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

A brine drilling fluid and ultra-deep well technology, which is applied in drilling compositions, chemical instruments and methods, etc., can solve the problems of unstable performance, high solid phase content, and many treatment agents, and achieves strong anti-pollution ability and loss of loss. The effect of good water wall building and good lubricity

Inactive Publication Date: 2012-06-20
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

Method used

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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] Example 1: Preparation method of saturated brine drilling fluid for deep wells and ultra-deep wells

[0018] The method for preparing the saturated brine drilling fluid for deep wells and ultra-deep wells is as follows: first measure 100 grams of tap water with a graduated cylinder to control the water temperature at 70°C, add 2 grams of bentonite under low-speed electric stirring, and add 5 grams of Na after stirring for 10 minutes. 2 CO 3 Stir for another 30 minutes. After pre-hydration at room temperature and pressure for 24 hours, add 2 grams of maleic anhydride under low-speed electric stirring and stir for 5 minutes. Add 0.4 grams of high-viscosity polyanionic cellulose and stir for 5 minutes. Add 8 grams of lignosulfonate Stir the acid salt for 5 minutes, 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 fo...

Embodiment 2

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

[0020] When drilling deep formations, it often encounters gypsum layers, salt water layers, cement plugs, etc., resulting in salt or calcium intrusion in the drilling fluid, resulting in a decrease in the density of the drilling fluid mud cake, an increase in permeability, and poor mud cake quality. The increase in fluid loss will eventually lead to the deterioration of drilling fluid rheology and wall-building properties due to loss of water. At the same time, the poor quality of mud cake and large fluid loss make the well wall unstable and aggravate the corrosion and damage to the drilling tool. , 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 and has good salt resistance, this embodiment only evaluates the calcium resistance

[0021] Table 2 Anti-CaSO 4 Pollution experiment

[0022]

[0023] Note: All HTHP water loss...

Embodiment 3

[0025] Example 3: Evaluation of inhibition

[0026] The inhibition of high-density water-based drilling fluids has two meanings: on the one hand, it inhibits the intrusion of high-density water-based drilling fluid cuttings; on the other hand, it maintains the stability of the borehole wall. The former is usually evaluated by rolling recovery experiments. , The latter is evaluated by linear expansion experiment

[0027] (1) Rolling recovery rate experiment

[0028] Table 3 Experimental results of rolling recovery rate

[0029] Drilling fluid formula Experimental conditions Recycling quality (g) Recovery rate(%) Distilled water + 50g cuttings 180℃×16h14.9830.0 WPQ-1+50g cuttings 180℃×16h49.899.6

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

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

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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 deep well and ultra-deep well saturated brine drilling fluid which is used in oil and gas field drilling operations under high temperature and high pressure environment and has good rheology, good wall-building properties, strong inhibition, good lubricity and strong blocking ability. Background technique [0002] Deep wells and ultra-deep wells are often used for high temperature resistance due to factors such as faults, multiple pressure systems, high temperature, large stratum dip, salt layers, salt-gypsum layers, multi-layer composite salt layers, and "soft mudstone" with strong plastic deformation ability. Density drilling fluid systems have extremely high requirements for both treatment agents and system performance. At present, there are many ultra-deep wells above 6100m in China. In order to discover oil and gas resources in deep formations, individual oilfields have developed into ultra-deep wells above 7000m or even 8000m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/24C09K8/46
Inventor 王平全白杨
Owner XINJIANG GRAND OILFIELD TECH
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