川西地区中深井快速钻井的钻井液应用技术

钻井液体系的改进是提高钻速最直接的手段之一。依据川西地区上三叠统须家河组实钻资料统计分析以及大量文献调研成果,以室内试验分析评价为基础,详细阐述了对钻速影响显著的钻井液因素,认为钻井液密度增高会造成钻井正压差增加和钻井液固相含量增加,由此造成钻速随钻井液密度的增加呈对数降低,其降低的幅度随钻井液增量的增加而降低;钻井液体系转化引起的钻井液黏度、切力增加,流变性能变差,瞬时失水量降低是钻速降低的关键因素。现场试验结果表明,优选出的钻井液体系不仅具有较好的流变性能,而且对于复合钻井工艺的顺利实施亦起到了积极作用,可有效地缩短钻井周期,提高钻井速度。

Application of drilling fluids in rapid drilling of deep wells in the western Sichuan Basin

The improvement of drilling fluid system is one of the direct means for enhancing the ROP in drilling. In light of statistical analysis of actual drilling data and deep investigation into a huge number of literatures on the upper Triassic Xujiahe Formation reservoirs in the western Sichuan Basin, this paper, based on the laboratory experimental analysis and evaluation, introduces in detail about the influence of drilling fluids on the ROP. It is summed up that the increase of drilling fluid density will result in the rise of both positive differential pressure and solid content in the fluid; thus, the ROP will decrease by the rise of drilling fluid density, and the transforming of drilling fluid system will lead to an increase of viscosity and shear force, a bad performance of rheological behavior, and a decrease of instantaneous fluid loss, thus, the ROP of drilling is lowered down. Pilot field tests show that the optimized drilling fluid system not only has a good performance of rheological behavior, but plays a positive role in the smooth implementation of the combined drilling technologies, helping shorten the drilling circle and enhance the ROP of drilling.