超低渗透油藏水平井压裂优化及应用

Fracturing optimization and application of horizontal wells in ultra-low permeability reservoir

鄂尔多斯盆地超低渗透油藏储层致密、物性差、孔喉细微,是典型的低压、低渗、低丰度油藏,超前注水和水平井分段压裂技术可提高其开发效果。文中以最具代表性的华庆油田长6超低渗透油藏为研究对象,结合注采井网根据水平井段与注水井的相对位置,将常规压裂和体积压裂进行组合设计,在距离水线较近的井段实施小规模压裂,距离水线较远的井段实施大规模体积压裂。该方案的实施,在减小早期水淹风险的同时进一步扩大了储层改造体积,提高了人工裂缝和井网、注水的适配性。同时,开展了8口水平井新型压裂设计的矿场试验,与采用常规压裂设计的邻近水平井相比,试油产量提高20 m3/d左右,投产初期3个月累计产油量提高184 t,含水率较低且保持稳定。

The ultra-low permeability reservoirs in Ordos Basin have the characteristics of tight formation,poor physical property and slight pore throat,which are typical low pressure,low permeability and low abundance oil reservoirs.Water injection to maintain reservoir pressure is important to develop the Chang 6 formation of horizontal wells.Taking Chang 6 ultra-low permeability reservoir of Huaqing Oilfield as an example and combined with the injection-production well pattern,this paper conducted the combined design for conventional fracturing and volume fracturing.In the well interval away from the water line,large-scale volume fracturing was implemented.In the process of project impletement,while reducing the risk of early watered-out,we can further expand the volume of reservoir reconstruction,improve the artificial fracture,well pattern and the suitability of water injection.This paper carried out the fracturing design of field experiment for eight new horizontal wells.Compared with the conventional fracturing design of near horizontal wells,the daily production of oil test increased about 20 m3.At the early three months of putting into production,the cumulative oil production increased 184 t and the water cut is low and stable.