The chance of shifting choke determined by forced closure time during forced unflowing procedure is always obtained by pressure drop analysis model.Considered two-dimensional leadoff and compression for fracturing fluid,combined with material balance theory,rock mechanics and fluid mechanics,a new mathematical model is developed.Compared with drawdown analysis model,this new model not only need no the long descending data,but also the calculated result is more reliable for full considerate factors,and the model is also suit to natural fracture closure.Based on the set model,corresponding worked out software,the calculation of an example is given.The model gives a new way to calculate forced closure time without field pressure drawdown data.

All types of up-to-date controlling fracture height technology applied domestically and abroad are comprehensively described,and also the conditions suitable for their applications are indicated.A generally applicable calculation method of design of various types of controlling fracture height technology is set forth.In the light of this method,selected five influence factors on fracture height,including operational displacement,poor stress in restraining barriers,viscosity of fracturing fluid,young’s modulus and leakoff coefficient and obtained the effects of formation and operation parameters on the facture height.This research guided fracture design of its height control in M gasfield.

稠油由于沥青胶质含量高,蜡质含量少,因而粘度很高,流动困难,开采难度很大。热采技术作为稠油开发的主要手段,已经广泛应用于国内外稠油油藏的开发。介绍了目前稠油热采的主要方法,并根据稠油开发中存在的问题提出了今后稠油热采技术的发展趋势。