ivar Aasen reservoir on the continental shelf of Norway is laterally extensive (>10km) and has major reservoir sections that are characterized by moderate to poor net to gross. Reservoir connectivity had been one of the most important reservoir risk factors. Different gas-oil contacts (GOC) in different sections of the field exacerbated connectivity concerns. A systematic evaluation of all fluid properties was carried out to address connectivity and other concerns. This evaluation incorporated charge history, fluid equilibration processes, biodegradation, and gas evolution with integration of thermodynamics and geochemistry. These results were also linked with key structural geodynamic processes confirming the petroleum system context of reservoir charge. Different GOCs are a natural consequence of charge into a connected reservoir. The key conclusion of good connectivity across almost the entire reservoir has been confirmed in two years of production. This textbook reservoir case study is relatively simple to understand and provides a systematic framework for evaluation of any reservoir.

Colin Schroeder, The University of Texas at Austin

Understanding and Improving Formation Fluid Sampling While Drilling Using Numerical Simulations

Unlike traditional wireline formation tester (WFT) sampling, conditions in the near-wellbore region during formation sampling while drilling (FSWD) operations are complicated by ongoing mud-filtrate invasion due to the absence of sealing mudcake during cleanup and sampling. Understanding the physical processes controlling dynamic mudcake deposition, mud-filtrate invasion, and formation-tester sampling is therefore paramount to ensuring that high-quality reservoir fluid samples can be acquired reliably and efficiently in the while-drilling environment. For the present study, numerical simulations were performed to identify critical parameters influencing FSWD operations. Using a detailed FSWD case study from published literature [1], simulation results were validated and a baseline reference case for sensitivity analysis was established. Borehole, reservoir, and mud properties were subsequently perturbed to identify primary factors controlling cleanup and sampling in the while-drilling environment.

Camilo Gelvez, The University of Texas at Austin

Study of the Efficiency of Fluid Cleanup in Heterogeneous Formations with Various Formation-Testing Tools

This study presents a reliable model to represent various formation testing tools during cleanup and sampling operations. Finding the best tool-probe configuration through a fully-calibrated model has a significant impact on cleanup efficiency. The model is constructed based on a field-case simulation of a water saturated reservoir drilled with a blue dye tracer water base mud (WBM). The tracer allows to track the contaminated zone during mud filtrate invasion and cleanup. Simulation and history match of lab test data and optical analyzer data for tracer cleanup serves to further represent several formation testing tools in a variety of reservoirs and cleanup-sampling schedules. In addition, the simulated contamination cleanup data is a powerful tool to analyze the cleanup derivatives and to evaluate different aspects of reservoirs during real-time cleanup and sampling operations.

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

Click here for the Formation Testing and Sampling LinkedIn Group.