FSWD formation sampling-while-drilling service is the only technology that provides representative fluid sampling, in situ downhole fluid analysis, and high-quality formation pressure measurements all while drilling—so you can make better steering decisions and optimize reservoir productivity.
“The FSWD service will soon give us the possibility to perform a complete formation evaluation in a single run, while also reducing acquisition time and rig cost.”
Gian Luca Atzeni
Operations Geology Manager, Eni
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Questions and Answers
How is fluid mapping while drilling similar to conventional sampling?
The existing applications of conventional sampling methods are a very small subset of what LWD data can deliver. As an option, you need all these different tiers of services, and fluid mapping while drilling is one tier of service. But for steering, conventional fluid sampling is out. However, fluid mapping while drilling will use downhole fluid analysis (DFA), link it to steering, and then enter into a completely different application of the fluid.
How can mapping fluid assist with wireline sampling runs?
Wireline data is acquired in exploration and appraisal. If LWD can tell me beforehand which probe to use or what hardware to select, then it can help the wireline run by enabling the operator to pick the right string. All exploration wells will have wireline sampling planned for a success case well. Statistically, only one third of exploration wells have enough hydrocarbon findings on the openhole data to justify running wireline sampling. Acquiring LWD beforehand helps us look at low-resistivity pay and thin bed formations, therefore LWD can serve as insurance in the exploration and appraisal drilling phase.
Sampling or fluid mapping while drilling?
If someone has to run one service only, the default today has to be wireline because you need its quantity and quality. But most likely, LWD will support it to help pick the right string. Appraisal is where the comparison will be made, and one will decide which one to pick; most of the time, we will only select one. Then it depends on the need. Do we need the same quantity and quality that we had in an exploration well? The operator will decide whether to run wireline or may already have enough information and now needs to calibrate their knowledge. If the figure is in the same ballpark, and the single-probe environment can work, then LWD will be there. In development, it’s all LWD. You don’t see wireline there because it is cost prohibitive.
Are all fluid samples the same?
Probe to probe, the quality of fluid we can get is very similar. Comparing a drillpipe-conveyed wireline service with an LWD, the time gain is also similar because the data acquisition time is very similar. But if you want to compare in the LWD world, bring in a focused probe, which might evolve over a period of time. It’s already a big leap of faith, bringing in a stationary measurement into a while-drilling one because you are on the driller’s time, not the data acquisition people’s time. It’s a very different mindset.
Formation Sampling-While-Drilling Service Saves Hess 3 Days Offshore Malaysia
Operator reduces risk and optimizes logging program with while-drilling formation pressure and fluid analysis in highly deviated wellbore
Acquire formation fluid samples and pressure measurements in a highly deviated wellbore that intersected pressure-depleted zones with increased risk of differential sticking.
Use formation sampling-while-drilling (FSWD) service to acquire reservoir-representative fluid samples and accurate pressure data to determine formation water salinity and to enhance completion and production planning.
Acquired fluid samples with less than
Obtained all fluid samples and pressure measurements in one run.
Completed sampling operations in 2 hours per station, avoiding differential sticking.
Saved 3 days by eliminating the need to conduct further formation testing in two additional wells.
Acquire water and gas samples for field development plan
To further develop a field offshore Malaysia, the Hess Corporation needed a complete understanding of the reservoir, particularly fluid properties. Unfortunately, no critical data was available from the existing exploration well. As a result, Hess needed to obtain formation fluid and gas samples and formation pressure measurements from three wells. Because these three wells were highly deviated and the well paths would likely intersect pressure-depleted formations, Hess was concerned about differential sticking during sampling.
The FSWD service provided real-time fluid fraction measurements that showed a decrease in the presence of oil-base drilling filtrate. This information allowed Hess to begin sampling after the cleanup process was completed. As indicated by the numbers above, Hess took a total of four samples—at 80.2 min (1), 89.3 min (2), 96.1 min (3), and 106.3 min (4).
Obtain fluid samples and perform downhole analysis
Schlumberger recommended obtaining the downhole pressure and fluid samples using the FSWD service. The service includes an advanced optical spectrometer and resistivity cell that both monitor the reservoir fluid properties and cleanup process as fluid is pumped through the flowline. When the pumped fluid meets the operator’s requirements, a downlink can be sent from surface to capture the formation fluid. Multiple sample bottles can be filled at a single sampling station, and as many as 12 fluid samples can be captured in a single run.
The real-time temperature and resistivity data indicated that the fluid being pumped was increasingly representative of the reservoir fluid. Simultaneously, fluid fraction data showed a decrease in the presence of oil. Hess used this data to begin obtaining reservoir-representative samples at 80.2 min.
Create field development plan sooner with increased knowledge
Using the FSWD service, Hess collected 4 fluid samples, 2 gas samples, and 21 formation pressure measurements over 12 hours while also avoiding differential sticking. Downhole testing showed the samples were contaminant-free, and later lab results confirmed that the samples were representative of the reservoir. Further sampling of the asset in a second and third well was deemed unnecessary, saving Hess 3 days.
This was the first sampling operation conducted by Hess in this field. With the collected water samples, the operator gained insight into formation water salinity, which is critical to calculating water saturation and optimizing completion design and production planning. The pressure data will help the operator understand zonal connectivity within the field.
Eni Receives Industry-First, While-Drilling Analysis of Individual Hydrocarbons
PVT lab testing validates results of fluid-profiling method in Gulf of Mexico
Determine capability of new sampling method to optimize sampling and formation pressure testing processes.
Use formation sampling-while-drilling (FSWD) service to obtain reservoir-representative downhole samples in a wildcat exploration well and provide in situ fluid properties in
Transmitted fluid compositions for C1, C2, C3, C4, C5, C6+, and CO2 in real time for first time while drilling.
Delivered lab-quality, in situ fluid property analysis, which would save an estimated 10 weeks of lab time in future sampling operations.
Identify new sampling method to save time and money in future operations
Eni US Operating Co. wanted to optimize formation sampling and formation testing processes to save time and money in future wells. The operator conducted a field test while drilling an exploratory well in the Mississippi Canyon area of the Gulf of Mexico in Miocene turbiditic sands. The target zone was located at a water depth of about 5,800 ft with uncertain reservoir characteristics and fluid properties. A new sampling method would need to be capable of acquiring pretests, capturing clean downhole samples and fully describing reservoir pressures at a cost and time savings.
Acquire individual fluid composition analysis up to C5 with FSWD service
Schlumberger recommended using the FSWD service to acquire samples, analyze the samples in real time, and measure formation pressures from the exploratory Mississippi Canyon well. This service is added to the downhole drilling assembly and collects reservoir-representative samples while drilling. Traditionally, sampling happens about a day after drilling, which often results in contamination of the reservoir by the drilling fluid filtrate. The FSWD service accurately delivers the following in situ hydrocarbons properties: individual compositions from C1 to C5, C6+, GOR, fluid color, hydrocarbon and water fractions, flowline fluid resistivity, temperature and pressure and formation volume factor, CO2.
PVT lab analysis results show good agreement with real-time, in situ analysis of fluid properties.
Transmitted individual hydrocarbon analysis in situ, delivered lab-quality fluid profiling
The FSWD service collected and analyzed six samples downhole in real time, setting an industry-first for the transmission of detailed in situ fluid properties. The FSWD service estimated contamination and time to clean up; performed fluid identification and typing; and measured GOR and fluid composition (C1 to C5, C6+, and CO2).
These results were verified 10 weeks later by lab results, which showed good agreement with field results on every measure. Contamination was estimated in real time to within ±2% of the laboratory-determined values. Pretests, pressure measurements, and fluid gradients were also successfully taken during the operation. A total of 28 pretests were taken—17 while drilling and 11 while pulling out—that provided Eni a full description of the reservoir pressure and fluid gradients.
By delivering lab-quality results while drilling, Eni concluded that the FSWD service is a reliable sampling service capable of gathering clean samples and good measurements while demonstrating a time savings of about 10 weeks.
Eni determined that the quality and amount of real-time data (shown above) from the FSWD service would enable it to accurately determine pressures, fluid composition, and fluid fraction in future wells.
Consistently acquire reservoir-representative fluid samples during drilling operations
Sampling While Drilling: An Emerging Technology
Even though it is the early days of the realization of sampling while-drilling (SWD) as a service, a picture of what might be achievable in practice is beginning to emerge.
Sampling technologies withstand and operate under rigorous drilling conditions
Characterization of Sampling While Drilling Operations
The while-drilling environment poses several potential challenges to acquiring representative formation-fluid samples; in particular, sampling times are expected to be restricted (perhaps severely) and dynamic filtration conditions are expected to predominate.