Synthesis And Application Of Lignin-grafting Polymerization As Filtrate Reducer

With the increasing of China’s economy and industrial growth during demand forenergy, the exploration and development of oil resources is also improving in our country.High temperature filtrate reducer is one of important oil drilling treatment agent, it canreduce the amount of drilling fluid loss, and ensure that the process of oil exploration isgoing successfully, that always is the focus in the field of oilfield chemicals. Lignin is thesecond largest natural polymer material and the main by-product in paper production, itsrational development and utilization will greatly solve environmental pollution problemsand create sustainable economic development.This paper relies on the active sites in the lignin macromolecule, according to therequirements of filtrate reducer in high-temperature and deep environment, we selectedacrylic acid, acrylamide, sodium p-styrene sulfonate and2-acrylamido-2-methyl propanesulfonic acid four monomers as graft-modified materials with lignin, and synthesized threedifferent modified lignin filtrate reducer(L-g-AM/AA, L-g-AM/AMPS, L-g-AA/SSS). Wecharacterized the structure and properties of them, and explored its adsorption mechanismwith clay particles.At first, we analyzed the amount of lignin, monomer mole ratio, potassium persulfateconcentration, temperature and time influence on the performance of filtrate reducer,through the five factors and four levels orthogonal experiment, and drawn their effect sizerelationship; we examined the single factor influence on the rate of graft products and theperformance of filtrate reducer by single factor experiment. By means of infraredspectroscopy, scanning electron microscopy, thermal gravimetric analysis and Soxhletextraction, we can characterize the structure of three graft copolymer, chemicalcomposition, thermal stability, microstructure and grafting percentage, and certainly themonomers have been grafted on the lignin macromolecules. Through high temperature andpressure performance test, we verified that the three productions have the required performance working in the high temperature and deep well. We studied the adsorptionmechanism between the polymer and clay particles from filter cake by infrared analysis,and compared the microstructure of before and after adding filtrate reducer by SEM,proved all of them can improve the hydration dispersion of clay particles through effectiveadsorption in high temperature environment, clog the pores between the clay particles andreduce the permeability of filter cake.In the paper, three kinds of filtrate reducer were synthesized and achieved good fluidloss results. Therefore, lignin as material has a broad development prospect in the oilfieldfiltrate reducer.