Pressure-bearing lost circulation additive for drilling fluid and for stably bearing pressure on smooth fracture leakage wall surface

A technology of drilling fluid and plugging agent, which is applied in the field of oil exploration, can solve the problems of low plugging success rate, fracture pressure plugging failure, low bearing pressure, etc. The effect of high pressure and sliding friction

Inactive Publication Date: 2013-01-16
SOUTHWEST PETROLEUM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the plugging success rate of bridge plugging in mud shale and sandstone fractures is high, but the plugging success rate in limestone fractures is low. The wall surface is smooth, and the bridge plug material is easy to produce a sliding effect under the action of the pressure difference after entering the fracture, and the plugging material slips off the crack wall as a whole, unable to bear the pressure or the bearing pressure is low, resulting in the failure of the pressure-bearing plugging in the fracture

Method used

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  • Pressure-bearing lost circulation additive for drilling fluid and for stably bearing pressure on smooth fracture leakage wall surface
  • Pressure-bearing lost circulation additive for drilling fluid and for stably bearing pressure on smooth fracture leakage wall surface
  • Pressure-bearing lost circulation additive for drilling fluid and for stably bearing pressure on smooth fracture leakage wall surface

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] A fracture module with a width of 2 mm was selected, and 3.5 L of plugging base slurry was prepared. The base slurry formula was: 6% bentonite + 1% CMC-HV. The dosage of the plugging agent is 6% of the plugging slurry (mass volume percentage g / ml). The size of the material is 14-20 mesh of the standard mesh of the sample sieve, and the size of the friction material is 1.0×1.0-1.6×1.6mm. The amount of plugging agent added is 21g of friction material; 105g of bridging material; 84g of filling material, of which the first level: 42g of calcium carbonate powder with a standard mesh size of 20-40 mesh in the sampling sieve, and the second level: standard mesh size in the sampling sieve 16.8g of calcium carbonate powder of 40-80 mesh, the third stage: 16.8g of calcium carbonate powder with a standard mesh size of 80-150 mesh in the sampling sieve, and 16.8g of calcium carbonate powder with a standard mesh number of 80-150 mesh in the sampling sieve, and 8.4g of flexible graph...

Embodiment 2

[0027] A fracture module with a width of 3 mm was selected, and 3.5 L of plugging base slurry was prepared. The base slurry formula was: 6% bentonite + 1% CMC-HV. The dosage of the plugging agent is 8% of the plugging slurry (mass volume percentage g / ml). The material is a sampling sieve with a standard mesh number of 10-20 mesh, and the size of the friction material is 1.0×1.0-2.0×2.0mm. The amount of plugging agent added is 33.6g of friction material; 140g of bridging material; 106.4g of filling material, of which the first stage: 53.2g of calcium carbonate powder with a standard mesh size of 20-40 mesh in the sampling sieve, and the second stage: sampling sieve 21.3g of calcium carbonate powder with a standard mesh number of 40-80 mesh, the third level: 21.3g of calcium carbonate powder with a standard mesh number of 80-150 mesh in the sampling sieve, 21.3g of calcium carbonate powder with a standard mesh number of 80-150 mesh in the sampling sieve, and 10.6 grams of flexib...

Embodiment 3

[0029] A fracture module with a width of 4 mm was selected, and 3.5 L of plugging base slurry was prepared. The base slurry formula was: 6% bentonite + 1% CMC-HV. The dosage of the plugging agent is 9% of the plugging slurry (mass volume percentage g / ml). The material is a sampling sieve with a standard mesh of 8-20 mesh, and the size of the friction material is 1.0×1.0-2.5×2.5mm. The amount of plugging agent added is 47.2g of friction material; 151.2g of bridging material; 116.6g of filling material, of which the first stage: 58.3g of calcium carbonate powder with a standard mesh size of 20-40 mesh in the sampling sieve, and the second stage: sampling 23.3g of calcium carbonate powder with a standard mesh of 40-80 mesh, the third stage: 23.3g of calcium carbonate powder with a standard mesh of 80-150 mesh in the sampling sieve, fourth stage: flexible graphite powder with a standard mesh of more than 150 mesh in the sampling sieve 11.7g. The cracks were successfully sealed, ...

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Abstract

The invention relates to a pressure-bearing lost circulation additive for a drilling fluid and for stably bearing pressure on a smooth fracture leakage wall surface. The lost circulation additive is composed of 10%-20% of damping material, 45%-50% of bridging material and 35%-40% of filling material by weight, wherein the damping material is an industrial metal screen, having the size of the damping material is 1.0*1.0mm to 3.0*3.0 mm and the thickness of the damping material is about 0.5 mm; the bridging material is calcium carbonate particles, and the standard mesh number of the screening mesh product of the bridging material is lower than 20 meshes; the filling material is a mixture composed of calcium carbonate powder and flexible graphite powder; the calcium carbonate powder is further divided into three grades to realize multi-grade filling and to form a compact shielding layer; and the mesh number of the flexible graphite is greater than 150, and the anti-pressure ability of a bridge plug section is improved. With the pressure-bearing lost circulation additive for the drilling fluid and for stably bearing pressure on the smooth fracture leakage wall surface disclosed by the invention, leak stoppage success rate and bearing pressure for smooth fracture leakage can be improved, leakage stoppage failure due to complexity is reduced, the benefits of exploring and developing a bored well are improved; and the preparation process of the lost circulation additive is simple and convenient, the source of the materials of the lost circulation additive is broad, and the lost circulation additive is easy to spread and apply.

Description

technical field [0001] The invention belongs to the field of petroleum exploration, in particular to a pressure-bearing plugging agent for drilling fluid used in the drilling process of oil and gas wells to block leaky layers of cracks on smooth walls and capable of stably bearing pressure inside the cracks. Background technique [0002] Lost circulation is one of the most serious and complicated situations in drilling engineering. Fractured lost circulation is the most common type of lost lost circulation, including fracturing induced fracture lost circulation and differential pressure natural fracture lost circulation. The former belongs to the problem of leakage prevention. The latter belongs to the plugging problem. Methods for dealing with fractured lost circulation include bridge plugging, cement slurry plugging, chemical plugging, etc. Among them, bridge plugging is the most widely used drilling fluid plugging technology at home and abroad. However, the plugging suc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/42
Inventor 蒲晓林赵正国贺明敏王贵苏俊霖
Owner SOUTHWEST PETROLEUM UNIV
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