Research And Application Of Gravel Packing Technology Of Sand Prevention And Sand Setting

Gudao oilfield is a typical porous sandstone reservoir, which has unconsolidatedreservoir rock，high shale content and serious sand production, all well have takenmeasures to prevent sand production, sand control technology is the basic process ofmaintaining the development and production of Gudao oilfield。The original sand controltechnology was designed by the traditional theory, without considering the adaptability after-formation having changed at later stage of production, which resulted in the production ofpartial sand well low and declining quickly. This paper analyzes the characteristics offormation sand production and find out that now the main factor of sand control effection issand mixed gravel and sand-prevention tubings plugged by sand setting. Basic on theappropriate sand concept, study on deeply the relationship between sand prevention, sanddischarging and sand setting，and put forward the classification of filling coordinating sandprevention and sand discharging. The lesser level of the gravel is filled in the deeper layerwhich is relatively close to the median size of sandstone; the coarse level gravel is filled inthe well bore and hole, which has larger pore throat and higher permeability，thus when thesand can’t be blocked by the lesser level of filling gravel and migrate to the coarse gravellayer, it is not enough to bridge the plugged pore throats, and the near wellbore area stillmaintains high permeability.Considering that sand mixed gravel reduces the permeability of gravel packing zone andsand-prevention tubings plugged by sand setting results in liquid production declining quickly,according to the far stability-the near prevention-the internal loose, the grave packingtechnology of the sand prevention-discharging-setting integration is based on the existingsand experimental，and form " classified packing+sand sinking tube". The technique is basedon the original gravel packing and formed by the optimization and improvement。The application shows that it can significantly improve the permeability of the near wellbore andhelp the well has a longer production cycle after increasing the oil well productivity.