CN106845043A - A kind of technological process of shale gas horizontal well refracturing and method for designing - Google Patents

Abstract

The invention provides a kind of technological process of shale gas horizontal well refracturing and method for designing, it is assessed after including the monitoring of refracturing constituency Ding Jing, refracturing engineering design, refracturing field conduct and refracturing and pressure.Shale gas horizontal well refracturing provided by the present invention technological process and method for designing can ensure rationally accurately analysis and assessment after construction, can also successfully improve shale gas reservoir fracture stimulation operations effect simultaneously, gas well deliverability and recovery ratio are improved, shale gas exploitation process is further speeded up.

Description

A kind of technological process of shale gas horizontal well refracturing and method for designing

Technical field

The present invention relates to non-conventional oil natural gas yield-increasing technology field, more particularly to a kind of shale gas horizontal well repeats to press Split technological process and method for designing.

Background technology

Shale gas reservoir is the Unconventional gas Tibetan of typical low-permeability, low-porosity, and the resource is in China's oil gas money Occupy very big proportion in source.Hydraulic fracturing technology increases production as unconventionaloil pool well, the major measure of augmented injection, has been widely used In the exploitation in shale gas field.However, after actual shale air water horizontal well transformation, because drillng operation brill chance is not good, or target transformation The selection of layer position is improper, or pit shaft is impaired sleeve pipe occurs and cause to lose section extremely, or is limited to fracturing technology, construction material at that time and sets Factors influence in terms of the operations such as standby implement power, some shale gas horizontal wells fail to realize effective in the range of full pit shaft Transformation, causes scope of construction item smaller, and completion factor is poor；Also it is then the production in later stage mining to have part shale air water horizontal well Institutional selection adjusts improper, causes Reservoir Fracture gradually to be failed because flow conductivity is greatly reduced.

To promote this kind of old well of shale gas horizontal well to recapture high yield, good the economic exploitation benefit is realized, it is necessary to this kind of Old well carries out refracturing, is found in the research of the old well refracturing operation operational feasibility of this shale gas horizontal well, Domestic shale field realizes that the refracturing transformation for completing this kind of well stills need to overcome many difficult points, and refracturing selects well needs to exist Reservoir quality, brill meet dessert, completion factor, the production index, the live condition such as material and equipment, wellbore integrity and disturbance from offset wells Upper implementation considers, therefore needs a kind of temporary stall of shale gas horizontal well of design badly to refracturing process.

Shale gas horizontal well multiple fracturing technique refers to the extension for those with the production cycle, initial post-fracturing gas Body yield is not good or declines to a great extent, but possess the shale gas well of economic worth and carry out the technique of secondary fracturing volume increase, its feasibility It is：The reservoir inside horizontal stress component parallel with incipient crack declines soon than vertical component when mining is produced, Pore Pressure Power is redistributed, if induced stress change is sufficiently large, overcomes initial level deviatoric stress, then the ellipse around pit shaft and crack In shape region, the direction of minimum level stress becomes the direction of maximum horizontal stress, refracturing can again fracturing fracture or Make crack reorientation, shale gas well deliverability is returned to original state even more high.Derive both at home and abroad at present various Related solution technology, is roughly divided into the mechanical and class of temporary blocking type two：

(1) mechanical repeated fracture technique

Technique one：Original perforated interval is blocked by squeezing off, pressing crack construction operation is again carried out after perforation again.The work The optimal duplication initial completion situation of artistic skill, also can be used perforation bridging plug combined tech, but implement the method most expensive, most time-consuming Between, and complex operation, also high to cement performance requirement, the eyelet for having aerogenesis to contribute originally can also be blocked.

Technique two：Realize coiled tubing across every system operatio using even oil and downhole packer.The method is worked as using pit shaft Preceding state is constructed, and the other transformation section of packing, effectively control need the transformation section of volume increase, but operational discharge capacity is limited, water long Horizontal well construction risk is big, and tubing string has the risk blocked.

Technique three：Using tubing string milling tool production casing, under enter expandable liner to shaft bottom, then by inflatable cone from Carried in bottom to well head, expandable liner is expanded to its maximum gauge, and be fixed on suitably the bushing pipe by elastomer Position, liner swell can be realized effectively sealing original preforation tunnel, and penetrate again after new bore carries out refracturing and accurately transform again, The method can install multistage bushing pipe and realize that pit shaft is rebuild simultaneously.But high to pit shaft quality requirement, duty cycle is long, it is necessary to accurate fixed Well section of the position without contribution to yield, there are the possibility that aerogenesis contribution eyelet is blocked.

Technique four：According to existing borehole condition, under enter small external diameter sleeve pipe after cement the well again, and with small external diameter bridging plug packing Reason, the small bridging plug technique is similar with conventional stage perforation, can effective staged fracturing, but require cementing quality height, operation is all Phase is long, and original eyelet can all be shut.

Technique five：With reference to fracturing sliding bush and hydraulic perforation, using packer packing every sliding sleeve, waterpower spray are opened in pitching The mode for penetrating perforations adding is effectively insulated, and realizes being precisely controlled, but operational discharge capacity can be limited during using the technique.

(2) refracturing technique is temporarily blocked up

Technique one：The perforation of different fracturing sections is blocked using rock salt, its consuming is low, can be blocked while continuous infusion The unknown geometry part of perforation or crack, it has the disadvantage that perforated interval can not be blocked in a designated order, it is necessary to saturated brine top Replaced for liquid, and need to remove undissolved salt with coiled tubing, while the defect unknown in the presence of section is removed.

Technique two：The perforation of different fracturing sections is blocked using temporary plugging ball, the technique not only realize reduction expend, it is continuous The purpose of infusion, closure eyelet, temporary plugging ball can also be discharged or from degraded by the row of returning, but existing can not be sealed in a designated order The shortcoming of stifled perforated interval, and formation temperature conditions there are certain requirements, can occur to corrode when proppant is by passage in addition and make With, can not be blocked if eyelet is non-circular, in addition when infusion stops, temporary plugging ball can also depart from eyelet.

Technique three：Block the perforation of different fracturing sections using temporary stifled particle, the technique can also realize reducing expend, it is continuous The purpose of infusion, closure eyelet and the unknown geometry part in crack, can also be by adjusting pit shaft pH value accelerated degradation, its Shortcoming is then to be only capable of provisional Shaft repair and sealing turns layer, and by stratum, weakness is layered in itself, it is impossible to realized accurate Pressure break, and the technique also can not in a designated order block perforated interval.

Technique four：The borehole or pit shaft of different fracturing sections are blocked using gelling system, it can be realized from borehole to pit shaft Whole sealing, it is relatively accurate realize refracturing, but pressure break after need infusion acid solution well-flushing, it is understood that there may be formation contaminant problem.

At present, both at home and abroad the direction research emphasis invest temporarily stifled material and the temporarily research and development of stifled refracturing technique, Using upper, but the temporary stall of shale gas horizontal well is still faced with larger risk and challenge to refracturing：(1) gone into operation candidate well Initial reservoir pressure it is exhausted, it is necessary to go to pre-process to pressure break exhaustion, crack-induced effect is reduced with this, promote to repeat to press Split difficulty of construction increase；(2) reservoir transverse crack development, fracturing fluid is taken proppant and is occurred in net horizontal section migration process seriously Fluid loss, causes pit shaft and Kong Zhaoxia, proppant settlement rate, liquid and proppant power etc. to change, and difficulty of construction becomes Greatly；(3) due to a lack of strike angle and the closure to original perforation cluster is extended to net horizontal section internal fissure, aggravation refracturing is transformed With difficulty of construction；(4) during refracturing, because construction well is linked up with offset well, and yield is adversely affected.The above First three items (Oil/gas Well exhaustion, fluid loss, the closure of perforation cluster) are the passes of the old well refracturing reservoir reconstruction effect quality of influence Key point, and simultaneously the temporary stall of not all is all effective to refracturing.

Specific to domestic shale field, realize the refracturing transformation for completing this kind of well need to overcome many difficult points enumerate as Under：(1) horizontal segment length, most horizontal well length is in 1500-2000m, and horizontal segment length, series is more, and measure scale is big, construction period It is relatively long, it is desirable to which that temporarily the performance of stifled diverting material closure proposes requirement higher, and coiled tubing is carried across every system to even oil Requirement higher is gone out, while horizontal segment is long, eyelet is more, fluid loss is big, it is difficult that the initial stage may play pressure；(2) due to set Pipe there may be deformation and bore the wellbore conditions that plug chip causes complexity, force squeezing off and secondary well cementation high cost and operation Cycle is long, and take machine tool realize across every means there is security risk, and first pressing does not run into the complicated well of pit shaft, after Phase produces it can also happen that deformation；(3) intrinsic fracture band or pressure depleted area may produce strong induction to repeating fracturing fracture, therefore Treatment and Steering for depleted area and intrinsic fracture propose requirement higher to temporary stifled material property；(4) horizontal segment The anisotropism of itself is strong, and stress difference is big, and the difficulty that crack may be caused to turn to increases, and temporary stall is difficult to process parameter optimizing Degree is big；(5) must accurate characterization horizontal segment gas-producing profile, determine that aerogenesis contributes well section and invalid eyelet, implement perforations adding well section and Emphasis transformation well section etc..

The content of the invention

In order to solve above-mentioned shortcoming and defect, it is an object of the invention to provide a kind of shale gas horizontal well refracturing Technological process and method for designing, specific aim solve the wrecked point of institute, realize fracture zone efficient isolation and pressure break office section it is effective Turn to, the non-feed liquor office section of transformation first pressing, new perforations adding office's section and the inadequate office's section of first pressing transformation degree, or split in original waterpower Realize that old seam is newborn on the basis of seam, open the measures such as sealed fracture, secondary extension, enhancing flow conductivity to improve discouraged face Product, or the new seam of extension after the presence and long-term production of first pressing back-up sand seam, are redistributed, in its vicinity using pore pressure The transposition of two horizontal stress sizes of appearance and the commutation of stress field, the inclination angle and azimuth of new seam deviate from always to some extent The chance of seam, is not transforming the new seam of area's extension, increases the area that loses heart, or by perforations adding mode or press off the non-feed liquor of first pressing Borehole, increases new fractured interval, improves reservoir development degree, increases production capacity.

To reach above-mentioned purpose, the present invention provides a kind of technological process of shale gas horizontal well refracturing and method for designing, It is comprised the following steps：

(1) refracturing constituency Ding Jing：Based on construction early stage comprehensive evaluation theory, with shale gas horizontal well reservoir matter Volume index, completion factor, the production index are important analytical parameters, while considering to include spacing and ground slabbing between well bore condition, well Seam links up the influence in interior situation, reservoir quality index is relatively high in selected target Oil/gas Well block, completion factor is relatively low, The production index is of a relatively high, and well bore condition completely and between well influences small, the shale gas horizontal well conduct for possessing refracturing potentiality Object from temporary stall to refracturing；

(2) refracturing engineering design：Construction early stage Fitting Analysis are carried out after determining well, refracturing model is set up, recognized Emphasis transforms region, selects perforations adding scheme and technique, preferably includes fracturing fluid, proppant and temporarily blocks up material and is produced in interior pressure break Product material, reasonable selection includes the pressure break instrument including packing mode, real-time monitoring and production analyzing and diagnosing mode or measure, Optimizing construction parameter and infusion pattern, and carry out pit shaft preparation, dead chick hole, close measure, across every entering under instrument, diverting material Input and infusion technique adjustment prediction scheme；

(3), refracturing field conduct：During site operation, should try one's best and be constructed according to given design scheme, also need Live actual optimization design of hydraulic fracturing scheme is combined, using last, temporarily stifled including temporary plugging ball and diverting agent, temporarily stifled particle and temporary blocking poawer Fiber and diverting agent in the stifled material closure of interior Degradable temporary pressure break eyelet or crack, realize fracture zone efficient isolation and Effective steering of pressure break office section, the non-feed liquor office section of transformation first pressing, new perforations adding office's section and the inadequate office's section of first pressing transformation degree, enters And realize that turning to shunting and horizontal wellbore uniformly transforms, and reaches the purpose for turning to shunting；

(4) assessed after refracturing monitoring and pressure：Refracturing construction real-time monitoring is carried out, so that real-time instruction is repeated The real-time adjustment of pressure break and analysis, the row's of returning test after real-time Crack Monitoring result, pressure after evaluation stage in later stage completes to include pressure Monitoring result, creation data monitoring result provide real-time Crack Monitoring after pressure in the assessment and prediction of interior every data target Material reaches and more accurately understand the mesh that underground aerogenesis contributes situation with including the data binding analysis including continuous production logging 's.

In the described method, it is preferable that the determination methods higher of reservoir quality index described in step (1) are：

To including including total content of organic carbon, porosity and permeability, or to including including air content, reservoir pressure Relevant parameter reservoir higher carries out geologic data statistical analysis in target Oil/gas Well block, with including including ultimate recovery Parameter is foundation, is given higher than the region of average ultimate recovery weight higher, to make up the reservoir of pressure break failure and get through not Oil reservoir region through employing, the storage of shale gas horizontal well of the layer position in sweet spot region is walked in combination with the upper track in plane and longitudinal direction Layer distribution situation, choose target Oil/gas Well block in hydrocarbon in given depth reservoir relative abundance Oil/gas Well higher, And have preferably stabilization initil output and cumulative production situation with reference to whether possessing after offset well transformation, it is final to determine that reservoir quality refers to Number target well higher.

In the described method, it is preferable that the relatively low determination methods of completion factor described in step (1) are：

According to including well completion type, fracturing fluid volume, proppant volume, pressure break length, pressure break hop count, perforating parameter and applying Work discharge capacity is in interior related completion parameter, well stimulation parameter, analysis completion parameter, Production development and refracturing technique and ginseng The relation of several, preferably goes out to exist not transforming well section, adds the relatively low completion factor in target Oil/gas Well block of sand intensity relatively low Shale gas reservoir horizontal well.

In the described method, it is preferable that the determination methods higher of the production index described in step (1) are：

Water section plane test, assessment different times, different production systems, different well heads are produced according to including production logging, aerogenesis Throughput contribution under pressure is in interior parameter, the preferably serious uneven well of throughput contribution section, cluster, or is given birth to for Oil/gas Well mining Great representatively a well during product, the data based on its creation data are used to substitute long-term production data and are analyzed, preferably because System is improper causes the equivalent production index not high for later stage production, but the prediction preferable Oil/gas Well of production capacity, finally the mesh to preferably going out Mark well carries out ultimate recovery and productive potentialities prediction and the analysis of causes, using initial production is high, cumulative production is low well as life Produce index horizontal well higher.

In the described method, it is preferable that the creation data includes production system, gas and oil when well head pressure.

In the described method, it is preferable that refracturing field conduct is comprised the following steps in step (3)：

1) actual conditions according to constructed shale gas reservoir horizontal well complete pit shaft lead to, scrape, clean-out service, perforating job；

2) squeezing test, if pressure is less than the 60-70% of previous operation pressure, first using temporarily stifled material to pressure exhaustion Area is blocked, and the plugging effect of temporarily stifled material is judged using real-time Crack Monitoring result, and according to the raising feelings of operation pressure Condition determines closure number of times, double delivery material operation；

3) pressure to be onstructed is gradually promoted to during close to previous operation pressure, just stops the closure operation of pressure depleted area, is opened Beginning carries out formal plus sand operation, at the same Crack Monitoring result in real time, and fracture strike is judged according to the monitoring result, instruct now Field real-time adjustment；

Plus during sand operation, if microseism Crack Monitoring result judges the development of fracture strike single-blade or repeats covering microseism Case point, then repeat step 2) delivery temporarily block up material movement, continue to construct after delivery, observe real-time Crack Monitoring result and judge Temporarily stifled material plugging effect is until fracture strike development normally, continues step 3)；

Plus during sand operation, early stage takes slug formula plus sand, if site operation pressure stability and pressure window abundance is controllable System, then adjustment adds sand model, and the later stage tries one's best and takes continuously plus based on sand mode；

4) it is that perforation is made during next section of construction is prepared or repeated the above steps 1) to be hot on the trail of the temporarily stifled material closure pressure break stage Industry；

5) repeat the above steps 2) to step 4) work flow be sequentially completed described in the multiple fracturing engineering design of ballast and press Split job content.

In the described method, it is preferable that the method that the refracturing construction real-time monitoring is used includes microseism pressure Split monitoring method, optical fiber production borehole logging tool method and tracer monitoring method.

In the described method, it is preferable that the equipment that the microseism Fracturing Monitoring method is used includes that underground or ground are micro- Earthquake equipment.

According to specific embodiment of the present invention, in the process, refracturing constituency Ding Jing specifically includes following step Suddenly：Data Collection → initial diagnosis analysis (primary election) → in-depth analysis (selected) → select repetition well.

(1) Data Collection includes：Collect completion essential information, capacity data, production pressure and yield, action data, pressure Split construction, pressure after report, microseism result, petrophysical data, well logging, special well logging, well log interpretation, geology physical characteristic, Other related datas such as geomechanical data, specify reservoir quality index, completion factor, the production capacity of the target oil gas block The criterion of index.Data for these requirements must as much as possible collect complete, and when needing to be analyzed offset well, Also can be collected according to data above type.

(2) initial diagnosis analysis (primary election)：Lay particular emphasis on and analyze oil gas well completion index and production in the target oil gas block Exponential case, mainly has implement general plan analysis, potential yield potential to evaluate two aspects.Needed to solid when implement general plan is analyzed The globality of well and sleeve pipe, completion limitation are kept a close eye on, and the cementing quality and sleeve pipe condition that its reason has been can attach most importance to Multiple pressure break provides safety assurance, and sleeve pipe and pipe aperture then limit instrument and enter implementation under completion tool again；It is latent evaluating Yield potential when then need to be evaluated according to operating analysis model, production matched curve (linear flow and double logarithmic curve) etc. and receive Beneficial rate, specifies average product, the parameter such as the production index and fluidised form.In addition, according to well spacing, formation fracture between Oil/gas Well and offset well Situations such as communication, to reject and influence big Oil/gas Well between presence or potential well.

(3) (selected) is analysed in depth：Oil/gas Well reservoir quality index, completion in the analysis target oil gas block is laid particular emphasis on to refer to Number situation, mainly there is evaluating reservoir, volume analysis, Geology geomechanics analysis, sensitivity analysis, production forecast analysis, net present value (NPV) meter Point counting analysis etc., understands the geology such as propped fracture area size, stress profile distribution, biggest principal stress direction aspect parameter, while Analysis proppant and the sensitive parameter such as liquid system type, proppant density and concentration, initial crack starter location and operational discharge capacity enter Row matching and optimizing research, accomplish precisely analysis as far as possible.

With the productive potentialities of reservoir rock and drilling well, completion, production system due to causing shale gas well deliverability not good Correlation, therefore when refracturing selects well to optimize and design, it is necessary to fine description pit shaft bores reservoir situation of meeting, and is repeated in identification pit shaft Pressure break emphasis adds sand to transform region, considers perforations adding scheme etc., i.e.,：The main points of well are selected to should be selection from economy point analysis Reservoir quality is good (reservoir quality index is higher than criterion), completion factor is less than criterion, and predicts that the production index is high In the shale gas reservoir horizontal well of criterion, while avoiding the well increase difficulty of construction that there is disturbance from offset wells.Wherein, wherein, storage Layer performance figure, completion factor, production index quality criterion according to reservoir quality in selected oil gas well area, completion and Depending on the concrete condition of production, decision method is known to the skilled person.

Specific well selecting principle is as follows：

(1) reservoir quality index is joined mainly around total content of organic carbon, porosity, permeability in target Oil/gas Well block etc. Number is higher, or the parameter reservoir higher such as air content, reservoir pressure carries out geologic data statistical analysis, and with ultimate recovery Be foundation Deng parameters obtained, give higher than the region of average ultimate recovery weight higher, with make up pressure break failure reservoir and Get through without the oil reservoir region employed, shale gas level of the layer position in sweet spot region is walked in combination with the upper track in plane and longitudinal direction The reservoir distribution situation of well, hydrocarbon is in given depth reservoir relative abundance oil higher in selection target Oil/gas Well block Gas well, and have preferably stabilization initil output and cumulative production situation with reference to whether possessing after offset well transformation, finally determine reservoir Performance figure target well higher.

(2) completion factor determines refracturing technique and parameter, it is intended to analyze completion parameter, Production development and they it Between relation, the data to completion parameter, well stimulation parameter are related, such as well completion type, fracturing fluid volume, proppant body The parameter such as product, pressure break length, pressure break hop count, perforating parameter, operational discharge capacity, have do not transform well section, plus the well of sand low strength be Good target well.

Fracturing reform technology is in the shale gas horizontal well of relative early stage, because early stage understanding and reforming technology are received , largely there is selection process, segmentation, construction material and scale in limit, set becomes or offset well pressure is altered, and the later stage returns row, bores plug, goes out The defect that situations such as sand is processed, causes in design and site operation parameter less than average the intensity of rebuilding；If having in work progress bright It is aobvious to press the well for altering offset well, needed in the selection of refractured well prudent, it is necessary to consider the influence to offset well and refracturing Crack-induced may influence the Expected Results of refracturing.

For domestic current shale gas horizontal well level, so that the shale gas level of bridging plug staged fracturing completion can be bored Well, its bore plug all right, pit shaft hole condition is relatively good can be used as the first-selection of target well；For being set using big orifice bridging plug Shale gas horizontal well, because underground situation is relative complex, it is proposed that not as the target well of shale gas horizontal well refracturing；It is right In the old well of shale gas horizontal well, implementation can bore some wells of bridging plug staged fracturing, due to the well that cannot be pumped perforation and abandon Section, or implement some wells of big orifice bridging plug staged fracturing, due to the well that bridging plug is realized mechanical packing and abandoned cannot be set Section, can be as the target well of refracturing.

(3) quality of production index explanation first pressing result, the target well that the well that initial production is high, cumulative production is low has been, Its analysis is to combine production logging, aerogenesis to produce water section plane test, assessment different times, different production systems, different well head pressures Under throughput contribution, pay the utmost attention to carry out the well of condition of production assessment and analysis, preferably those throughput contributions section, cluster be not seriously Equal well, or great representatively a well when being produced for those Oil/gas Well minings, based on its creation data data (including The parameters such as production system, gas-oil ratio, well head pressure), it is used to substitute long-term production data and is analyzed, preferably made because the later stage produces Degree is improper to cause the equivalent production index not high, but the prediction preferable Oil/gas Well of production capacity, and finally the target well for preferably going out is carried out most Whole recovery ratio and productive potentialities prediction and the analysis of causes, the well that initial production is high, cumulative production is low is higher as the production index Horizontal well.

On the basis of comprehensive assessment, shale gas horizontal well reservoir quality index, completion factor, the ternary of the production index are set up Comprehensive estimation method, for reservoir quality index high, low completion factor, the production index high well, as the head of refractured well Select target.The reservoir relatively uniform for rock characteristic, completion factor is higher, and production capacity is higher, if Oil/gas Well is fully pressed Split, then production capacity is higher, and production capacity is relatively low, the also low Oil/gas Well of completion factor then can be used as refracturing potential target well, its Construction chance of success is larger.

In the process, refracturing engineering design specifically includes following steps：

(1) after well is determined in constituency, it is necessary to which target well is analyzed, data before FRACTURING DESIGN are collected, implements refracturing side Case is designed, and following action is carried out in proper order：

1) early stage recognizes limited, geological model and updates, i.e.,：

Bore and meet repositioning → the portray near wellbore of reservoir stress model → set up refracturing model → simulation now Refracturing transformation, Optimum Fracturing design and capability forecasting.

2) first pressing scale is not enough, do not transform region, i.e.,：

Fine description → refracturing dessert selection, identification emphasis transformation region → dead chick hole process program are carried out to pit shaft Design → increase transformation scale → effective steering technique and parameter optimization.

3) former fracture condudtiviy is not enough or loses, i.e.,：

Proppant type and Combinatorial Optimization → raising proppant consumption and sanding concentration → promotion crack are turned to, and improve crack Complexity → liquid combination, infusion model-based optimization.

(2) every Scheme Choice classification during conceptual design

1) refracturing model is selected, implements optimization with prediction：This working set rock physics, geomechanics, waterpower pressure Split and be integrated with reservoir model, in order to understand relation between initial completion and reservoir depletion degree and its to repeating to press The influence split.Final target be confirm refracturing after the increased baseline of production capacity, for preferably with evaluate refracturing target Well.

2) reservoir characteristics analysis, selects perforations adding scheme：The rock mechanics of Main Analysis reservoir, geology, fracture pattern and oil Fluid behaviour is hidden, suitable fracturing fluid, proppant and perforating scheme are selected with this.If it is determined that refracturing candidate well or neighbour Well, then can combine the imaging of its borehole wall and core analysis understands Oil/gas Well geology characteristic in depth, comprising reservoir lithology, complexity and storage Layer rock behavio(u)r.By the anisotropy and rock brittleness of sound wave measuring well curve appreciable levels well section reservoir, according to lithology quality Realize that perforation is positioned, perforations adding is mainly in areas of high potential.

3) fracturing fluid type is selected, optimizes liquid combination：By the complexity point in dimensionless fracture condudtiviy and crack Analysis, based on the reservoir characteristics and to greatest extent requirement of raising production capacity selects refracturing type.Reservoir plasticity is stronger, and it should The anisotropy of power is more obvious, easier during pressure break to form main seam, and these main seams are then the important channel of hydrocarbon production, therefore is Increase sanding scope during transformation, using crosslinked fracturing fluid seem very necessary；Reservoir fragility is stronger, its stress it is each to different Property it is weaker, got over during pressure break and advantageously form complicated seam, sand should be taken using low viscous fracturing fluid promote secondary fracturing stitch net formation. At present, universal common recognition is the complexity that crosslinking or high viscosity fracturing fluid can suppress crack.For medium to high fragility and Most of unconventionaloil pools of complexity are hidden, and most of refracturings take sand and improve answering for secondary fracturing crack using slippery water Miscellaneous degree.

3) proppant type is selected, optimizes infusion pattern：The selection of refracturing scheme and proppant is required in reservoir Optimized on the basis of physical property, be applicable less 100 mesh or 70/140 mesh proppant.Reservoir plasticity is more strong more advantageously forms Plane suture, needs high concentration bulky grain proppant to participate in reservoir reconstruction, wants to form microcrack seam net in plastic formation, Then require that the major fracture for accounting for dominant advantage possesses certain flow conductivity, while needing bulky grain proppant and high concentration proppant Booster action, fracturing fluid used must be then linear or cross-linked gel.

4) packing mode, optimization temporarily stifled combination are selected：The i.e. available mechanical packing of the full pit shaft refracturing transformation of net horizontal section (i.e.：The packing of screen casing, packer and sliding sleeve), it is also possible to (temporary plugging ball+diverting agent, temporarily stifled particle+temporary blocking poawer are last, temporary temporarily to block up material Stifled fiber+diverting agent etc.) closure.Due to reasons such as proppant sedimentation and reservoir exhaustions, supported according to slippery water and bulky grain Refracturing reservoir reconstruction is implemented in agent, and effective transformation area of reservoir can be increased using mechanical packing.Because major part is repeated The old well of pressure break can form minimum drag passage area after lack of energy, if not dealing carefully with, most refracturings transformations These regions will be concentrated mainly on, cause refracturing to fail.Using the temporarily stifled material of favorable sealing property, envelope is fully able to These areas of low pressure are blocked up, the reconstruction scope of refracturing is improved, usage amount, combination of its specific temporarily stifled material etc. are necessary According to actual conditions, comprehensively formulated with reference to indoor thing mould evaluation result and digital-to-analogue analog result.

5) selection real-time monitoring and production analyzing and diagnosing mode：Increasingly focus on pressing construction during shale gas horizontal well development The monitoring of power and discharge capacity, by taking micro-seismic monitoring (MSM) as an example, can be by receiving the seismic wave fed back during refracturing, analysis is split Slit state and plugging effect, further learn reservoir reconstruction degree and distribution situation；Or with distributed temperature sensing (DTS) system Monitoring is used in combination, the fiber optic cables transmission that distributed temperature sensing (DTS) system is used, and is used to monitor pit shaft near zone Temperature change, both are combined using can more preferably evaluate fracture extension situation, while clearly influenceing the reservoir properties of fracture extension Parameter；Most accurate SRV values, fracture half-length are obtained in that and along the feed liquor number of clusters on net horizontal section by the analysis；Or use Tracer monitoring technique, selects the different liquid tracer of feature during staged fracturing, and stratum is together pumped into fracturing fluid, Then carried to ground by formation fluid during the row of returning, using the different characteristic of tracer light intensity value in different liquids, to output stream In body institute's tracer-containing classified, assay and calculating, the light intensity value of usual tracer with produce the quantum of output of liquid into just Than, and physicochemical properties in production fluid are stable, therefore change in concentration (light intensity value) of the tracer in discharge opeing is returned It is the important evidence for judging each interval output situation and contribution, also for volume fracturing pilot production effect assessment provides help.

(3) main contents and thinking is specifically transformed

In the specific embodiment of the invention, the fracturing reform specifically includes following steps：

1) pit shaft led to, scraped, after clean-out service, being implemented perforations adding well section, perforating parameter, being specified emphasis transformation region, Totally temporary stall is taken to refracturing technique, it is advanced using coiled tubing for the shale gas horizontal well that sleeve pipe has deformed Row perforations adding operation, disposably shoots away perforations adding well section；

2) squeezing test, if pressure is relatively low, is first blocked using temporarily stifled material to pressure depleted area, is pressed according to construction Power determines closure number of times, after pressure is gradually increasing, proceeds by plus sand operation, is hot on the trail of temporarily stifled material closure pressure break office section；

3) main body construction is generally carried out plus sand using low viscous slippery water, and glue is processed as the seam of making of construction early stage, every time Pressure break is divided to two sections, and centre is delivered temporarily stifled material and turned to, single hop liquid measure control 1000-1500 side, single hop proppant (100 mesh, 40/ 70 mesh, 30/50 mesh) 100-120t is controlled, specific specification used and sand amount distribution palpus basis can be according to specific regulations；

4) block up that particle+temporary blocking poawer is last using temporary plugging ball+diverting agent, temporarily, temporarily block up fiber+diverting agent etc. temporary stifled diverting material group Close, used in amounts will carry out after shaft drum form fits software the Fitting Calculation, empirical data being blocked up with reference to temporary, determine concentration and consumption；

5) sand model is added according to site operation pressure condition, early stage takes slug formula plus sand, the later stage tries one's best and takes continuous adding (it is judged as newly stitching based on slug plus sand) based on sand mode；

6) according to real-time Crack Monitoring result, judge temporarily stifled material plugging effect and fracture strike, instruct scene to adjust in real time It is whole.If examination is squeezed and cannot play pressure before pressure, temporary plugging ball closure pressure depleted area or low-pressure area are can use, the later stage can realize the weight of low-pressure area Multiple transformation.

In the process, refracturing field conduct is comprised the following steps：

1) actual conditions according to constructed shale gas reservoir horizontal well complete pit shaft lead to, scrape, clean-out service, perforating job；

2) squeezing test, if pressure less than previous operation pressure 60-70% and its it is following if first using temporarily stifled material pair Pressure depleted area is blocked, and the plugging effect of temporarily stifled material is judged using real-time Crack Monitoring result, and according to operation pressure Raising situation determine closure number of times, double delivery material operation；

3) pressure to be onstructed is gradually promoted to during close to previous operation pressure, after just stopping the closure operation of pressure depleted area, Formal plus sand operation is proceeded by, at the same Crack Monitoring result in real time, and fracture strike is judged according to the monitoring result, guidance Live real-time adjustment；

Plus during sand operation, if microseism Crack Monitoring result judges the development of fracture strike single-blade or repeats covering microseism Case point, then repeat step 2) delivery temporarily block up material movement, continue to construct after delivery, observe real-time Crack Monitoring result and judge Temporarily stifled material plugging effect is until fracture strike development normally, continues step 3)；

Plus during sand operation, early stage takes slug formula plus sand, if site operation pressure stability and pressure window abundance is controllable System adjustment plus sand model, the later stage try one's best and take continuously plus based on sand mode；

4) it is that perforation is made during next section of construction is prepared or repeated the above steps 1) to be hot on the trail of the temporarily stifled material closure pressure break stage Industry；

5) repeat the above steps 2) to step 4) work flow be sequentially completed described in the multiple fracturing engineering design of ballast and press Split job content.

In the embodiment of the invention, the refracturing field conduct includes：Certain well generally sealed using SRFR+ SRFR generally turns layer, and construction procedure is that all old all new office position → beginnings of eyelet → perforation of infusion SRFR sealings are pressed for the first time Split infusion operation → infusion SRFR and block the office → repetition 3 and 4 until completing all measures → infusion replacement → wait degraded, return Row → go into operation.

In the embodiment of the invention, the refracturing field conduct includes：Certain well generally sealed using SRFR+ Classification turns layer, construction procedure be infusion SRFR seal all old eyelets → with tubing transmission or abrasive perforating penetrate out first game → The closure of pressure break office → infusion SRFR → with tubing transmission or office → repetitions 4 and 5 completion of abrasive perforating next stage → pressure break All measures → infusion is replaced → waited and degrades, the row of returning → operation.

In the embodiment of the invention, the refracturing field conduct includes：Certain well generally turns layer using SRFR, Construction procedure is that disposable perforation all perforations addings office positions → carry out first time fracturing work → infusion SRFR block the office → repetition Step 2 and 3 completes all pressure breaks → infusion replacement → wait degraded, the row of returning → operation.

Wherein, SRFR used is east treasured unicorn development in science and technology (Beijing) Co., Ltd's patented product code name (Patents Shen Number 201410049875.0) please, it does not exist any Special Significance.

In the process, refracturing monitoring with press after assess and comprise the following steps：

Refracturing is monitored and the monitoring and analysis for analyzing the fracturing effect before and after refracturing is assessed after pressure, mainly Including the row's of returning test monitoring, creation data monitoring etc. after real-time Crack Monitoring, pressure after pressure, and refracturing completion data are combined, To repeat pressing crack construction well carry out accurately, the understanding of system, assessment with predict.Major technique and equipment work involved by the part Have：

(1) microseism Fracturing Monitoring technology mainly has underground microseism Crack Monitoring, shallow well (ground) microseism crack to supervise Monitoring technology is surveyed and inclined, fracture condudtiviy, geometric shape, complexity and its side are obtained after being used to real-time monitoring pressure break All multi informations such as position, assess operation effectiveness.Micro-seismic monitoring result can not completely characterize reservoir and truly transform degree, continuous production Well logging can more accurately understand underground aerogenesis contribution situation, and emphasis transformation region can be further assessed before pressure.

(2) optical fiber production borehole logging tool technology, capital equipment is distributed acoustics sensor (DAS) and distributed temperature sensing (DTS).Production logging technology can be derived that aerogenesis production profile, assess fracturing effect.Should be it is a technical advantage that being capable of the company of realization Continuous uninterrupted monitoring, draws continuous production profile.The pit shaft and generic array producing well for entering big orifice bridging plug under being applied to are surveyed The complicated pit shaft situation that well instrument cannot be tackled.

(3) tracer monitoring technique, is that the different liquid tracer of feature is selected during staged fracturing, with fracturing fluid Stratum is together pumped into, is then carried to ground by formation fluid during the row of returning, it is different using tracer light intensity value in different liquids Characteristic, is classified, assay and calculating to institute's tracer-containing in produced fluid.Generally, the light intensity value of tracer and product The quantum of output of liquid is directly proportional, and physicochemical properties in production fluid are stable, therefore concentration of the tracer in discharge opeing is returned Change (light intensity value) is the important evidence for judging each interval output situation and contribution, also for volume fracturing pilot production effect is commented Valency provides help.

The invention provides a kind of technological process of shale gas horizontal well refracturing and method for designing, the pass of its successful implementation Key be refracturing constituency Ding Jing, temporary stall to multiple fracturing technique, and aid in microseism real-time monitoring with adjustment；The method The efficient isolation of fracture zone and effective steering of pressure break office section, the non-feed liquor office section of transformation first pressing, new perforations adding office section can be realized And the inadequate office's section of first pressing transformation degree, or realize that old seam is newborn on the basis of original hydraulic fracture, open closure and split Seam, secondary extension, the measure of enhancing flow conductivity etc. are improving discouraged area；Or in the presence and long-term life of first pressing back-up sand seam The new seam of postpartum extension, is redistributed using pore pressure, in its vicinity the transposition of two horizontal stress sizes of appearance and stress field Commutation, the inclination angle and azimuth of new seam deviate from the chance of old seam, do not transforming the new seam of area's extension to some extent, and increase is let out Gas area；Or by perforations adding mode or the borehole of the non-feed liquor of first pressing is pressed off, and increase new fractured interval, improve reservoir and employ Degree, increases production capacity；

Additionally, the method can ensure rationally accurately analysis and assessment after construction, while successfully improving shale gas reservoir pressure break Stimulation work effect, improves gas well deliverability and recovery ratio, further speeds up shale gas exploitation process.

Brief description of the drawings

The temporary stall of shale gas reservoir horizontal well that Fig. 1 is provided by the embodiment of the present invention is to refracturing technological process and design Method flow diagram.

Specific embodiment

In order to be more clearly understood to technical characteristic of the invention, purpose and beneficial effect, in conjunction with detail below Embodiment and Figure of description technical scheme is carried out it is described further below, but it is not intended that to it is of the invention can The restriction of practical range.

Embodiment 1

A kind of technological process of shale gas horizontal well refracturing and method for designing are present embodiments provided, its flow chart is as schemed Shown in 1, from figure 1 it appears that the technological process and method for designing are comprised the following steps：

(1) well step is determined in shale gas horizontal well refracturing constituency

(1) Data Collection：Certain target Oil/gas Well block collect all old wells of shale gas horizontal well completion essential information, Report, microseism result, petrophysical data, survey after capacity data, production pressure and yield, action data, pressing crack construction, pressure Other related datas such as well, special well logging, well log interpretation, geology physical characteristic, geomechanical data, specify the target HYDROCARBON-BEARING REGION The reservoir quality index of block, completion factor, the criterion of the index of production capacity, while collecting the information material of related offset well；

(2) initial diagnosis：The data obtained according to more than carry out implement general plan analysis to all wells, just select casing cementing Quality and sleeve pipe integrality are good, can bear refracturing operation, and oil, casing inner diameter allow down fracturing tool or again completion The Oil/gas Well of instrument, then according to operating analysis model, production matched curve (linear flow and double logarithmic curve) etc., evaluates oil gas The earning rate of well, potential yield potential evaluation analysis is carried out to screening well, specifies every mouthful of average product of well, the production index and stream The parameters such as state, i.e., go out completion factor less than criterion according to upper type roughing, and the production index is higher than the page of criterion Rock air water horizontal well, and according to situations such as well spacing, formation fracture are linked up between Oil/gas Well and offset well, reject shadow between presence or potential well The big Oil/gas Well of sound；

(3) analyse in depth：For the Oil/gas Well by initial diagnosis, according to existing well completion type, fracturing fluid volume, support The parameters such as agent volume, pressure break length, pressure break hop count, perforating parameter, operational discharge capacity carry out pressing crack construction sensitive parameter matching first And optimizing research, preferably go out the Oil/gas Well that there is situations such as not transforming well section, add sand low strength, while to these Oil/gas Well institutes The parameter such as total content of organic carbon, porosity, permeability is higher in reservoir area, or the parameter such as air content, reservoir pressure compared with Reservoir high carries out geologic data statistical analysis and evaluating reservoir, volume analysis, Geology geomechanics analysis, sensitivity analysis, product Amount forecast analysis, net present value calculation analysis etc., understand propped fracture area size, stress profile distribution, biggest principal stress direction Etc. geology aspect parameter, and with parameters obtaineds such as ultimate recoveries as foundation, give higher than average ultimate recovery region more Weight high, to make up the reservoir of pressure break failure and get through without the oil reservoir region employed, in combination with the upper track in plane and longitudinal direction Reservoir distribution situation of the layer position in the shale gas horizontal well of sweet spot region is walked, hydrocarbon in target Oil/gas Well block is chosen In given depth reservoir relative abundance Oil/gas Well higher, and there is the initial product of preferably stabilization with reference to whether possessing after offset well transformation Amount and cumulative production situation, i.e., preferably go out completion factor less than criterion according to upper type, and reservoir quality index is higher than The Oil/gas Well of the block criterion.

(2) shale gas horizontal well refracturing engineering design step：

(1) on the basis of the limited understanding of early stage, the repositioning of reservoir is met to boring, updates geological model, portray pit shaft Neighbouring stress model now, sets up refracturing model, and the transformation of simulation refracturing, Optimum Fracturing are designed and capability forecasting, and Confirm the increased baseline of production capacity after refracturing；

(2) it is not enough for first pressing scale, do not transform region, fine description must be carried out to pit shaft, according to borehole wall imaging and Core analysis understands the Oil/gas Well geology characteristic such as reservoir lithology, complexity and reservoir rock in depth, analyze reservoir rock mechanics, Geology, fracture pattern and reservoir fluid characteristic, specify the selection of refracturing dessert, and identification emphasis transforms region, and by sound wave The anisotropy and rock brittleness of log data appreciable levels well section reservoir, realize that perforation is positioned, perforations adding master according to lithology quality Dead chick hole process planning completed in areas of high potential, increase transformation scale, effective optimization turns to technique and parameter；

(3) not enough for the former fracture condudtiviy or in the case of of losing, suitable fracturing fluid, proppant type, group are selected Close and consumption and infusion model-based optimization, improve proppant consumption and sanding concentration, promote crack to turn to, improve crack complexity journey Degree.Main body construction is generally carried out plus sand using low viscous slippery water, and glue is processed as the seam of making of construction early stage, the control of single hop liquid measure 1000-1500 side, single hop proppant (100 mesh, 40/70 mesh, 30/50 mesh) control 100-120t, specific specification used and sand amount Distribution palpus basis can be according to specific regulation, plus sand model, according to site operation pressure condition, early stage takes slug formula plus sand, later stage Take as far as possible continuously plus (be judged as newly stitching based on slug plus sand) based on sand mode；

(4) the temporarily stifled material confinement mode of selection favorable sealing property, is fully able to block area of low pressure, improves and repeats to press The reconstruction scope split, usage amount, combination of its specific temporarily stifled material etc. must be according to actual conditions, with reference to indoor thing mould Evaluation result and digital-to-analogue analog result are comprehensively formulated, and mainly block up that particle+temporary blocking poawer is last, temporarily block up fiber with temporary plugging ball+diverting agent, temporarily + diverting agent etc. temporarily stall to (proprietary material that above-mentioned temporarily stifled diverting material is used for this area, commercially available) based on combination of materials, This case is illustrated from temporarily stifled particle+temporary blocking poawer end combination, and its relevant design parameter list is as shown in table 1.

The temporary stall of table 1 is to material design parameters table

(5) during shale gas horizontal well development, real-time monitoring and production analyzing and diagnosing mode are main with micro-seismic monitoring (MSM) Real-time Crack Monitoring result, judges temporarily stifled material plugging effect and fracture strike, live real-time adjustment is instructed, if nothing is squeezed in examination before pressure Method rise pressure, then can use temporary plugging ball closure pressure depleted area or low-pressure area, the later stage can realize low-pressure area repetition transformation, while with point Cloth TEMP (DTS) system monitoring combining assessment fracture extension situation, while clearly influenceing the reservoir properties of fracture extension Parameter, most accurate SRV values, fracture half-length are obtained in that and along the feed liquor number of clusters on net horizontal section by the analysis.

(3) shale gas horizontal well refracturing field conduct step：

(1) actual conditions according to constructed shale gas reservoir horizontal well complete pit shaft lead to, scrape, clean-out service, perforating job；

(2) when test is squeezed in the stage one, operation pressure is less than the 60-70% of previous operation pressure and its following, use Material is temporarily blocked up using the mesh of 100 mesh+7 repeat to deliver points for 6 times and complete pressure depleted area and blocked；

(3) plugging effect of temporarily stifled material is judged using real-time Crack Monitoring result, while observing pressure to be onstructed gradually It is promoted to during close to previous operation pressure, just stops the closure operation of pressure depleted area；

(4) during the stage two implements the construction of normal refracturing plus sand operation, plus sand job execution, microseism Crack Monitoring Result judges that fracture strike occurs single-blade development micro-seismic event point, and adjustment supplement 100 mesh+7 mesh temporarily blocks up material to single-blade in time Crack is opened to be blocked；

(5) refracturing construction plus sand operation are continued, observation microseism Crack Monitoring result judges that fracture strike does not occur Covering micro-seismic event point is developed or repeated to single-blade, illustrates that real-time Crack Monitoring result judges that temporarily stifled material plugging effect is good, Continue plus sand construction, the mesh of 100 mesh+7 of delivering in hot pursuit temporarily blocks up the material closure pressure break stage for next section of construction is prepared；

(6) the repeating for above sequence number (5) of stage three to stage eight, specific data are referred to shown in table 2 below, shale gas Horizontal well refracturing job execution terminates.

Table 2 temporarily blocks up diverting material practice of construction job parameter table

(4) assessed after the monitoring of shale gas horizontal well refracturing and pressure

In evaluation stage in later stage, monitor after real-time Crack Monitoring, pressure after pressing, creation data is monitored by the row's of returning test for collection and analysis Data information, and assessment and prediction respectively combined point the data such as real-time Crack Monitoring data after pressure and continuous production logging Analysis, specifies the purpose that underground aerogenesis contributes situation.

Claims (6)

1. a kind of technological process of shale gas horizontal well refracturing and method for designing, it is comprised the following steps：

(1) refracturing constituency Ding Jing：Based on construction early stage comprehensive evaluation theory, referred to shale gas horizontal well reservoir quality Number, completion factor, the production index are important analytical parameters, while consideration includes spacing and formation fracture ditch between well bore condition, well Lead to the influence in interior situation, reservoir quality index is relatively high in selected target Oil/gas Well block, completion factor is relatively low, production Index is of a relatively high, and well bore condition completely and between well influences small, possesses the shale gas horizontal well of refracturing potentiality as temporarily stifled Turn to the object of refracturing；

(2) refracturing engineering design：Construction early stage Fitting Analysis are carried out after determining well, refracturing model is set up, emphasis is recognized Transformation region, selects perforations adding scheme and technique, preferably includes fracturing fluid, proppant and temporarily blocks up material in interior pressure break product material Material, reasonable selection includes the pressure break instrument including packing mode, real-time monitoring and production analyzing and diagnosing mode or measure, optimization Construction parameter and infusion pattern, and carry out pit shaft preparation, dead chick hole, close measure, across every entering under instrument, the input of diverting material And infusion technique adjustment prediction scheme；

(3), refracturing field conduct：During site operation, should try one's best and be constructed according to given design scheme, also need knot Close live actual optimization design of hydraulic fracturing scheme, using including temporary plugging ball and diverting agent, temporarily stifled particle and temporary blocking poawer are last, temporarily block up fiber Pressure break eyelet or crack are blocked in the stifled material of interior Degradable temporary with diverting agent, efficient isolation and the pressure break of fracture zone is realized Effective steering of office's section, the non-feed liquor office section of transformation first pressing, new perforations adding office's section and the inadequate office's section of first pressing transformation degree, Jin Ershi Turn now to shunting and horizontal wellbore is uniformly transformed, reach the purpose for turning to shunting；

(4) assessed after refracturing monitoring and pressure：Refracturing construction real-time monitoring is carried out, so as to real-time instruction refracturing Real-time adjustment and analysis, the row of returning tests and monitors after Crack Monitoring result, pressure in real time after evaluation stage in later stage completes to include pressure As a result, creation data monitoring result interior every data target assessment and prediction, by real-time Crack Monitoring data after pressure and Including the data binding analysis including continuous production logging, reach and more accurately understand the purpose that underground aerogenesis contributes situation.

2. method according to claim 1, it is characterised in that reservoir quality index determination methods higher are：

To including including total content of organic carbon, porosity and permeability, or to including the target including air content, reservoir pressure Relevant parameter reservoir higher carries out geologic data statistical analysis in Oil/gas Well block, with including the parameter including ultimate recovery It is foundation, gives higher than the region of average ultimate recovery weight higher, makes up the reservoir of pressure break failure and get through without dynamic Oil reservoir region, the reservoir point of shale gas horizontal well of the layer position in sweet spot region is walked in combination with the upper track in plane and longitudinal direction Cloth situation, hydrocarbon is in given depth reservoir relative abundance Oil/gas Well higher in selection target Oil/gas Well block, and joins Examine after offset well transformation whether to possess and have preferably stabilization initil output and cumulative production situation, it is final determine reservoir quality index compared with Target well high.

3. method according to claim 1, it is characterised in that the relatively low determination methods of the completion factor are：

According to including well completion type, fracturing fluid volume, proppant volume, pressure break length, pressure break hop count, perforating parameter and construction row Amount in interior related completion parameter, well stimulation parameter, analysis completion parameter, between Production development and refracturing technique and parameter Relation, preferably go out to exist not transforming well section, plus the relatively low page of the completion factor relatively low in target Oil/gas Well block of sand intensity Rock Horizontal Wells For Gas Reservoirs.

4. method according to claim 1, it is characterised in that production index determination methods higher are：

Water section plane test, assessment different times, different production systems, different well head pressures are produced according to including production logging, aerogenesis Under throughput contribution in interior parameter, the preferred serious uneven well of throughput contribution section, cluster, or when being produced for Oil/gas Well mining Great representatively a well, the data based on its creation data are used to substitute long-term production data and are analyzed, preferably because of the later stage Production system is improper to cause the equivalent production index not high, but the prediction preferable Oil/gas Well of production capacity, finally the target well to preferably going out Ultimate recovery and productive potentialities prediction and the analysis of causes are carried out, the well that initial production is high, cumulative production is low is referred to as production Number horizontal well higher.

5. method according to claim 1, it is characterised in that refracturing field conduct includes following step in step (3) Suddenly：

1) actual conditions according to constructed shale gas reservoir horizontal well complete pit shaft lead to, scrape, clean-out service, perforating job；

2) squeezing test, if pressure is first entered using temporarily stifled material less than the 60-70% of previous operation pressure to pressure depleted area Row closure, the plugging effect of temporarily stifled material is judged using real-time Crack Monitoring result, and is determined according to the raising situation of operation pressure Surely number of times, double delivery material operation are blocked；

3) pressure to be onstructed is gradually promoted to during close to previous operation pressure, just stops the closure operation of pressure depleted area, start into Row is formal plus sand operation, at the same Crack Monitoring result in real time, and fracture strike is judged according to the monitoring result, instruct scene in fact When adjust；

Plus during sand operation, if microseism Crack Monitoring result judges the development of fracture strike single-blade or repeats covering micro-seismic event Point, then repeat step 2) delivery temporarily block up material movement, continue to construct after delivery, observe real-time Crack Monitoring result and judge temporarily stifled Material plugging effect is until fracture strike development normally, continues step 3)；

Plus during sand operation, early stage takes slug formula plus sand, if site operation pressure stability and pressure window are sufficient controllable, Adjustment plus sand model, the later stage try one's best and take continuously plus based on sand mode；

4) it is perforating job during next section of construction is prepared or repeated the above steps 1) to be hot on the trail of the temporarily stifled material closure pressure break stage；

5) repeat the above steps 2) to step 4) work flow be sequentially completed pressure break described in the multiple fracturing engineering design of ballast and make Hold in the industry.

6. method according to claim 1, it is characterised in that the method bag that the refracturing construction real-time monitoring is used Include microseism Fracturing Monitoring method, optical fiber production borehole logging tool method and tracer monitoring method.