Tertiary Oil Recovery with Cellulose Derivatives as Water Thickeners

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers Inc. Abstract A large number of cellulose derivatives were investigated for the effects of gram molecular weight, nature of substitution, and control of substitution on their respective performances as water thickeners in the mobility buffer in the Maraflood (trade mark) oil recovery process in laboratory 3" × 2' linear Berea cores. The best performances obtained with carboxymethylcellulose (CMC) derivatives of one million gram molecular weight, uniformly substituted to about 0.7–0.9 of a total 3.0 with sodium carboxymethyl groups on the glucose hydroxyl functions. The best CMC tertiary oil recoveries compare quite favorably with results obtained with Dow 700 partially hydrolyzed polyacrylamide (PHPA) and Kelzan MF xanthan gum. Introduction This presentation summarizes our research on cellulose derivatives, especially carboxylcellulose (CMC). These commercial and research products were obtained from Herclules Corporation, products were obtained from Herclules Corporation, Dow Chemical Company, and Union Carbide. comparisons are also made with guar derivatives. Chemical and physical properties, synergistic interactions, stability data, mobility control properties, and oil recoveries from prepared cores are presented. prepared cores are presented. Cellulose derivatives may be used to improve efficiency of waterflood displacement of oil in tertiary recoveries. Optimumly, substituted, high molecular weight carboxymethylated cellulose derivatives give good tertiary oil recoveries in Berea cores in the 250 to 1500 ppm concentration range. This approaches performances of Dow 700 Pusher polymer, a partially hydrolyzed Pusher polymer, a partially hydrolyzed polyacrylamide (PHPA), and Kelzan MF xanthan gum. polyacrylamide (PHPA), and Kelzan MF xanthan gum. Cellulose derivatives are comparable to xanthan gum in shear stability and salt sensitivity and superior to PHPA in these properties. EXPERIMENTAL REAGENTS. Water-soluble cellulose derivatives of various types were investigated and are summarized in Table 1. Their solution characteristics depend upon the average chain length and the degree of substitution of functional groups. Two types of cellulose ethers were tested:ionic sodium carboxymethylcellulose (CMC)hydroxyalkyl hydroxyethylcellulose (HEC).