Oil Production After Breakthrough as Influenced by Mobility Ratio

Abstract

The study of the influence of fluid mobilities on the sweepout pattern resulting from the injection of gas or water has been extended to cover the production period which follows breakthrough of the injected material. Mobility ratios over the range common in field operations (0.1 to 17) were studied for several pattern floods (five-spot, staggered, and direct line drive). The experimental data required for these studies were obtained by the use of the x-ray shadow graph technique using miscible oil phases of different viscosities in porous plate models of a reservoir element. From the shadowgraph pictures obtained before and after breakthrough of the injected fluid, flowing ratios at the producing well and cumulative volumes injected were calculated. The method for applying such data in predicting field behavior is illustrated for a water flood of a five-spot. For this case a range of mobility ratios of 0.5 to 5.0 results in:nearly complete (95 to 100 per cent) sweepout pattern efficiencies at abandonment conditions,production after breakthrough being responsible for as much as one-third of the total recovery at the lower mobility ratios, anda twofold variation in the operating life of the reservoir.

A Study of the Effect of Mobility Ratios on Pattern Displacement Behavior and Steamlines to Infer Permeability Media, SUPRI TR-115

“…The results are also very close to the experimental da@ Dyes et al (1954), after breakthrough at various mobility ratios. We find physical dispersion in the Dyes et al…”

“…1 and the meaning of sweep-efficiency. Dyes et al (1954) used vanious oils as both the injected and displaced phases. These hydrocarbons were miscible and they assumed piston-like displacement.…”

“…We discuss the proper way to calculate fractional flow based on the flow rates at the producer. In comparing the simulation results wik the experimental results of Dyes et al (1954), physical dispersion in the experiments is found even though a piston-like displacement was assumed.…”

“…Although simulation is an important tool for design and evaluation, the fiist step often involves rough calculations based upon areal sweep efficiencies of displacements in homogeneous, two-dimensional, scaled, physical models (Dyes et al, 1954, Craig, 1971Lake, 1989). These results are available as a function of the displacement pattern and the mobility ratio, M. The mobility ratio is simply the mobility of the displacing phase over that of the displaced, or residen~phase.…”

Analytical Model for Zones Distributions in Non-Horizontal Miscible WAG Injection

“…These contradictory results happen mostly because of poor gas sweep efficiency and there are more examples of this mechanism explained in the literature. Caudle and Dyes (1958) and Dyes, Caudle and Erickson (1954) have discussed this mechanism in miscible process and in a pattern injection system, compared to waterflooding and also, the effect of mobility ratio on oil production after breakthrough.…”