富县区块浅层致密油藏压裂裂缝扩展形态研究

为了提高富县区块延长组浅层致密砂岩油藏压裂改造效果,研究了压裂裂缝扩展形态及其对压后产量的影响。采用室内声发射凯塞尔效应方法,结合现场裂缝监测、压裂压力降落特性和压后试油结果进行分析,认为裂缝扩展形态与油层埋深和层位直接相关,长2、长3和长6储层的压裂裂缝主要为水平缝或复杂缝,长7和长8储层的压裂裂缝主要为垂直缝。水平裂缝压后生产效果差,必须根据不同的深度与层位对压裂设计和现场施工工艺进行优化,尽可能避免形成单一水平裂缝。在一口水平井进行了现场试验,压裂施工11段,试油最高产油量13.54 t/d,目前稳产油量8.93 t/d,取得了较好的改造效果。研究结果可为其他地区浅层油藏的压裂设计与施工提供技术参考。 

Fracture Propogation in Shallow Tight Reservoirs of Fuxian Block

Reservoirs in Yanchang Fomation of Fuxian Block are shallow in buried depth,and complex in fracture propagation and shape.In order to improve fracturing effect in shallow tight sandstone reservoirs,the fracture propagation shape and its effect on production were investigated.On the basis of acoustic emission Kessel Effect experiment results,the analysis was made with fracture monitoring data,the fracturing pressure drop characterization and oil test results after fracturing,show that fracture propagation shape is directly related to the depth and layers of reservoirs,the main fractures created in the layers Chang 2,Chang 3and Chang 6were horizontal or complex,but main fractures in the layers Chang 7and Chang 8 are vertical.Because the horizontal fractures greatly affect the fracturing effect,it is very important to optimize the fracture design and the technique to avoid forming horizontal fractures.One horizontal well fractured with 11stages,has high output of oil 13.54t/d,and kept stable oil production of 8.93t/d currently,indicating good fracturing results.The research results of this article can provide technical reference for other similar shallow reservoirs.