CN105860942A

CN105860942A - Well wall film formation anti-sloughing drilling fluid

Info

Publication number: CN105860942A
Application number: CN201610247897.7A
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: 2016-04-20
Filing date: 2016-04-20
Publication date: 2016-08-17

Abstract

The invention relates to well wall film formation anti-sloughing drilling fluid applied to shale gas exploitation and shale drilling. The well wall film formation anti-sloughing drilling fluid solves the problem of wellbore instability, restrains hydrated collapse of a shale stratum and effectively plugs micro-nanometer holes of shale. The well wall film formation anti-sloughing drilling fluid is characterized by being prepared from raw materials of the content by mass unit of gram: 900-1000 of tap water, 30-60 of bentonite for drilling fluid, 1.5-2.5 of Na2CO3, 2-4 of high-efficiency thickening agent 80A51 for the drilling fluid, 10-20 of anti-compound salt filtrate reducer YJB-II for the drilling fluid, 10-15 of anti-sloughing filtrate reducer GSP for the drilling fluid, 10-20 of anti-sloughing lubricant K-31, 10-20 of film forming agent CMJ-1 for the drilling fluid and 15-20 of restraining anti-sloughing agent ZNP-I for the drilling agent. NaOH and water are prepared into alkali liquor with a mass percentage concentration as 40%, a system pH is adjusted as 8.5, the raw materials are stirred for 30 minutes, and a system density is aggravated to 1.20g/cm<3> through weighting agent barite for the drilling fluid, and the drilling fluid can be obtained. The drilling fluid system is small in environmental pollution, good in rheological property, strong in restraining and plugging capacity and applied to shale drilling.

Description

A kind of borehole wall film forming caving-preventing drilling fluid

Technical field

The present invention relates to a kind of borehole wall film forming caving-preventing drilling fluid for creeping into shale, be particularly suitable for microcrack and grow The creeping into of the long net horizontal section of shale.

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, for this kind of anti-collapse drilling well of borehole wall film forming of special offer Liquid.

In order to achieve the above object, the present invention is by the following technical solutions: a kind of borehole wall film forming caving-preventing drilling fluid, its feature Being to prepare 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 of the present invention a kind of borehole wall film forming caving-preventing 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；Under high speed 8000r/min electric stirring, add 2-4 gram of drilling fluid high-effective viscosity agent 80A51 again stir 5min, low Add the anti-complex salt fluid loss additive YJB-II of 10-20 gram of drilling fluid under speed 500r/min electric stirring and stir 5min, add 10- 15 grams of drilling fluid anti-collapse dehydration agent GSP stir 5min, add 10-20 gram of anti sinking lubricant K-31 and stir 5min, add 10- 20 grams of drilling fluid film former CMJ-1 stir 20min, are subsequently adding 15-20 gram of inhibiting and anti-sloughing agent for drilling fluid ZNP-I stirring 10min；Finally add water with NaOH be configured to 40% alkali liquor, regulation system pH is 8.5.Add barite after stirring 30min to adjust Joint drilling fluid density is to 1.20g/cm³Stir 1 hour, prepare this borehole wall film forming caving-preventing drilling fluid.

Drilling fluid bentonite, Na used by above-mentioned preparation method₂CO₃, drilling fluid high-effective viscosity agent 80A51, drilling fluid use Anti-complex salt fluid loss additive YJB-II, drilling fluid anti-collapse dehydration agent GSP, anti sinking lubricant K-31, drilling fluid film former CMJ-1, inhibiting and anti-sloughing agent for drilling fluid ZNP-I, barite are on market sale product, when purchasing strictly by industry standard or Enterprise's mark inspection, eligible could use.Specifically it is shown in Table 1.

1 borehole wall film forming caving-preventing drilling fluid base stock detail list of table

What the present invention provided creeps into shale low fluorescence and sinking-proof type drilling fluid and existing used shale drilling fluid system phase Ratio has the following advantages: 1. have stronger suppression shut-off capacity；2. cave-in is prevented；3. temperature resistance ability is strong；4. dirty to environment Contaminate little, have good rheological characteristic；5. outside the borehole wall, form protective layer, block crack, stratum, preferably reservoir protec-tion etc..

Detailed description of the invention:

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

Example 1: the compound method of a kind of borehole wall film forming caving-preventing 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, stirs 10min, adds 1.5 grams of Na₂CO₃It is stirred for 30min, prehydration 24h under normal temperature and pressure；Again at height Add 4 grams of drilling fluids high-effective viscosity agent 80A51 under speed 8000r/min electric stirring and stir 5min, at low speed 500r/min electricity The lower anti-complex salt fluid loss additive YJB-II of 20 grams of drilling fluids that adds of dynamic stirring stirs 5min, adds 20 grams of drilling fluid anti-collapses Dehydration agent GSP stirs 5min, adds 10 grams of anti sinking lubricant K-31 and stirs 5min, adds 20 grams of drilling fluid film former CMJ-1 Stirring 20min, adds 15 grams of inhibiting and anti-sloughing agent for drilling fluid ZNP-I and stirs 10min；Finally add water with NaOH and 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 borehole wall film forming caving-preventing drilling fluid.

Example 2: use XGRL-2 type roller heating stove that the borehole wall film forming caving-preventing sloughing drilling fluid system of the present invention is rolled Dynamic determination of recovery rates.

Table 2 rock sample rolls the response rate (150 DEG C/16h)

3 borehole wall film forming caving-preventing sloughing drilling fluid system linear expansion experimental results of table

Tested from table 2, the rolling response rate of 3 borehole wall film forming caving-preventing sloughing drilling fluid systems of table and linear expansion rate, rolling The dynamic response rate reaches more than 99%, and 16h linear expansion rate only has 18.17%, illustrates that this borehole wall film forming caving-preventing sloughing drilling fluid system has There is preferable rejection.

Claims

1. a borehole wall film forming caving-preventing drilling fluid, is characterized in that: prepare the raw materials used component of this drilling fluid and content is, its matter Amount 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。

Water temperature is risen to 70 DEG C by the tap water the most first measuring 1000 grams, adds 30-50 gram under low speed 500r/min electric stirring Drilling fluid bentonite, stir 10min, add 1.5-2.5 gram of Na₂CO₃It is stirred for 30min, prehydration 24h under normal temperature and pressure； Under high speed 8000r/min electric stirring, add 2-4 gram of drilling fluid high-effective viscosity agent 80A51 again stir 5min, at low speed Add the anti-complex salt fluid loss additive YJB-II of 10-20 gram of drilling fluid under 500r/min electric stirring and stir 5min, add 10-15 Gram drilling fluid anti-collapse dehydration agent GSP stirs 5min, adds 10-20 gram of anti sinking lubricant K-31 and stirs 5min, addition 10-20 Gram drilling fluid film former CMJ-1 stirs 20min, is subsequently adding 15-20 gram of inhibiting and anti-sloughing agent for drilling fluid ZNP-I stirring 10min；Finally add water with NaOH be configured to 40% alkali liquor, regulation system pH is 8.5.Add barite after stirring 30min to adjust Joint drilling fluid density is to 1.20g/cm³Stir 1 hour, prepare this borehole wall film forming caving-preventing drilling fluid.