SpectraSphere* fluid mapping-whiledrilling service is the industry’s first to provide high-quality formation pressure measurements, reservoir representative fluid sampling, and in situ downhole fluid analysis—all in real time, and all while drilling.

“The SpectraSphere fluid mapping-while-drilling service gives us the possibility to perform a complete formation evaluation in a single run while reducing acquisition time and rig cost.”
Gian Luca Atzeni
Operations Geology Manager, Eni

Animation: Realize Reservoir Potential While Drilling

Advanced PVT fluid properties play a vital role in estimating reserves, optimizing completions,designing surface facilities, and meeting production goals. However, these datasets are traditionally available only after performing conventional formation sampling. The unique ability to fully understand reservoir properties during drilling operations opens up new dimensions in well placement and reservoir characterization, while at the same time reducing costs. SpectraSphere service delivers these advantages in multiple environments, from enabling advanced knowledge of untapped reservoirs in exploration to de-risking fluid analysis and sampling in highly deviated development wells.

A New Generation of Measurements

Analyze and Capture Fluids ... Fast!

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Pretest module

This module can operate on its own as a stand-alone formation pressure-while-drilling tool or be combined

with the SpectraSphere service pumpout module and sample carriers for fluid mapping operations. The

pretest module performs all the functionalities of the industry-proven StethoScope* formation pressurewhile-

drilling service, including time-optimized and pumps-off pretesting. This module also includes

■■ high-precision Axton quartz pressure gauge

■■ 30,000-psi pressure rating

■■ large-diameter probe.

 

 

Fluid mapping module

The downhole fluid analyzer (DFA) provides real-time reservoir fluid contamination estimation, compositional

analysis, and in-situ GOR measurements. The pumpout module (POM) contains an electromechanical positive

displacement unit that enables accurate pump control that drives the pump-out process.

The pump has a nominal operating range of between 0.1 cc/sec and 40 cc/sec. This system enables the

sampling operation to be driven at constant rate or constant drawdown pressure, providing precise flowline

control to ensure that phase integrity of the fluid is maintained.

The POM also has a resistivity cell, a temperature cell, and two sensor bays that house the DFA. Because

the POM requires mud circulation for generating power, the risk of differential sticking is reduced.

 

 

Sample carrier module (SCM)

The SpectraSphere service can be fitted with up to four carriers, each holding up to three Department of

Transportation (DOT)-certified PVT containers. They are either 450 cc or 250 cc, single-phase N2-compensated

bottles that are mounted on the outside of the drill collar and protected by articulated shields.

These DOT–certified containers are designed to be removed from the SCM on the rig for draining on

site or at a PVT laboratory. Up to four SCMs may be combined in a single BHA to increase the number

of sample bottles per run.

 

Eni Receives Industry-First While-Drilling Analysis of Individual Hydrocarbons

PVT lab testing validates results of fluid-profiling method in Gulf of Mexico

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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 fluid mapping

Schlumberger recommended using fluid mapping to acquire samples, analyze them 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. Fluid mapping while drilling accurately delivers 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—all during drilling.

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

Fluid mapping was used to collect and analyze six samples downhole in real time, setting an industry first for the transmission of detailed in situ fluid properties. Fluid mapping estimated contamination and cleanup time; 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 fluid mapping is a reliable method 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 fluid mapping while drilling would enable it to accurately determine pressures, fluid composition, and fluid fraction in future wells.

Fluid Mapping 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

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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.

Fluid mapping 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 fluid mapping to 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 fluid mapping, 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.

Learn More About Fluid Mapping While Drilling - Read These SPE Papers

Technical Paper: Sampling While Drilling: An Emerging Technology

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Technical Paper: Characterization of Sampling While Drilling Operations

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