Process for preparing metal-chelate retarder by sol-gel method

Abstract

The present invention relates to a process for preparing a metal-chelate retarder by a sol-gel method. The method comprises the following steps: weighing calcium nitrate tetrahydrate, aluminum nitrate nonahydrate and ferric nitrate nonahydrate according to a certain mass ratio and adding them into deionized water; placing the mixed solution on a magnetic stirrer and stirring the mixed solution evenly; adding citric acid monohydrate or gluconic acid, ethylene glycol or glycerol, and placing the mixed solution into a water bath to react to obtain the metal-chelate retarder. The process of the present invention has a reliable principle, overcomes the defects of long production period, complex preparation and the like of the existing retarders, has the advantages of simple process operation, cheap and easily available raw materials, and short production period. The prepared retarder has wide temperature adaptation range and adjustable thickening time, is suitable for large-scale industrial production, and has a wide market application prospect.

Claims

1. A process for preparing a metal-chelate retarder by a sol-gel method, comprising the following steps: weighing calcium nitrate tetrahydrate, aluminum nitrate nonahydrate and ferric nitrate nonahydrate according to a certain mass ratio and adding them into deionized water; placing the mixed solution on a magnetic stirrer and stirring the mixed solution evenly; adding citric acid monohydrate or gluconic acid, ethylene glycol or glycerol, and placing the mixed solution into a water bath to react to obtain the metal-chelate retarder.

2. The process for preparing the metal-chelate retarder by the sol-gel method according to claim 1, sequentially comprising the following steps: (1) adding 80 to 120 g of calcium nitrate tetrahydrate, 20 to 40 g of aluminum nitrate nonahydrate and 10 to 15 g of ferric nitrate nonahydrate into 50 to 70 ml of deionized water, placing the mixed solution on a magnetic stirrer and stirring for 50 to 60 min to be mixed evenly to obtain a solution A; (2) adding 30 to 50 g of chelating agent to the solution A, placing the mixed solution in a water bath at 60 to 80° C. and stirring to obtain a light yellow solution B, wherein the chelating agent is citric acid monohydrate or gluconic acid; and (3) stirring and adding 5 to 20 g of esterifying agent to the solution B to perform an esterification reaction continuously for 12 to 24 hours to obtain the metal-chelate type retarder, wherein the esterifying agent is ethylene glycol or glycerol.

3. The process for preparing the metal-chelate retarder by the sol-gel method according to claim 2, wherein in the step (2), the chelating agent is added to the solution A, placed in a water bath at 60° C. and stirred for 1 to 2 hours, and then the water bath temperature is adjusted to 80° C.

Description

DETAILED DESCRIPTION

(1) The present invention is further described below with reference to the embodiments, for those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. As long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, they are all protected.

I. Preparation of High-Temperature Resistant Oil Well Cement Retarder

Embodiment 1

(2) A process for preparing a metal-chelate retarder by a sol-gel method sequentially comprises the following steps:

(3) weighing 80 g of calcium nitrate tetrahydrate (Ca(NO.sub.3).sub.2.4H.sub.2O), 20 g of aluminum nitrate nonahydrate (Al(NO.sub.3).sub.3.9H.sub.2O) and 10 g of ferric nitrate nonahydrate (Fe(NO.sub.3).sub.3.9H.sub.2O) in sequence with a scale and then adding them into 50 ml of deionized water; placing the mixed solution on a magnetic stirrer and stirring for 50 min to be mixed evenly to obtain a solution A; weighing 40 g of citric acid monohydrate (C.sub.6H.sub.8O.sub.7.H.sub.2O) and adding to the solution A, placing the mixed solution in a water bath at 80° C. and stirring to obtain a light yellow solution B; adding 5 g of ethylene glycol to the light yellow solution B sequentially to perform an esterification reaction continuously for 12 hours to obtain the metal-chelate type retarder.

Embodiment 2

(4) A process for preparing a metal-chelate retarder by a sol-gel method sequentially comprises the following steps:

(5) weighing 90 g of calcium nitrate tetrahydrate (Ca(NO.sub.3).sub.2.4H.sub.2O), 30 g of aluminum nitrate nonahydrate (Al(NO.sub.3).sub.3.9H.sub.2O) and 10 g of ferric nitrate nonahydrate (Fe(NO.sub.3).sub.3.9H.sub.2O) in sequence with a scale and then adding them into 60 ml of deionized water; placing the mixed solution on a magnetic stirrer and stirring for 50 min to be mixed evenly to obtain a solution A; weighing 30 g of gluconic acid and adding to the solution A, placing the mixed solution in a water bath at 80° C. and stirring to obtain a light yellow solution B; adding 10 g of glycerol to the light yellow solution B sequentially to perform an esterification reaction for 12 hours to obtain the metal-chelate type retarder.

Embodiment 3

(6) A process for preparing a metal-chelate retarder by a sol-gel method sequentially comprises the following steps:

(7) weighing 120 g of calcium nitrate tetrahydrate (Ca(NO.sub.3).sub.2.4H.sub.2O), 40 g of aluminum nitrate nonahydrate (Al(NO.sub.3).sub.3.9H.sub.2O) and 15 g of ferric nitrate nonahydrate (Fe(NO.sub.3).sub.3.9H.sub.2O) in sequence with a scale and then adding them into 70 ml of deionized water; placing the mixed solution on a magnetic stirrer and stirring for 60 min to be mixed evenly to obtain a solution A; weighing 50 g of citric acid monohydrate (C.sub.6H.sub.8O.sub.7.H.sub.2O) and adding to the solution A, placing the mixed solution in a water bath at 60° C. and stirring to obtain a light yellow solution B; adding 20 g of glycerol to the light yellow solution B to perform an esterification reaction, and adjusting the temperature of the water bath to 80° C. after one hour and continuing the reaction for 15 hours to obtain the metal-chelate type retarder.

Embodiment 4

(8) A process for preparing a metal-chelate retarder by a sol-gel method sequentially comprises the following steps:

(9) weighing 100 g of calcium nitrate tetrahydrate (Ca(NO.sub.3).sub.2.4H.sub.2O), 20 g of aluminum nitrate nonahydrate (Al(NO.sub.3).sub.3.9H.sub.2O) and 15 g of ferric nitrate nonahydrate (Fe(NO.sub.3).sub.3.9H.sub.2O) in sequence with a scale and then adding them into 70 ml of deionized water; placing the mixed solution on a magnetic stirrer and stirring for 60 min to be mixed evenly to obtain a solution A; weighing 40 g of gluconic acid and adding to the solution A, placing the mixed solution in a water bath at 60° C. and stirring to obtain a light yellow solution B; adding 15 g of ethylene glycol to the light yellow solution B to perform an esterification reaction, and adjusting the temperature of the water bath to 80° C. after two hours and continuing the reaction for 20 hours to obtain the metal-chelate type retarder.

II. Retardation Performance Test of High-Temperature Resistant Oil Well Cement Retarder

(10) The retarder synthesized in Embodiment 1 is added to the cement slurry formula (shown in Table 1) and tested under the thickening conditions at a temperature of 90° C. and a pressure of 45 MPa to verify the retardation performance of the chelate.

(11) TABLE-US-00001 TABLE 1 Experimental formula Quartz Fluid loss Cement formula Cement sand agent (G33S) Retarder Water Blank group (g) 600 210 15 0 330 Experimental 600 210 15 18 330 group (g)

(12) TABLE-US-00002 TABLE 2 Engineering performance test results of cement slurry for well cementing at different dosages and the same temperature (90° C.) (Embodiment 1) Jiahua Quartz Tap Cement sand G33S water Retarder Thickening No. (g) (g) (g) (g) (g) time (min) 1 600 210 15 330 0 180 2 600 210 15 330 6 210 3 600 210 15 330 12 240 4 600 210 15 330 18 304 5 600 210 15 330 24 330

(13) TABLE-US-00003 TABLE 3 Engineering performance test results of cement slurry for well cementing at the same dosage and different temperature (Embodiment 2) Jiahua Quartz Tap Experimental Thickening No. Cement(g) sand(g) G33S(g) water(g) Retarder(g) temperature(° C.) time (min) 1 600 210 15 330 18 90 304 2 600 210 15 330 18 100 255 3 600 210 15 330 18 110 219 4 600 210 15 330 18 120 146

III. Strength Test of High-Temperature Resistant Oil Well Cement Retarder

(14) The retarder synthesized in Embodiment 1 is added to the cement slurry formula (see Table 1), cured at a temperature of 90° C., and tested for the strengths at days 1, 3, and 7, respectively.

(15) TABLE-US-00004 TABLE 4 Compressive strength compressive strength (Mpa) Time 1 d 3 d 7 d Blank group 20.33 22.27 23.55 Experimental group — 12.34 25.15

(16) It can be seen from Table 4 that the retarder prepared by the process of the present invention effectively improves the cement thickening time, without affecting the strength of cement stone after high-temperature curing.