河50丛式井组加密调整井固井技术

Cementing technology for infilled wells of River 50 cluster wells

河50丛式井组原有42口定向斜井,为挖掘剩余原油潜力,重新布加密调整井35口。针对现实存在的难题,为保证固井质量,选择了增强低密度泡沫水泥浆体系、漂珠微硅低密度水泥浆体系、低失水微膨胀增韧水泥浆体系、滤饼固化成凝饼技术和全橡胶式管外封隔器。目前已在河50断块施工30口井,上部全部采用低密度水泥浆体系,油层全部采用低失水微膨胀增韧水泥浆体系,水泥返至井口,水泥浆封固段2065-3125m,实现了全井封固,没有发生漏失现象。变密度测井显示,固井合格率100%,优质率79%,相比于相邻区块调整井,固井质量优质率提高12%。

At the very beginning there were 42 deviation wells in River 50 cluster wells.To tap the potential of residual oil,35 infilled wells were spaced again.In view of the difficulties,the reinforced low-density foam cement slurry,the low-density cement slurry with micro-silicon and floating beads,the toughness-enhancing cement slurry with low-fluid loss and micro-expansion,the technology of turning mud cakes into gel cakes,and the full rubber external casing packer are selected to assure cementing quality,which have been applied to 30 wells in River 50 Block.Low-density cement slurry is applied to the upper part of the oil layer,while the toughness-enhancing cement slurry with low-fluid loss and micro-expansion is used in all oil layers.Cement goes back to the wellhead,and the slurry cementing section ranges from 2065 m to 3125 m.Cementing is achieved in all wells,and no leakage occurred.Variable density log shows that well quality qualified ratio reaches 100%,and quality rate is 79% which increases by 12% as compared with the adjustment wells in adjacent blocks.