Oil and gas reservoirs are not always the most hospitable environments. The industry has spent years perfecting HP/HT applications for downhole tools so that they do not melt or implode, but there are always new surprises in store.

Take coring, for instance. The whole idea of coring is to take an in situ sample of the reservoir, but in standard operations most of the oil, gas, and water leak out as the core is being brought to the surface. Trying to capture the core intact and maintaining its virgin reservoir pressure as it is being hauled out of the hole is, as Doug Kinsella, managing director for Corpro, said, “like bringing a natural gas bomb to the surface.”

To address these issues, Corpro, part of the Reservoir Group, has developed a coring platform that brings the core and fluids to the surface without endangering life and limb. The first part of the platform to be developed is QuickCore, a wireline coring tool that avoids tripping in and out of the hole during the coring process. More recently, the company introduced QuickCapture.

“In a coring program you might want to take a couple of capture cores to get another level of information out of your reservoir,” Kinsella said. QuickCapture relies on a wireline operation that is deployed once the well has been drilled to a coring point. The two-barrel system captures the core in an inner barrel, while the outer assembly consists of an outer barrel and a core bit. A telescoping sleeve collects the core, and temperature and pressure transducers monitor it during coring operations and the trip out of the hole. Meanwhile, part of the inner assembly consists of canisters that trap escaping gases and fluids. Although these gases and fluids are captured in situ, the pressure eventually drops to 500 psi by the time the canisters reach the surface. The canisters also contain pressure release valves, pressure sensors, and pressure and temperature recording transducers.

When the assembly reaches the surface, it is laid down, where the gas canisters are shut in and removed. Pressure and temperature readings are recorded and total volumes are measured; then the fluids are pumped out and sent to the lab.

Once the core reaches an acceptable pressure, it is extruded and transferred to transportable canisters. Afterward, the core barrel is wiped clean, and any residual gas or fluids are sent to the lab for testing.

Kinsella said the measurements taken at the well site are much more precise than those taken in traditional coring operations. “In traditional coring, some percentage of the fluid leaks out, goes into the mud column, and is lost forever,” he said. “This tool captures everything. It gives the customer a much better picture of what is actually in the reservoir.”

So far, the tool has proven itself in unconventional plays and also mature plays, where it can detect bypassed pay. Already, it has paid off for one operator, indicating that its reservoir contained more than twice the amount of gas estimates it had predicted.

While the system does save time at the well site, Kinsella said that its benefits are less about economics and more about delivering more and better data in a safe and responsible manner. “It will save operators money,” he said. “But the tool is really more about collecting pertinent information about the reservoir that customers really can’t get under any other circumstances and also delivering it in a way that no one gets hurt.