The Hydraulic Fracture Conductivity Lab was established to simulate the hydraulic fracturing fluid pumping, fracture closure, and to measure the fracture conductivity over closure stresses.

It mainly consists of 1) the fluid injection module; 2) the closure stress application unit; 3) the conductivity cell assembly; and 4) the data acquisition system. The fluid injection module can flow single phase gas, liquid, as well as proppant loaded cross-linked gel at flow rates equivalent to field applications. The hydraulic load frame can apply fracture closure stress up to 15,000 psi on rock samples with dimensions recommended by ISO 13503-5 at stress application rate of 100 psi/minute. The modified API conductivity cell can accommodate samples up to 6 inches thick in total, which makes it reasonable to account for fluid leakoff during the experiment. The data recorded in the experiment include differential pressure across the sample, sample mid-point pressure, fluid flow rate, closure stress, axial displacement of the stress loading piston, et al.

Overview of the fracture conductivity lab.

view of 613 lab with labeled components and equipment

Conductivity cell assembly with pressure sensors placed on the load frame.

conductivity cell assembly showing pressure sensor connection

This setup has been utilized to study dynamic placement of proppants in hydraulic fractures, to investigate gel damage mechanics and optimize fracturing fluids in tight gas sands, to measure shale fracture conductivity for a variety of North America shale formations, and to explore the mechanisms of shale fracture conductivity damage by water.

Assisted by the rock characterization apparatus in testing the rock mechanical properties, scanning the rock surface roughness and analyzing the rock mineralogical compositions, the conductivity lab functions at its full capacity to tackle the perplexing problems in hydraulic fracturing and makes significant contributions to the understanding of the unconventional resources development.