Many times the chemicals used during a fracture treatment either become contaminated or shelf-degraded. Whenever these problems occur, the concentration of the chemicals must be adjusted or the chemicals must be replaced with fresh chemicals. Quality control problems cannot be blamed on either operating company personnel or service company personnel because of neglect or disinterest. Rather, the fluids used to stimulate tight gas reservoirs can be described as complex fluid systems that simply require intense quality control to mix and pump correctly. Following are some of the most important actions necessary to perform fracture treatment quality control.
Check tanks for cleanliness and add bactericide.
Fill tanks with clean water and perform a complete water analysis on each tank. Inventory all fluids, chemicals, proppants and equipment. Mix samples of the fluids using on-site chemicals and materials, then run gel pilot tests to determine the optimum chemical mixture. Test all gels, buffers, crosslinkers and breakers to achieve the optimum formulation. All tests should be run at bottomhole temperature.