Location of Injectors and Producers

The injection and production wells in a waterflood should be placed to accomplish the following: (1) provide the desired oil productivity and the necessary water injection rate to yield this oil productivity and (2) take advantage of the reservoir characteristics, such as dip, faults, fractures, and permeability trends. In general, two kinds of flooding patterns are… Continue reading Location of Injectors and Producers

Waterflooding Candidates

Several factors lend an oil reservoir to a successful waterflood. They can be generalized in two categories: reservoir characteristics and fluid characteristics. The main reservoir characteristics that affect a waterflood are depth, structure, homogeneity, and petrophysical properties such as porosity, saturation, and average permeability. The depth of the reservoir affects the waterflood in two ways.… Continue reading Waterflooding Candidates

Waterflooding

The waterflooding process was discovered quite by accident more than 100 years ago when water from a shallow water-bearing horizon leaked around a packer and entered an oil column in a well. The oil production from the well was curtailed, but production from surrounding wells increased. Over the years, the use of waterflooding grew slowly… Continue reading Waterflooding

Secondary Oil Recovery

As mentioned in the previous section, there are in general two types of secondary recovery processes—waterflooding and gasflooding. These will both be discussed in this section. Waterflooding has been the most used process, but gasflooding has proven very useful with reservoirs with a gas cap and where the hydrocarbon formation has a significant dip structure… Continue reading Secondary Oil Recovery

Introduction

The initial production of hydrocarbons from an oil-bearing formation is accomplished by the use of natural reservoir energy. As discussed in this type of production is termed primary production. Sources of natural reservoir energy that lead to primary production include the swelling of reservoir fluids, the release of solution gas as the reservoir pressure declines, nearby… Continue reading Introduction

Oil Recovery by Internal Gas Drive

Oil is produced from volumetric, undersaturated reservoirs by expansion of the reservoir fluids. Down to the bubble-point pressure, the production is caused by liquid (oil and connate water) expansion and rock compressibility. Below the bubble point, the expansion of the connate water and the rock compressibility are negligible, and as the oil phase contracts owing… Continue reading Oil Recovery by Internal Gas Drive

The Displacement of Oil by Gas, with and without Gravitational Segregation

The method discussed in the previous section also applies to the displacement of oil by gas drive. The treatment of oil displacement by gas in this section considers only gravity drainage along dip. Richardson and Blackwell showed that in some cases there can be a significant vertical component of drainage.9 Due to the high oil-gas… Continue reading The Displacement of Oil by Gas, with and without Gravitational Segregation

Immiscible Displacement Processes

The Buckley-Leverett Displacement Mechanism Oil is displaced from a rock by water similar to how fluid is displaced from a cylinder by a leaky piston. Buckley and Leverett developed a theory of displacement based on the relative permeability concept.8 Their theory is presented here. Consider a linear bed containing oil and water (Fig. 10.7). Let the… Continue reading Immiscible Displacement Processes

Macroscopic Displacement Efficiency

The following factors affect the macroscopic displacement efficiency: heterogeneities and anisotropy, mobility of the displacing fluids compared with the mobility of the displaced fluids, the physical arrangement of injection and production wells, and the type of rock matrix in which the oil or gas exists. Heterogeneities and anisotropy of a hydrocarbon-bearing formation have a significant… Continue reading Macroscopic Displacement Efficiency