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Title: Analysis of unit mobility ratio well-to-well tracer flow to determine reservoir heterogeneity

Technical Report ·
OSTI ID:6784463

This study has been carried out in two related sections. In the first section, exact analytic equations have been derived to define breakthrough curves for different developed flooding well patterns for unit mobility ratio. The first section also includes an extension of an analytical definition of pattern breakthrough curves for mobility ratio other than one. The second part discusses flow of a tracer slug in various patterns. In each system, the longitudinal mixing of the tracer slug in a general streamtube of the pattern has been formulated mathematically. A line integral along a streamtube was derived which represents the length of the mixed zone. When this line integral was substituted into the mixing equation, an expression for the concentration of tracer at any location within a streamtube resulted. The study shows that the effluent tracer concentration depends upon the pattern geometry and size, and the dispersion constant of the formation. Tracer production curves for the different patterns considered have also been correlated into a set of curves depending on a/..cap alpha.., (a = distance between like wells, ..cap alpha.. = dispersion constant). The correlation was achieved by deriving two sets of correction factors, one for tracer peak concentration, and another for a/..cap alpha.. ratio. As a result of this correlation, a tracer response from any repeated homogeneous pattern can be estimated from the response of an equivalent five-spot system by utilizing the correction factors. A computer program based on a non-linear optimization technique was developed which decomposes a detected tracer breakthrough profile from a multilayered system into responses from individual layers. The algorithm utilizes the equations of the five-spot pattern in conjunction with the developed correction factors. A five-spot field example which has been successfully decomposed into several layers is shown to illustrate the use of this research. 42 figures, 15 tables.

Research Organization:
Stanford Univ., CA (USA). Petroleum Research Inst.
DOE Contract Number:
AC03-81SF11564
OSTI ID:
6784463
Report Number(s):
DOE/SF/11564-1; ON: DE83006922
Resource Relation:
Other Information: Portions are illegible in microfich products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English