Seawater-based well completion fluid

Abstract

The invention relates to seawater-based well completion fluid, which can effectively overcome the defects of the conventional well completion fluid in properties and application. A technical scheme for overcoming the defects is that: the seawater-based well completion fluid consists of clean seawater, a salt-resistant, thickening and fluid loss agent, an anti-collapse inhibitor, a well completionfluid lubricant, a reservoir protective agent, a well completion fluid preservative and a pH value regulator. The components of the seawater-based well completion fluid are environmentally-friendly additives, so that the seawater-based well completion fluid has the advantages of optimizing properties of well completion fluid and meeting the conventional properties (such as density, acidity and alkalinity, fluid loss property, rheological property, stability and the like), along with high biodegradability, no biological accumulation, low toxicity or no toxicity, environmental friendliness and the like. The EC50 value of the seawater-based well completion fluid is equal to 5.9*10<5> mg/L and the recovery value of core permeability reaches 88.7 percent, so that the aims of protecting the reservoir, protecting the environment and increasing the utilization ratio of petroleum and natural gas resources are fulfilled.

Description

1. Technical field [0001] The invention relates to a seawater-based well completion fluid used for well completion operations in medium and high permeability reservoirs in the field of offshore oil and gas exploration and development. 2. Background technology [0002] The proportion of my country's offshore oil and gas exploration and development in the entire oil and gas industry continues to increase. With the country's increasingly stringent environmental protection requirements, it is becoming more and more urgent to solve marine pollution in the process of offshore oil and gas exploration and development. The exploration and development of oil and gas in the offshore field requires completion fluids to meet conventional properties (including density, acidity, fluidity, rheology, stability, etc.), and at the same time require completion fluids to be less toxic or non-toxic and harmless to the environment etc. Currently, no patents for seawater-based completion fluids hav...

AI Technical Summary

Problems solved by technology

The inorganic salt components in the existing inorganic salt cleaning brine completion fluid (including sodium chloride, ammonium chloride, calcium chloride, calcium bromide, zinc bromide, etc.) Huge damage to pump trucks; inorganic salt components are easy to crystallize, which can easily cause blockage to the formation; some systems contain harmful components, which are harmful to people and the environment