A kind of calculation method of the low-permeability oil deposit water logging information of fluid replacementTechnical field
The invention belongs to petroleum well logging technology fields, are related to a kind of calculating of the low-permeability oil deposit water logging information of fluid replacementMethod.
Background technique
Research area's purpose reservoir properties are poor, and reservoir space is small, and porosity distribution is 4~16%, and permeability is mainly dividedCloth is 0.1~2 × 10-3μm2Between, belong to low porosity and permeability oil reservoir.After more than 20 years waterflooding extractions, lead to reservoirFluid properties, pore structure and oil and water zonation etc. change.Along with the rising of moisture content, water out behavior is complicated, electrically becomesChange increasing, it is difficult that water flooded grade sentences knowledge.The accurate division of water flooded grade must be solved in waterflooding oil field adjustment workCertainly the problem of, oil field old improve recovery ratio and in terms of play a crucial role.Currently, Water Flooding Layer waterIt is more to flood level evaluation method, such as log qualitative recognition method, crossplot method and movable fluid analytic approach, but domestic eachOil field is due to the difference of its geological state and Exploitation degree, and current evaluation method all has region limitation, without a kind of logicalThe calculation method of the low-permeability oil deposit water logging information of fast qualitative, it is difficult to promote and apply.Reconstruct Water Flooding Layer prime stratum electricityThe division water flooded grade of resistance rate fast qualitative is one of effective ways, but since this respect data is less, and the more bases of reconstructing methodIt establishes in a large amount of core experiment data, is limited and the scarcity of core experiment analysis data by expensive coring expense, applicationRange is little, especially in the secondary development of oil field old, it is difficult to meet actual production demand.
Summary of the invention
It is an object of the invention to overcome the above-mentioned prior art, a kind of low-permeability oil deposit of fluid replacement is providedThe calculation method of water logging information, this method accurately obtain low-permeability oil deposit water logging information.
In order to achieve the above objectives, the calculation method of the low-permeability oil deposit water logging information of fluid replacement of the present invention includesFollowing steps:
1) response characteristic logged well before and after reservoir water logging in region is obtained, and the well logging before and after reservoir water logging from the regionResponse characteristic in choose lithology and physical property natural gamma GR and interval transit time AC log without significant change before and after water logging；
2) in chosen area the model well of non-water logging well logging information, built further according to the well logging information of the model well of non-water loggingThe functional relation of the resistivity of contained original fluid and natural gamma and interval transit time in vertical reservoir pore space；
3) resistivity and natural gamma and interval transit time of contained original fluid in the reservoir pore space obtained using step 2)Functional relation calculate contained primary flow in the reservoir pore space for the model well for determining water logging to the model well of water logging in regionThe resistivity t of body1, and by the resistivity t of original fluid contained in the reservoir pore space of the model well of water logging1It is obtained with actual measurementThe resistivity t of the model well for the water logging arrived2It compares, obtains contained original fluid in the reservoir pore space of the model well of water loggingResistivity t1The resistivity t of the model well of the water logging obtained with actual measurement2Between change in resistance value Δ Rt；
4) moisture content F is determined by the formation testing information of the model well of water logging in regionw, according to the moisture content FwAnd stepThe rapid change in resistance value Δ R 2) obtainedtEstablish change in resistance value Δ RtIdentify the criteria for classifying of water flooded grade；
5) resistivity and natural gamma and interval transit time of contained original fluid in the reservoir pore space obtained using step 2)Functional relation well to be evaluated in region is calculated, obtain in region contained original fluid in the reservoir pore space of well to be evaluatedResistivity, then by the resistivity of contained original fluid in the reservoir pore space of well to be evaluated in region and actual measurement obtain toThe resistivity of evaluation well compares, and determines the resistivity and reality of contained original fluid in the reservoir pore space of well to be evaluated in regionChange in resistance value Δ R between the resistivity for the well to be evaluated that border measurement obtainss, then according to the change in resistance value ΔRsAnd the obtained criteria for classifying of water flooded grade of step 4) determines the water logging information of well to be evaluated in region.
The resistivity and nature of contained original fluid in reservoir pore space are established according to the well logging information of the model well of non-water loggingThe concrete operations of the functional relation of gamma and interval transit time are as follows:
Fuzzy clustering mathematics method, which is based on, according to the well logging information of the model well of non-water logging establishes contained original in reservoir pore spaceThe resistivity and natural gamma of beginning fluid and the functional relation of interval transit time.
The resistivity and nature of contained original fluid in reservoir pore space are established according to the well logging information of the model well of non-water loggingThe concrete operations of the functional relation of gamma and interval transit time are as follows:
The resistivity sample R in region to be measured is determined according to the well logging information of the model wellt, then to the resistance in region to be measuredRate sample Rt classifies, and the resistivity sample R in region to be measured is arrangedtFuzzy diagnosis matrix U and central index vector S,Then optimal fuzzy diagnosis matrix U is solved by loop iteration·, optimal fuzzy clustering central index S·And variable weight W·, soAfterwards according to optimal fuzzy diagnosis matrix U·, optimal fuzzy clustering central index S·And variable weight W·It determines contained in reservoir pore spaceThe resistivity of original fluid and the functional relation of natural gamma and interval transit time, wherein
Rt·=a × H+b；H=f (GR AC U· S· W· ρ)
In formula, Rt·For the resistivity curve data of original fluid contained in reservoir pore space, a and b are model coefficient, and f is to reflectThe functional relation penetrated, GR and AC are the natural gamma and interval transit time log data after normalization, 0.9≤ρ.
Model coefficient a and b are determined using fuzzy clustering mathematics method, obtain a=0.1783, b=1.003.
Optimal fuzzy clustering central index S is determined using fuzzy clustering mathematics method·, obtain
Variable weight W is determined using fuzzy clustering mathematics method·, obtain W·=(0.6425 0.3575)；
ρ=0.9017.
The invention has the following advantages:
The calculation method of the low-permeability oil deposit water logging information of fluid replacement of the present invention is calculating low-permeability oil deposit waterDuring flooding information, the electricity of contained original fluid in reservoir pore space is established by establishing the well logging information of model well of non-water loggingThe functional relation of resistance rate and natural gamma and interval transit time, is then calculated in region to be measured contained primary flow in reservoir pore spaceThe resistivity of body obtains the low-permeability oil deposit water logging in region to be measured and believes further according to the difference of actual measurement and the resistivity being calculatedBreath, the present invention can satisfy the needs of actual production, and real well data processing in 120 through oil field old secondary development mouthful obtainsLow-permeability oil deposit water logging information coincidence rate reach 83% or more, have preferable application value.
Detailed description of the invention
Fig. 1 is model well resistivity sample R in the embodiment of the present invention onetCumulative frequency distribution map；
Fig. 2 is moisture content F in the embodiment of the present invention onewWith change in resistance value Δ RtChanging rule figure；
Fig. 3 (a) is the reservoir resistivity changing value Δ R of 60-63 layer in the embodiment of the present invention onetSchematic diagram；
Fig. 3 (b) is the reservoir resistivity changing value Δ R of 64-68 layer in the embodiment of the present invention onetSchematic diagram；
Fig. 3 (c) is the reservoir resistivity changing value Δ R of 56-59 layer in the embodiment of the present invention onetSchematic diagram.
Specific embodiment
The invention will be described in further detail with reference to the accompanying drawing:
The calculation method of the low-permeability oil deposit water logging information of fluid of the present invention replacement the following steps are included:
1) response characteristic logged well before and after reservoir water logging in region is obtained, and the well logging before and after reservoir water logging from the regionResponse characteristic in choose lithology and physical property natural gamma GR and interval transit time AC log without significant change before and after water logging；
2) in chosen area the model well of non-water logging well logging information, built further according to the well logging information of the model well of non-water loggingThe functional relation of the resistivity of contained original fluid and natural gamma and interval transit time in vertical reservoir pore space；
3) resistivity and natural gamma and interval transit time of contained original fluid in the reservoir pore space obtained using step 2)Functional relation calculate contained primary flow in the reservoir pore space for the model well for determining water logging to the model well of water logging in regionThe resistivity t of body1, and by the resistivity t of original fluid contained in the reservoir pore space of the model well of water logging1It is obtained with actual measurementThe resistivity t of the model well for the water logging arrived2It compares, obtains contained original fluid in the reservoir pore space of the model well of water loggingResistivity t1The resistivity t of the model well of the water logging obtained with actual measurement2Between change in resistance value Δ Rt；
4) moisture content F is determined by the formation testing information of the model well of water logging in regionw, according to the moisture content FwAnd stepThe rapid change in resistance value Δ R 2) obtainedtEstablish change in resistance value Δ RtIdentify the criteria for classifying of water flooded grade；
5) resistivity and natural gamma and interval transit time of contained original fluid in the reservoir pore space obtained using step 2)Functional relation well to be evaluated in region is calculated, obtain in region contained original fluid in the reservoir pore space of well to be evaluatedResistivity, then by the resistivity of contained original fluid in the reservoir pore space of well to be evaluated in region and actual measurement obtain toThe resistivity of evaluation well compares, and determines the resistivity and reality of contained original fluid in the reservoir pore space of well to be evaluated in regionChange in resistance value Δ R between the resistivity for the well to be evaluated that border measurement obtainss, then according to the change in resistance value ΔRsAnd the obtained criteria for classifying of water flooded grade of step 4) determines the water logging information of well to be evaluated in region.
The resistivity and nature of contained original fluid in reservoir pore space are established according to the well logging information of the model well of non-water loggingThe concrete operations of the functional relation of gamma and interval transit time are as follows: fuzzy clustering is based on according to the well logging information of the model well of non-water loggingMathematical method establishes the functional relation of the resistivity of contained original fluid and natural gamma and interval transit time in reservoir pore space.
The resistivity and nature of contained original fluid in reservoir pore space are established according to the well logging information of the model well of non-water loggingThe concrete operations of the functional relation of gamma and interval transit time are as follows:
The resistivity sample R in region to be measured is determined according to the well logging information of the model wellt, then to the resistance in region to be measuredRate sample RtClassify, and the resistivity sample R in region to be measured is settFuzzy diagnosis matrix U and central index vector S, soOptimal fuzzy diagnosis matrix U is solved by loop iteration afterwards·, optimal fuzzy clustering central index S·And variable weight W·, thenAccording to optimal fuzzy diagnosis matrix U·, optimal fuzzy clustering central index S·And variable weight W·Determine contained original in reservoir pore spaceThe resistivity of beginning fluid and the functional relation of natural gamma and interval transit time, wherein
Rt·=a × H+b；H=f (GR AC U· S· W· ρ)
In formula, Rt·For the resistivity curve data of original fluid contained in reservoir pore space, a and b are model coefficient, and f is to reflectThe functional relation penetrated, GR and AC are the natural gamma and interval transit time log data after normalization, 0.9≤ρ.
Model coefficient a and b are determined using fuzzy clustering mathematics method, obtain a=0.1783, b=1.003.
Optimal fuzzy clustering central index S is determined using fuzzy clustering mathematics method·, obtain
Variable weight W is determined using fuzzy clustering mathematics method·, obtain W·=(0.6425 0.3575)；
ρ=0.9017.
Embodiment one
According to region oil reservoir development background, by the comparative analysis to logging response character before and after research area's reservoir water logging,It is preferred that lithology and physical property natural gamma and interval transit time log without significant change before and after water logging；According to " Water Flooding Layer is surveyedWell datum processing specification (SY/T6178-2011) " in moisture content division limits, in conjunction with oil test data, selection has generationModel well (the F of the non-water logging of tablew≤ 10% be non-water logging) well logging information, reservoir hole is established using fuzzy clustering mathematics methodThe functional relation of the resistivity of contained original fluid and natural gamma and interval transit time in gap, Fig. 1 are model well resistivity RtSampleThe cumulative frequency distribution map of this collection can be divided into 4 classes, functional relation by resistivity sample set are as follows: Rt·=a × H+b；H=f(GR AC U· S· W·ρ), in formula, Rt·For the resistivity curve data of original fluid contained in reservoir pore space；A and b is mouldThe coefficient of type, a=0.1783, b=1.003；F is the functional relation of mapping；GR and AC is the natural gamma harmony after normalizationWave time difference log data；S·For optimal fuzzy clustering center matrix,
W·For variable weight,
W·=(0.6425 0.3575)；ρ is related coefficient, ρ=0.9017, using the functional relation of above-mentioned foundation, to instituteIt states research area and chooses the model well of representative water logging and calculated, calculate the resistance of contained original fluid in reservoir pore spaceRate, and with actual measurement resistivity contrasts, actual measurement resistivity and calculate resistivity difference be change in resistance value Δ Rt, change in resistanceIt is worth Δ RtAs caused by fluid properties variation in reservoir pore space；To change in resistance value Δ RtWith moisture content FwIt is analyzed, the twoIt presents and is positively correlated, and meet One- place 2-th Order functional relation, then in conjunction with moisture content FwDivision limits, utilize change in resistance valueΔRtObtain low-permeability oil deposit water logging information.In practical application, the criteria for classifying of water flooded grade is Δ Rt≤ 3.83 Ω .m are weak waterIt floods, the 3.83 Ω .m < Ω of Δ Rt < 51.34 .m is middle water logging, Δ Rt>=51.34 Ω .m are strong water logging, and Fig. 2 is change in resistance valueΔRtWith moisture content FwRelational graph.
In real data treatment process, the resistivity curve of contained original fluid is by writing program in inverting reservoir pore spaceIt realizes.Fig. 3 is the water flooded grade well log interpretation result map replaced based on fluid: referring to Fig. 3 (a), No. 60 floor are replaced based on fluidIn the reservoir pore space of method inverting the resistivity of contained original fluid close to actual measurement resistivity, change in resistance value Δ RtIt is 1.46Ω m, less than 3.83 Ω m, according to the criteria for classifying of water flooded grade, well log interpretation is weak water logging.It is tested through Production development dataCard, the well is in 1435.0~1441.0m well section perforation, formation testing: oily 7.5t, water 4.05m3, moisture content 35.06%；It goes into operation: oil5.84t, water 2.29m3, moisture content 14.5%, formation testing conclusion is weak water logging, and well log interpretation is actually consistent with production.With reference to Fig. 3(b), contained original fluid resistivity ratio actual measurement resistivity is small in the reservoir pore space that No. 65 floor are calculated based on fluid Shift Method, resistanceRate changing value Δ RtFor 16.44 Ω m, between 3.83 and 51.34 Ω m, according to the criteria for classifying of water flooded grade, well log interpretationFor middle water logging.Through Production development data verification, the well is in 1325~1328m well section perforation, formation testing: oily 10.08t, water 2.74m3,Moisture content 21.3% is gone into operation: oily 1.59t, water 2.56m3, moisture content 61.6%, formation testing conclusion is middle water logging, well log interpretation and lifeProduction is actually consistent.With reference to Fig. 3 (c), contained original fluid resistivity in the reservoir pore space that No. 58 floor are calculated based on fluid Shift MethodMuch smaller than actual measurement resistivity, change in resistance value Δ RtFor 116.74 Ω m, it is greater than 51.34 Ω m, according to water flooded gradeThe criteria for classifying, well log interpretation are strong water logging.Through Production development data verification, the well is in 1642~1644m well section perforation, examinationOil: oil bloom, water 12.6m3, go into operation: oily 0.79t, water 4.95m3, moisture content 86.2%, formation testing conclusion is strong water logging, well log interpretationIt is practical to meet production.Processing through 120 mouthfuls of real well data, and with Oil testing Comparative result, interpretation coincidence rate reaches 83%,The validity of the low-permeability oil deposit water logging information calculation method based on fluid replacement is demonstrated, there is preferable application effect.
The foregoing is merely preferable implementation of the invention figures, are not intended to limit the invention, for those skilled in the artMember, all within the spirits and principles of the present invention, made any modification and improvement etc., should all include protection scope of the present inventionIt is interior.