多胺型泥页岩抑制剂对黏土水化膨胀的抑制性能评价

泥页岩水化膨胀和分散引起的井壁失稳一直是钻井工程中的技术难题,因此钻遇泥页岩地层的水基钻井液中必须提高钻井液对泥页岩的抑制性,最大限度地降低井下复杂情况的发生率。为此,以有机二酸与胺为原料合成多胺型泥页岩抑制剂,并通过线性膨胀性、防膨、抑制黏土造浆、钻井液性能评价等实验,评价了其抑制性。实验结果表明:草酸、丁二酸、己二酸与四乙烯五胺按照酸与胺的摩尔比为1∶2时的反应产物的抑制性最佳,浓度为0.1%的溶液与4%氯化钾溶液的抑制作用相当;钻井液加入筛选出的抑制剂后的动切力值明显降低,且土容量越大,变化越明显;在0.1%二酸-四乙烯五胺(1∶2)溶液中,90min时膨润土的线性膨胀率与同条件下4.0%氯化钾溶液中的效果相近,防膨率最高可达34.41%;室温下,多胺类抑制剂所需加量少,对水基钻井液有一定的增黏作用,对膨润土水化膨胀、分散的抑制效果较好。

Performance assessment of a polyamine swelling inhibitor for clays and shales

Borehole instability caused by mudstone hydrous disintegration has always been a technical difficulty in drilling operation, so it is necessary to improve the inhibitive capability of water based drilling fluid used in shale formation drilling to minimize the incidence of downhole problems. For this purpose, dicarboxylic acids and amines were used as raw materials to synthesize the polyamine shale inhibitor, of which the inhibitive capability was evaluated through clay swelling test, anti expansion test, mud making inhibition experiment, drilling fluid property evaluation, and other experiments. The evaluation results indicate that the product from oxalic acid, succinic acid, adipic acid and tetraethylenepentamine with a mole ratio of acid and amine at 1∶2 shows the best inhibitive capability, and the inhibitive capability of the solution with a concentration of 0.1% is equal to the potassium chloride solution with a concentration of 4.0%; the dynamic shear value will be significantly reduced after selected inhibition is added into the drilling fluid and the value change will be more obvious if the soil volume is larger. The linear bentonite swelling ratio in 0.1% dicarboxylic acid tetraethylenepentamine solution within 90 min is similar to that in the 4.0% potassium chloride solution under the same conditions, and the anti swelling rate also reaches up to 34.41%. The polyamine inhibitor enhances the viscosity of water based drilling fluid with low dosage and shows a strong inhibitive capability to bentonite hydration swelling and dispersion at room temperature.