Contract well drilling services for oil and gas; drilling of oil and gas wells; oil and gas extraction; leasing of oil and gas drilling rigs; oil and gas pumping and extraction, in the nature of well production, completion, improvement, enhancement, and stimulation services; hydraulic fracturing of oil and gas wells; oil and gas well pressure pumping services; oilfield services, namely, cementing well casing strings as part of the well construction process, hydraulic fracturing and acidizing of target geologic formations to enhance production of the well; oil and gas reservoir enhancement services, namely, hydraulic fracturing of subsurface geologic formations to enhance well production; cementing services for oil and gas wells; oil and gas well enhancing services, namely, the injection of nitrogen and acid to oil and gas wells to increase the oil and gas recovery; remedial work on oil and gas wells, namely, re-hydraulic fracturing and re-cementing services