MCCAIN GAS OIL RATIO SERIES

The PVT behavior for each fluid was determined experimentally in the laboratory, and the depletion performance of each fluid was then calculated. This paper presents the depletion-performance correlations developed using data from PVT studies and well-completion tests of 27 rich gas-condensate and volatile-oil reservoir fluids. Selection of secondary or enhanced recovery methods. Processes for predicting future production rates. Techniques for predicting oil and gas reserves. Procedures for determining oil and gas in place. Laboratory tests used in analyzing the samples. The reservoir fluid type determines the: Method of fluid sampling. The type of fluid is critical to production decisions and, more » therefore, must be determined early in the life of a reservoir. Each type is produced by different engineering techniques. The paper classifies petroleum reservoir fluids into five types-black oils, volatile oils, retrograde gas-condensates, wet gases, and dry gases. Subsequent parts of this article will address fluid classification using the initial gas-oil ratio, stock-tank liquid gravity, and stock-tank liquid color. Further, phase diagram shapes affect the actions of the fluids in the reservoir. These also affect the sizes and shapes of each fluid's phase diagram. The most important factors in classifying the five types of reservoir fluids are the differences in composition. Regulatory definitions of oil, crude oil, condensate, gas, natural gas, casing-head gas, etc., are not related to these engineering definitions and, in fact, often contradict them. They should not be confused with reservoir fluid descriptions defined by legal agencies that regulate the petroleum industry. These fluid types are defined for engineering purposes. The paper also summarizes schematically the trends of producing GOR and stock-tank liquid gravity. It also shows the expected results of laboratory analysis of the fluids. If any of these three properties fails to meet the criteria described, the test fails and a representative sample more » of the reservoir fluid must be examined in a laboratory to establish fluid type.

This paper summarizes the guidelines for determining fluid type from field data. The fluid type must be determined very early in the life of a reservoir (often before sampling or initial production) because fluid type is the critical factor in many of the decisions that must be made about producing the fluid from the reservoir. The five reservoir fluids (black oils, volatile oils, retrograde gas-condensates, wet gases, and dry gases) are defined because production of each fluid requires different engineering techniques. This paper also shows the expected laboratory analysis results of the five = , Darker colors are associated with the largest, heaviest molecules in the petroleum mixture. Stock-tank liquid gravity and color are both indicators of the quantity of heavy components present in the initial reservoir fluid. Initial producing GOR is by far the most important of the indicators and should be considered first, with the other two indicators used to confirm fluid type. Three properties are readily available: the initial producing gas-oil ratio (GOR), the gravity of the stock-tank liquid and the color of the stock-tank liquid. This paper gives the guidelines for determining fluid type from field data. This concluding article discusses guidelines for using field data to determine the fluid type, the laboratory evidence that verifies fluid type and the production behavior of the five fluids.

MCCAIN GAS OIL RATIO SERIES

The previous four articles in this series revealed the differences and similarities among the five reservoir fluids in detail.

Mccain gas oil ratio