Anti-high temperature bridging plugging agent suitable for lost circulation in deep and ultra-deep formations

Abstract

The invention discloses a high-temperature-resistant bridging leaking stoppage agent applicable to lost circulation of a deep stratum and an extra-deep stratum.The leaking stoppage agent is formed by compounding, by mass, 70-80% of coke and 20-30% of fine rubber powder, wherein the coke is 4-100 meshes in particle size, and the fine rubber powder is 80-120 meshes in particle size; 0.2% of alkylphenol ethoxylates is further added so as to increase hydrophilia of the fine rubber powder and improve dispersibility in water-based drilling fluid of the fine rubber powder.Compared with a traditional bridging leaking stoppage technology, the leaking stoppage agent of coarse particles, medium-sized particles and fine particles is adopted, a dense blocking layer is formed in a stratum leakage channel through bridging, filling and blocking, losing of drilling liquid is prevented, and two types of novel leaking stoppage materials, namely the fine rubber powder and coke particles, are further adopted and compounded for leaking stoppage.The high-temperature-resistant bridging leaking stoppage agent is adjustable in grain class distribution, the coke particles are high in rigidity, compounding with the fine rubber powder is conducted, rigidity and elasticity are achieved simultaneously, density is low, the suspension property is good, and the formed blocking layer is high in compressive strength, good in compactness and capable of being resistant to the high temperature of 180DEG C.

Description

Technical field [0001] The invention relates to a plugging agent for drilling fluid lost in formations in petroleum drilling engineering, in particular to a high-temperature-resistant bridging plugging agent suitable for well leakage in deep formations and ultra-deep formations. Background technique [0002] With the depletion of shallow and medium-deep oil and gas resources, the exploitation of deep wells and ultra-deep wells has become the mainstream technology for oil and gas exploration and development. Lost circulation in deep formations, especially vicious lost circulation is a difficult problem in drilling engineering. The passages of deep malignant leakage are generally cracks with a wide opening, and the conventional plugging method is mostly bridging plugging technology. This technology is to use bridging plugging agents of various shapes and particle sizes to enter the leaking layer, and form a dense plugging layer through bridging-filling-plugging to block the d...

AI Technical Summary

Problems solved by technology

Plant-based materials have low density, weak strength, poor temperature resistance, and are easy to ferment at high temperatures. The formed plugging has low pressure bearing capacity and is easy to leak again. The application range is limited by the well temperature.

Limestone material has high strength but high density (2.7g / cm 3 ), the suspension stability is poor, and the coarse-grained limestone is easy to sink into the bottom of the tank in the drilling fluid, and cannot enter the well effectively, which affects the plugging effect

Asbestos materials are highly toxic and highly carcinogenic

In addition, there is a lack of flexible filling materials between limestone particles, and the plugging density is insufficient, which is easily affected by the excitation of liquid column pressure and causes re-leakage.

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