Study On Improving Stability Of Horizontal Well Cement Slurry In Placanticline Area

Daqing placanticline area has a complex geological structure, it belongs to the multizones and multi-pressure layers hetergenous reservoir. It has been in the third development stage so far and the development object is low permeability thin and poor layer. With the progress of drilling and completion technology, horizontal wells have gradually become effective method for improving the productivity of low permeability reservoirs and the important means of oilfield development. Therefore, we carry out research on improving the stability of cement slurry so as to effectively prevent free water caused by subsidence phenomenon and uneven density due to gravitational settling which is very urgent and necessary for improving the cementing quality especially horizontal well cementing quality.This article starts with the research of slurry sedimentation stability test, it puts forward an idea of developing horizontal well cementing slurry system applicable to Daqing oilfield by appropriately improving cement slurry gel strength, reducing free water and water loss, shortening slurry thickening transition time.This study analyzes the effects of various additives on cement slurry by repeated experiments, we start by method of lowering slurry free water, improving slurry stability, controlling water loss and gel strength in order to further eliminate high-side water channeling and low-side cement particles sedimentation channeling, improve the overall slurry anti-channeling ability. Thus we can finally realize gradually solidification of slurry from bottom to top by sections to ensure the cementing quality of cement ring.