Water-based drilling fluid for shale gas wells and production method thereof

Abstract

The invention relates to a water-based drilling fluid for shale gas wells and a production method thereof. The method sequentially includes the following steps of: (1) preparing the following raw materials: 1000 parts of water, 45-50 parts of sodium bentonite, 500 parts of a water-soluble inhibition weighting agent II; 100 parts of a water-soluble inhibition weighting agent III; 15-20 parts of aninhibiting and anti-collapse agent non-fluorescence white asphalt, 10-20 parts of solid polymeric alcohol, 10-20 parts of a filtrate reducer, 0.5-1 part of a polyamine inhibitor, 20-30 parts of ultrafine calcium carbonate, 10-25 parts of an extreme pressure lubricant, and 0.5-1 part of a coating inhibitor; (2) mixing the sodium bentonite and water, and performing curing for at least 24h at normaltemperature; and (3) adding the water-soluble inhibition weighting agent II and water-soluble inhibition weighting agent III under stirring, then adding the inhibiting and anti-collapse agent non-fluorescence white asphalt and the solid polymeric alcohol, then adding the filtrate reducer and the polyamine inhibitor, then adding the ultrafine calcium carbonate and the extreme pressure lubricant, finally adding the coating inhibitor, and then adjusting the pH value and density. The drilling fluid has the advantages of high plugging properties, strong inhibition and excellent lubricating properties, and can meet the safe drilling requirements of shale gas horizontal wells.

Description

technical field [0001] The invention relates to a water-based drilling fluid for shale gas wells, and also relates to a production method of water-based drilling fluid for shale gas wells, which belongs to the technical field of oil and gas drilling and can meet the needs of shale gas well construction to replace oil-based drilling fluids . Background technique [0002] Since the 21st century, the United States has set off a "shale gas revolution" through horizontal well drilling and multi-stage hydraulic fracturing development technology. Soon this wave swept the world. At present, about 30 countries have joined the shale gas exploration development ranks. my country has also successively carried out shale gas development in Changning and Weiyuan in Sichuan, Fuling and Pengshui in Chongqing, Zhaotong in Yunnan and other places, and realized the commercial development of shale gas in Fuling in Chongqing in 2014. [0003] During the construction of shale gas wells, due to t...

AI Technical Summary

Problems solved by technology

The specific manifestations are as follows: (1) Inhibition and plugging are not good, and the well wall instability problem is serious, which cannot meet the construction requirements of the long horizontal section; (2) The lubrication and anti-seize are not good, the frictional torque is high during construction, and the risk of pipe sticking is high

Some application wells have to be converted to oil-based drilling fluid again in the later stage of construction, and some drilling operations are no problem, but complex failures frequently occur in late completion operations, and they have to be converted to oil-based drilling fluid as a last resort

[0008] Inhibition, plugging, and lubrication are the keys to this type of water-based drilling fluid technology. However, the formulas of many research institutions are single in the research and selection of treatment agents in these three aspects, and it is impossible to achieve the needs of simultaneous consideration. Therefore, as long as there is one item in the construction If the requirements are not met, it will cause frequent underground complex faults

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