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Case Study: Fluid Sample Purity Increased by >60%
Quicksilver Probe focused technique slashes fluid acquisition time and contamination levels to provide new analytical insight
Challenge
Collect fluid samples with less than 5% contamination from a highly deviated well drilled with oil-base mud in the Gulf of Mexico.
Solution
Quicksilver Probe focused fluid extraction acquired reservoir fluids downhole with unprecedented purity and in a fraction of the time needed for conventional sampling.
Results
From analysis of the ultralowcontamination fluid samples, the operator reduced drilling risk by modifying drilling plans to use oil-base mud instead of water-base mud.
Samples contaminated with oil-base mud filtrate
An operator in the Gulf of Mexico needed fluid samples with a contamination level of less than 5% from a key exploration well. Higher levels of filtrate contamination would produce unresolvable uncertainties in the laboratory analysis of fluid viscosity that would severely impair decision making.
Not only was the highly deviated well a challenging environment for extracting formation fluid, but the large viscosity contrast between the oil-base mud filtrate and formation fluid resulted in a minimum 40% contamination level in conventionally obtained samples after 500 min of pumping more than 0.189 m3 [50 galUS] of fluid.
The fluid purity needed in a fraction of the time
The Quicksilver Probe tool took only 330 min in the same formation to extract fluid with a contamination level of less than 3% for sampling. Rig time—and associated risk—were reduced by one-third, whereas sample purity increased more than 60%.
Sample benchmark set at near-zero contamination
The analytical results gave the operator the confidence to change long-term drilling plans from using water-base mud to oil-base mud, which reduced drilling risk. Because the reliable Quicksilver Probe technique makes it possible to successfully collect ultralow-contamination samples from this environment, the operator has further lowered the sample contamination target from 5% to 2%, effectively setting a new benchmark for state-of-the-art formation fluid acquisition.
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