摘要
以高级脂肪酸、二乙烯三氨为主要原料、浓H2SO4为催化剂，利用缩合法得到浅黄色片状或颗粒状的增黏剂。测试了增黏剂在三种体系，即5号白油、5号白油+有机土体系以及全油基钻井液体系中的流变性能，考察了增黏剂加量、钻井液密度对全油基钻井液流变性能的影响。全油基钻井液配方为：5号白油、3.0%有机土、2.0%降失水剂Ａ、2.0%降失水剂Ｂ、0.5% CaO、3.0%超细重质CaCO3、0~180%重晶石、0.2%润湿剂、0~2.0%自制增黏剂。结果表明，在不同体系中加入1.0% VIS-3型增黏剂后，热滚前后均能较好成胶，体系未出现分层和沉淀。该增黏剂在三种体系中均有较好的增黏效果。当增黏剂的加量由0增至2.0%时，全油基钻井液热滚前的f3（黏度计3转下的读数）由2增至27?，静切力（Gel，Pa）由2/2增至26/27，塑性黏度（PV）由58降至28 mPa·s，动切力（YP）由3.5增至20 Pa，API滤失量由5降至3 mL；150℃热滚16 h后的f3由2增至21，Gel由4/5增至22/25，PV由59降至24 mPa·s，YP由3.5增至21 Pa，API滤失量由4降至2 mL。当含1.0％ VIS-3型增黏剂的全油基钻井液密度由0.9×103增至2.0×103 kg/m3时，老化前的f3由2增至10，Gel由2/3增至10/11；老化后的f3由2增至7，Gel由2/3增至9/11。钻井液密度增加，增黏剂对全油基钻井液的增黏作用增强。钻井液密度相同时，老化后的f3和Gel略有降低。钻井液密度对PV和YP的影响没有明显规律，总体影响不大。
Abstract
A viscosifier for oil-based drilling fluid was synthesized by condensation method, using senior fatty acid and divinyl triammonium as main raw materials, and concentrated sulfuric acid as catalyst. The rheological property of different fluid systems which contained the same dose of viscosifier was characterized. These fluid systems included No. 5 white oil, No.5 white oil plus organoclay and oil-based drilling fluid system. The effect of dosage of viscosifier and density of drilling fluid on the rheological property of oil-based drilling fluid was also discussed. The formula of oil-based drilling fluid was obtained as follows: No.5 white oil, 3.0% organoclay, 2.0% fluid loss (FL) agent A, 2.0% FL agent B, 0.5% CaO, 3% superfine CaCO3, 0—180% barite, 0.2% wetting agent and 0—2.0% homemade viscosifier. The results showed that different fluid systems would become gel before and after hot rolling and there were no delamination and sedimentation if 1.0% VIS-3 viscosifier was added. Furthermore, the viscosifier had relatively excellent thicking properties in three fluid systems. When the dosage of viscosifier increased from 0 to 2.0%, the dates of rheological properties of oil-based drilling fluid before aging were obtained as follows: f3 value increased from 2 to 27, gel strength (Gel, Pa) increased from 2/2 to 26/27, plastic viscosity(PV) decreased from 58 to 28 mPa·s, yield point (YP) increased from 3.5 to 20 Pa and API filtration decreased from 5 to 3 mL. The dates after aging at 150℃ for 16 hrs were obtained as follows: f3 value increased from 2 to 21 Pa, Gel increased from 4/5 to 22/25, PV decreased from 59 to 24 mPa·s, YP increased from 3.5 to 21 Pa and API filtration decreased from 4 to 2 mL. When the density of oil-based drilling fluid which contained 1.0% VIS-3 viscosifier increased from 0.9×103 to 2.0×103 kg/m3, the f3 value increased from 2 to 10 and Gel increased from 2/3 to 10/11 before aging, and the f3 value increased from 2 to 7 and Gel increased from 2/3 to 9/11 after aging. The density of drilling fluid could improve the viscosifying ability. However, the f3 value and Gel were slightly lower after aging, when the density of drilling fluid was similar. Moreover, the effect of density of drilling fluid on PV and YP was no obvious rule.
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