高能气体压裂最佳装药量与峰压设计计算

在高能气体压裂过程中,设计最佳装药量使之产生合理的峰值压力,实现既能压裂地层又能有效地保护井壁及套管不受损坏和有害变形,是压裂成败的关键。将气体发生器中火药气体作为体系,把压井液、套管与地层等作为外界,根据热力学第一定律,建立了装药量与压力关系的数学计算模型,并编制了相应的计算软件。通过对现场12井次的实测数据进行计算对比,最大误差为4.63MPa,与实测峰压相比,相对误差仅为5.65%,结果令人满意。

OPTIMUM CHARGE AND PEAK PRESSURE CALCULATION OF HIGH ENERGY GAS FRACTURING

During formation fracturing with high energy gas, the successful key is to design an optimum charge that can produce a reasonable peak pressure which both,can fracture formation and can effectively protect well wall and casing from damaging and deforming. In this paper, considering factors such as the explosive gas in gas generator, killing fluid, casing, formation and so on, established a mathematical calculation model of charge versus pressure based on the first law of thermodynamics, and compiled a relevant calculation software. The maximum error between calculated and measured pressures (measured for 12 times on site) is 4. 63 MPa, the relative error is only 5. 65% comparing with the measured peak pressure. The results are satisfactory.