Chen W.-G.,Chengdu University of Technology |
Luo T.-T.,Drilling and Production Technology Research Institute |
Sun Q.-L.,Chengdu University of Technology |
Li R.-M.,Drilling Fluid Service Company |
And 2 more authors.
Journal of Chengdu University of Technology (Science and Technology Edition) | Year: 2014
The retarded acid (RE-Acid) is solved into the (Completion well fluid to relieve the deep damage in strata resulted from the drilling or/and well completion operations. The retarded acid (RE-Acid) slowly produces hydrochloric acid at low temperature and quickly lowers the solution pH value to less than 1 at high temperature with stronger dissolution performance. The dissolution rate of 22% concentration RE-Acid can reach more than 10%. For the well completion fluids added to salt, the potassium formate slows down the speed that RE-Acid generates hydrochloric acid because the formate can be easily combined with calciumion and unfolds better dissolution performance than the other salt solution. 12% concentration RE-Acid can dissolve limestone with more than 20% dissolution rate in formate well completion fluid (weight: 1. 3 g/cm 3). For the low-density foam well completion fluid, AFM-1 foam agent has good properties in RE-Acid fluid. The RE-Acid dissolution rate is more than 16% for limestone in the AFM-1 foam basal agent fluid. The results of displacement experiments indicate that the hydrochloric acid only improves the permeability of the first segment core, but the retarded acid can improve the permeability of the second and third segment core in the deep, reaching more than 2. 5 times and 1. 7 times, respectively.