Sampling and Transient Testing Prove Major Land Discovery in HPHT Carbonate for Pemex

Published: 09/18/2019

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Pemex's concerns

The submillidarcy permeability of the heterogeneous, naturally fractured carbonate formation had prevented conventional wireline formation testers from collecting the necessary PVT samples for analysis, much less conducting interval pressure transient testing (IPTT). Two new wells had been drilled in the formation to ~7,700 m, and they posed the same daunting conditions for collecting representative gas condensate samples: miscible contamination, bottomhole temperature of >175 degC [338 degF], 20,000-psi pressure, and <0.1-mD permeability.

What Schlumberger recommended

The Ora platform integrates efficient dual-flowline fluid acquisition with superior metrology to confirm fluid purity for sample collection, all digitally enabled with intelligent planning and contextual insights in a collaborative cloud environment. The ability of the Ora platform’s flow manager to pump at rates as low as 0.1 cm3/s facilitates controlled flow from the tightest conventional formations.

What Pemex achieved

Two sampling stations, one each at the top and bottom of the hydrocarbon-bearing interval in the wells, were efficiently performed—despite permeability lower than 0.03 mD, as confirmed by core analysis and a drillstem test (DST), and 182-degC [360-degF] bottomhole temperature—to collect gas condensate samples of sufficient representative quality for PVT analysis and conduct IPTT. This reliable information enabled Pemex to confirm reserves estimates early and expedite designing the completion strategy.

Ora platform's pressure, temperature, and compositional plot from Pemex's HPHT carbonate job.
The Ora platform’s pressure, temperature, and compositional plot (CO2 , C1 , C2 , C3 , C4 , C5, and C6+) confirming gas at the first sampling station.
Ora platform's pressure, temperature, and compositional plot from Pemex's HPHT carbonate job.

"The new platform helped us test, find gas condensate reserves, and collect samples for PVT analysis in our most important land discovery in Mexico of the last 25 years. Tests were conducted in submillidarcy heterogeneous carbonate formation at reservoir temperature above 175 degC and showed results similar to subsequent DST."

--Victor Navedo Lead Reservoir Engineer Petróleos Mexicanos

Mexico, North America, Onshore

Qualified to 200 degC [392 degF], the new Ora intelligent wireline formation testing platform’s focused fluid acquisition is powered by dual pumps capable of extremely slow rates. The accurate flow control made it possible for Pemex to collect representative gas condensate samples and conduct transient testing in a tight HPHT formation to prove the most important land discovery in Mexico in the last 25 years.

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