Which stage of development of drilling technology for deep well and ultra-deep well is potassium formate drilling fluid?

The field of oil and gas exploration and development is expanding and expanding, and the difficulty of drilling is increasing. From land to tidal flat shallow seas, from shallow layers to deep layers, the requirements for well control technology and drilling fluid are getting higher and higher. Potassium formate drilling fluid has been widely used in the late 1990s. It can implement rapid drilling scientifically, safely, and with high quality to meet the requirements of increasingly complex formation pressure strata.

Drilling in deep and ultra-deep wells has always been a problem in the drilling industry. Now that scientific drilling technology is widely used and the overall technical level of drilling is increasing, only when the control technology for oil and gas wells is developed can near-balanced pressure drilling be effectively implemented. The development of drilling fluid in the discovery of oil and gas layers, protection and liberation of oil and gas layers also played a significant role in stages.

The first stage: drilling fluid system represented by calcium treatment drilling fluid and brine drilling fluid. The deep wells drilled in the 1960s and 1970s were basically drilled using calcium-treated (lime or gypsum-treated) drilling fluid and water drilling fluid. These drilling fluids use iron chromium lignin xanthate (Fcls), sodium methylcellulose (cMc), coal breaker (Nac) and surfactant, etc., to solve the inhibition and fluid loss of drilling fluid , Rheology and other properties.

The second stage: drilling fluid system represented by Sanshihuang drilling fluid. The successful development and use of "Sanshihuang Drilling Fluid" in the 1970s was a major advancement in my country's deep well drilling fluid technology. The so-called "trisulfonate drilling fluid" refers to a drilling fluid system that uses yellowing phenolic resin (sMP), mineralized lignite (sMc) and sulfonated tannin (sMT) as main treatment agents.

The third stage: a drilling fluid system represented by polymer drilling fluid and polystone yellow drilling fluid. In the late 1970s and early 1980s, high-molecular-weight polyimide: enoic acid amine polymers were successfully used as coating flocculants in drilling fluids, which is another major advancement in the research and technology of water-based drilling fluids. . High-molecular-weight organic polymer (such as pH_PA, KPHPA, NH4 PHPA, etc.) combined with flocculation and potassium chloride (Kcl) mud shale inhibition combined chloride-polymer drilling fluid system", combined use polymerization "Mineral ore drilling fluid system" of materials and mineralization treatment agents, etc., have been successfully used in deep well and ultra-deep well drilling.

At this stage: a formate drilling fluid system based on potassium formate. In the process of drilling into shale formations, due to the use of water-based drilling fluids, mud shale will undergo hydration and infiltration. The concentration of potassium formate drilling fluid can effectively inhibit the formation of chemical potential gradients caused by the difference in pore fluid concentration in mud shale formations. In mud shale formations, especially those containing large amounts of montmorillonite. High-valent cations are replaced by other low-valent cations and become negatively charged. In order to achieve charge balance, positive ions are adsorbed from the surrounding solution to form a diffusion potential.

Potassium formate is a strong base and weak acid salt, and the aqueous solution is weakly alkaline. As the concentration of potassium formate increases, the alkalinity increases, and the pH value of the saturated solution is 10.6, which can further ensure the safety of drilling downhole, stabilize the borehole wall, increase the drilling speed, protect the reservoir, etc. Therefore, when drilling deep wells, ultra-deep wells and special process wells in complex formations, potassium formate drilling fluid is an additive that is widely used at present and has better effects.