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A Method for Evaluation of Mud Cake Quality Before Cementing

An evaluation method and quality evaluation technology, applied in the field of oil drilling, can solve the problems of inability to evaluate the quality of the mud cake, low adaptability of the flushing method, and inability to effectively flush the mud cake, etc., and achieve the effect of improving the effect.

Active Publication Date: 2022-03-01
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The existing technology only evaluates the quality of the solid mud cake, without considering other influencing factors, such as the quality, temperature, pressure, and gel strength of the virtual mud cake, which makes it impossible to reasonably evaluate the quality of the mud cake. The selected flushing method has low adaptability and cannot effectively flush the mud cake on the well wall

Method used

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  • A Method for Evaluation of Mud Cake Quality Before Cementing
  • A Method for Evaluation of Mud Cake Quality Before Cementing
  • A Method for Evaluation of Mud Cake Quality Before Cementing

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Experimental program
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Embodiment 1

[0172] Based on the method provided in the embodiment of the present invention, this embodiment takes Gang XX-1 well as an example to illustrate the mud cake quality evaluation method before cementing.

[0173] The logging data of Well Gang XX-1 can be obtained according to the logging data, bottom pressure fitting and experimental data. The specific logging data are: the vertical depth of the well is 1500m, the outlet temperature of the drilling fluid is 38°C, and the density of the drilling fluid is 1.20 g / cm 3 , the formation compaction coefficient is 2.7×10 -4 , the initial time difference is 380μs, the measured acoustic time difference at the bottom of the well is 279μs, the pressure gradient of the overlying strata near the bottom of the well is 23.54KPa / m, the hydrostatic pressure gradient is 9.8KPa / m, and the Eaton coefficient is 0.3.

[0174] (1) Predict the bottom hole temperature and bottom hole pressure difference

[0175] According to the logging data of Well Ga...

Embodiment 2

[0193] Based on the method provided in the embodiment of the present invention, this embodiment takes the Gang XX-2 well as an example to illustrate the mud cake quality evaluation method before cementing.

[0194] The logging data of Well Gang XX-2 can be obtained according to the logging data, bottom pressure fitting and experimental data. The specific logging data are: the well vertical depth is 1800m, the drilling fluid outlet temperature is 40°C, and the drilling fluid density is 1.22g / cm 3 , the formation compaction coefficient is 2.72×10 -4 , the initial time difference is 385μs, the measured acoustic time difference at the bottom of the well is 289μs, the pressure gradient of the overlying strata near the bottom of the well is 23.74KPa / m, the hydrostatic pressure gradient is 9.8KPa / m, and the Eaton coefficient is 0.3.

[0195] (1) Predict the bottom hole temperature and bottom hole pressure difference

[0196] According to the logging data of Well Gang XX-2, and thr...

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Abstract

The invention discloses a mud cake quality evaluation method before well cementing, which belongs to the technical field of petroleum drilling. The evaluation method includes: obtaining the bottom hole temperature and the bottom hole pressure difference, using the bottom hole temperature and the bottom hole pressure difference as the conditions of the fluid loss experiment, carrying out the fluid loss experiment, and preparing the mud cake; respectively obtaining the solid mud cake, virtual The thickness of the mud cake; use the mud cake to obtain the fluidity of the drilling fluid; obtain the comprehensive coefficient of the mud cake quality according to the thickness of the real mud cake, the thickness of the virtual mud cake and the fluidity of the drilling fluid; according to the comprehensive coefficient of the mud cake quality, evaluate The quality of the mud cake. The present invention can more accurately simulate the formation of the mud cake at the bottom of the well by obtaining the bottom hole temperature and the bottom hole pressure difference as the fluid loss test conditions, and also considers the influence of temperature and pressure on the quality of the mud cake; the evaluation method provided by the invention The influence of the quality of the virtual mud cake and the gel strength of the drilling fluid near the mud cake on the quality of the mud cake is also considered, so that the evaluation method can more reasonably evaluate the quality of the mud cake before cementing.

Description

technical field [0001] The invention relates to the technical field of petroleum drilling, in particular to a method for evaluating mud cake quality before cementing. Background technique [0002] Well cementing is an indispensable link in the drilling operation process, which includes the process of running the casing and injecting cement into the annular space between the well wall and the casing. During the cementing process, the drilling fluid forms a mud cake on the surface of the well wall due to water loss, which directly affects the bonding quality between the cement and the casing and the well wall. In order to improve the quality of cementing and prolong the life of the oil well, it is necessary to clean the mud cake on the well wall. The cleaning process is as follows: first, the flushing fluid is used to displace the drilling fluid in the area near the mud cake; after that, the flushing fluid is used to wash the virtual mud cake and the solid mud cake in sequenc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B47/005E21B47/00
CPCE21B47/00E21B47/005
Inventor 张学强唐世忠吴华李娟曹磊
Owner PETROCHINA CO LTD