Summary of the invention
In order to solve above-mentioned technical problem, the present invention utilizes fluid mud logging techniques to be identified oil gas aqueous nature in reservoir judging, evaluate oil-gas Layer in real time, exactly, provide basic data for the selection of logging method in follow-up wellbore operations, the formulation of test measure and the selection of testing scheme in time.
The present invention provides a kind of fluid well logging oil-gas-water interpretation method based on oil gas aqua index plate, it is characterised in that including: parameter acquisition step, fluid logging parameters includes heavy hydrocarbon component;Parameter pre-treatment step, chooses and can reflect the parameter of fluid properties change in stratum;Parameter calculation procedure, choosing can the oily index of direct reaction oil gas water characteristic, gas index, three derivative parameter of aqua index;Set up oil gas aqua index standard plate step, according to known formation testing conclusion, with oil index, gas index, the derivative parameter graphing hurdle of aqua index three;Target zone is carried out the step of parameter calculating;According to the step that target zone is evaluated by standard plate.
In parameter acquisition step, fluid well logging acquisition parameter includes total hydrocarbon and each hydrocarbon component methane C1, ethane C2, propane C3, iso-butane iC4, normal butane nC4, isopentane iC5, pentane nC5, normal hexane nC6, normal heptane nC7, normal octane nC8, benzene C6H6, toluene C7H8, alkene C7H14。
Additionally, in parameter calculation procedure, gas index IGIt is C1Account for the percentage ratio index as reaction reservoir gassiness of whole gas component, gas formula of index: IG=100*C1/ (C1+C2+C3+C4+C5+nC6+nC7+nC8)。
In parameter calculation procedure, oil index IOIt is to indicating oil-containing than more sensitive parameter nC in gas component5、nC6、nC7、nC8、C7H14With light component C1、C2、C3Ratio as reflection oil-containing index, oil formula of index: IO=10*(nC5+nC6+nC7+nC8+C7H14)2/ (C1+C2+C3)。
In parameter calculation procedure, aqua index IW: reservoir oil-containing was suffered the in the case of of putting into the melting pot, aqua index is that in improved reservoir, benzene and toluene both components account for gas component ratio, relative to oil reservoir phase proportion, significant change can occur;Aqua index computing formula: IW=(C6H6+C7H8)/(a*nC6+nC7);
Wherein, a is correction coefficient, selects the fluid mud logging gas parameter of offset well formation testing reservoir, cumulative every meter of gas data of Effective Reservoirs thickness, tries to achieve correction coefficient a according to formula below,
In formula, n is the constant for certain reservoir, and value is the effective thickness of this reservoir, dimensionless.
In addition, set up in oil gas aqua index standard plate step, select gas index, oil index and three derivative parameters of aqua index, figure is become in a graphical bar, according to three curves section longitudinally on variation tendency and parameter area, with reference to the lithology of geological logging, oiliness situation, according to known formation testing conclusion, comprehensive enough statistical datas are set up oil gas aqua index plate and are set up oil gas aqua index plate.
Include it addition, carry out parameter calculation procedure at target zone: reservoir thickness calculates: change according to landwaste percentage ratio, when boring, the parameter such as the pressure of the drill, moment of torsion, dc index, the thickness of reservoir is divided;Determine reservoir effective thickness according to reservoir gas parameter total gas curve form, play depth of stratum corresponding to peak for initial well depth H with abnormal show layer total gas curve1, single display peak-to-peak top or continuously high level reduce flex point place layer depth accordingly for terminating well depth H2, reservoir effective thickness HEffectivelyFor terminating the difference of well depth and initial well depth, i.e. HEffectively=H2-H1;Reservoir gas index, oil index, aqua index calculate: from data base extraction process, check and correction after target zone parameter, calculate three derivative parameters respectively.
It addition, target zone is evaluated in step according to criteria for interpretation plate: the gas index calculated, oil index, aqua index are depicted as curve, the metamorphosis of reference standard plate, parameter area according to master scale, complete the judgement to target zone.
By the present invention fluid well logging oil-gas-water interpretation method based on oil gas aqua index plate, fluid mud logging techniques is utilized to gather gas parameter, according to the oil gas water feature that each gas component reflects, select the parameter combination that profit is sensitive, it is proposed to oil index, gas index and aqua index three are derivative calculates parameter.According to three parameters well logging longitudinally on variation tendency and parameter area, in conjunction with the lithology of geological logging, oiliness (fluorescence) situation, oil-gas-water layer is identified.Utilize oil gas aqua index plate that reservoir is made an explanation, there is real-time, directly perceived, high accuracy for examination.
Detailed description of the invention
For the defect of above-mentioned means of interpretation, the gas component that fluid mud logging techniques newly increases is added in gas explanation evaluating method by the present invention, it is proposed that oil gas aqua index plate.It is able to more comprehensively react oil gas water feature in reservoir, further abundant, perfect fluid means of interpretation, explanation accuracy rate is greatly improved.Achieve good result in actual applications.
Concrete methods of realizing of the present invention is the fluid well logging oil-gas-water interpretation method based on oil gas aqua index plate, specifically comprises the following steps that
1. parameter acquisition:
1. fluid logging parameters gathers: fluid parameter collection use quantitative degasser to carry out gas is de-takes, acquisition parameter is: total hydrocarbon TG (ppm) and each hydrocarbon component C1(ppm)、C2(ppm)、C3(ppm)、iC4(ppm)、nC4(ppm)、iC5(ppm)、nC5(ppm)、nC6(ppm)、nC7(ppm)、nC8(ppm)、C6H6(ppm)、C7H8(ppm)、C7H14(ppm) content.
2. comprehensive logging parameters collection: comprehensive logging parameters uses the data that collect of comprehensive logging instrument, ROP (min/m), the pressure of the drill WOB (t), torque T ORQ (kN m), drillability index Dc (d exp) and calculate the parameter such as depth H (m) of reservoir thickness during including the brill of reflection reservoir pore space.
The above, each logging parameters collection, record step-length are 1m/1 point.
3. geological logging parameter acquisition: obtain the reflection parameter such as reservoir lithology and oiliness (fluorescence area (%)) by geological logging.
2. parameter pretreatment:
1. the fluid logging parameters quality gathered is analyzed, to owing to making up a joint, the non-formation factor such as leakage (gushing), gas cut, drilling fluid contaminated product cause abnormal the giving of gas parameter to identify and eliminate so that Parameters variation can reflect the change of fluid properties in stratum.
2. to>0 and<numerical value of 1, assignment is that 1ppm is standardized normalization.
3. acquired logging parameters carried out preferably, sort out, integrated explanation data base.
3. parameter calculates:
The gas component parameter that fluid mud logging techniques detects is a lot, chooses the gas parameter to the reaction of oil gas water is sensitive and is combined, and calculating can three derivative parameter of reaction oil air water feature very well:
1. gas index (IG) calculate: generally, gas component is based on methane, and ethane and propane are relatively conventional, and after butane, component is more rare.So selecting C1Account for the percentage ratio index as reaction reservoir gassiness of whole gas component, i.e. gas index (IG)。
Gas formula of index: IG=100*C1/ (C1+C2+C3+C4+C5+nC6+nC7+nC8)。
2. oil index (IO) calculate: under room temperature, atmospheric pressure state, pentane (C5) later component is all liquid, the isopentane (iC under room temperature, atmospheric pressure state5) boiling point is 27.8 °, pentane is (nC5) boiling point be 36.1 °, C5The later oil-containing situation in gas component instruction reservoir, C5The proportion that later gas component accounts for all gas component is more big, illustrates that in reservoir, oil-containing is more abundant, otherwise illustrates that in reservoir, oil-containing does not enrich.Select in gas component indicating oil-containing than more sensitive parameter (nC5、nC6、nC7、nC8、C7H14) and light component (C1、C2、C3) ratio as reflection oil-containing index, namely oil index.
Oil formula of index: IO=10*(nC5+nC6+nC7+nC8+C7H14)2/ (C1+C2+C3)。
3. aqua index (IW): in reservoir, moisture content is two kinds of situations: the water layer that reservoir is pure water layer and oil-containing reservoir is put into the melting pot.
A. reservoir is pure water layer.If reservoir is pure water layer inherently, oil gas is not migrated to this reservoir, then the oily index in reservoir is very low, and the component of benzene class also can be very low simultaneously, and specifically on oil gas aqua index plate, the most obvious feature is exactly IOCurve in reservoir relative to upper formation without significant change or numerical value close to 0.
B. the water layer that oil-containing reservoir is put into the melting pot.When reservoir is put into the melting pot, the oil gas being originally stored in hole is replaced by water, is now mainly water and a small amount of hydro carbons solution gas in hole.Benzene (C6H6) dissolubility in water is 1780mg/l, toluene (C7H8) it is 538mg/l for dissolubility in water, normal hexane (nC6) dissolubility in water is 9.5mg/l, normal heptane (nC7) dissolubility in water is 2.93mg/l.When oil-gas migration is subject to washing effect through reservoir or reservoir, owing to benzene and toluene both gas components are more hydrophilic relative to normal hexane, normal heptane and hexahydrotoluene component, therefore improved reservoir benzene and toluene both components account for gas ratio and change relative to the ratio regular meeting of oil reservoir phase.The ratio selecting them can as reflecting moisture index, i.e. aqua index.In practice process, due to nC6Component absolute value is relative to nC7、C6H6And C7H8Exceed a lot, so needing to one correction coefficient, in order to compare.Select the fluid mud logging gas component parameter of offset well formation testing reservoir, the cumulative each every meter of gas parameter of Effective Reservoirs thickness, try to achieve correction coefficient a according to according to formula below,
In formula, n is the constant for certain reservoir, and value is the effective thickness of this reservoir, dimensionless.Then a coefficient is substituted in the reservoir needing to analyze, obtain aqua index computing formula.
Aqua index computing formula: IW=(C6H6+C7H8)/(a*nC6+nC7)。
4. set up oil gas aqua index plate according to known formation testing conclusion:
Such as Fig. 2, selection gas index (IG), oil index (Io) and aqua index (Iw) three derivative parameters, in a graphical bar, become figure.Gas exponential curve scale range is 50-100, and oil exponential curve scale range is 0-100, and aqua index curve scale is 0-10 (can suitably magnification ratio), and three curves are linear graduation.
According to three curves section longitudinally on variation tendency and parameter area, with reference to the lithology of geological logging, oiliness (fluorescence display) situation, according to known formation testing conclusion, oil gas aqua index plate set up by comprehensive enough statistical datas.
Multilayer statistics result shows, the judgement of fluid properties meets description below standard:
Gas-bearing formation: total hydrocarbon high level, unstressed configuration, component is with C1It is main, a small amount of C2, C3;IG> 95%.
Oil reservoir: relative to upper formation, fluorescence display is good, IGIt is greatly lowered, IOSignificantly raising, both cross in formation, simultaneously IWReduce.
Oil-containing water layer: have fluorescence display, relative to top oil reservoir, total hydrocarbon value substantially reduces, IGReduce, IOSlightly raising, both are not formed and cross, generally IW<2.0;If IGAnd IODo not cross, IWRaise inconspicuous, IO> 20, reservoir mostly is the oil-containing water layer upper limit.
Water layer: relative to upper formation IGReduce, IOWithout significantly raised, IW> 2.0 and increase substantially.
Water layer: relative to upper formation nC6、nC7And C7H14Very low etc. component, IGReduce, IOWithout significantly raised, reservoir is pure water layer.
The conclusions such as the above gas-bearing formation of the present invention, oil reservoir, oil-containing water layer, water layer, refer to the well logging stage identification conclusion to reservoir, have following corresponding relation (table 1) with well logging, test result:
Table 1: index plate method interpretation conclusion and well logging, test result mapping table
5. pair target zone carries out parameter calculating:
1. reservoir thickness calculates: change according to landwaste percentage ratio, when boring, the parameter such as the pressure of the drill, moment of torsion, dc index, the thickness of reservoir is divided.Determine reservoir effective thickness according to reservoir gas parameter total gas curve form, play depth of stratum corresponding to peak for initial well depth H with abnormal show layer total gas curve1, single display peak-to-peak top or continuously high level reduce flex point place layer depth accordingly for terminating well depth H2, reservoir effective thickness HEffectivelyFor terminating the difference of well depth and initial well depth, i.e. HEffectively=H2-H1。
2. reservoir gas index, oil index, aqua index calculate: from data base extraction process, check and correction after target zone parameter, calculate three derivative parameters respectively.
6. according to criteria for interpretation plate, target zone is evaluated: the gas index calculated, oil index, aqua index are depicted as curve according to master scale, the metamorphosis of reference standard plate (Fig. 2), parameter area, in conjunction with the lithology of geological logging, oiliness (fluorescence) situation, take into full account the variation tendency of reservoir hydrocarbon abundance and superstratum, be finally completed the judgement to target zone.
The present invention takes full advantage of C5Later heavy hydrocarbon component, it is proposed to three calculate derivative parameter, utilizes the change on section is longitudinal of three parameters, in conjunction with the lithology of geological logging, oiliness (fluorescence) situation, is evaluated target zone explaining.The present invention explains that parameter calculates and database synchronization, carries out real-time interpretation, evaluation to opening reservoir;Explain that parameter can graphically illustrate, explain more directly perceived;Judge process has taken into full account gas parameter variation tendency on section is longitudinal, it was therefore concluded that more objective.
The present invention caves in Bohai Sea, Qin Nan caves in and Yellow River mouth sag 20 multiple wells is applied, interpretation and evaluation oil-gas Layer 50 layers, and wherein 45 layers are consistent with formation testing conclusion, and coincidence rate is 90%, is worth of widely use.
Fig. 1 is interpretation chart and the brief description of the present invention, and the oil gas water figure that the situation that this plate provides is all under ideal state shows, wherein water layer divides 2 kinds of situations to provide, first pure water layer, and it two is improved water layer.Change, with standard curve, the target zone not corresponded, it is necessary to comprehensively analyze according to middle specific explanations standard above if run into.
Fig. 3 is the application example of a Reservoir interpretation of the present invention.According to tracing pattern, analyzing well section is 3305-3334m, fluorescence area 35%, component C1-nC7、C7H14Increase substantially relative to base value, C6H6、C7H8Change does not become apparent, without C8.Figure road, Fig. 3 rightmost side is oil gas aqua index curve, and aqua index coefficient is a=0.5 according to offset well material computation;Gas index IGIt is reduced in reservoir minimum 61.9 by 86.9 in upper formation, oil index IORaised reservoir peak 83.3 by 3.9 in stratum, portion, and both are substantially formed and cross, aqua index IWIt is slightly decreased to 0.4 in reservoir by 1.3 in upper formation;Meeting the reservoir characteristics in interpretation chart, explanation conclusion is oil reservoir.To 3306-3333m well section formation testing, oil-producing 21.12m taken out by pump3/ d.
Fig. 4 is the application example of a water layer explanation of the present invention.According to tracing pattern, 2452-2460m is reservoir bottom water, is directly judged as water layer, and effective thickness is 2448-2452m;2448-2452m fluorescence area 10-20%, component C1-nC5、C6H6、C7H8Increasing substantially relative to base value, other component increases inconspicuous, it is possible to analyzes this reservoir and suffered transformation.Figure road, Fig. 3 rightmost side is oil gas aqua index curve, and aqua index coefficient is a=0.7 according to offset well material computation.Gas index IGBy minimum 88.6 in 95.7 decreasing value reservoirs in upper formation, oil index IOSlightly increasing, maximum 1.4, both are without crossing;Aqua index IWIncreased to the 15.6 of effective reservoir by 3.2 in upper formation;Meeting the water layer feature in interpretation chart, explanation conclusion is water layer.To 2448-2460m formation testing, produce water 24.90m3/ d, without oil gas output.
By specific embodiment, the present invention is further described above; although it is understood that; here concrete description; should not be construed as the restriction to the spirit and scope of the invention; the various amendments that above-described embodiment is made by one of ordinary skilled in the art after reading this specification, broadly fall into the scope that the present invention protects.