Remediation of asphaltene-induced plugging of an oil-bearing formation

a technology of asphaltene and oil-bearing formations, which is applied in the direction of fluid removal, chemistry apparatus and processes, and wellbore/well accessories, etc., can solve the problems of asphaltene flocculation, aggregate, and deposit of asphaltene, and the production of oil from an oil-bearing formation may be impeded, and solvents, however, have certain disadvantages attached

Inactive Publication Date: 2014-12-11
SHELL OIL CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0013]introducing the asphaltene solvent into an oil-bearing formation containing one or more asphaltene deposits; and
[0014]contacting the asphaltene solvent with one or more of the asphaltene deposits in the formation.

Problems solved by technology

Production of oil from an oil-bearing formation may be impeded by hydrocarbonaceous deposits within the formation.
Asphaltene flocculation may be induced, in particular, in the formation near a production well, where changes in pressure, temperature, composition, and shear rate caused by production of oil from the well may destabilize the asphaltenes in the oil near the production well and cause the asphaltenes to flocculate, aggregate, and deposit, plugging the formation near the production well.
Such solvents, however, have certain disadvantages attached to them.
Injection of deasphalted oil to remediate asphaltene deposition in a formation is inefficient since it requires injecting oil produced from the formation and subsequently processed back into the formation, where some of the injected oil may not be recovered again from the formation.
Injection of aromatics such as toluene and o-xylene may be subject to regulatory limitation, and is economically inefficient since such aromatics are even more highly processed and valuable than deasphalted oil.
Disulfide solvents may be subject to hydrolysis within the formation, and, in the case of carbon disulfide, may result in souring the formation.
Carbon disulfide is also highly toxic.

Method used

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  • Remediation of asphaltene-induced plugging of an oil-bearing formation
  • Remediation of asphaltene-induced plugging of an oil-bearing formation
  • Remediation of asphaltene-induced plugging of an oil-bearing formation

Examples

Experimental program
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Effect test

example 1

[0074]The quality of dimethyl sulfide as an asphaltene solvent based on the miscibility of dimethyl sulfide with a crude oil relative to other compounds was evaluated. The miscibility of dimethyl sulfide, ethyl acetate, o-xylene, carbon disulfide, chloroform, dichloromethane, tetrahydrofuran, and pentane solvents with mined oil sands was measured by extracting the oil sands with the solvents at 10° C. and at 30° C. to determine the fraction of hydrocarbons extracted from the oil sands by the solvents. The bitumen content of the mined oil sands was measured at 11 wt. % as an average of bitumen extraction yield values for solvents known to effectively extract substantially all of bitumen from oil sands—in particular chloroform, dichloromethane, o-xylene, tetrahydrofuran, and carbon disulfide. One oil sands sample per solvent per extraction temperature was prepared for extraction, where the solvents used for extraction of the oil sands samples were dimethyl sulfide, ethyl acetate, o-xy...

example 2

[0080]Two experiments were conducted on a naturally occurring tar mat material recovered from an oil-bearing formation to compare the rate of dissolution of the tar mat material using dimethyl sulfide and A150, a commercially available solvent comprised of a mixture of aromatic hydrocarbons that is commonly used to dissolve tar mats. A naturally occurring tar mat material recovered from an oil-bearing formation at a depth of 4690 meters and at a formation temperature of 50° C. was utilized as the tar mat material for the comparison.

[0081]In the first experiment, two samples of DMS solvent and two samples of A150 solvent were individually mixed with the tar mat material at ambient temperature and pressure, where the volume (ml) to weight (g) ratio of each solvent sample to the tar mat material was approximately 100:1. The length of time required to entirely dissolve the tar mat material was measured and recorded. Table 3 below shows the results.

TABLE 3Time Required for Dissolution of...

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Abstract

A system and method for remediation of asphaltene-induced fouling of an oil-bearing formation is provided wherein an asphaltene solvent comprising at least 75 mol % dimethyl sulfide is introduced into an oil-bearing formation containing asphaltene deposits and the dimethyl sulfide is contacted with the asphaltene deposits.

Description

RELATED CASES[0001]This application claims benefit of U.S. Provisional Application No. 61 / 832,272, filed on Jun. 7, 2013, which is incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention is directed to improving oil recovery from an oil-bearing formation fouled by asphaltene deposits. In particular, the present invention is directed to improving oil recovery from an oil-bearing formation fouled by asphaltene deposits using an asphaltene solvent to dissolve the asphaltene deposits.BACKGROUND OF THE INVENTION[0003]Production of oil from an oil-bearing formation may be impeded by hydrocarbonaceous deposits within the formation. Asphaltene deposits are one type of hydrocarbonaceous deposit that may impede the flow of oil through a formation by reducing the permeability of the formation. Asphaltenes are a fraction of crude oil formed predominately of aromatic hydrocarbons and heteroatom-containing hydrocarbons that are high in molecular weight relative to other...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): E21B43/16E21B43/14
CPCE21B43/14E21B43/16E21B43/162C09K8/524C09K8/58
Inventor MILAM, STANLEY NEMECTEGELAAR, ERIK WILLEMFREEMAN, JOHN JUSTIN
Owner SHELL OIL CO
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