Pressure Buildup - Chemical Incompatibility Liquid Injection Wells

Abstract

This paper was prepared for the Rocky Mountain Regional Meeting of the Society of Petroleum Engineers of AIME, to be held in Billings, Mont., May 15–16, 1974. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract Forecasting future injection well performance is usually difficult, particularly performance is usually difficult, particularly when the future receptivity of the reservoir is unknown. Chemical reactions between the injected liquids and native reservoir fluids, together with suspended solids plugging, can reduce the receptivity of an injection well considerably. Laboratory investigations of the injectivity of reactive liquids into sandstone cores have produced permeability histories that could represent the future behavior of an injection zone. A permeability decrease during the life of the injection well is expressed as a functional relationship with time, and is utilized in the pressure buildup equation to replace the constant permeability value normally used. Such abnormally large buildups resulting from permeability declines are shown in comparison to that of constant permeability. The higher pressure buildup permeability. The higher pressure buildup levels resulting from reduced permeability could affect the cost of construction, operation, and modification of liquid injection facilities. Introduction Experience in the practice of deep-well injection has shown that the capacity of injection wells frequently diminishes with time and volume of liquid injected. This has often been related to the impairment of permeability and porosity of the reservoir as a permeability and porosity of the reservoir as a result of the chemical interactions among injected liquids, native liquids, and the rock materials themselves. This paper summarizes research directed toward evaluation of the long-term effects of the chemical compatibility (or incompatibility) of injected liquids and native reservoir materials that could affect permeability and hence change the receptivity and ultimate useful life of a particular injection well or reservoir. Since permeability has a direct effect on the design and cost of liquid injection wells and facilities, its effect on pressure buildup is examined from these considerations. A computer program originally written to make design and cost calculations for waste disposal wells was modified to include permeability histories as design parameters. permeability histories as design parameters.