Testimonials
The SPIDR device is attractive to us at EOR for many reasons. For our St. John’s CO2/Helium project, the information we gather in the evaluation phase of the reservoir is valuable for future development plans going ...
- Jim Skurner, P.E.
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SUBSEA SPIDR
Introduction
Production optimization requires an under-standing of the reservoir, completion, wellbore and downstream systems. This understanding is gained by analysis of the pressure and rate data from the system. A correct analysis allows an engineer to maximize production without risking completion failure or formation collapse. The importance of pressure and rate data is evidenced by the number of extremely expensive installations of downhole permanent gauges in subsea wells around the world.
Downhole permanent gauges are effective ... as long as they're working. When a downhole permanent gauge fails on a dry tree, it is readily replaced with either a SPIDR or a wireline gauge.
However, when a downhole permanent gauge fails on a subsea well, the only previous option for pressure data acquisition has been to perform a costly subsea intervention. An alternative to expensive and risky subsea intervention is the DRC developed SUBSEA SPIDR. Using the SUBSEA SPIDR, an operator can gather the critical pressure data necessary for production optimization without risking damage to the well or reservoir.
SUBSEA SPIDR Description
The SUBSEA SPIDR provides the functionality of DRC's SPIDR in a package suitable for temporary installation on a subsea tree by a standard ROV submersible or diver. The tree must be equipped with an industry standard hot-stab port (ISO/CD 13628-8). The SUBSEA SPIDR weighs 40 lbs (20 lbs in water) and is rated to 10,000 feet of water depth. It houses a high-accuracy, high-resolution, thermally-compensated dual-quartz transducer. In addition to subsea well-head pressure, the SUBSEA SPIDR can acquire two additional measurements. The additional measurements can be any combination of temperature, pressure or differential pressure. The sampling rate is determined by the operator and may be as often as once per second. Data (up to 130,000 records) is stored either based on a fixed time interval or a time interval plus a required pressure change. The unit can operate for up to two years or 2,000,000 samples, whichever occurs first.
Data Analysis
The SUBSEA SPIDR can be used on virtually any well that unloads naturally. Once data is gathered with the SUBSEA SPIDR, it must be processed to downhole or reservoir conditions. DRC uses proprietary wellbore models to calculate frictional losses and the hydrostatic pressure drop. These models also incorporate phase behavior and well bore temperature changes. The result is a calculated bottomhole pressure file that can be analyzed to determine skin, reservoir permeability and the locations of boundaries in the reservoir.
The Process
1) Call DRC to determine if the well in question is a candidate for the SUBSEA SPIDR.
2) Tell DRC your well test objectives (completion evaluation, reservoir limits test, etc.)
3) Develop a test procedure using DRC's free well test planning service
4) Schedule and conduct the test.
5) Remove the SUBSEA SPIDR from the well and DRC processes the data.
6) Receive the Well Test Report from DRC.
Tool Specifications
Dimensions: 20" x 8" diameter Weight in air: 40 lbs
Weight in water: 20 lbs Full-scale pressure: 10,000 psi Maximum pressure: 15,000 psi Resolution: 0.01 psi
Repeatability: <0.01 % of full scale
Hysteresis: <0.01 % of full scale
Linearity: <0.01 % of full scale
Maximum Water Depth: 10,000 feet
Battery life of SUBSEA SPIDR: up to 2 years
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