SpectraSphere fluid mapping-while drilling 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 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

From providing advanced knowledge of untapped reservoirs in exploration to de-risking fluid analysis and sampling in highly deviated development wells, the SpectraSphere service opens up new dimensions in well placement and reservoir characterization, all while reducing cost.

 

SUCCESS STORIES

Eni Receives Industry-First While-Drilling Analysis of Hydrocarbon Composition

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 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 reservoir fluid mapping 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 with SpectraSphere service

Schlumberger recommended using the SpectraSphere service to measure formation pressures, acquire samples, and analyze the fluid characteristics in real time from the exploratory Mississippi Canyon well. This service is added to the downhole drilling assembly and collects reservoir-representative samples while accurate fluid analysis before sampling while drilling. Traditionally, sampling happens about a day after drilling, which often results in deeper invasion of the reservoir by the drilling fluid filtrate. The SpectraSphere service accurately delivers the following in situ hydrocarbon properties: individual compositions from C1 to C5, C6+, GOR, fluid color, hydrocarbon and water fractions, flowline fluid resistivity, temperature and pressure, and 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 SpectraSphere service analyzed and collected six samples downhole in real time, setting an industry first for the transmission of detailed in situ fluid properties. The service estimated contamination and time to cleanup, 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. Contamination was estimated in real time to within ±2% of the laboratory-determined values. Pressure measurements and fluid gradients were also successfully obtained 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, the SpectraSphere service proved its capability of gathering good measurements and clean samples, saving Eni about 10 weeks.

Eni determined that the quality and amount of real-time data (shown above) from the SpectraSphere service would enable it to accurately determine pressures, fluid composition, and fluid fraction in future wells.

SpectraSphere Fluid Mapping-While-Drilling Service Saves Hess 3 Days Offshore Malaysia

Hess Corporation reduces risk and optimizes logging program by analyzing fluid, gas, and pressure data 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.

The SpectraSphere 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 SpectraSphere 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 SpectraSphere 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 subsequent 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.

SpectraSphere Service Confirms Movable Hydrocarbons in Tight Carbonates

Real-time fluid property analysis and LWD data deliver high-quality fluid information and minimize operational risks

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Evaluate production potential in tight formation with risky borehole conditions

An operator working in the Middle East planned to drill a multilateral horizontal oil well to help assess the field’s continued production potential. The operator sought to verify the presence of movable hydrocarbon into the 4- to 6-mD/cP section of the reservoir, confirming its production potential. Additionally, the operator collaborated with Schlumberger to overcome high-stick/slip conditions.

Combine SpectraSphere and EcoScope services for real-time fluid and pressure data

Schlumberger recommended using the SpectraSphere service in combination with the EcoScope service, providing an opportunity for the first fluid mapping-while-drilling operation in the Middle East. Deployment would be in the 8½-in section and would enable measuring formation pressure and evaluating fluid properties while drilling. The proposal included several pretests that, to obtain formation pressure, would provide a mobility estimate prior to fluid analysis and sampling. It would also enable the mud weight to be adjusted according to data to minimize differential sticking risks.

Validated drilling plans with pretest and DFA results

Schlumberger performed 16 pretests to obtain formation pressure and to estimate mobility prior to fluid analysis or sampling. Two initial pretests were taken in the gas zone to optimize the mud weight for the section, which verified that no adjustment was needed. The mobility measured during the pretests also enabled the identification of the optimal location for the first pumpout station. The operator initiated DFA operations at the target depth. Although the BHA had been on station for nearly 3 hours, it was successfully moved and no significant overpull was observed, despite the known high sticking conditions in this section of the reservoir.

The water-cut data obtained from the SpectraSphere service was shown in agreement with the data acquired through offsite laboratory testing, demonstrating that the fluid-mapping service delivers laboratory-quality data while drilling.

Hydrocarbon breakthrough was observed at the first sampling station within 25 minutes of pumpout. At the second sampling station, the hydrocarbon breakthrough was observed within 45 minutes of pumpout. Some gas was observed in the flowline, which most likely liberated out of the solution. This confirmed the ability of the SpectraSphere service to identify different fluid phases in complex flow regimes.

The estimated mobilities soon after drilling were around 6 mD/cP and 4 mD/cP, respectively. However, due to the ability of the SpectraSphere service to precisely control flow rate, formation fluid was pumped despite the very low mobility. Additionally, fluid mapping while drilling determined in real time that the fluid regime included three-phase flow. Based on data acquired during operations at previous sampling stations, the operator moved the BHA to the final sampling location. Efforts yielded three sampling bottles. The captured samples were subsequently tested in an offsite laboratory, and the water-cut measurements quantified in the laboratory showed good correlation with the measurements obtained through fluid mapping while drilling.

Video: Expert Discusses Benefits of SpectraSphere Service

Video: Hess Optimizes Completion and Production Plans

Video: Eni Acquires Lab-Quality Fluid Profiles in Real-Time

Enhance the Value of the SpectraSphere Service

Information from the SpectraSphere service flows into datasets from GeoSphere, FLAIR, and proVISION Plus services, as well as Petrel and Techlog platforms and ECLIPSE simulator.

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Real-time rock and fluid mapping at the reservoir scale

The SpectraSphere service can be used with the GeoSphere reservoir mapping-while-drilling service (image below) to combine structural information with reservoir fluid data, resulting in a true reservoir structural and fluid map. Using deep, directional electromagnetic measurements, the GeoSphere service reveals subsurface-bedding and fluid-contact details more than 100 ft [30 m] from the wellbore. This combined reservoir-scale view of rock and fluid properties provides an unprecedented depth of investigation, enabling operators to optimize landing, maximize reservoir exposure, and refine field development plans.

GeoSphere Reservoir Mapping-While-Drilling Service

Accurate at-surface formation evaluation with zero added risk

Surface logging can complement fluid mapping data acquired using the SpectraSphere service. The FLAIR real-time fluid logging and analysis service provides early insight into reservoir fluid properties and composition through at-surface quantification of C1–C6 and qualification of C7–C8, including methylcyclohexane, light aromatics, and nonhydrocarbons. The combination of the FLAIR and SpectraSphere services enables a continuous fluid profile that can be used to assess reservoir fluid distribution. Additionally, data gathered by the FLAIR service can be used to optimize downhole fluid analysis and sampling at depths.

While-drilling completion and production optimization in complex reservoirs

Fluid typing can be further optimized with the proVISION Plus magnetic resonance-while-drilling service, which provides lithology-independent porosity, pore-size distribution, continuous permeability, and direct hydrocarbon detection. The proVISION Plus service measures magnetic resonance and T2 distribution, enabling the real-time identification of bypassed pay zones and the determination of high-permeability areas. Integrating this information with SpectraSphere service data delivers advancement in real-time producibility assessment, especially in complex lithologies such as heterogeneous carbonates, shaly sands, and low-resistivity pay zones. Paired with SpectraSphere service representative in situ fluid analysis, this information can be used to optimize your entire completion strategy and to design completions programs that yield increased production.

Maximized value of reservoir answers through interpretation support

To get the most out of your fluid-mapping program, Schlumberger petrotechnical and reservoir evaluation experts can help you at every stage of planning, execution, and post-job analysis. From designing the optimal module arrangement and specifying test procedures to updating reservoir and field models with acquired data, our teams work with you to ensure that objectives are met.

Wellsite answers include recommendations based on formation pressure, drawdown mobility, hydrocarbon and fluid composition analysis, and GOR. For more in-depth evaluation, advanced interpretation is also available from remote experts at operations centers around the world.

Using advanced software applications, our experts can maximize the value of SpectraSphere service data to enable comprehensive formation evaluation.

Petrel E&P software platform (image below) enhances drilling operations by bringing multiple disciplines together with best-in-class science in an unparalleled productivity environment.The Petrel platform supports automated, repeatable workflows to capture best practices and share them across the organization. Data acquired by the SpectraSphere service is easily incorporated into existing models, keeping the subsurface live and current. Embedded cross-domain uncertainty analysis and optimization workflows enable straightforward testing of parameter sensitivity and scenario analysis. Petrel 2016 includes updates to drilling optimization features, such as interactive well path design tools, well plan objects, drilling structure slots, and lateral well plans.

Petrel Reservoir Boundaries

ECLIPSE industry-reference reservoir simulator and INTERSECT high-resolution reservoir simulator offer the industry’s most complete and comprehensive set of numerical solutions for fast, accurate prediction of dynamic behavior for all types of reservoirs, development planning, and operations. Using information gathered with the SpectraSphere service, the ECLIPSE and INTERSECT simulators can model any field type and any recovery method—from waterflooding to heavy-oil recovery and chemical-enhanced oil recovery.

Techlog wellbore software platform (image below) helps you can bring all of your wellbore data into one highly intuitive application for analyses. The Techlog platform dynamically incorporates the latest data, which can be streamed directly from the wellsite for real-time processing and instantaneous analysis as the well is drilled, aiding decision making during operations. This single-well model is then used to create a multiwell interpretation that provides the input to a simulation model for dynamic behavior evaluation of the reservoir. Detailed 3D interpretations maximize the value of all the sophisticated data collected in modern wells.

Techlog LWD Log

The formation testing suite based in the Techlog platform enables detailed analysis and reporting of pretests, DFA stations, and sampling data, both in real time and postacquisition. For real-time monitoring and QC, data is received via InterACT global connectivity, collaboration, and information service directly at the customer office or Schlumberger iCenter secure network collaborative environment. Detailed interpretation can also be performed after the job to combine reservoir fluid information with petrophysical data.

The SpectraSphere service's three innovative modules: Can you tell me more about ...

Q
... the pretest module?
A
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 pressure-while-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.
Q
... the fluid mapping module?
A
The fluid mapping module comprises a downhole fluid analyzer (DFA) for real-time reservoir fluid contamination estimation, compositional analysis, and in situ GOR measurements, plus a pumpout module (POM) for accurate pump control.

The pump has a nominal operating range of between 0.1 and 40 cm3/s. This system enables the sampling operation to be driven at a 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.
Q
... the sample carrier module?
A
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- or 250-cm3, 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.

For more information, including the latest case studies and technical papers, visit slb.com/spectrasphere.