Process Introduction

Process Introduction

The chemical flooding process is to reduce the permeability of the high-permeability layer/section, reduce the permeability differences between layers by injecting gel that could flow in the large pore path of the formation or fractures into the water injection well, thus attaining the targets of controlling the channeling of injected water, adjusting the interlayer water absorption so as to enlarge the swept volume of the injected water and improve the production of the wells. This technology is mainly dominated by organic gel systems, together with the inorganic gel system, which can be adjusted according to different reservoir conditions, and has been widely used in water-cut controlling and production stabilization measures on offshore oilfields due to its simple process, low costs and safe system, etc. At present, there are polymer systems, pre crosslinked particle systems and surfactant systems. The corresponding system or combination application is selected according to the reservoir nature and the problems to be solved in the target well group.

Technical Indicators

Technical Applicability

Application

Complete the fluid preparation on the ground, and pump into the formation by plunger pump via filter after curing. Subsequently, replace with injected water, test the pressure drop curves, shut-in the well for coagulation, and restore the injection.

Process Introduction

The Marketing Department has two technologies - chemical commingled plugging and staged packer plugging of horizontal well. For the oil wells with unknown effluent or with effluent from multiple points, the chemical commingled plugging utilizes the plugging agents to plug and seal off the channeling selectively in an automatic control manner, adjusts the producing profile of the oil wells, which is characterized by simple process, low costs and safe systems, etc. The staged packer plugging technology of horizontal wells, determines the water production interval (point) accurately through fiber-optical well logging, array-type multiphase combination logging and other water exploration technologies, attain the targets of locating the water shutoff or chemically plugging the water points, which is featured with high successful rate, large plugging strength, long period of validity, etc. At present, there are seven water plugging systems of nitrogen foam system, initial low viscosity polymer gel system, temperature control temporary plugging system, scattering gel system, water-based composite gel system, temporary plugging protection system and annulus chemical sealing system. The corresponding system or combination application is selected according to the reservoir nature and the problems to be solved in the target well group.

Technical Indicators

Technical Applicability

Application

Process Introduction

The wellbore integrity management technology based on ZoneSHIELD casing sealing agent is adopted to address wellbore integrity issues caused by dynamic/static seal failure, cement sheath damage, etc. It has the advantages of short construction period, long effective period, and no impact on production. The sealing agent system applied by this technology can achieve autonomous settlement to the leakage position, penetrate into fine pores, and not mix with oil-water slurry, ensuring the sealing strength and successfully solving the problem of safe liquid preparation under high temperature conditions and complete solidification under low temperature conditions, ensuring safe operation during the injection process of sealing agent.

Technical Indicators

Initial viscosity < 150mPa‧s;

Insoluble in water and oil, with self settling properties;

High compressive strength, bonding strength > 150 MPa/m.

Technical Applicability

Production wells with failed dynamic/static seals;

Production wells with cement ring damage;

Production wells with corroded and damaged casing.

Supporting Systems, Software and Tools

This technology adopts supporting equipment and tools such as automated annular insertion tube plugging agent injection equipment, magnetic drill and diversion groove, which improves the adaptability of this technology to complex on-site operations.

Application

During homework, auxiliary operations such as casing drilling and wing valve insertion can be carried out as needed. The process flow is as follows: (1) Casing drilling or wing valve insertion; (2) Prepare a small amount of sealing agent multiple times; (3) Inject ZoneSHIELD casing sealant into the annulus using a plunger pump; (4) Close the injection valve and wait for solidification.

Process Introduction

HGSC composite plugging removal technology, in collaboration with four functions of "generating heat chemically, increasing the energy by gas, chelation and dissolution, penetration cleaning", integrates the plugging removal concept of mechanical method, chemical method and thermal method organically, removes the organic plugging in the shaft and the immediate vicinity of wellbore resulting from the deposition of heavy components as well as the inorganic plugging caused by scaling of metal ions, releases the production capacity of oil well and improve its yield as well. This technology, which is mainly dominated by chemical heat generation system together with chelating system and organic cleaning system, could deal with organic and inorganic pollution at the same time, with the features of simple process, low costs, safe system, etc.

Technical Indicators

·Cleaning efficiency of heavy components ≥ 90%；

·Corrosion rate:＜1g/(m2•h);

·With better compatibility, free from observed precipitation and flocculation.

Technical Applicability

·Low producing wells once with high-yield period;

·Wells plugged due to deposition of organic matters;

·Applicable to medium and high porosity and permeability formation;

·Water cut ≥40%

Supporting Systems, Software and Tools

This technology can cooperate with string operation, and support with hydraulic flushing nozzle for operations. Inject parallel with two pumps, support with reaction inhibitor for operations.

Methods of Application

No special equipment required when operating, the process flow is as follows: (1) The slurry pump (acidizing pump) injects the front-placed slug; (2) Shut in for soaking; (3) the slurry pump (acidizing pump) injects the slug of HGSC-A+B as well as the slug of HGSC-C; (4) Shut in for soaking.

Application

HGSC composite plugging removal technology has been implemented in Bohai Oilfield for more than 50 wells since 2013, with a success rate of 100%. The liquid increase efficiency is 98.5%, and the cumulative oil increase exceeds 102,000 tons.

Process Introduction

Chelating plug removal system is an environment-friendly oil well plug removal system, which is suitable for removing calcium magnesium scale and solid particles formed in the near wellbore formation pores, blastholes and screen sections during oil well production. It has the advantages of strong permeability, fast decomposition and no precipitation. The special additives in the system enable it to have long-term anti swelling, anti scaling and sand control functions, remove the plugging damage, reduce the possibility of sand production in the formation, and achieve the protection of oil and gas reservoirs. The main agent is a multi nitrogen heterocyclic ring structure. As a multi dentate ligand, it "fixes" multivalent metal ions to the inside of the ring structure. The state is stable. The main agent has strong chelating ability, is acidic, and has corrosion and scale inhibition characteristics. It forms polycarboxylate coordination ions with metal ions such as calcium, magnesium and iron in the water medium to form a dense protective film on the metal surface, with strong corrosion inhibition performance and extremely low corrosion rate to metals.

Technical Indicators

·PH (fresh liquid): 1~3/6

·PH (residue): 6

·Surface tension: ≤ 28mN/m

·Interfacial tension: ≤ 3mN/m

·Calcium scale corrosion rate: ≥ 90%

·Clay dissolution rate: 10-20%

·Anti swelling rate: ≥ 85%

·Shrinkage expansion rate: ≥ 25%

·Demulsification rate (2h): ≥ 95%

·Corrosion rate (4h, 65 ℃): ≤ 1.5g/(m2·h)

Technical Applicability

·Slow speed system, which can realize deep unblocking treatment;

·Removal of calcium, magnesium, barium, strontium, iron and other inorganic scale blockage;

·Clay mineral expansion, particle migration and other sensitive minerals are relieved;

·Damage to reservoir caused by invasion of foreign fluids such as drilling and completion filtrate and solid invasion;

·Low corrosion, extremely low secondary damage, and low flowback requirements;

·No emulsification with crude oil, and the returned liquid can directly enter the production process;

·Applicable temperature range: 50~100 ℃.

Application

This technology has been applied in Bohai Oilfield for more than 150 well times and increased oil production by more than 230,000 m3