The development of viscous acid systems has improved the effectiveness of acid fracturing. A specific case in point is the Warren Unit of Southeastern New Mexico, which produces oil and gas from the Drinkard, Tubh and Blinebry formations. The Drinkard and Tubb formations have been found to respond favorably to acid fracture stimulation through the use of gelled and crosslinked acid systems. A crosslinked 15% hydrochloric acid gel fracturing treatment provides an economic and effective initial stimulation of the Drinkard and Tubb, while re-stimulation of Tubb wells has yielded similar results independent of the treatment type.
Production results are evaluated for the different treatments. Included are comparisons of various viscous treating fluids and treatment procedures. Rotating disk reaction rate information, rheological properties of various fluids, fluid loss characteristics, formation lithological differences and well locations are also discussed. The limitations of usage of the various fluids and techniques within the Warren Unit are addressed.