Time-lapse (4D) effect and reservoir sand production pattern in a mature North Sea field

Abstract

Sand production is not uncommon in producing fields. Its severity, however, remains a growing concern in many mature fields and deepwater reservoirs often characterized by poor consolidation. Reservoir sand production is sim-ultaneously a source of concern and benefit in conventional and heavy oil production. Porosity increase and changes in local stress magnitude, which often enhance permeability, have been associated with severe sanding. On the other hand, sand production has been linked to a large number of field incidences involving loss of well integrity, casing collapse, and corrosion of downhole systems. It also poses problems for separators and transport facilities. The poorly consolidated Gudao reservoir in Shengli oil field, China, provides a typical example of casing failure, resulting from severe reservoir sanding (Figure 1). Sand-production-induced casing problems can vary from complete shearing to contortion of well casing depending on the severity of the sand flow.