弱凝胶提高海上稠油油田采收率影响因素分析

Analyses of the Factors Affecting EOR of Offshore Heavy Oilfields with Weak Gel

渤海湾某稠油油田L、M、N 3个区块地层纵向和平面非均值性严重、油水流度比大,主力注水井各层吸水不均、油井水驱效果差异大。为保持地层能量、改善流度比、调整吸水剖面,先后在3个区块各选1个井组开展弱凝胶调驱矿场试验。以3个井组调驱的不同效果为基础,通过聚合物性质、地质油藏条件以及注入参数等分析,分别对影响弱凝胶效果的聚合物浓度、原油黏度、渗透率级差、边底水影响、调驱时机、注入速度等因素进行了对比。矿场试验表明,弱凝胶调驱可以调节层间吸水、缓解平面矛盾、改变注入水驱替方向,其调驱矿场效果受地层油藏条件、调驱时机、调驱参数的影响。

There exist problems in blocks of L,M and N of an oilfield of Bohai Bay,namely,severe vertical and lateral heterogeneity,large water to oil mobility ratio,un-uniform water absorption for all the zones of main water injection wells and poor water flooding effect.In order to maintain reservoir energy,improve water to oil mobility ratio and control profile,the field test of profile control with weak gel is conducted in 3 well groups which are selected from the 3 blocks respectively.The factors,namely,polymer concentration,oil viscosity,permeability difference,edge water and bottom water effect,profile control time,injection rate,etc.,affecting the effect of weak gel are compared based on the different effects of the 3 well groups and the analyses of polymer property,reservoir conditions and injection parameters.The field test shows that the profile control with weak gel can adjust the water absorption of all the zones,mitigate lateral contradiction and change the direction of injected water;and the effect of profile control on field is affected by reservoir conditions,profile control time and profile control parameters.