黄沙坨油田火山岩油藏注水开发影响因素分析

黄沙坨油田为裂缝型边底水火山粗面岩油藏,储层属于裂缝-孔隙型双重介质。黄沙坨油田注水开发后,油藏能量虽然得以补充,但水驱控制程度、波及范围和注水效果却难以控制,增产效果不明显。为黄沙坨油田下步调整提供依据,分析了裂缝发育程度、注采井相对位置、油井生产状况、驱油效率、注水时间、注水强度等因素对注水开发的影响。分析结果表明:影响注水效果因素主要是裂缝、孔隙的发育程度及走向,裂缝发育区油井产能高,见水见效快、含水上升快,裂缝欠发育区油井产量低、见水见效慢;同一井组内井距及注水高差小的井注水见效快,反之则见效慢;平均日产液量大于10t/d、平均日产水量大于2t/d的油井注水效果好;油水两相区区域较窄,油藏可动油饱和度较低,油藏采收率不高;注水时间越长,注水强度越高,井组注水见效的反应越明显。

Analysis on Influencing Factors of Water Flooding in Volcanic Oil Reservoir of Huangshatuo Oilfield

Huangshatuo oilfield is a fractured volcanic trachyte one with edge and bottom water.It has fracture-pore media reservoirs.After the water flooding in Huangshatuo oilfield,reservoir energy was supplied,but controlling degree,sweep area and water injection response of the water drive were difficult to control and there were no obvious stimulation results.In order to provide foundation for the next adjustment in the oilfield,the influencing factors of water flooding were analyzed including development degree of the fractures , relative position of injector and producer,producing situation of the oil well,oil displacement efficiency,injection time and water intake per unit thickness.The results show that the main influencing factors are the development degree and trend of the fractures and pores.In the developed fracture area,oil wells have high productivity with rapid breakthrough and response and water cut increasing;in the underdeveloped fracture area,the situation is on the contrary.In the same well group,the wells with small well spacing and injection height difference have rapid response of water flooding,so is the reverse.The oil wells with more than 10t/d of average daily liquid production and more than 2t/d of average daily water production have good response.Recovery efficiency of oil reservoir is not high for thin oil-water two-phrase region and low movable oil saturation.Longer injection time brings higher water intake and more response of water flooding in well group.