Oval Focused Probe results in Clean Reservoir Samples

Overview 

Operators want the cleanest formation fluid samples in the most efficient manner possible. However, depending on the tool design and the formation characteristics, these tests can be time-consuming. While collecting fluid samples from an offshore well for a major operator in Brazil, Halliburton recommended using its new Reservoir Description Tool (RDT™) tester with Oval Focused Pad. The Oval Focused Pad tester has a larger contact area than any other focused probe in the industry and separates fluid samples into two sections while pumping. This enables the tool to filter out mud filtrate contamination and obtain a cleaner sample faster than other tools. The RDT tester with Oval Focused Pad obtained clean samples from the formation in just an hour and a half -– rather than the expected three hours. The samples taken from clean side of the oval focused pad had contamination levels as low as only 1.3 percent, proving the effectiveness of the tool.

Challenge 

The operator wanted to obtain these samples as quickly as possible. Although sampling time varies between sample stations and formations, conventional sampling in this offshore well took three hours in one sampling station. 

Varying formation permeability and fluid viscosities affect the pumping rate of testers. Lower permeability formations or higher fluid viscosities require slower pump rates than higher permeability formations. Many formation testers are not designed to pump faster in highly permeable formations.

 The operator sought the cleanest fluid samples possible, with less than two percent contamination. It also needed accurate readings of fluid density and resistivity and real-time contamination analysis during testing. 

Solution

The RDT tester with Oval Focused Pad divides fluids into two sections. The system discards contaminated fluids in the outer section and captures cleaner fluids in the inner section. Halliburton showed that this technology could cut sampling time in half for this job.

The RDT tester has both the slowest and fastest pumping rates in the market, allowing for total flow rates from 0.2 – 90 cc/sec that are matched to reservoir conditions. In this highly permeable formation, Halliburton could pump at higher rates for faster results.

Halliburton used its Fluid Identification (FLID) sensor, which combines high-resolution fluid density, fluid resistivity and capacitance in one tool. The RDT Oval Focused Pad tester used FLID sensors in each section, providing real-time contamination analysis to guarantee the cleanest sample possible.

Result

Halliburton successfully collected samples with the RDT tester with Oval Focused Pad, proving the benefits by delivering samples with less than two percent contamination in just an hour and a half. Because of these impressive results, the operator is including the RDT tester with Oval Focused Pad in its wireline program on future wells.