Saturated salt water drilling fluid for deep wells and extra-deep wells

A brine drilling fluid and ultra-deep well technology, applied in the direction of drilling composition, chemical instruments and methods, etc., can solve the problems of high solid content, unstable performance, and many treatment agents, and achieve strong anti-pollution ability, loss of life, etc. Good water wall building and good lubricity

Inactive Publication Date: 2013-06-19
XINJIANG GRAND OILFIELD TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is to provide a deep and ultra-deep well saturated brine drilling fluid in order to overcome the shortcomings of high solid content, too many treatment agents but not precise, complicated formula and unstable performance in the drilling fluid system used in deep well and ultra-deep well drilling. liquid

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  • Saturated salt water drilling fluid for deep wells and extra-deep wells
  • Saturated salt water drilling fluid for deep wells and extra-deep wells

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Embodiment 1: the preparation method of deep well, ultra-deep well saturated brine drilling fluid

[0018] The preparation method of the deep well and ultra-deep well saturated brine drilling fluid is as follows: first use a measuring cylinder to measure 100 grams of tap water to control the water temperature at 70 °C, add 2 grams of bentonite under low-speed electric stirring, and add 5 grams of Na 2 CO 3 Stir for another 30 minutes, after prehydration at normal temperature and pressure for 24 hours, add 2 grams of maleic anhydride and stir for 5 minutes under low-speed electric stirring, add 0.4 grams of high-viscosity-polyanionic cellulose and stir for 5 minutes, add 8 grams of lignosulfonate Add 9 grams of sulfonated phenolic resin-lignosulfonate-humic acid copolymer and stir for 5 minutes, add 4 grams of emulsified asphalt and stir for 5 minutes, add 5 grams of C12-C18 linear alkane emulsion and stir for 5 minutes Add 2 grams of emulsified paraffin and stir for 5 ...

Embodiment 2

[0019] Embodiment 2: Evaluation of anti-pollution ability

[0020] When drilling deep formations, gypsum layers, brine layers, cement plugs, etc. are often encountered, resulting in salt intrusion or calcium intrusion in the drilling fluid, resulting in a decrease in the density of the drilling fluid mud cake and an increase in permeability, and the quality of the mud cake deteriorates. The increase of filtration loss will eventually lead to the deterioration of drilling fluid rheology and water loss wall-building properties. At the same time, the poor quality of mud cake and large filtration loss will lead to instability of the well wall and aggravate the corrosion and damage to drilling tools. Therefore, , it is necessary to evaluate the salt resistance and calcium resistance of the system. Since the system of the present invention is a saturated brine system with good salt resistance, this example only evaluates the calcium resistance

[0021] Table 2 Anti-CaSO 4 Pollution...

Embodiment 3

[0025] Example 3: Inhibition Evaluation

[0026] The inhibition of high-density water-based drilling fluid includes two aspects: one is the inhibition of cuttings intruding into high-density water-based drilling fluid; the other is to maintain the stability of the borehole wall. Usually, the former is evaluated by rolling recovery test , the latter is evaluated using linear expansion experiments

[0027] (1) Rolling recovery rate experiment

[0028] Table 3 Experimental results of rolling recovery rate

[0029] Drilling Fluid Formula Experimental conditions Recovery mass (g) Recovery rate(%) Distilled water + 50g cuttings 180℃×16h 14.98 30.0 WPQ-1+50g cuttings 180℃×16h 49.8 99.6

[0030] Note: 1. Cuttings are Sichuan red dust, drilling cuttings are 6-10 mesh, and the recovery rate is that of shale with 40 mesh; 2. The results in the table are the average value of 4 experimental data

[0031] The rolling recovery rate of the deep and ultra...

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Abstract

The invention relates to a saturated salt water drilling fluid for deep wells and extra-deep wells, which is used for drilling operation in petroleum fields under high-temperature and high-pressure environments and can overcome the defects of high solid concentration, complex formula and unstable properties of a drilling fluid system used in extra-deep well drilling. The invention adopts the technical scheme that the components of the raw materials for preparing the drilling fluid and the contents of the components are as follows: tap water: 90 to 100; bentonite: 2 to 6; Na2CO3: 4-8; maleic anhydride: 1 to 3; polyanion cellulose: 0.1 to 0.4; lignosulfonate: 5 to 9; sulfomethal phenolaldehy resin-lignosulfonate-humic acid copolymer: 7 to 11; emulsified asphalt: 2 to 5; C12-C18 straight chain paraffin emulsion: 3 to 6; emulsified paraffin: 2 to 5; Span 80: 0.2 to 0.5; CaO: 0.3 to 0.7; KOH: 0.3 to 0.7; KCl: 4 to 7; NaCl: 20 to 30; and barite for adjusting the density of the drilling fluid to 2.40 g / cm<3>. The drilling fluid has better rheological behavior under high temperature, has the advantages of good filtration properties, strong anti-pollution capacity, strong inhibitive capacity, good lubricity and strong shut-off capacity, and is used for extra-deep well drilling.

Description

technical field [0001] The invention relates to a saturated brine drilling fluid for deep wells and ultra-deep wells, which is used in the high-temperature and high-pressure environment of drilling operations in oil and gas fields, and has good rheology, good dehydration and wall-building properties, strong inhibition, good lubricity and strong plugging ability. Background technique [0002] Deep and ultra-deep wells are often drilled due to factors such as faults, multiple sets of pressure systems, high temperature, large formation dips, salt layers, salt gypsum layers, multi-layer composite salt layers, and "soft mud rock" with strong plastic deformation capabilities. The density drilling fluid system puts forward extremely high requirements on both the treatment agent and the performance of the system. At present, there are many ultra-deep wells above 6100m in China. In order to discover oil and gas resources in deep formations, some oil fields have developed to ultra-deep...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/24
Inventor 王平全白杨
Owner XINJIANG GRAND OILFIELD TECH
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