Acid Fracture Research Laboratory

The Acid Fracture Research Lab is designed to study acid fracture conductivity behavior as functions of important parameters. Each experiment has 4 major steps; rock sample preparation, cell preparation and loading, acid injection, and fracture conductivity measurement. The set-up consists of an acid injection apparatus, a fracture conductivity measurement apparatus, and a profilometer for surface scanning.

Acid injector apparatus

Cylindrical metal device topped by dark electronic box with protruding wires.

Fracture conductivity measurement apparatus

Over-sized three-shelf unit with connected instruments on shelves and adjacent red metal standing apparatus.


Small tan electronic device attached to a slide and laser light which is connected to computer by wires.

The acid injection uses a modified API conductivity cell that holds the samples in place during the experiments. The cell is corrosion resistant and can withstand pressures that over 10,000 psi. This injection system is designed to flow acid through the API cell at high pressures (greater than 1000 psi). The pressure transducers display the pressure inside the cell, across the fracture, and the leak-off pressure (across the samples). The Chem-Pump is a metered pump that is able to flow up to a rate of 1.05 liters/minutes. Thermocouples located upstream and downstream of the cell provide temperature data during the injection. Backpressure regulators ensure that the system stays at the desired pressure of 1000 psi.

The apparatus used to measure fracture conductivity is designed to flow a fluid through the API cell that is subject to varying closure stresses. A load frame holds the cell in a horizontal position. Pressure transducers measure the pressure across the fracture and in the cell. Three pressure transducers measure different ranges of pressure drop. A thermocouple located downstream of the cell provides temperature data. The flow rate of the fluid flowing through the cell is measured using a stopwatch and a graduated cylinder.

The surface of the rock samples can be scanned with a profilometer before and after acid injection to determine the volume of rock removed during the acid injection. The apparatus includes a laser sensor, control box, and PC software interface. The profilometer uses the laser displacement sensor to record the vertical height of the sample as it travels over the entire length and width of the sample.