川东北高含硫气藏钻井液抗硫工艺优化与应用

Optimization of Sulfur-Resistant Drilling Fluid Techniques and Its Application in Drilling High Sulfur Content Reservoirs in Northeast Sichuan

川东北地区铁山坡、罗家寨、渡口河、七里峡、正坝和菩萨殿气田飞仙关组气藏属于高含硫气藏~特高含硫气藏。针对川东北高含硫气藏地质特点和钻井液技术难点分析,提出钻井液抗硫工艺优化对策,并通过室内实验优选出抗硫钻井液体系配方,进行了钻井液黏度、pH值、碱度、油水比对吸收H_(2)S效果的评价。研究结果表明,水基钻井液和油基钻井液优化抗硫工艺后具有较强的抗硫除硫能力。该抗硫钻井液体系在坡002-H4井和罗家24井现场试用非常成功,钻井周期大幅缩短、机械钻速明显提高,平均井眼扩大率降低,抗硫除硫效果明显,能够满足高含硫井钻进的要求,在下川东高含硫地层钻井方面有着广阔的应用前景。

Reservoirs in the Tieshanpo formation,the Luojiazhai formation,the Dukouhe formation,the Qilixia formation,the Zhengba formation and the Feixianguan formation in the Pushadan gas field in northeastern Sichuan are those with high or extra-high sulfur content gas reservoirs.This paper discusses the optimization of sulfur-resistant drilling fluid techniques for the drilling of these high sulfur content reservoirs based on the analyses of the reservoir formation geology and of the difficulties in drilling fluid operation.A drilling fluid with sulfur resistance was formulated through laboratory experiment.Laboratory evaluation of the effects of mud viscosity,pH value,alkalinity and oil/water ratio on the absorption of H_(2)S has shown that the optimized water-based drilling fluid and the oil-based drilling fluid have good sulfur resistance.The sulfur-resistant drilling fluid formulated has been very successfully used on the well Po-002-H4 and the well Luojia-24;the drilling time was greatly shortened,the rate of penetration obviously increased,the average hole enlargement reduced,and the drilling fluid showed good sulfur-resistance and sulfur-removal during drilling.This drilling fluid has satisfied the requirements of drilling wells with high sulfur content,and has broad development and application prospects in drilling the high sulfur content formations in the lower east Sichuan area.