Integrated Interpretation of Interwell Connectivity Using Injection and Production Fluctuations

• Published in: Mathematical geosciences Vol. 41; no. 1; pp. 81 - 102
• Main Authors: Yousef, Ali A., Jensen, Jerry L., Lake, Larry W.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2009; Springer; Springer Nature B.V
• Subjects: Chemistry and Earth Sciences; Computer Science; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Exact sciences and technology; Fluctuations; Fluids; Geotechnical Engineering & Applied Earth Sciences; Hydrocarbons; Hydrogeology; Injection; Oil wells; Petroleum geology; Physics; Reservoirs; Sedimentary rocks; Statistics for Engineering; Studies; Wells; United States; Wyoming; Capacitance model; Reservoir characterization; North Buck Draw field; Lorenz plot; reservoir rocks; models; hydrocarbons; tracers; permeability; reservoirs; North America; oil and gas fields; fluctuations; interpretation; mathematical methods; injection; flow; fractures
• ISSN: 1874-8961; 1874-8953
• DOI: 10.1007/s11004-008-9189-x

A method to characterize reservoirs, based on matching temporal fluctuations in injection and production rates, has recently been developed. The method produces two coefficients for each injector–producer pair; one parameter, λ , quantifies the connectivity and the other, τ , quantifies the fluid storage in the vicinity of the pair. Previous analyses used λ and τ separately to infer the presence of transmissibility barriers and conduits in the reservoir, but several common conditions could not be easily distinguished. This paper describes how λ and τ can be jointly interpreted to enhance inference about preferential transmissibility trends and barriers. Two different combinations are useful: one is a plot of log ( λ ) versus log ( τ ) for a producer and nearby injectors, and the second is a Lorenz-style flow capacity ( F ) versus storativity ( C ) plot. These techniques were tested against the results of a numerical simulator and applied to data from the North Buck Draw field. Using the simulated data, we find that the F – C plots and the λ – τ plots are capable of identifying whether the connectivity of an injector–producer well pair is through fractures, a high-permeability layer, multiple-layers or through partially completed wells. Analysis of data from the North Buck Draw field shows a reasonable correspondence between τ and the tracer breakthrough times. Of two possible geological models for Buck Draw, the F – C and λ – τ plots support the model that has less connectivity in the field. The wells in fluvial deposits show better communication than those wells in more estuarine-dominated regions.