NP油田Ed1储层泥浆伤害综合评价与解堵技术研究

酸化是解除该类储层伤害,恢复、提高油气井产能最主要的手段。对于各种特定的伤害类型若仅采用笼统的酸化措施,往往难以取得理想的增产效果,如何从伤害机理的角度出发对症解除污染是研究者面临的重要课题。NP油田Ed1储层在以往的酸化改造中,由于对钻井泥浆伤害机理认识不够准确,导致酸液选择存在较大的盲目性,严重影响解堵效果。为解决上述问题,提出酸化解堵设计方法,通过泥浆固相粒度和滤液红外波谱分析试验评价,明确了Ed1储层钻井泥浆伤害产生的机理。在此基础上,设计在同一组试验内先模拟泥浆伤害的产生,发现岩心伤害后渗透率降低至基准渗透率的0.12倍,然后比较评价不同类型的酸液解除该类泥浆污染的能力,最终筛选出解堵效果最好的4%多氢酸体系推荐现场施工使用。

Comprehensive evaluation on drilling mud damage in Ed1 reservoir of NP Oilfield and study on plug removal technique

Acidizing is the main measure to get rid of the reservoir damage and improves the oil gas well productivity.For each specific type of damage,it is very difficult to achieve the desired stimulation result if using a general acidizing method.Therefore,it is an important issue to acidize specifically according to the reservoir damage mechanisms.Due to the poor understanding about the damage mechanism of drilling mud on Ed1 reservoir of NP Oilfield before this study,unsuitable acidizing fluid has been chosen,which affecting seriously the effect of plug removal.In order to solve this problem,a specific acidizing design method has been put forward.By evaluation on grain size of mud solid phase and infrared spectrum laboratory testing and analysis,the reservoir damage degree and mechanism by drilling mud in Ed1 reservoir have been understood.On this basis,simulation on the generation of mud damage has been done.Through simulation it has been found that permeability of damaged core will reduce to 0.12 times.Finally,evaluation has been done on the ability to remove this kind of mud damage by using different types of acid systems,and eventually the most effective 4% multi-hydrogen acid system has been chosen to use in reservoir acidizing.