1、Designation: D 4520 03 (Reapproved 2008)Standard Practice forDetermining Water Injectivity Through the Use of On-SiteFloods1This standard is issued under the fixed designation D 4520; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a procedure for conducting on-sitecore flood tests to determine the filtration and
3、chemicaltreatment requirements for subsurface injection of water.2,31.2 This practice applies to water disposal, secondary re-covery, and enhanced oil recovery projects and is applicable toinjection waters with all ranges of total dissolved solidscontents.1.3 This standard does not purport to addres
4、s all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4D 420 Guide to S
5、ite Characterization for Engineering De-sign and Construction PurposesD 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 1129 Terminology Relating to WaterD 2434 Test Method for Permeability of Granular Soils(Constant Head)D 4404 Test Method for Determination of Pore Volume andPore Volum
6、e Distribution of Soil and Rock by MercuryIntrusion Porosimetry2.2 American Petroleum Institute Standards:5API RP27 Recommended Practice for Determining Perme-ability of Porous MediaAPI RP40 Recommended Practice for Core-Analysis Pro-cedure3. Terminology3.1 Definitions:3.1.1 For definitions of terms
7、 relating to water and waterchemistry, refer to Terminology D 1129. Refer to TerminologyD 653 for definitions relating to soil and rock.3.2 Definitions of Terms Specific to This Standard:3.2.1 filtration requirementthe maximum suspended sol-ids size (in micrometres) allowed in an injection water tom
8、inimize formation plugging.3.2.2 test corea sample cut from a full core that has beenrecovered from the formation into which water is injected.3.2.3 permeabilitythe capacity of a rock (or other porousmedium) to conduct liquid or gas. It is measured as theproportionality constant between flow velocit
9、y and hydraulicgradient.3.2.4 pore volumethe volid volume of a porous mediumthat can be saturated with the transmitted fluid.3.2.5 porositythe ratio, usually expressed as a percentageof the volume of voids of a given soil, rock mass, or otherporous medium to the total volume of the soil, rock mass,
10、orother porous medium.3.2.6 rock-water interactiona reaction between a porousrock and the injected water causing precipitation or swelling orrelease of fines (clays) within the rock.4. Summary of Practice4.1 This practice assumes that the injection water has beencharacterized in terms of dissolved a
11、nd suspended solidscontents (including hydrocarbons and other organics as appli-cable) by established standard practices and methods.4.2 Test core material is selected by consultation betweengeologists and engineers and prepared for the tests by standardpractices.4.3 In the on-site core flood the pe
12、rmeability of the test coreis monitored to detect interactions between the formation rockand the injection water. The water is filtered at various levels to1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the direct responsibility of Subcommittee D19.05 on Inorganic Cons
13、tituents inWater.Current edition approved May 1, 2008. Published May 2008. Originallyapproved in 1986. Last previous edition approved in 2003 as D 4520 03.2Farley, J. T., and Redline, D. G., “Evaluation of Flood Water Quality in the WestMontalvo Field,” Journal Petroleum Technology, July 1968, pp. 6
14、83687.3McCune, C. C., “On-Site Testing to Define Injection Water Quality Require-ments,” Journal Petroleum Technology, January 1977, pp. 1724.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards vol
15、ume information, refer to the standards Document Summary page onthe ASTM website.5Available from American Petroleum Institute (API), 1220 L. St., NW, Wash-ington, DC 20005-4070, http:/www.api.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Uni
16、ted States.determine the filtration required (in micrometres) to minimizepermeability loss (damage) from suspended solids. Backflow-ing injection wells are simulated by reversing the flow direc-tion through the cores.5. Significance and Use5.1 The injectivity of a water is best determined by mea-sur
17、ements as near to the well as possible to minimize changesin water properties due to air contact and time. This practicedescribes how core flow tests are carried out near the well.5.2 This practice permits the differentiation of permeabilitylosses from the effects of chemical interaction of water an
18、drock and from the effects of plugging by suspended solids. Theprocedure can be utilized to estimate the chemical and filtrationrequirements for the full-scale injection project.5.3 Application of the test results to injection wells requiresconsideration of test core selection and geometry effects.5
19、.4 This practice as described assumes that the water doesnot contain free oil or other immiscible hydrocarbons. Thepresence of free oil would require the method to be modified toaccount for the effect of oil saturation in the test cores on thewater permeability.6. Sources of Rock-Water Interactions6
20、.1 Water injected into a porous rock may interact with therock to reduce the permeability as a result of the formation ofprecipitates, clay swelling, clay dispersion, or the migration ofother fine solids.6.2 Rock-water interactions are more common in sand-stones than in carbonate rocks. However, wit
21、hin carbonaterocks dissolved iron in the injection water may precipitateespecially in the presence of dissolved oxygen. Alkalineprecipitates (CaCO3and Mg(OH)2) may also form in carbonaterocks.6.2.1 Dissolved hydrogen sulfide in the presence of dis-solved iron and oxygen can also be a problem in wate
22、rsinjected into carbonate and sandstones resulting in precipita-tion of sulfides and hydroxides of iron.6.3 The iron and alkaline precipitates described in 6.2 canalso form from waters injected into sandstones. Swelling typeclays (montmorillonite and mixed layer clays) and dispersibleclays (kaolinit
23、e and chlorite) are potential sources of perme-ability losses due to changes in salinity or ionic content of theinjected water compared to the natural waters in the formation.In some sandstones fine mica particles have been caused tomigrate by the injection of a potassium ion deficient water.6.4 In
24、some instances in both sandstones and carbonatessome fine particles are released to migrate as a result of watersaturating the cleaned and dried test cores.7. Apparatus7.1 A schematic diagram of the test apparatus is shown inFig. 1. The component parts are assembled from commerciallyavailable labora
25、tory apparatus with the exception of the coreholders (Fig. 2). While four cores are shown in Fig. 1 thenumber used in a test is optional. The apparatus essentiallyconsists of a filtration section and a core flood section. Thevarious components are connected with plastic or stainlesssteel flow lines
26、with required valves and gauges as illustrated.7.2 The filtration section is assembled from four cartridgefilter holders mounted two each in series. Valves are installedto permit flow through either filter pair or to bypass the filters.Pressure gauges are included for monitoring the inlet anddischar
27、ge pressure of the filters. Commercial filters are avail-able with ratings ranging as low as 0.2 m. The rated sizes usedin the on-site core flood tests generally range from 0.45 to 10m. The filter holders should be provided with vents to saturatethe filters and purge air from the system.FIG. 1 Schem
28、atic of Test EquipmentD 4520 03 (2008)27.3 The core flood section of the apparatus consists of alaboratory constant temperature bath rated for up to 150C(302F) and of adequate capacity to hold up to four coreholders (Fig. 2). Necessary valves and gauges are provided. Asshown in Fig. 1, two of the co
29、re holders (No. 1 and No. 2) areplumbed to allow the flow through the cores to be reversedwithout removing the core holders. The pressure to the coreflood section is controlled with a regulator, and a test gauge isused to accurately monitor the test core inlet pressure. The testcore discharge pressu
30、re is atmospheric when the apparatus isassembled as shown in Fig. 1.7.3.1 Another option is to control the discharge at a pressureabove atmospheric by the addition of a regulator on each coresample discharge line. This option is recommended if theevolution of dissolved gas is anticipated from the wa
31、ter as itflows through the test core.7.4 An alternative to the core holders (Fig. 2) is a Hassler-type permeability cell (API RP40) which uses a rubber orplastic sleeve to form the seal around the core sample. Ahigh-pressure air (nitrogen) or liquid supply to maintain theseal would be required.7.5 T
32、he operating gauge pressure of the test apparatus isusually 700 kPa (100 psig) or less.7.6 As shown in Fig. 1, facilities may also be provided forthe addition of chemicals to the water being tested. A chemicalsupply tank and an injection pump with pressure and flowratings corresponding to specific n
33、eeds would be required.7.7 The apparatus is attached to a line carrying the waterbeing tested. Usually, the line pressure of the water source(regulated as required) satisfies the pressure requirement forflowing the water through the filters and test cores. If thesupply pressure is insufficient, a sm
34、all pump capable ofdelivering about 1 L/min at 700 kPa is used.7.8 Other required apparatus are the following:7.8.1 Mechanical (non-aspirator type) vacuum pump,7.8.2 Assorted beakers (250 to 1000 mL),7.8.3 Assorted graduated cylinders (10 to 100 mL),7.8.4 Stopwatch,7.8.5 Vacuum tubing, and7.8.6 Asso
35、rted tools for assembling and disassembling theequipment as required.8. Procedure8.1 Core Selection:8.1.1 Choose proper core samples to yield the most mean-ingful test results through close coordination with geologists,chemists, and engineers responsible for the water injectionproject.8.1.2 To assis
36、t in that choice include well logs, mineralogy,porosity, pore size distribution, permeability, and other coredescriptive data.8.1.3 Choose test cores to represent the zones that willreceive the injected water. The best samples are from wholecores cut from those zones. Prepare sufficient samples tore
37、present the ranges of permeability, porosity, and mineralogyof the injected zones. Consider the presence of natural frac-tures.8.1.4 Select the number and properties of the cores for aparticular test according to one of the following options:8.1.4.1 Use cores having similar properties (porosity, per
38、-meability, mineralogy, etc.). Average the results.8.1.4.2 Use a set of cores with one of these propertiesdifferent in each core to test the effect of this property on thetest results.8.1.5 If cores from the flooded zone are not available,choose another zone with similar properties as the next besta
39、lternative sample source. As a third choice use synthetic corematerial (alumina, silica, porous glass, etc.).8.2 Core Sample Preparation:8.2.1 Follow the recommended procedures for core han-dling, preservation, cutting, and cleaning described in APIRP40. (This extensive document describes various pr
40、oceduresand options that the investigator may choose depending on thetype and condition of the cores being tested.) Related ASTMstandards are Guide D 420, Test Method D 2434, and TestMethod D 4404.8.2.2 The preferred sample dimensions for the core floodtest are 19 mm (0.75 in.) to 38 mm (1.5 in.) ou
41、tside diameterwith a minimum length to diameter ratio of 1:0.8.2.3 Carry out the following procedure for each coresample in the set to be tested:8.2.3.1 Cut the core sample parallel to the formation bed-ding plane and then clean by solvent-extraction to removeresidual hydrocarbons and water from the
42、 pore space. Dry thesample and determine the porosity according to the recom-mended procedures in API RP40.8.2.3.2 Use the air permeability of the core sample as aguide for choosing representative samples of the formationFIG. 2 Schematic Diagram of Sample HolderD 4520 03 (2008)3being tested. The pro
43、cedure for measuring air permeabilities isdescribed in API RP27.8.2.3.3 Seal the core sample with an epoxy resin or othersuitable sealant in a metal (stainless steel, aluminum, brass)tube having an inside diameter about 6.4 mm (0.25 in.) largerthan the outside diameter of the sample.8.2.3.4 Machine
44、the ends of the core sample and metal tubeflat and perpendicular to the tube axis. Generally a stream ofcompressed air on the core ends during machining will preventthe intrusion of fines into the rock pores.8.2.3.5 Mount the metal tube (containing the core sample)in a holder designed to allow water
45、 to be flowed through thesample. An example of such a sample holder is shownschematically in Fig. 2.8.3 Vacuum Saturation of Test Cores:8.3.1 Install a 10-m rated cartridge in filter No. 1 and a0.45-m cartridge in filter No. 2. Close valves to and fromfilters No. 3 and No. 4, the filter bypass valve
46、, and valves to allcore sample holders.8.3.2 Open the valve-to-waste upstream and downstream ofthe regulator and the valves to and from filters No. 1 and No.2. Start water flow through the filters to waste.8.3.3 Close the valve-to-waste upstream of the pressureregulator. Set the regulator at about 1
47、20 kPa (17 psi) more thanthe pressure planned for the test. After about 2 min, close thevalve-to-waste downstream of the regulator.8.3.4 Mount from one to four sample cores in the holders(lines should not contain water) and attach the core sampleholders to the valves.8.3.5 Open the valves on the eff
48、luent ends of the coreholders and attach the vacuum pump (with vacuum tubing) tothe lines from the effluent end of the core holders. Run thevacuum pump for at least 1 h noting the vacuum gauge on thepump to check for leaks.8.3.6 After at least 1 h, close the valves from the effluentends of core hold
49、ers and shut off and disconnect the vacuumpump and tubing.8.3.7 Open the valve-to-waste downstream of the regulatorto check water flow and then close the valve. Open the valvesto the inlet ends of core holders one at a time to beginsaturation of the evacuated core samples. Pressure on the testgauge should read at least the pressure that will be used duringthe test. Adjust the regulator as required. Leave the systemshut-in with pressure on the test cores for at least 30 min.8.3.8 Close the valves to the core holders to await next step.8.3.9 This procedure assumes samp
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