Sandstone Reservoir More Than Hydrogen And Sour Technology Research

Matrix acidizing has been used as the preferred method of damage removing and stimulating for sandstone formations. Hydrochloride-hydrofluoric acid mixtures have been extensively used to treat sandstone reservoirs. However, their application has been restricted because of a combination of rapid spending with clays and silicates, which results the short acid penetration, and the second precipitation damage. Several existing "retarded HF acids" mixture have been tried to resolve these two problems, but the results are not satisfactory because those acid mixtures can not overcome the huge contrast in surface area between clays and quartz. This paper provides a new acid system for sandstone formation acidizing, which is named as Multi-hydrogen Acid System. Multi-hydrogen Acid is a phosphonic acid compound, and it has several hydrogens. This paper discusses the properties and the retarding mechanics and the mechanics of contolling secondary precipitation of Multi-hydrogen Acid. And this paper sets up the of Multi-hydrogen Acid acidizing model, moreover, the successful case study of application in Bohai Oilfield is also documented in this paper. This paper accomplishes the following:(1) The chemical components of new Multi-hydrogen Acid is found on the basis of a great amount of researching and studying on the sandstone formation acid system papers and varied materials.(2) The essential properties of Multi-hydrogen Acid is documented, moreover, the retarding mechanics and secondary precipitation controlling mechanics of this new type acid are also discussed in detail. This paper studies the retarding mechanics by the means of all sorts of experimental analysis and Scanning Electron Microscope, which shows the physical adsorption and chemical adsorption are the basic retarding mechanics. The secondary precipitation controlling mechanics are also studied detailed by researching the specialty of Multi-hydrogen Acid and kinetics of the acid-rock reaction in sandstone formation.(3) The specialty study of Multi-hydrogen Acid includes solubility, wetting properties, compatibility, etc. The stimulation effect tests employed the real cores in Bohai Oilfield and Tarim Oilfield, and the result of it indicates that Multi-hydrogen Acid can improve the permeability of the formation. A new acid system for sandstone formation acidizing treatments is successfully achieved.(4) A new sandstone formation acidizing model of Multi-hydrogen Acid is set up, which mainly considers kinetics of acid-rock reaction of this new acid. Respectively, radial model of acid and mineral model are also set up, and the numerical models are given out synchronously.(5) Combining the characteristics of high porosity and permeability sandstone formation, a optimized acidizing design is given out for Multi-hydrogen Acid treatment.(6) As a compliment, several Bohai Oilfield treatments are discussed and a complete database with production data is presented. The achievement of Multi-hydrogen Acid in Bohai Oilfield provides a new technique for matrix acidizing over this area. The application of the new acid in China oil fields has a wonderful prospect.