Use of a solids-free viscous carrying fluid in fracturing applications: An economic and productivity comparison in shallow completions

The paper presents the findings of 20 completions in both oil and gas wells. These completions were performed from the period of 1973 through 1994. The early completions employed sand control technology of the 1970`s and 1980`s with most requiring acid stimulation immediately after sand placement to assure the removal of completion damage. The 1994 completions involved fracturing combined with sand control (frac-packing) in the same reservoirs which has been gravel packed in the `70`s and `80`s. The unique aspect of this review is that these fracturing treatments were carried out using a solids-free viscoelastic surfactant fluid. The fluid system is discussed along with the reasons why this particular fluid was selected. The implications that this fluid has on the fracture placement as well as productivity are discussed. Laboratory testing indicates that the solids based polymer fluids actually exhibit deep bed filtration and plug the formation pore throats, the fracture packs, and perforations. This damage can require acid stimulation for optimized production. The completion results are compared by use of a productivity index (J), normalized J{sup 14}, and bottom hole pressure build-up analysis.