Hypersalinity solid-free micro-foam drilling fluid or completion fluid

Abstract

The invention discloses a hypersalinity solid-free micro-foam drilling fluid or completion fluid. The drilling fluid is prepared from the following raw materials in parts by weight: (1) 0.3-0.6 parts of a tackifier, (2) 0.3-0.5 parts of a foam stabilizing agent, (3) 0.7-1.1 parts of a foaming agent, (4) 2-3 parts of a filtrate reducer, (5) 0.3-0.5 parts of a flow-pattern adjusting agent, (6) 0.2-0.3 parts of sodium carbonate and (7) 100 parts of a base fluid. The preparation method comprises: successively adding the compositions (1)-(6) according to the weight ratio into the composition (7) under the conditions of normal temperature, normal pressure and mechanical stirring in a routine manner, and stirring for 2-6 h after all compositions are added. The related hypersalinity solid-free micro-foam drilling fluid or completion fluid has excellent rheological performance, relatively good filtrate reducing performance and relatively good stability, and is applicable to well-drilling or well-completion construction of high-salinity (salt bed), low-pressure and easily-leaked stratums.

Description

technical field [0001] The invention relates to a drilling fluid and a well completion fluid, in particular to a high salinity solid-free microfoam drilling fluid or well completion fluid. Background technique [0002] At present, many old oil fields in my country have entered the late stage of development, and there are depleted reservoirs. Depleted reservoirs are dominated by water-wet sandstones, often with large fractures, belonging to highly permeable or fractured and leaky formations. During the drilling process, serious leakage and differential pressure sticking often occur, and it is difficult to drill through smoothly with conventional drilling fluids depleted formations, and can easily cause damage to reservoirs. Micro-foam drilling fluid is mainly used to solve the drilling and protection problems of reservoirs with low porosity, low permeability and low formation pressure coefficient, and is widely used in the field. With the continuous expansion of the app...

AI Technical Summary

Problems solved by technology

[0007] The disadvantages of the above technology are: 1. The system contains a relatively large amount of bentonite, which needs to be pre-hydrated and mixed, and the process is complicated and the waiting time is long; 2. The sub-micron solid particles such as clay contained in the system are prone to hydration expansion and blockage. Pores in the gas layer will cause damage to the reservoir, making it difficult to protect and discover oil and gas layers to the maximum extent

However, the paper does not introduce the salt resistance performance of the drilling fluid system, which limits its use in high-salt formations such as salt-gypsum formations

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