深层砂砾岩水平井组立体缝网压裂优化技术

深层致密砂砾岩储层盐227区块为厚层特低渗常压油藏，常规直井压裂效果差、建产难，单一水平井开发难以实现纵向厚层有效动用。借鉴国外页岩气工厂化开发理念，发展了"三层楼"工厂化整体压裂开发模式，即1套层系、3层开发，8口水平井组作为一个整体进行压裂，第一层为3口井，第二层为3口井，第三层为2口井，水平段长900~1 400 m，三层之间纵向跨度为80 m。综合考虑平面上同层井间、纵向上层间裂缝参数匹配，建立层间立体体积缝网，提高储量控制程度。通过优化施工参数，应用新型实时混配压裂液技术，配套泵送桥塞分段压裂工艺、裂缝实时监测技术，完成4个井组8口井87段的集中压裂，裂缝监测显示立体缝网基本形成。工厂化整体压裂平均施工周期比单一水平井压裂缩短50%，单井投产费用减少395.5万元。压裂后单井平均产油量11.8 t/d，为同区块直井的4倍以上，取得了良好的改造效果，为今后同类致密油储层的经济开发积累了经验。 

3D Fracturing Network Optimization Techniques for Horizontal Wells in Sandstone-Conglomerate Formations

Block Yan 227 is a thick tight sandstone-conglomerate reservoir with ultra low permeability.The result of fracturing in a conventional vertical well was too poor to obtain a satisfactory yield,to the point that it is even not desirable to develop such a thick reservoir with a single horizontal well.Based on the concept of factory production from numerous countries for shale gas,a three-layer development model was developed.The model included a group of eight horizontal wells for fracturing:three wells were included in the first layer,another three wells in the second layer,and remaining two wells in the third layer.The length of the horizontal section ranged from 900 to 1 400 m,the vertical span in the three layers was 80 m.Fracture parameter matching was done with wells within the same layer as well as between layers to establish a 3-D fracture network to improve the controlling degree of reserves.Operating parameters were optimized,with a new type of real-time mixing technology for fracture fluids,which included pumping a bridge plug for staged fracturing,and monitoring fractures in real time,which allowed eight wells in four well groups with 87 sections to be fractured.The fracture monitoring results showed that a 3D fracture network was formed.The centralized multi-well fracturing technology has many advantages compared with single horizontal well fracturing,including the fact that average operation cycle time was shortened by 50%,and the production cost of a single well was reduced by 3.955 million RMB.After treatment,average daily oil production of single well was 11.8 t/d,which was four times higher than that in the vertical well in the same block.It is a good experiment for economic recovery in similar tight oil reservoirs.