The preliminary practices show that underbalanced pressure drilling is completely fit to high pressure and low permeability as well as low pressure and leakage formations.

初步实践表明，负压钻井技术完全适用于高压低渗地层和低压易漏地层，其效果明显。

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Just as you spend money to build market share, launch new products and increase brand recognition, be willing to invest in initiatives that will change longstanding workplace practices--like performing preliminary activities off the clock or attending midday meetings--that put you at risk.

FORBES: Magazine Article

They are seen as a preliminary step in an investigation into suspected anti-competitive practices.

BBC: Oil company offices raided in EU pricing probe