马深1超深井四开钻井液技术

马深1井是中石化勘探分公司部署在川东北通南巴构造带马路背构造高部位的一口重点预探井。完钻井深为8 418 m，目的层主探下寒武统龙王庙组储层。该井四开作业井段为6 225.4~7 699 m，钻遇龙马溪组时存在大段泥页岩地层，井壁稳定问题比较突出，且地层压力系数高，超深井段井温高，钻井液易受酸根污染，施工风险较大。该井四开钻井液技术难点主要是高温下高密度钻井液流变性控制、井壁稳定及酸根污染问题等。针对以上难点，通过大量室内实验，优选出以下几种主要处理剂:抗温强的聚胺抑制剂BCG-7，加量控制在0.4%；抗温主剂采用高温下降滤失效果好且不提黏的SMP-3，加量控制在5%~6%；抗温降滤失效果好且不提黏的聚合物类降滤失剂PFL-L及HPL-3，加量分别控制在2%及1.5%；抗温降黏剂选用HR-300、SMS-19，加量视情况而定；同时引入抗氧化剂，以提高体系的抗温性。最终确定钻井液基本配方为3% NV-1+0.3% KOH+5% KCl+1.5% HPL-3+1% AOP-1+3% SCL+3% FT+5% SMP-3+3% LF-1+0.4% BCG-7+3% QS-2。在马深1井现场应用时，根据实钻情况及时调整处理剂加量，对钻井液配方进行微调，在该井四开井段使用过程中，表现出高温高密度下流变性好、抑制能力强、封堵效果好及抗酸根能力强的特点。KCl-胺基聚磺钻井液技术为顺利完成马深1井四开井段的钻探工作提供了强有力的技术支撑，最终形成了一套完整的超深井钻井液技术。 

Application of KCl-Amine Polymer Sulfonate Drilling Fluid in Well Mashen-1

The Well Mashen-1 is a key wildcat well of the Exploration Branch of Sinopec located at the high position of the Malubei Structure in the Tongnanba tectonic zone, northeast Sichuan. Completed at a depth of 8418 m, the well was designed to explore the Longwang Temple Formation of Lower Cambrian Series. The fourth interval of the well was drilled to 6 225.4~7 699 m, penetrating the Longmaxi Formation consisting of thick shales, which caused severe borehole instability. Problems also encountered in this interval included high formation pressure coefficient, high formation temperature, and contamination to the drilling fluid by carbonate ions, rendering high risk to the drilling operation. Difficulties in running the drilling fluid in the fourth interval were rheology control of high density mud at elevated temperatures, borehole stabilization and carbonate/bicarbonate ions contamination to the drilling fluid. To deal with these difficulties and problems, a series of laboratory experiments were done to select proper additives and then to formulate a drilling fluid suitable for use in drilling the Well Mashen-1. Based on laboratory experiments, a high temperature polyamine BCG-7 was selected as shale inhibitor at a concentration of 0.4% in the drilling fluid. SMP-3, a quality high temperature filter loss reducer that did not viscosify the drilling fluid, was used at a concentration between 5% and 6%. High performance polymer filter loss reducer PFL-L and HPL-3 were added at concentrations of 2% and 1.5%, respectively, they did not viscosify the drilling fluid either. HR-300 and SMS-19, two thinners, were to be used based on the actual situation. An anti-oxidant was used to try to improve the high temperature stability of the drilling fluid. The final basic formulation was as follows:3%NV-1+0.3%KOH+5%KCl+1.5%HPL-3+1%AOP-1+3% SCL+3%FT+5%SMP-3+3%LF-1+0.4%BCG-7+3%QS-2. The actual concentration of each additive was adjusted based on the actual situation if filed application. In drilling the fourth interval, the drilling fluid had good high temperature rheology, strong inhibitive capacity, high plugging performance and tolerance to carbonate/bicarbonate ions contamination. This drilling fluid provided a powerful technical support for the successful drilling of the fourth interval of the Well Mashen-1, and a KCl-amine based polymer sulfonate drilling fluid finally came into being.