超高温高密度钻井液体系的研究与应用

Study and Application of an Ultra-High Temperature High Density Drilling Fluid

针对大多数采用重晶石加重的高密度钻井液在高温下存在的流变性能调控难、高温高压滤失量大、重晶石沉降等技术难题,从抗温、降滤失、控制黏度和切力、提高沉降稳定性能等方面提出了钻井液体系的设计思路,通过研发超高温封堵降滤失剂SMPFL-UP、超高温高密度分散剂SMS-H等核心处理剂,优选抗高温封堵防塌剂SMNA-1、高温稳定剂GWW、高效润滑剂SMJH-1等关键配套处理剂,经过配方优化及评价,研发出了一套超高温高密度钻井液体系(SMUTHD),抗温达220℃。SMUTHD密度不超过2.40 g/cm3时,经220℃老化后流变性能稳定,高温高压滤失量小于12 mL,极压润滑系数为0.178,在220℃下静置7 d沉降系数(SF)小于0.54,表现出良好流变性能、滤失性能和高温沉降稳定性能。SMUTHD在顺南蓬1井五开进行了成功应用,累计进尺581 m,井底温度为207.4℃,实钻钻井液密度为1.75~1.80 g/cm3,不同施工阶段井浆的SF均小于0.52,施工期间钻井液性能稳定,井下安全,取心顺利。SMUTHD的成功研发及现场应用,有力保障了深部油气层的勘探发现、增储建产和低成本高效开发,提高了我国超高温高密度钻井液技术的自主化水平。

Most of the high-density drilling fluids weighted with barite are often faced with high temperature problems such as difficulty in rheology control,high HTHP filter loss and barite sag etc.A drilling fluid design clue is presented to deal with these problems.An ultra-high temperature high density drilling fluid SMUTHD was formulated with a self-developed ultra-high temperature filter loss reducer SMPFL-UP,a self-developed dispersant for use in ultra-high temperature high density fluids,a high temperature plugging antisloughing agent SMNA-1,a high temperature stabilizer GWW and a high-efficiency lubricant SMJH-1 etc.The SMUTHD drilling fluid can be used at high temperatures up to 220℃.At density of less than 2.40 g/cm3,the SMUTHD drilling fluid had stable rheology,HTHP filter loss of less than 12 mL and extreme friction coefficient of 0.178 after aging at 220℃.The settling factor(SF)of SMUTHD standing for 7 d at 220℃was less than 0.54.These data indicate that the SMUTHD drilling fluid has good rheological and filtration control properties as well as high temperature settling performance when its density is not higher than 2.40 g/cm3.The SMUTHD drilling fluid has been successfully used in drilling the 5th interval of the well Shunnanpeng-1,with total footage of 581 m drilled.The bottom hole temperature of this well was 207.4℃,and the density of the drilling fluid was 1.75-1.80 g/cm3.Drilling fluids in different operational stages all had SF of less than 0.52.The properties of the drilling fluid were stable and no downhole troubles happened during drilling.Coring operation was performed smoothly.The development of SMUTHD has not only greatly ensured the exploration and discovering of deep oil and gas reservoirs,the increase of petroleum reserves and production as well as oil and gas development with low cost and high efficiency,it has also improved the level of autonomy of China’s ultra-high temperature and high density drilling fluid technology.