吉7井区水敏储层酸化预处理工艺研究及应用

STUDY AND APPLICATION OF WATER SENSITIVE RESERVOIR ACIDIFICATION PRETREATMENT PROCESS IN JI 7 WELL AREA

吉7井区是采用常规注水开发的深层稠油砂岩油藏,储层粘土矿物含量较高且为中等偏强-强水敏。注入水会使粘土矿物膨胀,注水压力快速上升导致水井欠注或注不进,加剧注采矛盾。为吉7井区长期稳定的注水开发和动用,根据储层敏感性评价结果,开展室内粘土防膨试验,对粘土使用不同酸液体系和防膨剂进行多轮次浸泡和冲刷,实验表明粘土酸化后再用水浸泡冲刷几乎不发生膨胀和运移,防膨效果远高于后期酸化或同步防膨,因此引入注水前酸化预处理的治理思路,并筛选出缓速酸酸液体系配方。在现场选择物性较差的31口井进行应用,酸化预处理井的注水压力明显低于未酸化的井,压力上升梯度也低于未酸化井,该技术对敏感储层注水开发具有较好的借鉴意义。

Ji 7 well area is a deep heavy oil sandstone reservoir developed by conventional waterflooding,the content of clay minerals in reservoir is high and middle strong-strong water sensitivity.Injection of water will swell clay minerals,the rapid increase of water injection pressure leads to the lack of water injection or note not into,exacerbated the contradiction between injection and production.Long. In order to have a long-term stable water injection development and utilization for Ji 7 well area,according to the results of reservoir sensitivity evaluation, the indoor clay swelling test was launched,the clay used in different acid systems and anti swelling agent for multi round soaking and scouring.The results showed that the clay is almost no swelling and migration after acidification,the effect of anti swelling is much higher than that of the later period, or the anti swelling,therefore, the idea of acidizing pretreatment before water injection is introduced, and the formula of retarded acid liquid system is selected.31 wells with poor physical properties in the field were applied, the water injection pressure of acidizing pre-treatment wells is obviously lower than that non-acidification wells, the pressure gradient is lower also, the technology is a good referential significance for sensitive reservoir waterflooding.