Dagang Oilfield Qianmiqiao High Temperature Low Permeability Reservoir Depth Of Acid Fracturing Theory And Technology

In this paper, theoretical researches, experimental researches as well as practical ones have been carried out focusing on the problems of the deep acid fracturing of the Qianmiqiao carbonate reservoir bed. which is of low permeability and high temperature, starting from the reservoir properties.The main points of this paper are following.1.Researches on Theoretical ModelsIn this part, some research works have been completed, using the basic principles and research approaches of hydrodynamics, rock mechanics, and fracture mechanics and fractal geometry. These researches are (l)deriving the PSD model for artificial fractures prolongation, the numerical calculation model for temperature field of vertical well bore and artificial fractures, (2)establishing the model for acid leaking affected by the wormholes, and(3) analyzing the seepage mechanism and fractal characteristics about the fingering of the acid.2. Researches on Acid Fluid SystemAiming at lengthening the effected distance, the experiments and selection about the acid ingredients have been made, which resulted in two new type acid systems (solid acid and retardant acid) due to which controlling over the process of acid /rock reaction became much easier.3.Researches on Practical TechniquesThe treatments process of acid fracturing using solid acid has been developed. The main points about flowback and the value of treatment parameters have been given out, too.4.Appraise of the Practical ApplicationThe calculation models for effected distance, conductivity and production- increasing ratio were educed. And it is showed that after the acid fracturing treatment, the production-increasing ratio increased at 6 times.There are some innovations of this paper.(1 )The model for acid leaking affected by the wormholes has been developed, which could solve the ubiquitous problem -taking leaking models of fracturing fluid for acid leaking.(2) The researches on fractal characteristics of acid fingering have been made, and also the fractal dimension of the fingering has been educed, through combination of the theory and experiments.(3) The two new type acid systems (solid acid and retardant acid) have been developed, which solved the problem of flow speed retardance, drag reduction, compatibleness about the acid systems in the HTHP condition.