Progressively, the oil and gas industry is producing from unconventional reservoirs with low permeability in numerous small pay zones that require close well spacing and multiple stimulations in each well. To effectively produce from such reservoirs and reduce the surface footprint, ExxonMobil has drilled multiple wells from single pads, and new technologies have been developed to efficiently stimulate the multiple pay zones in each well. ExxonMobil has developed and licensed Multi-Zone Stimulation Technologies (MZST), which are designed to efficiently stimulate wells with multiple pays zones. The technologies have been applied in fracturing tight gas reservoirs with numerous lenticular sands in the Rocky Mountains. We have also developed a technology that enables the simultaneous stimulation of multiple wells on the same or different well pads, and while drilling additional wells. The benefits of this technology include reduced environmental impact, time saving, and improved production rates. Most importantly we have demonstrated that these simultaneous operations can be conducted in a safe and responsible manner to ensure the highest standards of operations integrity. This paper introduces the method and apparatus for this technology and discusses the results from several years of field applications, including the Piceance Basin. Some specific elements of the simultaneous operations safety plan will also be provided. Introduction Worldwide, substantial oil and gas resources are contained in low permeability formations. Many of these resources are characterized by thick intervals and/or multiple reservoir targets. In addition, matrix or fracture stimulation treatments are typically required to effectively and optimally produce these resources. However, the increased geologic and reservoir heterogeneities present in these resources can lead to substantial challenges in the stimulation treatment operations and effectiveness. Over the last several decades, industry has invested substantial research in attempts to develop new drilling and completion technologies for application in tight gas sand reservoirs. Various government and industry studies indicate a vast amount of tight gas resources exist within the United States alone, with similar resources located outside the U.S. Examples of such resources are found widely distributed in the western United States, and include the Green River, Piceance, Wind River and Uinta Basins.