CN105733528A

CN105733528A - Low-density fluorescent drilling fluid for drilling shale

Info

Publication number: CN105733528A
Application number: CN201610136671.XA
Authority: CN
Inventors: 白杨; 石晛; 王平全; 陈婷; 陶鹏; 敬玉娟; 余冰洋; 杨萍; 胡亚琴
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2016-03-11
Filing date: 2016-03-11
Publication date: 2016-07-06
Anticipated expiration: 2036-03-11
Also published as: CN105733528B

Abstract

The invention relates to low-density fluorescent drilling fluid for drilling shale for shale gas exploitation. The low-density fluorescent drilling fluid can overcome instability of the well wall and avoid hydration collapse of shale stratum. The technical scheme includes that the drilling fluid comprises, by weight, 1.5-2.5 g of sodium carbonate, 30-50 g of bentonite for drilling fluid, 10-20 g of PAC-141, encapsulating agent FBY-502-4 for drilling fluid, 10-20 g of anti-high-temperature anti-salt filtrate reducer WSG, 0.3-0.8 g of viscosity reducer JN for drilling fluid, 30-50 g of highlight calcium carbonate BZ3500, 10-20 g of lubricant SYP for drilling fluid, 30-50 g of anti-collapse blocking agent FDT-150 for drilling fluid, 20-30 g of emulsion paraffin JLRP-40, and 900-1000 g of tap water. The drilling fluid is prepared by adjusting system pH into 8.5 by 40% of alkaline liquid, and adding barite to adjust the density to 1.20 g/cm<3>. The drilling fluid is low in environmental pollution, has excellent rheological property, low fluorescence, and high blockage reducing property, and is used for shale drilling.

Description

One creeps into shale low-density fluorescence drilling fluid

Technical field

The present invention relates to a kind of for shale gas exploitation creep into shale low-density fluorescence drilling fluid, be particularly suitable for micro- Creeping into of the long net horizontal section of shale of fracture development.

Background technology

The commonly used oil base drilling fluid of shale gas well the most both at home and abroad, owing to oil base drilling fluid can improve hygroscopicity shale Capillary pressure, prevents the drilling fluid intrusion to shale, by using oil base drilling fluid and synthetic base drilling fluid, and can be effectively The problem solving hole instability.In terms of reply shale gas horizontal well wellbore stability, it is external for using oil base drilling fluid system Current maximally effective measure.The shale formation educated even if employing oil base drilling fluid, fracture or layer are got a haircut, it is necessary to strengthening envelope Stifled, to reduce the pressure transmission (block fluid passage) that liquid entrance stratum is caused.Oil base drilling fluid is in lubrication, anti-sticking and fall resistance Effect aspect has the advantage that water-base drilling fluid is incomparable, drags pressure problem when can avoid slide drilling, and this is also that it is wide The basic reason place of general application.But owing to oil base working solution makes low permeability pay and the wettability modification of gas-bearing formation cause wound Evil, makes reservoir permeability be greatly lowered, thus reduces oil well output.Indoor core experiment shows, when core is changed into by hydrophilic During oleophylic, its recovery ratio is dropped to 17% by 51%.Therefore, oil base drilling fluid should be used cautiously to bore at low permeability pay and open product Layer, when especially having emulsifying agent, surfactant in oil base drilling fluid.

The pluses and minuses water-base drilling fluid advantage comparing oil base drilling fluid has: 1. environmental protection；2. natural gas leaching easily finds；3. temperature Less to rheology impact；4. cost is relatively low；5. meeting leakage to be easily processed, shortcoming has: 1. borehole wall stability is poor；2. heat is steady Qualitative relatively poor, it is easy to high temperature gel；3. resistance tocrocking poor (solid phase and CO₂、H₂S gaseous contamination), maintenance processes workload Greatly；4. lubrication anti-sticking scarce capacity.Therefore, develop a kind of novel water-based drilling fluid that can be suitably used for shale formation and substitute oil base brill Well liquid can solve the problem that the problem such as wellbore stability, reservoir pollution is then the key technology of current shale gas drilling well, is also domestic and international page The difficult point place of rock drilling well.

Summary of the invention

It is an object of the invention to: borehole well instability problem during in order to overcome currently used water-base drilling fluid to creep into shale formation, Suppression shale formation aquation is caved in, and can effectively block the micro-nano slit of shale, creeps into shale low-density for this special offer one Fluorescence drilling fluid.

In order to achieve the above object, the present invention is by the following technical solutions: one creeps into shale low-density fluorescence drilling well Liquid, is characterized in that preparing the raw materials used component of this drilling fluid and content is, wherein mass unit is gram:

It is 8.5 with the NaOH solution regulation system pH value that mass percentage concentration is 40%；Liquid-tight with barite regulation drilling well Spend to 1.20g/cm³。

The preparation method that the present invention is a kind of creeps into shale low-density fluorescence drilling fluid is:

Water temperature is risen to 70 DEG C by the tap water first measuring 1000 grams, adds 30-50 under low speed 500r/min electric stirring Gram drilling fluid bentonite, stir 10min, add 1.5-2.5 gram of Na₂CO₃It is stirred for 30min, prehydration under normal temperature and pressure 24h；10-20 gram of extracting and cutting agent PAC-141 stirring 6min is added again, at low speed 500r/ under high speed 8000r/min electric stirring Add 2-4 gram of drilling fluid coating agent FBY-50 under min electric stirring and stir 5min, add 10-20 gram of high-temperature resisting and salt-resisting fall filter Lose agent WSG-099 and stir 5min, add 0.3-0.8 gram of viscosity depressant for drilling fluid JN-1Z and stir 5min；It is subsequently adding 30-50 gram High light calcium carbonate BZ-3500 stirs 15min, adds 10-20 gram of lubricant for drilling fluids SYP-2 and stirs 5min, adds 30-50 gram Drilling fluid stirs 5min with anti-collapse sealing agent FDT-150, adds 20-30 gram of emulsified wax JLRP-40 and stirs 10min；Finally use NaOH add water be configured to 40% alkali liquor, regulation system pH is 8.5.Barite regulating density of drilling liquid is added after stirring 30min To 1.20g/cm³Stir 1 hour, prepare this low-density fluorescence drilling fluid.

Drilling fluid bentonite, Na used by above-mentioned preparation method₂CO₃, extracting and cutting agent PAC-141, drilling fluid coating agent FBY- 50, high-temperature resisting and salt-resisting fluid loss additive WSG-099, viscosity depressant for drilling fluid JN-1Z, high light calcium carbonate BZ-3500, drilling fluid profit Lubrication prescription SYP-2, drilling fluid anti-collapse sealing agent FDT-150, emulsified wax JLRP-40, barite are on market sale product, Strictly by industry standard or enterprise's mark inspection when purchasing, eligible could use.Specifically it is shown in Table 1.

1 low-density fluorescence drilling fluid base stock detail list of table

The shale drilling fluid system phase crept into shale low density water base drilling fluid with used at present that the present invention provides Ratio has the advantages that: 1. to compare oil base drilling fluid environmental pollution little for this drilling fluid；2. there is stronger suppression closure energy Power；3. caving pressure can effectively be reduced；4. fluorescent material can follow the trail of the process of creeping at any time；5. cost is relatively low；6. leakage is met It is easily processed.

Detailed description of the invention:

Below in conjunction with instantiation, the present invention is further illustrated

Example 1: a kind of compound method creeping into shale low-density fluorescence drilling fluid.

Water temperature is risen to 70 DEG C by the tap water first measuring 1000 grams, adds 30 grams under low speed 500r/min electric stirring Drilling fluid bentonite, stirring 10min adds 1.5 grams of Na₂CO₃It is stirred for 30min, under normal temperature and pressure after prehydration 24h, at height 15 grams of extracting and cutting agent PAC-141 stirring 6min are added under speed 8000r/min electric stirring, then under low speed 500r/min electric stirring Add 2 grams of drilling fluids coating agent FBY-50 and stir 5min, add 10 grams of high-temperature resisting and salt-resisting fluid loss additive WSG-099 stirrings 5min, adds 0.5 gram of viscosity depressant for drilling fluid JN-1Z and stirs 5min, adds 40 grams high smooth calcium carbonate BZ-3500 and stirs 15min, Add 10 grams of lubricant for drilling fluids SYP-2 and stir 5min, add 40 grams of drilling fluids and stir with anti-collapse sealing agent FDT-150 5min, adds 25 grams of emulsified wax JLRP-40 and stirs 10min, add water with NaOH be configured to 40% alkali liquor, regulation system pH is 8.5.Barite regulating density of drilling liquid is added to 1.20g/cm after stirring 30min³Stir 1 hour, prepare this low-density fluorescence Drilling fluid.

Example 2: use XGRL-2 type roller heating stove that drilling fluid system of the present invention has been carried out rolling determination of recovery rates.

2 low-density fluorescence drilling fluid systems of table roll response rate experimental result

Drilling fluid composition	Experiment condition	Reclaim quality (g)	The response rate (%)
				Clear water+50g red beds soil	105℃/16h	5.54	11.08
Low-density fluorescence drilling fluid system+50g red beds soil	105℃/16h	48.32	96.64

Note: 1) red beds soil is Sichuan red beds soil landwaste, shale is appeared and is appeared for long 7 shale, is 6～10 mesh, the response rate For crossing the 40 mesh response rate；2) in table, result is 2 experimental data averages.

3 low-density fluorescence drilling fluid system linear expansion experimental results of table

Note: 1) core is that drilling fluid bentonite (soil with slurry) is compressing；2) after filtrate is system heat 105 DEG C/16h of rolling The filtrate extruded；3) in table, result is 2 experimental data averages.

Tested from table 2, the rolling response rate of this low-density fluorescence drilling fluid of table 3 and linear expansion rate, roll and reclaim Rate reaches more than 95%, and 16h linear expansion rate only has 22.46% to have the preferably dispersion of suppression aquation and dilatancy.

Example 3: use the rolling of XGRL-2 type roller heating stove Continuous Heat, test this low-density fluorescence drilling fluid heat stability Effect.

4 low-density fluorescence drilling fluid system Evaluation of Thermal Stabilities of table

5 low-density fluorescence drilling fluid system temperature resistance merit ratings of table

Understood system by the thermal stability results of table 4 to glue, cut with filter loss along with the increase of rolling time changes little, tool There is good heat stability.Glue under the conditions of 150 DEG C from this low-density fluorescence drilling fluid knowable to the temperature resistance capacity experimental of table 5 and cut greatly Amplitude reduction, HTHP dehydration increase considerably, but can maintain rheological characteristic, HTHP dehydration under the conditions of 120 DEG C well, can temperature resistance 120℃。

Claims

1. creep into a shale low-density fluorescence drilling fluid, it is characterized in that: prepare the raw materials used component of this drilling fluid and contain Amount is, its mass unit is gram:

It is 8.5 with the NaOH solution regulation system pH value that mass percentage concentration is 40%；With barite regulating density of drilling liquid extremely 1.20g/cm³。

2. a compound method for drilling fluid as claimed in claim 1, is characterized in that: first measure the tap water of 1000 grams by water temperature Rise to 70 DEG C, under low speed 500r/min electric stirring, add the drilling fluid bentonite of 30-50 gram, stir 10min, add 1.5-2.5 gram of Na₂CO₃It is stirred for 30min, prehydration 24h under normal temperature and pressure；Add under high speed 8000r/min electric stirring again 10-20 gram of extracting and cutting agent PAC-141 stirring 6min, adds 2-4 gram of drilling fluid coating agent under low speed 500r/min electric stirring FBY-50 stirs 5min, adds 10-20 gram of high-temperature resisting and salt-resisting fluid loss additive WSG-099 and stirs 5min, adds 0.3-0.8 gram of drilling well Liquid thinner JN-1Z stirs 5min；It is subsequently adding 30-50 gram high smooth calcium carbonate BZ-3500 and stirs 15min, add 10-20 gram Lubricant for drilling fluids SYP-2 stirs 5min, adds the anti-collapse sealing agent FDT-150 of 30-50 gram of drilling fluid and stirs 5min, adds 20-30 gram of emulsified wax JLRP-40 stirs 10min；Finally add water with NaOH be configured to 40% alkali liquor, regulation system pH is 8.5, add barite regulating density of drilling liquid after stirring 30min to 1.20g/cm³Stir 1 hour, prepare this low-density fluorescence Drilling fluid.