Impact of formation damage on sand production in deep eocene reservoirs, lake maracaibo, venezuela: a case history

摘要

In the deep and layered Eocene reservoirs of southern Lake Maracaibo, Western Venezuela, some of the most productive fields such as Ceuta were discovered in 1978. Sanding problems are common in VLG 3676, Block VII, one of the most important reservoirs in the area where hydrocarbon production is from various intercalated thin. A major initiative was started in 1996 to evaluate the geomechanical, reservoir, drilling and production profile of the field in order to identify the problems and the options available to maximise production and final recovery. Intensive laboratory and field testing programs were carried out to develop the geomechanical model required and identify potential formation failure mechanisms. A review of drilling and completion practices indicated that formation damage contributed significantly to the sanding problem, while collapsed casing and, severe equipment erosion made, loss of production and well integrity common in the area. The evaluation of reservoir and production data from five (5) wells in order to quantify formation damage revealed skin values >80. The well model that was developed indicated that optimising drilling and completion practices could minimise and in some cases eliminate the sanding problem. A number of recommended changes to existing practices are now being implemented.