Simulation Of Multi - Stage Injection Acid Pressure In Puguang Gas Field

Alternating Phase Fracture Acidizing is an important stimulation technique that has been widely used in carbonate reservoirs. Puguang gas field is the most uncompartmentalized marine facies gas field at now in our country, and it have such properties as deep buried depth, thick thickness, high operating facture Pressure and high acidizing fluid loss, Puguang gas field is a typical high sulfur gas filed. Using Alternating Phase Fracture Acidizing in this field has been proven successful.To satisfy the designs requirment in Alternating Phase Fracture Acidizing, I have completed an optimizing computer programs. With the simulative calculation of whole treatment procedure, the parameters such as the tempetature, the geometry of fractures, the effective penetration distance, the acid ecthed fracture conductivity, the stimulation ratio can be determined. The detailed work as follows:(1) Wellbore temperature field is calculated by using the Eickmerier model; fracture geometry parameter is calculated by using the I.D.Palmer model; Acid solution concentration distribution is calculated by the Acid concentration distribution model.(2) Considering the difference between fracturing fluid leakoff and acid leakoff, established a calculation procedure of the fracture fluid leakoff velocity fluid loss the acidizing fluid leakoff velocity and fluid loss which the acid wormhole existing in Alternating Phase Fracture Acidizing.(3) Modeling calculate the Acid concentration along the length of fracture, and then we obtaining the acid effective distance. It uses wormhole mean length and acid leakoff delayed time calculation methods, as well as the calculation of the filtration.(4) Considering these factors and using Visual Basic language, we develop a Alternating Phase Fracture Acidizing program such as fully considering the effects of formation temperature, homo-ionic effect, wormhole effect and acid leakoff delayed.(5) With field document of Puguang 104-1 well, Calculation is made by the established model. The calculation results indicate that the predictions of this program simulation well with the field practice.