火山岩储层供气特征与开发规律

大庆徐深气田火山岩气藏属于中-低孔隙、致密气藏。岩心实验虽然揭示了储层中不同孔隙结构的供气机理,但是不能体现储层中人工裂缝、天然裂缝和基质孔隙的供气特点与开发规律。通过对徐深A区块密井网试验区的解剖,揭示了储层的供气特征与开发规律。火山岩储层压裂改造后形成双区供气结构,与气井直接相连的是主流区,主流区外存在补给区。主流区控制气井初期产量的高低,补给区是气井长期供气的保障。随着补给区的逐步补给,气井的井控动态储量逐步增加。通过井间加密可以改善老井补给区的渗流能力,减缓老井产能的递减。加密井形成了新的主流区,缩短了渗流距离,有利于致密储量的动用。井间主流区距离远,补给区中广泛分布的基质产生低渗阻隔,因此连通的气井间难相互干扰。

GAS SUPPLY CHARACTERISTICS AND DEVELOPMENT LAWS OF THE VOLCANIC RESERVOIR

Volcanic gas reservoirs of Daqing Xushen Gas Field belong to middle-low-porosity,and tight gas reservoirs.Although the core test reveals the gas supply mechanism of different pore structures in the reservoirs,the gas supply characteristics and development rules of the artificial fractures,natural fracture and matrix pores in the reservoirs can't be reflected.By the analysis of the dense-well-pattern test area in Xushen Block A,the gas supply characteristics and development laws have been revealed.After the reconstruction of the reservoir fracturing,the two-area gas supply structure was formed,the main flow area was directly connected to the gas well,the recharge area was outside the main area.The main flow area controls the gas well production in the early period,while the recharge area is the guarantee of long-term gas supply for the gas well.With the gradual supply,the controlled dynamic reserves of the gas well were gradually increased.With the help of the interwell infilling,the encryption flow ability can be improved for the old-well recharge area,and moreover the productivity decline of the well can be reduced.The Infilled well block becomes the new main stream area,thus the flow distance can be shortened and the tight reserves can be favoritely developed.The main stream area is far away and the wide-distributed matrix in the recharge area results in the low-permeability barrier,therefore the mutual interference among the connected gas wells is difficult to produce.