Case Study: Vx Technology Provides Well Testing Efficiency and Rig Time Savings

Shell uses the PhaseTester multiphase flowmeter with Vx technology to support its SIMOPS strategy on the Pearl GTL project

Challenge: Measure gas rate and monitor fluid returns from initial well opening; minimize rig-up time and the footprint on the platform; keep deck loading under 1.74 psi; estimate well deliverability from surface data; and enable safer operations with a smaller crew.

Solution: Use PhaseTester portable multiphase well testing equipment with Vx† technology for continuous measurements of instantaneous and cumulative flow at high gas rates and to minimize the rig space required.

Result: Conducted test confirming cleanup as soon as it was accomplished, providing good estimates of well deliverability and improving operational safety.

Shell wanted optimized well testing and cleanup monitoring and a minimized rig footprint

Shell implemented a simultaneous operations (SIMOPS) strategy whereby drilling and completions were conducted at the same time as the stimulation, perforating, and cleanup for the North field production operations feeding Pearl GTL, a project under development by Qatar Petroleum and Shell in Qatar.

The highly successful SIMOPS approach reduced the average overall rig time to deliver a well for production from 76 d to 45 d. One thing required to accomplish this 40% reduction in rig time was a significantly reduced footprint for well testing operations.

Shell chose the PhaseTester multiphase flowmeter to test the wells and confirm cleanup before putting them on production

Shell elected to use PhaseTester portable multiphase well testing equipment with Vx technology to reduce the well testing operations footprint, improve safety, and achieve operational flexibility when acquiring high-frequency measurements of produced gas and completion fluids.

ArchiTest well test design methodology, software, and report was used to design the 10,000-psi system, which featured flanged connections and flare-boom lines rated for flow rates to 120 MMcf/d. Continuous measurements ensured that the velocities in the line remained within design limits.

The gas wells were cleaned up successfully, tested accurately, and switched to production immediately upon confirmation of cleanup

The wells were cleaned up and tested at gas rates above 100 MMcf/d. Flow at such high rates improved the cleanup of the wells and perforation tunnels.

All fluids were flowed through the PhaseTester equipment from initial cleanup. The instantaneous and cumulative brine and spent acid production rates were measured continuously with the PhaseTester multiphase flowmeter, making it possible to quantify the efficiency of cleanup operations from the first opening of the wells and assist in the evaluation of formation damage caused by residual stimulation fluids. The well effluents were sent directly from the flowmeter to the flare without separation.

The PhaseTester flowmeter used for the tests was rated to working conditions of 7,500 psi [51.7 MPa] and 302 degF [150 degC]. The Vx technology PVT model incorporated in the flowmeter converted the volumetric flow rate calculation in the high-temperature, high-pressure operating conditions to standard conditions and emulated the two-stage separation Shell had in place. (Any number of separation stages can be emulated in this PVT model.) As a result, the dynamic response of the flowmeter made it possible to estimate the performance of the gas wells very quickly, even during choke changes. Quick surface performance analyses from multi-rate gas tests provided good estimates of well performance and deliverability.

Additionally, accurate monitoring of the basic sediment and water allowed the well to be switched to production with confidence that it had been cleaned. Early routing to the production line saved hydrocarbons and reduced emissions.

Compared with traditional test separators, the PhaseTester equipment improved safety by eliminating the need for pressurized vessels on the platform and by reducing the number of field personnel required.

Download: Vx Technology Provides Well Testing Efficiency and Rig Time Savings (2.07 MB PDF)

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map of North field offshore Qatar GTLgas  plantTesting setup using the PhaseTester multiphase flowmeter
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