A Novel Massive Acid Fracturing Technique With Improving Stimulated Reservoir Volume in HTHP Reservoir in China

摘要

X carbonate formation was the deepest and highest temperature reservoirs in Eastern China. Acid fracturing stimulation need to be treated for further exploration and development. Fracturing treatment can’t be effectively carried because of problems as following:1) Complex storage types and fluid flow mechanics as a result of natural fractures distributed stochastically;2)Extral high in-situ stress(105MPa); 3)high treatment pressure and high temperature (201°C)leading rapid acid/rock reaction speed;4) unde- termined fracture height growth with large open-hole span (388m). To solve these problems, a systematic technologies are put forward in this paper, the highlights are:1) Systematic formation fine evaluation which contains Nclear Magnetic Resonance, X-diffraction clay mineral analysis and so on; 2)A new fracturing fluids which has a higher viscosity in 200°C, lower residue and low damage; 3)A new comprehensive acid fracturing method of multiple stage optimization was put forward to ensure not only the success of stimulation treatment but also the maximal stimulated reservoir volume (SRV) as possible and post-treatment performance; 4) Counter measuxes were applied systematically such as fracture height control and post-treatment management etc. By the application of this technique, a volume of 1491m~3 fluid with high strength ceramic 6.9m~3 proppant was successfully pumped into this formation, As a result the performance of post-fracturing is very remarkable with the daily oil rate being 642.9m3/d and gas rate 56.28×104 m~3/d. while the pre-frac production of oil and gas was only 19.2m~3/d and 1.5×104 m~3/d respectively, it has a great significance in HTHP reservoir in the Eastern China.