深部煤系地层抗高温低成本盐水钻井液研究

Study on high-temperature low-cost brine drilling fluid for deep coal measure strata

摘要:

针对深部煤系地层钻探中钻井液抗温、抗盐性能不足和处理剂成本偏高的钻探难题，以膨润土、NaCl、Na?CO?与NaOH为原料制备盐水钻井液基浆，选取HCalvis?5、HCalvis?4、S092、阳离子淀粉、HE?150五种添加剂，探究不同种类及浓度的添加剂对钻井液流变性、滤失量的影响；通过复配不同类型、不同加量的抗氧化剂优化体系综合性能，确定最优配方，并采用红外光谱（FT?IR）及Zeta电位分析揭示处理剂协同作用机理。结果表明：最优配方为“基浆+2.0% HCalvis?5+1.0% Na?SO?”，最优使用温度为120 ℃。该钻井液120 ℃热滚16 h后表观黏度为27mPa·s，API滤失量仅8.0 mL，膨润土24 h线性膨胀率仅1.67%，高温滚动回收率达58.64%，表现出优异的抗高温、抑制水化与降滤失能力。微观机理显示，HCalvis?5通过氢键吸附包裹黏土颗粒并形成致密滤饼，Na?SO?捕获高温自由基抑制聚合物氧化降解，二者协同保障体系高温稳定性。该配方原料成本低廉、配制工艺简便，基本满足深部煤系地层钻探工程需求，为低成本抗高温盐水钻井液工业化应用提供实验依据与理论支撑。

Abstract:

To address the drilling challenges of insufficient thermal stability and salt resistance as well as high costs of treatment agents in deep coal measure strata， a brine drilling fluid base slurry was prepared using bentonite， NaCl， Na?CO?， and NaOH as raw materials. HCalvis-5， HCalvis-4， S092， cationic starch， and HE-150-were selected to investigate the effects of additive type and concentration on the rheological properties and fluid loss of the drilling fluid. The overall system performance was optimized by compounding antioxidants of different types and dosages， and the optimal formulation was determined. Fourier transform infrared spectroscopy （FT-IR） and Zeta potential analysis were employed to elucidate the synergistic mechanism of the treatment agents. The results indicate that the optimal formulation is "base slurry + 2.0% HCalvis-5 + 1.0% Na?SO?，" with an optimal application temperature of 120 °C. After hot rolling at 120 °C for 16 h， the drilling fluid exhibited an apparent viscosity of 27 mPa·s and an API filtrate loss of only 8.0 mL. The 24 h linear swelling ratio of bentonite was merely 1.67%， and the high-temperature rolling recovery rate reached 58.64%， demonstrating excellent high-temperature resistance， hydration inhibition， and filtration control. Microscopic mechanism analysis reveals that HCalvis-5 adsorbs onto and encapsulates clay particles via hydrogen bonding， forming a dense filter cake， while Na?SO? scavenges high-temperature free radicals to suppress oxidative degradation of polymers. The synergistic action of the two components ensures the high-temperature stability of the system. Featuring low raw material costs and a simple preparation process， this formulation can effectively meet the engineering requirements for drilling in deep coal measure strata， thereby providing experimental evidence and theoretical support for further optimization and upgrading of drilling fluid systems for higher-temperature ultradeep formations.