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Process for preparing drilling fluid for preventing polycrystalline diamond compact (PDC) bit balling

A drill bit mud bag and drilling fluid technology, applied in the field of oil drilling, can solve the problems of rapid increase in specific gravity, poor inhibition of drilling fluid, poor lubrication performance, etc., and achieve the effects of increasing the proportion of the mud cake, improving the quality of the mud cake, and improving the lubricity.

Inactive Publication Date: 2012-12-12
中国石油集团川庆钻探工程有限公司长庆钻井总公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the polysulfide drilling fluid system itself has limitations, such as poor inhibition, high solid content, rapid increase in specific gravity, poor drilling fluid inhibition, and cannot control the hydration and dispersion of shale; the solid content and viscosity shear are too high, and the drilled Cuttings are difficult to remove and are easily adsorbed on the surface of the drill bit; the specific gravity of the drilling fluid is high, the water loss is large, and an excessively thick rough mud cake is easily formed; the lubrication performance is poor, and an effective protective film cannot be formed on the surface of the drill bit. It is easy to be adsorbed on the drill bit, resulting in the mud bag of the PDC bit, which seriously affects the speed-up of the Sulige gas field and becomes a technical bottleneck restricting the speed-up
Especially in the construction of horizontal wells, the mud bag problem is more prominent. There have been downhole accidents in many wells where the PDC bit cannot be used and the cone bit has lost the cone due to the serious mud bag of the "double rock layer" bit.

Method used

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  • Process for preparing drilling fluid for preventing polycrystalline diamond compact (PDC) bit balling
  • Process for preparing drilling fluid for preventing polycrystalline diamond compact (PDC) bit balling
  • Process for preparing drilling fluid for preventing polycrystalline diamond compact (PDC) bit balling

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Effect test

Embodiment 1

[0030] 1. Drilling fluid requirements for vertical well sections before sidetracking

[0031] Before sidetracking, block drilling fluid technical measures should be implemented, and the focus of drilling fluid work should be to prevent collapse of the entire well section and ensure wellbore rules. It is required that the average diameter expansion of the vertical well section be controlled within 10%, and the maximum diameter expansion be controlled within 15%.

[0032] 2. Conversion of drilling fluid:

[0033] Under normal downhole conditions in the vertical well section, polymer drilling fluid should be used as much as possible to drill through the slurry formation in the upper part of Shiqianfeng. Then it is completely transformed into a compound salt-free soil-phase drilling fluid system.

[0034] In the case of abnormal downhole conditions, 40 cubic meters of white clay mud must be used to clean the sand that has not been carried out of the wellbore during conversion, a...

Embodiment 2

[0058] Embodiment 2 is substantially the same as Embodiment 1, and difference is that the treatment agent addition formula of the drilling fluid of the present invention is to be formulated by the following mass ratios in step 2: clear water polymer protoplasm: PAC: QS -4:CMS:SMP:SFT-1:NaCL:WT-1=1000:2:30:20:2:1.5:50:20, performance control: density ρ=1.06-1.10g / cm 3 , funnel viscosity T=38-45s, API dehydration FL=4-6ml; Wherein clear water polymer stock is prepared by the following mass ratio by PAM, K-PAM component: PAM: K-PAM: clear water=1.5 :2:1000. The CMS that present embodiment 2 adopts is carboxymethyl starch CMS-1 type.

Embodiment 3

[0059] Embodiment 3 is substantially the same as embodiment 1, and difference is that the treatment agent addition formula of drilling fluid of the present invention is to be prepared by following components by following mass ratio in step 2: clear water polymer former slurry: PAC: QS -4:CMS:SMP:SFT-1:NaCL:WT-1 is 1000:3:40:30:3:2:100:20, performance control: density ρ is 1.06-1.10g / cm 3 , funnel viscosity T=38-45s, API dehydration FL=4-6ml; Wherein clear water polymer stock is prepared by the following mass ratio by PAM, K-PAM component: PAM: K-PAM: clear water=2.5 :3:1000. The CMS that present embodiment 3 adopts is carboxymethyl starch CMS-1 type.

[0060] In the above-mentioned embodiment, CMS is not limited to carboxymethyl starch CMS-1 type, it can also be carboxymethyl starch CMS-2 type, carboxymethyl starch CMS-3 type and other specification models. The reagents in the formulas of the above examples were all purchased from the Equipment Company of Changqing Drilling ...

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Abstract

The invention relates to a process for preparing drilling fluid, in particular to a process for preparing the drilling fluid for preventing polycrystalline diamond compact (PDC) bit balling. The process comprises a construction process and a dosage formula of treating agents and is characterized in that: according to the dosage formula, the treating agents are prepared by mixing clear water polymer original slurry, poly anionic cellulose (PAC), calcium carbonate (QS-4), carboxymethyl starch (CMS), sulfonated phenolic resin(SMP-2), water dispersible cation emulsified asphalt powder (SFT-1), sodium chloride(NaCL) and sodium formate (WT-1) in a mass ratio of 1,000:2-3:30-40:20-30:2-3:1.5-2:50-100:20; and the construction process comprises the following steps of: according to a circulation circle, uniformly mixing a coating agent PAC, a filtrate reducer CMS, a salt and high-temperature resistant filtrate reducer SMP-2 and an anti-sloughing lubricant SFT-1 for 12h at first; adding QA-4, NaCL, WT-1 into the mixture and uniformly mixing the mixture; and regulating the mixture to have a density Rho of 1.06 to 1.10g / cm<3>, a funnel viscosity T of 38 to 45s and an API water loss FL of 4 to 6ml. The process has the advantages of effectively preventing the balling of a sticking bit and a PDC bit at a lower curved section, reducing a frictional resistance and a torque, eliminating a sticking phenomenon, improving a mechanical drilling rate and ensuring downhole safety.

Description

technical field [0001] The invention relates to a drilling fluid preparation process, especially a drilling fluid preparation process for preventing PDC bit balling. The process is suitable for the prevention of drill bit balling in the "shuangshi layer" formation of Sulige gas field, and belongs to oil drilling field. technical background [0002] The "Shuangshi Formation" of the Sulige Gas Field belongs to the Permian system, and the burial depth of the formation is about 3000m to 3600m. The mudstone content in the formation is high and easy to hydrate and disperse, which greatly increases the content of mud or solid phase in the wellbore and is adsorbed on the surface of the drill bit. At the same time, this well section is just in the transition from clear water polymer to completion fluid, and the performance of the drilling fluid is poor immediately after conversion, such as large water loss, thick filter cake, poor inhibition, and poor lubrication performance. influe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/12C09K8/035C09K8/03
Inventor 赵福荣张建卿刘兆利陈华
Owner 中国石油集团川庆钻探工程有限公司长庆钻井总公司
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