Complete and precise measurements allow calculations of
proppant uniformity with complete trust in the integrity and validity of acquired data
imaging technologies are proven tools for evaluating completions effectiveness.
They achieve one component of this evaluation by comparing the entry hole sizes
of perforations. As a perforation is abraded from proppant, the hole enlarges. Data
measuring the magnitude of this erosion can be aggregated to provide more
accurate insight into overall treatment distribution. Imaging technologies have
helped operators optimize critical variables and identify the optimal
perforation charge phase positions.
recently, two separate downhole imaging technologies have been deployed to
evaluate perforation erosion: downhole video camera arrays that capture a 360o
borehole view and multiple-transducer ultrasonic tools. Historically, the two
have been considered separate methodologies, which means that operators only used
one or the other to measure perforations.
of each technology could cite the advantages of their chosen tool. Cameras have
much higher resolution than ultrasound sensors and can measure perforation
geometry with greater accuracy under suitable wellbore conditions. In fluids
with low optical clarity, where cameras may not perform well, ultrasound
sensors can provide measurements that capture general trends in proppant
placement. Ultrasound arrays also can accurately measure inner pipe diameter
and wall thickness, which can help detect and measure casing erosion,
particularly at plug-setting depths.
technology also has disadvantages. Camera lenses can become inoperative when
they have been covered with opaque materials. In addition to delivering lower
resolution than cameras, ultrasound can be susceptible to downhole motion
effects, interfering with accurate measurement of perforations.
limiting downhole data capture to just one technology, research has shown that
combining the two arrays captures more accurate and trustworthy data than either
one could generate separately, Fig. 1. For example, two recent field-tested wells
offer insight into the benefits of the combined video-ultrasound tool string.
Data for Well 1 was acquired for the 3,000 ft and 16 stages of the lateral
section closest to the heel. For Well 2, the interval increased to 4,500 ft and
of combined strategy.
Results demonstrate clear benefits of the combined tool string. If downhole
conditions prevent one type of sensor from collecting usable data, the other
can often fill in, allowing at or near 100% measurement of perforations. In
Well 1, ultrasound sensors were able to measure 618 out of 663 perforations,
while the camera array imaged all but one. In Well 2, the camera array was
prevented from measuring 16% of the perforations, because its lenses became
coated with an opaque material near the bottom of the logged interval. This
material did not affect the ultrasound sensors, which missed only 3% of the
perforations. As a result, the combined optical ultrasound arrays missed one
perforation in Well 1 and six perforations in Well 2.
can now gain significant benefits through tandem use of the two technologies. EV
ClearVision™ offers such a solution,
combining 360o video and phased array ultrasound technologies. An
integrated video and ultrasound scanning tool, it offers the most advanced 4D
evaluation system for wellbore applications. ClearVision allows operators to
see and measure 100% of perforations, including small-dimension perforations
and those plugged with sand, Fig. 2. Such complete and accurate data
deliver trustworthy information related to perforation erosion and proppant
For a well
in the Permian basin, the ClearVision tool string was deployed on coiled tubing,
and data were acquired for the 3,000 ft and 16 stages of the lateral section
closest to the heel. The well included some untreated base holes, providing
in-situ dimensions used as a reference to calculate the eroded area of the
implementing ClearVision, the operator used technology that resulted in 56% of
the 16 stages missing perforations from two or more clusters, which invalidated
the data for analysis purposes. In contrast, when the operator used ClearVision,
100% of the perforations were measured, delivering valid data for all stages to
ensure accurate analysis.
Such a high
level of data completeness and precise perforation measurements allowed the
calculation of proppant uniformity with complete trust in the integrity and
validity of the acquired data. The operator identified the best-performing
stage design and applied it to all stages of the next well, which improved
reservoir stimulation. In its first year of production, the single well delivered
additional production revenue of $1.4 million. Furthermore, the resulting
increase in stage length and subsequent reduction in operating time yielded
$350,000 in cost-savings and greater economic gain for the operator.
Accurate data empower improved well
performance. With the
ability to deliver a high level of data completeness and precise perforation
measurements, combined video and ultrasound arrays produce data at a previously
unachievable level of validity and accuracy. Such trustworthy information is
essential for making critical decisions with confidence and enabling improvements
in the field that significantly impact the bottom line. WO
TYMONS is a member
of the senior management team and the visual analytics director for EV, which
provides downhole analytics services. Having spent 25 years in the upstream oil
and gas sector, he has experience managing and leading product development,
data analytics and sales and marketing. Mr. Tymons received a BS degree in
physics and computer science from the University of Reading, England, in 2000
before starting his career as a research and development engineer for
specialized downhole equipment.