SHAD oilfield, located in one of the fields with the highest onshore production in the Middle East; more than 70% of its production wells are flowing wells, with an average single well production capacity of more than 3000 bbl/d. Its main oil production formation is loose sandstone reservoir. The completion style of its production wells are generally completed casing perforation, and sand production is obvious after a period of exploitation. In the process of production, sand cleaning and sand discharging are often needed in the perforated section of oil well; however, after 3-5 years of production, serious sand burial still forces developers to give up the original production formation. In addition to the problem of sand production, there are many complex layers, some of them are oil-water layer, and the increase of water in the liquid production gradually affects the well flowing.
Fishable and sectional expandable sand screen (ESS) completion technology is developed to deal with sand production and the increase of water production. The upper of the original production formation of the old wells is as the new production formation. The new formation is divided into several sections due to different physical properties. Perforation is carried out at the same time for all sections. After this, each the ESS completion string is run into each section. The top sealing hanger and the bottom packer will seal each ends of the annular between ESS and perforating casing, thus to form independent production section. In later process of production, plugging tools is run for sections if needed, so as to realize selective open/ close of different sections. Special fishing tools are developed, combined with the mechanical plastic characteristics of ESS, which can realize the fishing of the completion string. This solves the problem of fishing long string, and provides good conditions for subsequent operations.
The research results show that two good results are obtained. One is that arranging several sections of ESS completion strings in the old well bore gives full play to the characteristics of ESS with strong flow capacity, good sand control effect, and is suitable for sand control in high-yield wells. The other is that selective open/close is realized for different sections which meets the sand control and production needs of in SHAD oilfield.
The research results have applied to 9 wells in SHAD oilfield, and the success rate is 100%. Among them, one single well is divided into three sections, and the production is stable, the sand production is near to 0, and the sand control effect is significant. The successful application of this technology fills up the gap of multi-stage ESS completion in the Middle East.