三元复合驱水驱干扰井封堵技术界限

Technical limits of the waterflooding interfering well plugging in ASP flooding

大庆油田三元复合驱开发区块都有水驱井网同时生产,而且水驱井网也射开了一部分三元复合驱目的油层,使得水驱井干扰对复合驱开发效果产生了不利影响。为了降低水驱井的干扰,矿场采取了对水驱井进行封堵的做法,但由于没有合理统一的封堵原则和技术界限,各开发区块的封堵效果差别较大。针对这一问题,应用数值模拟方法研究了不同条件下水驱干扰井对三元复合驱提高采收率效果的影响程度,给出了水驱干扰注入井和采油井的封堵原则。结果表明:水驱干扰井所处位置不同、共射层的注入量或采液量不同、干扰井数不同,对三元复合驱的效果影响程度也不同;与三元复合驱具共射层的水驱干扰注入井均应该对其共射层段进行封堵或停注;具共射层的水驱干扰采油井,当一个井组内只有1口,且离三元采油井距离大于注采井距的1/2、共射层有效厚度低于三元采油井有效厚度的1/6时,可以考虑不封堵,其他情况均考虑封堵共射层。

There are some waterflooding well patterns producing simultaneously in the ASP flooded blocks of Daqing Oilfield, and moreover partial ASP flooded oil layers are perforated and produced by the waterflooding well patterns, which makes the waterflooding interfering wells adversely influence the development effects of the ASP flooding. In order to reduce the interferences of the waterflooding wells, the plugging method was adopted for the wells in the field, but there was no reasonable and uniform principles and technical limits, the plugged effects of each development block were quite different. Aiming at this problem, the influence degrees of the waterflooding interfering wells on the enhanced oil recovery of the ASP flooding in different conditions were studied by the numerical simulating method, the plugging principles of the waterflooding injection wells and production wells were presented. The results show that the effects of the ASP flooding were influenced by the location of the waterflooding interfering wells, the injection volume or liquid production of the co-perforated layers and the number of the interfering wells;the co-perforated intervals between the waterflooding interfering injection wells and the ASP flooding should be plugged or stopped the injection;when there is only one waterflooding interfering oil-production well in a well group with the co-perforated layer, with the distance from the oil production well by the ASP flooding is more than 1/2 of the injection-production well spacing and the effective thickness of the co-perforated layers is less than 1/6 of the ASP flooded oil well, it may be considered not to plug, and other case the co-perforated layer should be plugged.