Sand control flowback process after shale gas horizontal well fracturing

A technology for horizontal wells and shale gas, which is applied in the direction of flushing wellbore, wellbore/well components, earthwork drilling and production, etc. sand risk effect

Active Publication Date: 2019-08-27
CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above two methods have the following difficulties: the difficulty of method ① lies in the accurate judgment of whether sand is produced in the formation and the control of the flowback rate; method ② for horizontal wells using large-diameter bridge plugs, since the large-diameter bridge plug has been placed in place after fracturing Placed in the horizontal section, and the diameter is generally between

Method used

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  • Sand control flowback process after shale gas horizontal well fracturing
  • Sand control flowback process after shale gas horizontal well fracturing

Examples

Experimental program
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Example Embodiment

[0033] Example 1

[0034] As a preferred embodiment of the present invention, it discloses a sand control flowback process after fracturing in a shale gas horizontal well. The steps are as follows:

[0035] (1) Use a 2mm nozzle to open and drain the fractured shale gas horizontal well, continuously record the wellhead pressure changes, if the pressure drop rate is less than 0.05MPa / h for 10 consecutive hours, increase to 3mm nozzle Draining, the sum of the draining time of 2mm and 3mm nozzles is not less than 72 hours;

[0036] (2) 72 hours after the well is opened and drained, the following two measures shall be taken according to whether gas is seen:

[0037] If no gas is seen, calculate the pressure in the bottom hole fracture according to the wellhead pressure. If the pressure in the fracture is greater than the formation closure pressure in the area, continue to use a 3mm nozzle to drain until the formation is closed; if the pressure in the fracture is less than the formation clo...

Example Embodiment

[0039] Example 2

[0040] On the basis of Example 1, in the step (2), the specific methods for judging whether the formation is sanding and adjusting the working system after sanding are as follows:

[0041] For normal flowback wells, the wellhead pressure changes regularly with the adjustment of the nozzle work system. If there is an abnormal response to the wellhead pressure, the pressure drop rate analysis can directly determine whether the formation is sanding;

[0042] After determining the formation of sand production, real-time calculation of the wellbore lifting efficiency under the current nozzle system according to the wellbore flow pattern, and then adjust the nozzle according to the degree of sand production, and use the formation energy to carry sand until the wellhead pressure returns to normal and the surface process does not see sand return. Adjust to the original nozzle work system and continue to drain.

Example Embodiment

[0043] Example 3

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Abstract

The invention discloses a sand control flowback process after shale gas horizontal well fracturing. A 2mm oil nozzle is adopted for carrying out well opening liquid discharge on a fractured shale gashorizontal well, the well opening pressure changes are recorded, and if the pressure drop rate within continuous 10 hours is lower than 0.05MPa/h, the oil nozzle is increased to a 3mm oil nozzle for draining; after well opening draining is carried out for 72 hours, and measures are taken according to whether gas breakthrough appears or not; if gas breakthrough does not appear, according to the well opening pressure, the pressure in the well bottom seam is calculated, and if the pressure in the seam is larger than the closing pressure of the regional stratum, the 3mm oil nozzle is continuouslyadopted for draining until the stratum is closed; if the pressure in the seam is smaller than the regional stratum closing pressure, at the moment, the stratum is closed, if gas breakthrough appears,the oil nozzle is directly increased to a 4mm oil nozzle for draining, on the premise that the sand production does not appear in the stratum, when the pressure drop rate is lower than 0.2 MPa/h within continuous 12 hours, the oil nozzle is increased stage by stage with 1 mm as the unit to the test work system, and the well test yield is solved. According to the method, in the flowback process, the crack closing degree, the gas and liquid ratio and the well cylinder flow state are judged in real time, the flowback system is optimized in real time, and the shaft sand production rate at the flowback primary period can be effectively controlled.

Description

technical field [0001] The invention relates to the technical field of oil and gas well fracturing flowback testing operations in the field of oil and gas field exploration and development, in particular to a sand control flowback method after staged fracturing of shale gas horizontal wells. Background technique [0002] Domestic shale gas development generally adopts staged fracturing of horizontal wells. After the fracturing is completed, it is necessary to use the energy of the formation itself to drain liquid. Only when a certain flowback rate reaches a certain flowback rate can the test and production conditions be met. However, sand production often occurs during the flowback process after fracturing. After sand production, the formation energy is insufficient to carry the proppant in the horizontal wellbore out of the well, resulting in the sand-buried perforation section, the fluid flow channel is blocked, and the fluid drainage rate decreases rapidly. Seriously affe...

Claims

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Application Information

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IPC IPC(8): E21B21/00
CPCE21B21/00
Inventor 李军龙杨海朱炬辉王丹吴凯焦亚军肖剑峰陈明忠周文高步永伟黎恭成
Owner CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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