CN108222910A - A kind of fixed displacement slug formula fracturing technology - Google Patents

Abstract

The invention discloses a kind of fixed displacement slug formula fracturing technologies, it includes the following steps：S1, it gets parms, judge the failure mode of reservoir rock and obtains hydraulic fracture and intrinsic fracture in the expanded configuration of underground, fracturing stratum is analyzed and determined according to measured result；S2, add the sand period for a slug by one plus sand stage and an insulating liquid stage closely followed, the multicycle alternately constructs；S3, add in the sand period plus sand stage in each slug of shale gas pressing crack construction, increase sand proportion adding the sand later stage, form a high sand ratio stage, this stage sand, than identical, enters pressure changing behind stratum than the sand with next plus sand period by observing this high sand ratio stage.The beneficial effects of the invention are as follows：It solves the problems, such as that xeothermic granite heat storage pressure break cannot be pressed off effectively to involve radius with long-time pressure break and reduce, while solve in the xeothermic conventional fracturing process of granite heat storage, the problem of fluid injection period is long, reservoir quantity is larger.

Description

A kind of fixed displacement slug formula fracturing technology

Technical field

The present invention relates to oil gas, geothermal exploration development fracturing field of engineering technology, particularly a kind of fixed displacement slug formula pressure Split technique.

Background technology

Geothermal energy resources are clean energy resourcies, and utilization are mainly realized by drilling engineering.Geothermal energy resources amount（Water） Size decides the value of utilization.In practice, because of the complexity and uncertainty of the conditions such as stratum, lead to underground heat well yield It cannot reach the set goal with temperature.Particularly in mountain area basement rock water-deficient area Development of Geothermal Resources, due to water and temperature Index is relatively low, has seriously affected the utilization of clean energy resource.It need to use artificial fracturing renovation technique that could obtain industrial hot-fluid Yield.Xeothermic granite heat storage in geothermal energy resources, reservoir granitic formation is stable, densification is harder, stress is stronger, both at home and abroad on ground Generally use is extensive in the pressing crack construction of hot well, long-time injection mode carries out pressure break.The continuous fluid injection that conventional pressure break uses Pattern has that stratum cannot effectively press off, and pressing crack construction is caused to fail, it is impossible to achieve the effect that fracturing reform increases production.Cause Usually using multilevel hierarchy acidizing fracturing process, connected under higher than rock rupture pressure in this geothermal well routine pressing crack construction It is continuous it is steps acid is injected into stratum, crack is formed in stratum, passes through the uneven corrosion shape of acid solution fracture wall surface substance Into the crack of high flow conductivity.This pressure break mode is suitable for pressure in xeothermic granite heat storage pressure break than conventional continuous pressure break Excessive, stratum presses off the problem of effect is poor, and pressure break success rate is made to increase.But the acidification of this successive steps pump liquid Pressure break pattern makes that reservoir quantity is larger in entire pressing crack construction and the fluid injection period is long, with the increase of pressure break injection number of days, due near Well area is constantly liquid filled, and fluid is more and more difficult to earth formation deep propulsion, and stratum water absorbing capacity gradually weakens, fluid wave And radius is not further added by, and construction is caused to terminate in advance, influences fracturing work effect.

Xeothermic granite geothermal energy resources are the clean energy resourcies of most application value and Exploitative potential.The xeothermic granite in China Thermal resource amount is huge, and Efficient Development has great strategic significance for China's Energy restructuring, guarantee energy security.Underground heat Xeothermic granite heat storage in resource, reservoir granitic formation is stable, densification is harder, stress is stronger, and formation condition is complicated and not true Qualitative, the effective exploitation for seriously affecting geothermal energy resources utilizes, and need to use artificial fracturing renovation technique that could obtain industrial hot-fluid production Amount.Because of the densification of granite rock, mechanical strength is higher, while under the effects that tectonic stress, thermal stress, and subsurface rock is in different Normal high three-dimensional stress state, the difficulty that conventional fracturing technology presses off rock is larger, easily causes pressing crack construction failure.

At present in the construction of petroleum exploration and development shale gas fracturing sand feeding, sand technique is usually added using slug formula, that is, is pumped After certain prepad fluid, add the sand period for a slug by one plus sand stage and an insulating liquid stage closely followed, the multicycle hands over For to the construction later stage, start continuously plus sand to construction terminates, each period sand compares previous cycle than keeping a fixed value Sand ratio has a little raising.The sand that this sand injection manner is easy to cause a certain period enters stratum pressure anomaly is caused to increase, and makes Into sand is added to stop in advance or cause construction sand plug cause construction fail.

Invention content

It is an object of the invention to solve xeothermic granite heat storage pressure break and cannot effectively press off to involve with long-time pressure break The problem of radius reduces, while solve in the conventional fracturing process of xeothermic granite heat storage, the fluid injection period is long, reservoir quantity is larger Problem provides a kind of raising granite underground heat fracturing reform success rate, reaches xeothermic granite heat storage formation breakdown transformation volume increase Needs, have boundless application prospect fixed displacement slug formula fracturing technology.

The purpose of the present invention is achieved through the following technical solutions：A kind of fixed displacement slug formula fracturing technology, it include with Lower step：

S1, target zone rock rupture pressure, fracture propagation pressure, bending friction, fracture parameters and fracturing fluid leak coefficient are obtained FRACTURING DESIGN parameter further judges the failure mode of reservoir rock and obtains hydraulic fracture and intrinsic fracture in underground Expanded configuration analyzes and determines fracturing stratum according to measured result；

S2, add sand technique using slug formula, after pumping prepad fluid, be by one plus sand stage and an insulating liquid stage closely followed One slug adds the sand period, and the multicycle alternately constructs；

In S3, step S2, add in the sand period plus sand stage in each slug of shale gas pressing crack construction, increase adding the sand later stage Sand proportion, forms a high sand ratio stage, this stage sand than the sand with next plus sand period than identical, by observing this takasago Enter pressure changing behind stratum than stage, if pressure, without apparent fluctuation, pressing crack construction can be normally carried out；If pressure is apparent Rise fluctuation, it can be determined that current formation is unfavorable for follow-up high sand ratio and sand is added to construct, then there are sand plug risks；

S4, construction later stage start continuously plus sand to construction terminate.

The present invention has the following advantages：（1）The present invention solves xeothermic granite heat storage pressure break and effectively cannot press off and grow Time pressure break involves the problem of radius reduces.（2）The present invention improves pressing crack construction success rate, increases economic benefit.（3）This Invention improves xeothermic granite underground heat fracturing reform success rate, has preferable social benefit.（4）The present invention is first directed to reservoir Specificity analysis is developed programs, then implements fracturing work step by step, finally improves the effective success rate of pressing crack construction.

Specific embodiment

The present invention will be further described below, and protection scope of the present invention is not limited to as described below：

A kind of fixed displacement slug formula fracturing technology, it includes the following steps：

S1, target zone rock rupture pressure, fracture propagation pressure, bending friction, fracture parameters and fracturing fluid leak coefficient are obtained FRACTURING DESIGN parameter further judges the failure mode of reservoir rock and obtains hydraulic fracture and intrinsic fracture in underground Expanded configuration analyzes and determines fracturing stratum according to measured result, then specific aim formulate and implement fracturing technique measure into Row operation can effectively improve pressure break efficiency and success rate；

S2, add sand technique using slug formula, after pumping prepad fluid, be by one plus sand stage and an insulating liquid stage closely followed One slug adds the sand period, and the multicycle alternately constructs；

In S3, step S2, add in the sand period plus sand stage in each slug of shale gas pressing crack construction, increase adding the sand later stage Sand proportion, forms a high sand ratio stage, this stage sand than the sand with next plus sand period than identical, by observing this takasago Enter pressure changing behind stratum than stage, if pressure, without apparent fluctuation, pressing crack construction can be normally carried out；If pressure is apparent Rise fluctuation, it can be determined that current formation is unfavorable for follow-up high sand ratio and sand is added to construct, then there are sand plug risk, but because it is increased this A high sand ratio stage liquid measure is few, the time is short, and when causing pressure oscillation, insulating liquid has been basically completed replacement, Bu Huizao in pit shaft Fail into sand construction is added to terminate or construct in advance；

S4, construction later stage start continuously plus sand to construction terminate.The technique brings the technological guidance of machine gun to pressing crack construction Property.It disclosure satisfy that the operation of shale gas pressing crack construction improves the needs of construction success rate, and application effect is notable, have boundless Application prospect.In addition the technique also solves xeothermic granite heat storage pressure break and cannot effectively press off involves half with long-time pressure break The problem of diameter reduces, while solve in the xeothermic conventional fracturing process of granite heat storage, the fluid injection period is long, reservoir quantity is larger asks Topic.

The above is only the preferred embodiment of the present invention, it should be understood that the present invention is not limited to described herein Form is not to be taken as the exclusion to other embodiment, and available for other combinations, modifications, and environments, and can be at this In the text contemplated scope, modifications can be made through the above teachings or related fields of technology or knowledge.And those skilled in the art institute into Capable modifications and changes do not depart from the spirit and scope of the present invention, then all should be in the protection domain of appended claims of the present invention It is interior.

Claims (1)

1. a kind of fixed displacement slug formula fracturing technology, it is characterised in that：It includes the following steps：

S1, target zone rock rupture pressure, fracture propagation pressure, bending friction, fracture parameters and fracturing fluid leak coefficient are obtained FRACTURING DESIGN parameter further judges the failure mode of reservoir rock and obtains hydraulic fracture and intrinsic fracture in underground Expanded configuration analyzes and determines fracturing stratum according to measured result；

S2, add sand technique using slug formula, after pumping prepad fluid, be by one plus sand stage and an insulating liquid stage closely followed One slug adds the sand period, and the multicycle alternately constructs；

In S3, step S2, add in the sand period plus sand stage in each slug of shale gas pressing crack construction, increase adding the sand later stage Sand proportion, forms a high sand ratio stage, this stage sand than the sand with next plus sand period than identical, by observing this takasago Enter pressure changing behind stratum than stage, if pressure, without apparent fluctuation, pressing crack construction can be normally carried out；If pressure is apparent Rise fluctuation, it can be determined that current formation is unfavorable for follow-up high sand ratio and sand is added to construct, then there are sand plug risks；

S4, construction later stage start continuously plus sand to construction terminate.