American Oil and Gas Reporter - August 2019 - 76

SpecialReport: Horizontal Wellbore Architecture
East Nesson is a standard 1,280-acre
DSU located in Mountrail County, N.D.
Total well depths average ±20,000 feet
with lateral lengths averaging 10,000
feet. The H1 parent well was drilled in
late 2010 in the center of the DSU, and a
batch of development wells consisting of
H2, H3 and H4 were drilled in 2013. The
third batch of wells was the focus of the
multidisciplinary data gathering project.
It consisted of six wells with 10,000-foot
laterals (H5, H6, H7, H8, H9 and H12)
drilled from south to north across the
DSU. Figure 1 shows the well layout
and completion sequence.
To better understand the optimal distance between wells, spacing on the sixwell pad was reduced to 500 feet between

like formations and 250 feet between the
Middle Bakken and Three Forks, which
was tighter than the standard spacing
Hess uses in the area. Wells H5, H7 and
H9 were drilled in the Middle Bakken
(MB) formation. Wells H6 and H8 were
drilled in the first bench of the Three
Forks (TF1), and Well H12 was drilled
in the second Three Forks bench (TF2).
Data gathered as part of the spacing trial
included:
· Microseismic monitoring;
· Microseismic depletion delineation
(MDD);
· Radioactive (RA) tracers;
· Chemical oil and water tracers;
· Image logs;
· Pressure measurements during com-

FIGURE 1
Overview of East Nesson DSU Project Wells and Completion Sequence

TABLE 1
Well
H1
H5
H6
H7
H8
H9
H12

Summary of Completions and Data Acquisition

Formation
MB
MB
TF1
MB
TF1
MB
TF2

Completion
Sleeve/22 stages
Sleeve/35 stages
CT Sleeve/50 stages
Sleeve/35 stages
Sleeve/35 stages
Sleeve/35 stages
Sleeve/35 stages

Data Gathering
MDD and BHP
MSM, DFIT, RA tracer, image log, mud gas, oil/water tracer
Observation well, oil/water tracer
MSM, DFIT, RA tracer, pumped RA tracer
MSM, DFIT
DFIT, RA tracer, oil/water tracer
MSM, DFIT, image log, mud gas, pumped RA tracer

76 THE AMERICAN OIL & GAS REPORTER

pletion, flowback and early-time production; and
· Diagnostic fracture injection tests
(DFITs).
Microseismic data was acquired with
a geophone array positioned in the H6's
cemented lateral in the TF1. Located in
the middle of the batch of six wells, the
geophones were placed in the H6 to capture hydraulic fracture geometries recorded during the stimulation treatments on
the other five wells. MDD in the H1
parent well provided data to "map"
drainage patterns. RA tracers and chemical
tracers were used to evaluate propped
fracture lengths and connectivity between
wells.
The modeling results showed significant well-to-well interference and fracture-to-fracture communication across
the six-well pad. Although MDD in the
H1 indicated that drainage was limited
to the MB formation, microseismic data
showed hydraulic fracture height extending
from the TF2 upward through the TF1
and Middle Bakken into the overlying
Lodgepole formation, thereby connecting
the entire Bakken petroleum system. Microseismic data also indicated asymmetric
fracture growth toward the parent well,
with the asymmetry diminishing as completions progressed away from the H1.
In addition to MB-TF connectivity indications from microseismic, RA tracer
pumped from the TF2 well was detected
in an MB well. The implied transport of
proppant from a lower TF completion
into a MB completion suggests the likelihood of production communication between formations. Chemical tracers
pumped during hydraulic fracturing operations on all wells to evaluate interference between wells were found from one
end of the pad to the other (2,500-plus
feet), regardless of formation. This was
yet more evidence of hydraulic communication between MB and TF wells.
Multidisciplinary Data
The multidisciplinary dataset collected
during the project was used to guide
next-generation reservoir simulation history matching to characterize multiwell
production behavior. Specifically, the hydraulic fracture model was calibrated
using the microseismic data and used for

American Oil and Gas Reporter - August 2019

Table of Contents for the Digital Edition of American Oil and Gas Reporter - August 2019