CASE STUDY
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
Acquire water and gas samples for field development plan
Acquire formation fluid samples and pressure
measurements in a highly deviated wellbore
that intersected pressure-depleted zones with
increased risk of differential sticking.
To further develop a field offshore Malaysia, 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.
SOLUTION
RESULTS
■■
■■
■■
Acquired fluid samples with less than
1% contamination.
Obtained all fluid samples and pressure
measurements in one run.
140
3,000
120
2,500
100
2,000
80
1,500
60
1,000
40
500
20
0
Completed sampling operations in 2 hours
per station, avoiding differential sticking.
0
Saved 3 days by eliminating the need to
conduct further formation testing in two
additional wells.
20
40
60
Time, min
80
1
2
3
100
0
4
Pump outlet pressure, psi
Probe pressure, psi
Annular pressure, psi
Pumped volume, L
Pumping rate, cm3/s
Fluid fraction, %
■■
3,500
Pumped volume, L
Pumping rate, cm3/s
Use the SpectraSphere* fluid mappingwhile-drilling service to acquire reservoirrepresentative fluid samples and accurate
pressure data to determine formation water
salinity and to enhance completion and
production planning.
Pressure, psi
CHALLENGE
100
80
60
40
20
0
Water fraction
0
20
40
60
Time, min
80
1
2
Oil fraction
3
100
4
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).
Drilling
1.0
92
0.8
90
0.6
88
0.4
86
0.2
84
0
0
20
40
60
Time, min
Fluid fraction, %
Temperature, degC
100
80
60
40
20
0
80
20
40
82
Resistivity, ohm.m
Water fraction
0
100
Temperature, degC
Resistivity, ohm.m
CASE STUDY: SpectraSphere fluid mapping-while-drilling service saves Hess 3 days, offshore Malaysia
60
Time, min
80
Oil fraction
100
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.
Obtain fluid samples and perform downhole analysis
Create field development plan sooner with increased knowledge
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.
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.
slb.com/spectrasphere
Source: SPE-176126-MS, “Reducing Risk and Improving Efficiency of Extended Reach
Drilling Through Use of Sampling While Drilling Technology.”
*­ Mark of Schlumberger
Other company, product, and service names are the properties of their respective owners.
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