PC Program for Improving the Success Rate of Gel Conformance-Control and Fluid-Shutoff Treatments

Abstract

Abstract A new Windows-based personal computer program has been written to improve the success rate of oilfield polymer-gel treatments. By providing a quick, accurate, and easy means for calculating polymer-gel formulations and recipes, the user-friendly program can be employed to significantly improve quality control during field application of conformance-control and fluid-shutoff gel treatments. After the user has specified the design parameters for a given gel formulation, the computer program will calculate the gel recipe on both a weight and volume basis. Provisions are included within the program calculations to accommodate the following gel makeup constituents:the polymer,the crosslinking agent,the makeup water,a retarding agent if used, anda fourth chemical ingredient if used. The program also permits the gel recipe to be entered, and the program will, in this case, back calculate the gel design parameters. Options are available in the program to output the calculated results in the form of:field-scale formulations and recipes to aid in properly designing and implementing actual conformance-control, water-shutoff, and gas-shutoff gel treatments,laboratory-scale formulations and recipes to support the laboratory evaluation and testing of oilfield gels, ora detailed breakdown of the gel formulation. Data input and output can be performed using a variety of weight and volume units, including both English and metric units. The new computer program contains a number of subroutines that can be used to improve the design and implementation of improved-oil-recovery (IOR) gel treatments. The program is written in Microsoft Visual Basic TM and can be run on any MS-DOS personal computer configured with Windows Version 3.0 or higher. This paper documents the computer program, its capabilities, and its potential uses. Introduction Oilfield polymer-gel treatments have recently been widely applied as conformance-control, sweep-improvement, profile-modification, water-shutoff, gas-shutoff, chemical-liner-completion, lost-circulation, and casing-leak-repair treatments. Many of these low-cost IOR treatments have resulted in both technical and economic successes. Oilfield polymer-gel treatments have been used to:profitably generate relatively large volumes of incremental oil production,substantially reduce operating costs,extend the economic lives of marginal wells and fields, andmitigate environmental concerns and liabilities. Polymer gels may also find a number of applications within drilling, completion, and workover fluids. However, because of difficulties often encountered in properly formulating oilfield polymer gels and because of historical shortcomings relating to many of the earlier oilfield gel technologies, the success rate of gel IOR treatments needs to be improved. Complexities associated with properly formulating oilfield polymer gels have caused some independent oil operators to be wary of this emerging and promising technology. On the other hand, a number of major oil companies have recently achieved substantial benefits through the application of such oilfield gel treatments. To help alleviate oilfield gel formulation problems and to help facilitate the technology transfer of this emerging IOR technology, the user-friendly MARGELFORMTM computer program was written by Marathon Oil Co. to improve the success rate of oilfield gel treatments, especially Cr(III)carboxylate/acrylamide-polymer gel treatments. By providing a quick, accurate, and easy means for calculating oilfield polymer-gel formulations, the new Windows-based PC program can be used to help improve quality control during field implementation of such gel treatments. P. 427