CN1987044A - Method for adding hydraulic fractured well gel breaker - Google Patents

Abstract

A method for additionally adding the degelating agent in hydraulic fracturing well in order to decrease the damage of hydraulic fracturing liquid to oil stratum and increasing the hydraulic fracturing effect features that the concenhtration of degelating agent is different for different phases. An equation for calculating the concentration of degelating agent is also disclosed.

Description

Method for adding hydraulic fractured well gel breaker

Technical field:

The present invention relates to down-hole, oil recovery field, oil field rock and creep into the used a kind of method of back pressure break, belong to a kind of method for adding hydraulic fractured well gel breaker.

Background technology:

After low permeability oil field fracturing construction finishes, fracturing fluid need reduce viscosity as early as possible, so that the row of returning, minimizing is to reservoir damage caused, so broken colloidality can be the key that influences pressure break supporting crack flow conductivity, the selection of gel breaker and use are the preferred important steps of fracturing fluid additive, are the bases of improving fracturing effect.After pressing off the stratum, the thermal field is from closely to far in the crack, temperature from low to high, last identical with formation temperature, simultaneously fracturing fluid finish take the sand task after, need fast broken glue, so prior art is evenly appended gel breaker, gel breaker is excessive in the time of certainly will causing beginning, makes the broken in advance glue of fracturing fluid cause the pressure break sand plug; Later stage gel breaker amount is few, causes brokenly glue not thorough, pollutes the stratum, influences fracturing effect.

Summary of the invention:

In order to solve the deficiency in the background technology, the purpose of this invention is to provide a kind of method for adding hydraulic fractured well gel breaker, this method can reduce the injury of fracturing fluid to reservoir, improves fracturing effect.

The technical solution used in the present invention is: this method for adding hydraulic fractured well gel breaker comprises the following steps:

(1), the adding of gel breaker divides prepad fluid, load fluid and three stages of displacement fluid;

(2), prepad fluid stage gel breaker addition is m ₁, load fluid stage gel breaker addition is m ₂, displacement fluid stage gel breaker addition is m ₃

(3), the gel breaker joining day in prepad fluid stage is x ₁, the gel breaker joining day in load fluid stage is x ₂, the gel breaker joining day in displacement fluid stage is x ₃

(4), breaker concentration is ascending, it is y that the prepad fluid stage adds breaker concentration ₁, it is y that the load fluid stage adds breaker concentration ₂, it is y that the displacement fluid stage adds breaker concentration ₃, the concentration of gel breaker is calculated as follows:

y＝0.0019e ^0.349×9

Y---breaker concentration (w/w%) wherein, mass percent; X---accumulates the pressure break time, minute.

The invention has the beneficial effects as follows: the technical program is according to peripheral Depth of Oil Well, and the part formation pressure is low, and the fracturing fluid recovery (backflow) difficulty reaches the characteristics of fractured layer thermal field greatly, and the breaker concentration that adds during fracturing fluid recovery (backflow) is ascending, i.e. y=0.0019e ^0.349x, the gel breaker amount is little when beginning brokenly glue, can not make the broken in advance glue of fracturing fluid cause the pressure break sand plug; Later stage gel breaker amount is many, and broken glue is thorough, does not pollute the stratum, and fracturing effect is good.

Description of drawings:

Fig. 1 is N16-25 well gel breake supplementary proceedings figure.

The specific embodiment:

The invention will be further described below in conjunction with embodiment:

Embodiment 1, the prepad fluid in pressure break, load fluid, each stage of displacement fluid are calculated corresponding gel breaker addition according to concentration and fracturing fluid consumption in different time sections, draw out breaker concentration curve over time with the excel form, as accompanying drawing 1, utilize the method for adding the exponential function Trendline to draw this formula y=0.0019e ^0.349x

According to formula y=0.0019e ^0.349xCalculate big 84-92 well and big 80-88 well gel breake concentration and quantity.

Big 84-92 well gel breake appends table 1

Stage	X accumulated time (min)	M consumption (kg)	Y concentration (%)
				Prepad fluid	15	0.1	0.003
3	0.1	0.005
			4		0.8	0.008
Load fluid	5	0.3					0.011
			7	1.2	0.022
	9.5	3.3				0.052
			12	7.5	0.125
	14	11.6				0.252
			15	8.2	0.357
	Displacement fluid	16.1				17.3	0.524

Big 80-88 well gel breake appends table 2

Stage	X accumulated time (min)	M consumption (kg)	Y concentration (%)
				Prepad fluid	2	0.5	0.004
4	0.2	0.008
			6		0.7	0.015
Load fluid	7	1.3					0.022
			8.8	2.9	0.041
	9.8	2.7				0.058
			11.8	2.7	0.117
	14.6	10.2				0.310
			15.5	9.8	0.425
	Displacement fluid	16.6				20.6	0.623

Embodiment 2, be example with Longnan 16-25 well, prepad fluid stage breaker concentration 0.002～0.01%, total addition 1.26kg; Load fluid stage concentration 0.018～0.1%, addition are 16.53kg; Displacement fluid stage concentration 0.2%, addition are 8.1kg.

Table 3

Longnan 16-25 well gel breake supplementary proceedings table

Stage	The x time (min)	M consumption (kg)	Y concentration (%)
				Prepad fluid	0	0	0.002
1.75	0.16	0.004
			3.5		0.26	0.006
5.25	0.37	0.008
			7		0.47	0.01
Load fluid	8.45	0.6					0.018
			9.9	0.92	0.025
	11.35	1.25				0.033
			12.8	1.58	0.04
	14.73	2.9				0.06
			16.67	4.06	0.08
	18.6	5.22				0.1
			Displacement fluid	20.4	8.1		0.2

Press the back effect analysis:

1, press the back effect assessment:

Longnan 16-25 well presses the back effect to see the following form, and can draw from table, and pressure break is efficient to be 100%.Press the back obvious effect of increasing production.

Longnan 16-25 well fracturing effect table 4

Pound sign	Pressure break thickness (m)	Effective thickness (m)	Before the pressure break			After the pressure break
									Production fluid (t/d)	Produce oil (t/d)	Producing fluid level (m)	Production fluid (t/d)	Produce oil (t/d)	Producing fluid level (m)
			Longnan 16-25	5	3.8	1.6	1.6	1388							10.5	4.7	800
Difference												+9.1	+3.1	588

2, press the back effect analysis:

Gel breaker is according to formula y=0.0019e ^0.349xUse " taper " adding method, it is ascending that promptly gel breaker adds concentration, both helped prepad fluid and load fluid section fracturing fluid and kept high viscosity, being beneficial to fracturing fluid makes seam and takes sand, help pressing the fast broken glue in back to return row thoroughly again, reduce the injury of fracturing fluid, improved fracturing effect the stratum.

Claims (1)

1, a kind of method for adding hydraulic fractured well gel breaker is characterized in that: comprise the following steps:

(1), the adding of gel breaker divides prepad fluid, load fluid and three stages of displacement fluid;

(2), prepad fluid stage gel breaker addition is m ₁, load fluid stage gel breaker addition is m ₂, displacement fluid stage gel breaker addition is m ₃

(3), the gel breaker joining day in prepad fluid stage is x ₁, the gel breaker joining day in load fluid stage is x ₂, the gel breaker joining day in displacement fluid stage is x ₃

(4), breaker concentration is ascending, it is y that the prepad fluid stage adds breaker concentration ₁, it is y that the load fluid stage adds breaker concentration ₂, it is y that the displacement fluid stage adds breaker concentration ₃, the concentration of gel breaker is calculated as follows:

y＝0.0019e ^0.34x

Y-breaker concentration (w/w%) wherein, mass percent; X---accumulates the pressure break time, minute.