A plugging material and plugging slurry for protecting low-pressure fractured reservoirs

Abstract

The invention discloses a plugging material and plugging slurry for protecting a reservoir stratum with the low fracturing fracture ability. The plugging material is prepared from, by weight, 5-6 parts of walnut shell powder, 2-3 parts of a composite plugging agent, 1.5-2 parts of an agent for plugging while drilling, 4-5 parts of an acid soluble plugging agent, 4-5 parts of a high-dehydration-rate plugging agent and 0.2-0.3 part of calcium oxide. The natural plant inertia material, the fiber plugging agent and the acid soluble plugging agent are mixed according to the certain matching ratio to form the acid soluble plugging material in granule and fiber shapes. The material has the advantages that the bridging effect of a bridging material is good and the plugging success rate is high, and also has the advantages that the density is low, stratum pressure is effectively balanced, the stratum damage is small, the plugging property is strong and acid solubility is achieved. The plugging slurry prepared from the plugging material and water has the advantages of being low in density, high in pressure bearing capability, good in malignant leakage plugging effect, high in acid solubility and the like; the on-site preparation process is simple, construction is safe and reliable, and the purposes of reducing well leakage loss and protecting the reservoir stratum can be achieved.

Description

Technical field

[0001] The invention belongs to the technical field of plugging for petroleum drilling, and specifically relates to a plugging material for protecting low-pressure fractured reservoirs, and also relates to a plugging slurry for protecting low-pressure fractured reservoirs. Background technique

[0002] Lost circulation is when the fluid column pressure in the wellbore is greater than the formation fracture pressure or the formation pores or fractures are drilled, causing the fluid in the well to enter the formation on a large scale. It is the most common and most difficult problem in drilling engineering. , Not only delays the drilling operation time, prolongs the drilling cycle, and causes huge economic losses, but also the solid particles in the mud (including clay, weighting agent, treatment agent and fine drill cuttings) will be in the narrow throat of the oil and gas channel of the reservoir. The channels are piled up, and part of the circulation channels are...

Examples

Embodiment 1

[0027] The plugging slurry for protecting low-pressure fractured reservoirs of this embodiment is composed of the following parts by weight: 2 parts of walnut shell with a particle size of 7-20 mesh, 3 parts of walnut shell with a particle size of 5-7 mesh, 2 parts of compound plugging agent FD-2, 1.5 parts of rigid while drilling plugging agent GXD for drilling, 3 parts of fine particle acid-soluble shielding temporary plugging agent RFD-1, 2 parts of medium particle acid-soluble plugging agent RFD -2, 4 parts of high water loss plugging agent R-19, 0.3 parts of calcium oxide, 100 parts of water.

[0028] The method for preparing the plugging slurry is as follows: adding the raw materials of each component except water into water and mixing them uniformly.

Embodiment 2

[0030] The plugging slurry for protecting low-pressure fractured reservoirs in this embodiment is composed of the following components by weight: 3 parts of walnut shells with a particle size of 7-20 mesh, 3 parts of walnut shells with a particle size of 5-7 mesh, 3 parts of compound plugging agent FD-2, 2 parts of rigid while drilling plugging agent GXD for drilling, 2 parts of fine particle acid-soluble shielding temporary plugging agent RFD-1, 2 parts of medium particle acid-soluble plugging agent RFD -2, 5 parts of high water loss plugging agent R-19, 0.2 parts of calcium oxide, 100 parts of water.

[0031] The method for preparing the plugging slurry is as follows: adding the raw materials of each component except water into water and mixing them uniformly.

experiment example 1

[0032] Experimental example 1 (indoor experiment)

[0033] In this experimental example, the plugging performance of the plugging slurry of Example 2 was tested.

[0034] The experimental method is as follows:

[0035] 1) Take the formula amount of water, add soda ash, sodium sakamoto, high-viscosity sodium carboxymethyl cellulose (HV-CMC), potassium polyacrylate (K-PAM) in sequence, stir at high speed for 10 hours until the mixture is uniform, and then cover and seal. Let stand for 24h to get the base slurry;

[0036] In the base slurry, relative to 100 parts by weight of water, the amount of soda ash is 0.3 parts by weight, the amount of Nasaka clay is 5 parts by weight, the amount of HV-CMC is 0.3 parts by weight, and the amount of K-PAM is 0.3 parts by weight;

[0037] 2) In the base slurry obtained in step 1), a formula amount of walnut shells, a composite plugging agent, a plugging agent while drilling, an acid-soluble plugging agent, a high water loss plugging agent, and calcium...

Technical field

[0001] The invention belongs to the technical field of plugging for petroleum drilling, and specifically relates to a plugging material for protecting low-pressure fractured reservoirs, and also relates to a plugging slurry for protecting low-pressure fractured reservoirs. Background technique

[0002] Lost circulation is when the fluid column pressure in the wellbore is greater than the formation fracture pressure or the formation pores or fractures are drilled, causing the fluid in the well to enter the formation on a large scale. It is the most common and most difficult problem in drilling engineering. , Not only delays the drilling operation time, prolongs the drilling cycle, and causes huge economic losses, but also the solid particles in the mud (including clay, weighting agent, treatment agent and fine drill cuttings) will be in the narrow throat of the oil and gas channel of the reservoir. The channels are piled up, and part of the circulation channels are...

Examples

Embodiment 1

[0027] The plugging slurry for protecting low-pressure fractured reservoirs of this embodiment is composed of the following parts by weight: 2 parts of walnut shell with a particle size of 7-20 mesh, 3 parts of walnut shell with a particle size of 5-7 mesh, 2 parts of compound plugging agent FD-2, 1.5 parts of rigid while drilling plugging agent GXD for drilling, 3 parts of fine particle acid-soluble shielding temporary plugging agent RFD-1, 2 parts of medium particle acid-soluble plugging agent RFD -2, 4 parts of high water loss plugging agent R-19, 0.3 parts of calcium oxide, 100 parts of water.

[0028] The method for preparing the plugging slurry is as follows: adding the raw materials of each component except water into water and mixing them uniformly.

Embodiment 2

[0030] The plugging slurry for protecting low-pressure fractured reservoirs in this embodiment is composed of the following components by weight: 3 parts of walnut shells with a particle size of 7-20 mesh, 3 parts of walnut shells with a particle size of 5-7 mesh, 3 parts of compound plugging agent FD-2, 2 parts of rigid while drilling plugging agent GXD for drilling, 2 parts of fine particle acid-soluble shielding temporary plugging agent RFD-1, 2 parts of medium particle acid-soluble plugging agent RFD -2, 5 parts of high water loss plugging agent R-19, 0.2 parts of calcium oxide, 100 parts of water.

[0031] The method for preparing the plugging slurry is as follows: adding the raw materials of each component except water into water and mixing them uniformly.

experiment example 1

[0032] Experimental example 1 (indoor experiment)

[0033] In this experimental example, the plugging performance of the plugging slurry of Example 2 was tested.

[0034] The experimental method is as follows:

[0035] 1) Take the formula amount of water, add soda ash, sodium sakamoto, high-viscosity sodium carboxymethyl cellulose (HV-CMC), potassium polyacrylate (K-PAM) in sequence, stir at high speed for 10 hours until the mixture is uniform, and then cover and seal. Let stand for 24h to get the base slurry;

[0036] In the base slurry, relative to 100 parts by weight of water, the amount of soda ash is 0.3 parts by weight, the amount of Nasaka clay is 5 parts by weight, the amount of HV-CMC is 0.3 parts by weight, and the amount of K-PAM is 0.3 parts by weight;

[0037] 2) In the base slurry obtained in step 1), a formula amount of walnut shells, a composite plugging agent, a plugging agent while drilling, an acid-soluble plugging agent, a high water loss plugging agent, and calcium...

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