High-temperature-resistant clay-phase-free hypotonic reservoir stratum drilling fluid

A drilling fluid and clay-free technology, applied in the direction of drilling compositions, chemical instruments and methods, etc., can solve the problems of poor permeability, large oil and gas flow resistance, heterogeneity, etc., and achieve easy control of rheology and water loss properties , Good compatibility, little damage to the reservoir

Inactive Publication Date: 2011-07-20
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Low-permeability oil and gas reservoirs have the characteristics of high muddy cement content, water saturation, capillary pressure, water sensitivity, small pore throats, poor permeability, serious heterogeneity, large oil and gas flow resistance, and often accompanied by natural fractures, etc. , in the process of drilling and completion, it is very easy to cause water sensitivity and effective stress change to cause pollution damage such as stress sensitivity due to external fluid intrusion into the reservoir, and once damaged, it will be difficult to recover

Method used

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  • High-temperature-resistant clay-phase-free hypotonic reservoir stratum drilling fluid

Examples

Experimental program
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Effect test

Embodiment 1

[0041] The preparation density is 1.2g / cm 3 High-efficiency water-based drilling fluid with fast adsorption, strong inhibition, and low damage: Take 400ml of seawater with a measuring cylinder and place it in the slurry cup, add 40g of potassium formate, 1.6g of PF-PAC, and 8.0g of PF while stirring at a speed of 12000r / min -SMP I, 8.0g PF-FLO T, 1.2g PF-XCH, 6.0g PF-HJW, 4.0g PF-UHIB, stirred at high speed for 20 minutes.

[0042] 1. Routine performance evaluation of drilling fluid

[0043] The sample of Example 1 was hot rolled at 180°C for 16 hours, and then the rheology, API fluid loss and HTHP fluid loss at 150°C and 3.5MPa of the drilling fluid at room temperature were measured after hot rolling. The results are shown in Table 1.

[0044] Table 1. Evaluation data of temperature resistance of high temperature resistant clay-free drilling fluid system

[0045]

[0046]

[0047] It can be seen from Table 1 that although the viscosity of the system has decreased, the...

Embodiment 2

[0066] The anti-high temperature clay-free drilling fluid system was applied for the first time in the 6” section of a well in the BZ13-1 oilfield, and it was successful. The drilling depth of this well was 4170 meters. The high-temperature anti-clay-free drilling fluid was prepared according to the following formula before drilling 260 square meters, the on-site recipe is as follows:

[0067] 100ml seawater+5g KCl+10g sodium formate+0.2g ​​PF-XCH+0.3gPF-PAC+2.0gPF-SMP I+0.5gPF-UHIB+0.5g PF-HJW.

[0068] Use seawater to drill the cement plug, replace the mud 10 meters before entering the new formation, and start drilling after the circulation is established. During the measurement, the viscosity of the mud is maintained at 45-50 seconds, the water loss at normal temperature and pressure is 0ml, and the density is 1.14g / cm 3 Around 4,120 meters drilled, the wellhead overflowed, and after the well was shut down, the engineer used the weighting method to increase the drilling flu...

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Abstract

The invention discloses high-temperature-resistant clay-phase-free hypotonic reservoir stratum drilling fluid, which can be absorbed quickly, has high inhibiting performance and causes little damage, which comprises the following components: 100 parts of sea water or fresh water, 0.2 to 0.5 part of fluid loss additive, 2.0 to 4.0 parts of high-temperature fluid loss additive, 0.2 to 0.5 part of extracting and cutting agent, 0.5 to 1.5 parts of high-temperature stabilizer, 0.5 to 1 part of water blocking agent and 10 to 233 parts of organic salt. The invention has the following advantages: (1) the drilling fluid can resist a temperature as high as 180 DEG C; (2) the rheological behaviour and water loss property of the drilling fluid are easy to control; (3) the drilling fluid can be well mixed with the fluid in a reservoir stratum with small damage to the reservoir stratum and is particularly suitable for hypotonic oil and gas reservoir; and (4) the drilling fluid can be applied to drilling completion operation of reservoir stratum sections of deep and medium-deep wells, particularly hypotonic reservoir stratums.

Description

technical field [0001] The invention relates to a drilling and completion working fluid in well drilling engineering, in particular to a high-temperature-resistant, clay-free low-permeability reservoir drilling fluid. Background technique [0002] Ordinary clay-free (solid phase-free) drilling fluids cannot meet the needs of high-temperature drilling in medium-deep wells, and there is no targeted research on low-permeability reservoirs. For reservoirs in high-temperature sections of medium-deep wells, in order to minimize the damage to the reservoir, pressure control drilling technology is usually used, and at the same time, a clay-free drilling fluid system is used. In addition to ensuring the stability of the system, it is also necessary to meet the needs of operation safety and reservoir protection of low-permeability oil and gas reservoirs. [0003] The clay-free drilling fluid system generally refers to the drilling fluid system that does not contain clay or insoluble ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/12
Inventor 苗海龙徐博韬何瑞兵王健龚莲芬张荣耿铁
Owner CHINA NAT OFFSHORE OIL CORP
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