CN102852505A

CN102852505A - Oil production method for thin-medium thick layer super heavy oil hard-to-recover reserve

Info

Publication number: CN102852505A
Application number: CN201210357060XA
Authority: CN
Inventors: 不公告发明人
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-09-24
Filing date: 2012-09-24
Publication date: 2013-01-02

Abstract

The invention provides an oil production method for a thin-medium thick layer super heavy oil hard-to-recover reserve; and super heavy oil hard-to-recover reserves are mainly centralized in a thin-medium thick layer interbedded reservoir, the share of the reserve of the interbedded reservoir is high and the interbedded reservoir is an important area of developing follow-up successive capacity in oil thermal recovery. At present, the oil production method for the thin-medium thick layer super heavy oil hard-to-recover reserve is mainly a straight well and horizontal well steam stimulation conventional thermal recovery method, which has the defects of large steam injection pressure of a production well, short production period, low oil production, frequent sand outlet operation of an oilwell and fault block oil recovery in a low-capacity and low-efficiency stage. Mainly for geological characteristics of the thin-medium thick layer super heavy oil reservoir and conflicts in the development, the analysis of a thermal recovery mechanism is emphasized and a creative ideal is proposed in the method; therefore, a thermal recovery method for the thin-medium thick layer super heavy oil hard-to-recover reserve is designed according to the technical level of the traditional drilling and oil recovery process equipment; and the method is also applicable to medium-thick layer block-shaped super heavy oil reservoirs and has an important effect on the deep development of the super heavy oil.

Description

The super viscous crude difficulty of thin-medium bed is adopted the reserves oil production method

Technical field

This method belongs to an oil recovery technique in the super-heavy oil deposit exploitation, mainly for the difficult mining-employed reserves development and Design of super viscous crude, but also is applicable to the thick massive super-heavy oil deposit.The difficult mining-employed reserves of super viscous crude mainly concentrates in thin-medium bed alternating layers shape reservoir, and its reserves portion is high, is that ultra-thick oil thermal is adopted the follow-up important area of taking over production capacity of exploitation.

Background technology

Super thickened oil steam-stimulated Simulation on whole pay zones mode in-the thick massive oil reservoir effectively realized, but steam soak enters the middle and later periods at present, although steam flooding, SAGD etc. be compound take over development technique effectively improve in-the thick-layer oil recovery factor, the subsequent development technology still faces the bottleneck problem that can't evade: high, the indivedual fault block recoverable reserves of old liberated area natural declining rate recovery percent of reserves has surpassed 80%, fault block volume increase stable yields difficulty strengthens, in-to seek new well Effective deployment area domain space in the thick-layer reservoir narrow and small.Super heavy oil development is in the face of situation like this, next step oil recovery direction except in-thick-layer shape oil reservoir takes over development technique makes an effort, must turn to thin-on the effective exploitation of thick alternating layers shape super-heavy oil deposit.At present, the difficult mining-employed reserves of the super viscous crude of thin-medium bed accounts for more than 60% of super viscous crude gross reserves, and the stage recovery percent of reserves is less than 8%, oil production method mainly is on the conventional thermal process of straight well and horizontal well steam soak, the producing well steam injection pressure is large, and is with short production cycle, and oil production is low, the sand production operation is frequent, and the fault block oil production division is in the low yield poor efficiency stage.Therefore, make great efforts the super viscous crude difficulty of exploitation mining-employed reserves significant, the deep exploitation of super viscous crude is had far-reaching influence.

Summary of the invention

Fine study of reservoir+multi-branched high angle hole+bore hole sand control completion+segmentation fracturing+steam oil production method

Method And Principle:

This oil production method is on thermal recovery principle basis, adopt particularity and present drilling technique and the oil production technology technical characterstic of reserves geologic characteristics for super viscous crude difficulty, explore " fine study of reservoir+multi-branched high angle hole+bore hole sand control method completion+segmentation hydraulic fracturing technology+steam soak " the oil recovery by heating method of proposition.The core concept of the method is, on the Fine Reservoir Research foundation, (determine reservoir plane and longitudinal distributing law and characteristics), dispose the multi-branched high angle hole, change low (non-) permeability that reservoir causes because crude oil solidifies in segmentation fracturing mode, in the effectively basis dependence multi-branched well realization central heating supply of sand control, fast and effeciently set up the thermal field, the multi-branched high angle hole can also be realized employing the difficult mining-employed reserves of the super viscous crude of thin-medium bed from vertically reaching the plane as much as possible.The key point of technology is, enter steam soak after, because producing well is that multi-branched well and reservoir were subjected to pressure break, so the initial stage steam injection pressure can be very low, steam injection amount and steam injection mass dryness fraction require according to the reservoir producing status corresponding raising to be arranged.This technical method energy Effective Raise rate of oil production is improved because the operation of shaking out causes low yield poor efficiency production status, helps to open super-heavy oil deposit exploitation new world, contributes for further improving the final recovery percent of reserves of super viscous crude;

Mechanism describes in detail:

1) the hot physical property of crude oil.Under the formation condition, super viscous crude is in plasticity half curdled appearance, without percolation ability.Along with temperature and pressure increases, the viscosity of in-place oil reduces obviously, and this variation is reversible.Under the steam soak condition, in-place oil will experience once by plasticity half curdled appearance to sticky fluid again to the sloppy condition transition process, and along with the end cycle of handling up, the crude oil that is not plucked out of is condensed to sticky by flow regime again or even plasticity half curdled appearance.Therefore, want effectively extraction crude oil, steam injection provides heat energy necessary first preheating stratum, set up necessary thermal field, make crude oil enter flow regime, simultaneously, also to there be follow-up enough heat energy to guarantee flowable crude stream to the shaft bottom, could realizes thus the Efficient Development of super viscous crude;

2) reservoir hypotonicity.Generally speaking, the reservoir hypotonicity refers to that the reservoir degree of consolidation is high, and the cage construction degree of porosity is little, permeability is low, and this lithology refers generally to carbonate rock and low infiltration sandrock etc.But for super-heavy oil deposit, Gao Konggao oozes although reservoir belongs to, the loose cementation reservoir, and crude oil plasticity half curdled appearance causes the low or impermeability of reservoir.The impermeability of in-place oil causes under the high-temperature and high-pressure conditions steam to be difficult to inject, and affected by crude oil heat conductivility and well spacing, steam injection initial stage heating power involves less than offset well, even all wells carry out steam soak simultaneously in the same well group, can not produce heating power sympathetic response effect, the supply of producing well heating power still is equivalent to a heating, and pre-heat effect is poor.Therefore, adopt fracturing process can effectively change the low or impermeability that reservoir causes because of the crude oil shutoff; Employing adds quartz sand or ceramic fracturing liquid method can prevent effectively that super viscous crude plasticity low permeability reservoir pressure break closing phenomenon from occuring, and satisfies the steam injection requirement, favourable hole is provided, oozes condition;

The limitation of 3) simply handling up.In the steam soak thermal process, crude oil is in successively to be peeled off, similar ice sheet melting state, the super heavy oil production speed of this properties influence without the reservoir of crossing pressure break.Empirical data shows, simple steam soak wants 2～3 cycle oil wells just can enter production plateau at least, and adopt first pressure break again cyclic steam stimulation method can change oil reservoir and successively be subjected to thermal phenomenon, being similar to broken ice cube more easily melts equally than monoblock ice, help the quick formation in vapour chamber;

4) reservoir development degree.The horizontal well steam soak is mainly for medium bed oil reservoir more than 3 meters at present, and requiring has certain stability on the sandstone reservoir plane.And it is discontinuous for plane distribution, vertically upper stack is thin-in thick alternating layers shape reservoir, can only carry out the poor efficiency exploitation by straight well at present, the reserves development degree is low, the deployment of horizontal well also will cause remaining reservoir because can't the well spacing exploitation causing the reserves loss, and the multi-branched high angle hole can maximization be employed reservoir on the plane and vertically;

5) necessity of multi-branched high angle hole foundation.Under the formation condition, zones of different and different depth point stratum temperature and pressure have different, and two or three class oil reservoirs are less better than a class oil reservoir geological conditions, formation temperature is low, Crude viscosity is large, thickness in monolayer is thin, reservoir thermal communication weak effect, individual well point steam injection in the development process, the vapour chamber is difficult to form than the thick massive oil reservoir more, and the producing well weak effect of handling up is natural phenomena.Multi-branched high angle hole steam soak, it is equivalent to many mouthfuls of well while steam injections in same well point, is conducive to like this Rapid Establishment of thermal field, and can efficiently utilizes steam thermal energy;

6) operation of shaking out.Shallow, the low common problem that causes of compaction that is that reservoir buries that super viscous crude loose lithology, degree of consolidation are poor.Territory, difficult exploiting field core intersection is thin, monocycle steam radially advance distance is short, the vapour cavity volume is little in the oil reservoir, caloric receptivity is few, and therefore, the former oil mass that can flow is also fewer, compare the thick massive oil reservoir, the control of rate of oil production, producing pressure differential is improper in process of production, and the nature phenomenon of can shaking out is serious and cause frequent operation in the oil well production process, affects the oil well output same period.Multi-branched bore hole sand control completion mode, the one, in order to increase as much as possible oil reservoir heated surface area and draining passage adapting on the basis of reservoir characteristic, the 2nd, in order to adapt to present multi-branched well drilled well technology level.

Implementation step:

1. the fine study of reservoir emphasis 1) the geology subdivision of reservoir; 2) reservoir Micro-structure research; 3) sandstone reservoir space distribution rule; 4) the profit regularity of distribution;

2. the multi-branched high angle hole is disposed take the sandstone group as deployment unit, reaches the angle of inclination of longitudinally distribution characteristics deployment branch directions, quantity and high angle hole on the plane according to profit in the substratum;

3. add quartz sand or haydite is done sand control treatment, main shaft is with slot sand control cased hole completion, and multi-lateral well is with bore hole sand control method completion;

During the segmentation fracturing in fracturing fluid the adding ceramic cracking-proof closed;

5. steam soak is gone into operation, and (steam injection amount, steam injection mass dryness fraction the routine method of handling up improve intensity, are not 1+1=2, should adjust as the case may be; Producing pressure differential is unsuitable excessive in the oil recovery process, the anti-infringement sleeve pipe that shakes out).

Technical equipment

Geological research, reservoir engineering research, drilling equipment, fracturing unit, cauldron steam injection facility, oil production equipment.

Claims

1. the super viscous crude difficulty of thin-medium bed is adopted the reserves oil production method, be characterized in determining multi-branched high angle hole branch quantity and angle of inclination according to reservoir characteristic, carry out fracturing behind the bore hole sand control completion, allocate steam injection amount and steam injection mass dryness fraction according to quantity and the well segment length of multi-lateral well again, employ the super viscous crude difficulty of thin-medium bed with the steam soak form adopts reserves, realizes the quick formation of vapor chamber and effectively prevents the operation of shaking out comprehensively, improve oil well cycle oil production, finally improve the recovery percent of reserves in territory, difficult exploiting field.