Oil Recovery

Oil Recovery

 

a measure of the completeness of extraction of oil from a bed. Oil recovery also refers to the degree of depletion of an oil bed. The coefficient is defined as the ratio of the quantity of oil extracted to the quantity originally contained in the bed under similar conditions and is expressed numerically in fractions of a unit or in percentages.

In the extraction of oil through displacement by various agents, the recovery factor is determined by the completeness of displacement of oil by water, gas, solvents, or other agents (called the displacement factor) and by the degree of conformance of the entire bed—that is, the totality of oil-saturated beds, intercalated beds, and lenses making up the object of exploitation (the conformance factor). In this case the recovery factor is expressed as the product of the displacement and conformance factors. The conformance factor depends to a great extent on the nonuniformity of the bed and the ratio of the viscosity of the oil to that of the displacing agent. The more heterogeneous the structure and physical properties of the bed and the greater the ratio of the oil viscosity to the agent viscosity, the lower the value of the conformance factor. The conformance factor is close to 1 in oil field recovery operations using depletion (drive) or predominantly gravity drainage. The recovery factor depends on the properties of the oil under reservoir conditions, the physical and chemical characteristics of the bed and the natural or artificial recovery conditions, and the system of development of the deposit.

For water drive, the most common and efficient oil recovery method, a distinction is made among waterless production, which characterizes the completeness of oil extraction at the start of water contamination of the output (that is, the appearance of water together with the oil); current production, which determines the completeness of oil extraction at any given moment in the exploitation of an oil-bearing bed; and final production, which is determined by the maximum water contamination of the output, which halts the operation of individual wells, the bed, or the oil field as a whole. The maximum water contamination is determined by economic indicators and depends on the properties of the oil and the depth of the bed. With water drive, the final production ranges from 0.25 to 0.7, depending on the viscosity of the oil, the heterogeneity of the bed, and other factors (low values occur in the recovery of oil pools having high viscosity under reservoir conditions). The maximum, or limiting, production that can be attained by the use of a given method is also distinguished. For example, the maximum production with water flooding can be reached by prolonged washing of the bed with water until the output is completely contaminated with water.

As the petroleum industry develops and as methods for working oil-bearing beds appear and are improved, the recovery factor has risen from 0.3 to 0.5 and, for certain oil fields, to 0.7. The average recovery factor for individual petroleum-extracting countries is increasing relatively slowly (Figure 1) because of the exploitation of oil fields in which the properties of the oil and reservoirs have deteriorated.

Figure 1. Change of absolute and extractable oil reserves in the USA: (1) total geological reserves, (2) actual cumulative production (values of the average recovery factor are shown in percent)

(See also: Production.)

A. G. KOVALEV

References in periodicals archive ?
Onyekonwu, "Enhanced oil recovery using nanoparticles," in Proceedings of the SPE Saudi Arabia Section Technical Symposium and Exhibition 2012, pp.
Infill drilling lies in the category of Improved Oil Recovery (IOR) techniques which enhances the production due to reservoir heterogeneous behavior.
Muscat, Oct 4 (ONA) During the 3 rd Annual Research Forum that will be held at Grand Millennium Muscat, Innovation Park Muscat (IPM) of the Research Council will sign tomorrow (Wednesday) the first agreement to establish a research and development (RD) Centre in the field of heavy oil recovery with Enhanced Oil Recover Company.
Depleting oil reserves make a strong case for the implementation of enhanced oil recovery (EOR) systems, and this will emerge as the strongest growth driver for the global enhanced oil recovery market, says a report.
Muscat: Petroleum Development Oman (PDO), the Sultanate's national oil company, will continue to focus on enhanced oil recovery projects, which is expected to contribute one-fourth of the company's total crude oil output by 2019 and one-third by 2025, a top-level official of the company told journalists here on Tuesday.
The Minister said in order to reduce dependence on imports of oil and gas to meet the energy needs of the growing Indian economy, a number of steps have been taken by the government for enhancing domestic production including improved oil recovery, enhanced oil recovery implemented by exploration and production companies for increasing oil recovery from fields.
The laboratory - the first of its kind in the Middle East region - will support ongoing applied research efforts in the area of enhanced oil recovery, particularly in carbonate reservoirs such as Qatar's Al Shaheen oil field, which is one of the most complex in the world.
The budget is being bolstered to help the EMSA maintain its network of oil recovery vessels - the EMSA currently has 17 ships, covering most of the EU's maritime areas - to complement intervention by the member states when they are affected by maritime pollution.
Petroleum engineers mostly from oil and equipment companies draw on the field experience of specialists in enhanced oil recovery as well as from the technical literature and other sources to provide a reference to all aspects of enhanced oil recovery.
Oil density and viscosity are few of the utmost parameters, which governs the mobility of oil within the reservoir and also plays a key role in designing enhanced oil recovery projects.
Hosnia Hashim, the deputy managing director (North Kuwait), Kuwait Oil Company said the search for ways to maximise oil recovery had opened opportunities for special extraction techniques like Enhanced Oil Recovery.
It is equipped with state of the art pollution response and control equipment that include containment equipment like Hi sprint booms and river booms, recovery devices like skimmers and side sweeping arms and storage devices like Oil Recovery Operation (ORO) tanks and inflatable barges.