The Lower Cretaceous Buda Limestone Formation in Gonzales County, Texas, and its potential as a fractured carbonate hydrocarbon reservoir

The Lower Cretaceous Buda Limestone Formation in Gonzales County, Texas is a proven fractured carbonate hydrocarbon reservoir. Reservoir development is due to fracturing that was created in response to the tensional forces that occurred as the Gulf Coast and East Texas Basins began subsiding under the tremendous overburden load of Tertiary sediments. The fractures are associated with the extensive fault system trend that developed along the margins of the basins. By examining dip oriented seismic data and oriented well cores along this trend, with the intent of discerning areas of anomalous seismic continuity, a suggestion of fracture swarming can be made. Areas immediately adjacent to normal faults tend to have a higher percentage of vertical fracturing that is interconnected, thus allowing for more migration of fluids while the fractures are open. The Buda lies disconformably over the organic rich Del Rio Clay and is overlain by the hydrocarbon rich Eagleford Shale, which are the main source rocks for hydrocarbon accumulation in this unit.; The development of horizontal drilling techniques has created an excellent solution for extracting hydrocarbons from vertically fractured reservoirs. By identifying areas of fracture swarms and selecting proper orientation, a long horizontally drilled well can encounter numerous fracture zones, thereby greatly increasing the production potential.; Well core examination in the study area reveals an extensive diagenetic fracturing history in the Buda Limestone. Proven oil and gas production history in the study area, and areas of seismic anomalies associated with faulting, greatly enhance the chances for successful horizontal completions.