天然裂缝滤失计算和控制技术应用

引用天然裂缝滤失系数和基质滤失系数的指数关系式，对塔里木油田裂缝性K气藏小型测试压裂的压降分析，计算出K气藏天然裂缝滤失系数为10-3~10-2 m/min1/2级别；净压力控制在10 MPa以内，即能将裂缝滤失系数控制在基质滤失系数的10倍以内。现场应用表明，使用多级高质量浓度段塞和大段塞量是控制K气藏加砂压裂净压力和天然裂缝滤失的有效措施之一。塔里木油田裂缝性砂岩储层加砂压裂的段塞级数为4—6级，质量浓度60~520 kg/m3，体积7~15 m3，段塞量增加1倍，平均净加砂量增加1.5倍。研究结果对类似天然裂缝发育储层的裂缝滤失规律研究和加砂压裂优化设计有很好的借鉴意义。

Based on the pressure drawdown analysis of mini-frac in natural fracture K gas reservoir of Tarim Oilfield, the leak-off coefficient with natural fissure is calculated to be 10-3-10-2 m/min1/2 level by the exponential relationship of fracture leak-off coefficient and matrix leak-off coefficient. The fracture leak-off coefficient will be less than 10 times matrix loss if the net pressure is less than 10 MPa. The multi-high concentration slug and massive slug are the effective methods to control the net pressure and loss with fissure in K gas reservoir. According to field applications, the average proppant volume increased by 50% while doubling the amount of slug, with the condition of slug stages 4~6, slug concentration 60~520 kg/m3, slug volume 7~15 m3. The conclusions in this paper are helpful to other natural fracture loss research and fracturing design.

10.6056/dkyqt201402031