Method for increasing communication length of SAGD horizontal section of double horizontal wells

A dual-horizontal well, horizontal section technology, applied in chemical instruments and methods, earthmoving, wellbore/well components, etc. The problem of high storage viscosity, etc., achieves the effect of good technology implementation, easier production control, and improved seepage capacity.

Active Publication Date: 2021-04-30
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Due to the high viscosity of ultra-heavy oil reservoirs, there is no flow ability under normal temperature conditions, and the pressure difference between injection and production wells is generally less than 100KPa. It is difficult to drive the flow of high-viscosity cold oil under low pressure difference. In this case, SAGD operation is implemented , will consume a lot of steam, and the long-term cycle preheating time will still cause the unevenness of the heating effect of the horizontal section, thereby reducing the degree of utilization of the horizontal section

Method used

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  • Method for increasing communication length of SAGD horizontal section of double horizontal wells
  • Method for increasing communication length of SAGD horizontal section of double horizontal wells

Examples

Experimental program
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Effect test

Embodiment 1

[0053] This embodiment provides a process of increasing the producing length of the horizontal section by using small-diameter deep-penetrating dense perforation stimulation and mixed viscosity-reducing agent mixed injection before cyclic preheating of a certain oilfield block.

[0054] In an oil reservoir block in Xinjiang Oilfield, the burial depth of the reservoir is 200m, the average formation pressure is 2.1MPa, the formation temperature is 18.0°C, the effective thickness of oil layer 5 is 15m, the porosity is 28.8%, the permeability of the oil layer is 800mD, and the average crude oil viscosity at 50°C is 50000mPa. s, oil saturation 65.0%.

[0055] The reservoir block is planned to be exploited by SAGD technology. In order to make full use of the thickness of the oil layer, the horizontal section of a steam injection well 1 is arranged at the bottom of the oil layer 5, and the horizontal section of an oil production well 2 is arranged 5m above the bottom of the oil reserv...

Embodiment 2

[0072] This example provides a case of SAGD in an oilfield block that has been transferred to the production stage and the low-level production degree transformation case, using large-aperture deep-penetrating low-density perforation stimulation, electric pulse artificial fractures and mixed viscosity reducer mixed injection to improve the horizontal section The process of using length.

[0073] In the SAGD block of a certain oil reservoir in Xinjiang Oilfield, the burial depth of the oil reservoir is 250m, the average formation pressure is 2.5MPa, the formation temperature is 18.0°C; the effective thickness of the oil layer is 15m, the porosity is 32%, the permeability of the oil layer is 2500md, and the average crude oil viscosity at 50°C is 25000mPa. s, the oil saturation is 77.0%.

[0074] The reservoir block has entered the production stage of SAGD production, the length of the horizontal section of steam injection well 1 and the horizontal section of oil production well ...

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Abstract

The invention discloses a method for increasing the communication length of an SAGD horizontal section of double horizontal wells. The method comprises the following steps that 1, through fine geological research and reservoir unit depiction, a low-permeability interlayer (3) of a well group control reservoir is recognized; 2, according to permeability range distribution of an oil layer between a steam injection well (1) and an oil production well (2), the steam injection well (1) is divided into a high-range difference section (11) and a middle-range difference section (12); 3, small-aperture high-density deep penetration perforation is conducted on the high-range difference section (11) of the steam injection well (1), and large-aperture deep penetration perforation and electric pulse artificial micro-crack operation are conducted on the middle-range difference section (12) of the steam injection well (1); and 4, viscosity reduction operation is conducted. According to the method for increasing the communication length of the SAGD horizontal section of the double horizontal wells, the flowing capacity of the horizontal section which is not used can be obviously improved, the production effect of a strong-heterogeneity super-heavy oil reservoir SAGD is guaranteed, and the oil production speed and the crude oil recovery ratio can be greatly increased.

Description

technical field [0001] The invention relates to a method for increasing the communication length of the SAGD horizontal section of a double-horizontal well. Background technique [0002] Super-heavy oil reservoirs refer to reservoirs with a degassed crude oil viscosity greater than 50,000mPa.s at the reservoir temperature. At present, super-heavy oil reservoirs use steam-assisted gravity drainage (SAGD) technology with dual horizontal wells. In this process, steam is used as a heat source, and heavy oil is exploited by gravity of crude oil after viscosity reduction. If the dual-horizontal wells want to obtain a good production effect, the continuous thickness of the oil layer must be greater than 12m. When the thickness of the continuous oil layer is less than 12m, the oil field is generally exploited by steam huff and puff in horizontal wells. [0003] The length of the effective connecting section of the horizontal section of steam-assisted gravity drainage has a great i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B43/24E21B43/22C09K8/588C09K8/592
CPCE21B43/26E21B43/2408E21B43/2405E21B43/16E21B43/24C09K8/588C09K8/592E21B43/11
Inventor 周游刘彤李秀峦席长丰赵睿罗池辉杜宣石兰香齐宗耀
Owner PETROCHINA CO LTD
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