Evaluation of Frac and Pack Completions and Future Outlook

Abstract

Summary Frac and pack introduced in the early 1990's in the Gulf of Mexico has become a well-established completion procedure aimed at enhancing the productivity of gravel packed wells. The technique consists of incorporating a "tip screenout"1 hydraulic fracturing treatment as part of the gravel packing procedure, thus stimulating the well. However, published well test data, although showing generally better productivity than classic gravel packs, presents positive skin values indicating near-wellbore damage and often questioning the existence of a fracture intersecting the wellbore. This paper quickly reviews published data and outlines a methodology which integrates the analyses of the fracture placement data and the well test data. This integration results in a more realistic modeling of the system well and reservoir and characterizes the hydraulic fracture intersecting the wellbore. It is shown that poor fracture conductivity and/or high fracture face skin damage coupled with wellbore storage can reproduce the behavior observed in well test data and commonly interpreted with a nonfractured model. The effects of additional pressure losses across the gravel pack can also be incorporated for a more realistic modeling. Field examples are discussed to illustrate the technique and a quick outlook of how completions of unconsolidated sandstones may evolve is presented.