Great challenges had been faced in the design and selection of artificial lift methods at Lungu reservoir of Tarim field in the North West China due to the extremely deep reservoir and extra-viscous crude. The average depth of the reservoir is about 5500m. The initial reservoir temperature is about 127°C, and pressure ranges from 57 to 64 MPa. With very high content of resins and asphaltenes, the oil from this reservoir has a viscosity of about 10×10 4 mPa⋅s at 50°C and density varying from 0.95 to 1.08 g/cm 3 . Thanks to the high reservoir temperature along with high pressure, the oil has fairly enough mobility to flow into the well bore under reservoir conditions. However, as it flows towards the surface, the decrease in temperature along the well bore causes dramatic increase of viscosity. Both calculations and field experience suggested that it is not possible to meet the required production rate with only one particular available mechanical lift method, such as rod pump, jet pump, or other individual lifting method.To overcome the lifting difficulty and achieve the production volume, a composite pumping system which combines both jet and rod pumps was proposed and practiced in this field. The proposed composite jet-rod pumping system was proven to be a great success, which significantly increased and maintained production volume in the wells tested. This paper discusses the working mechanisms involved in the composite jet-rod pumping system, the lifting parameter optimization methodology and workflow, and the field application experience. This composite jet-rod pumping system was demonstrated to be the most promising mechanical lift system for Lungu reservoir and it can be potentially used in the other deep heavy oil fields world wide.

Gas injection has become an important means of enhancing oil recovery (EOR) in clastic reservoirs, the Donghe Oilfield, Tarim, has been undergoing gas injection to enhanced oil recovery. During the gas injection, dynamic justification of gas injection was the most severe challenges, which needed to monitor the pressure profile, temperature profile and gas injection profile. Therefore, monitoring gas injection profile has becoming an important part of gas drive reservoirs. Donghe Oilfield was characterized by ultra-deep (>6000m), high temperature (>140°C) and high content of carbon dioxide, conventional manometer and thermometer cannot meet the downhole condition of ultra-deep and high temperature. To continuously monitor gas injection well, permanent fibre-optic surveillance technique featured with outstanding conformance, nice corrosion resistance and long-life span was developed, and a program was developed to use real-time fiber-optic Distributed Temperature Sensing (DTS) and Distributed Acoustic sensing (DAS) to identify the gas injection profile (gas channeling). Monitoring principle and system assembly of the fibre-optic was demonstrated in detail, the DTS utilized Joule - Thompson cooling principle as the gas injected into formation through screen pipe, while the DAS captured the amplitude and frequency of acoustics from the gas flow. DTS and DAS data obtained at the same time by using fiber wireline outside the gas injection string during gas injection. There was a field application in gas injection well of DH1-H3 and gas injection profiles derived from DTS and DAS had the extremely high consistency to radioactive tracer profiles run at about the same time and under similar injection rates and pressure. The success of the fibre-optic surveillance in DH1-H3 exhibited great potential of fiber-optic sensing in gas injection EOR projects, which could provide a new and effective tool in identifying gas channeling.

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We present linear conjugated combined aberration modes with a concentric pupil diameter of 4 mm. The combinations are according to the coupling relationship between Zernike modes over the concentric circle domain within the unit circle and the root mean square decreasing amplitude ratio of the corresponding aberration modes in the concentric pupil, in which the reconstruction pupil diameter is 6 mm. Each combined mode shares the characters of 2 radial orders apart, the same azimuth frequency, the same coefficient sign, and the prescribed amount, such as (C = 0.3λ), and so on. We also analyze the influence of the combined modes on optical quality. Simulations and experiments show improvement after combination; they also indicate that the influence of conjugated combination on optical quality has compensation and not superposition.

Aiming at the high temperature and high salinity of Keshen 8 gas reservoir, the selective water plugging agent system with high temperature resistance, salt resistance and water permeability was studied. The effect of the plugging system components on the performance of plugging agent was investigated by single factor experiment, and the best formula was determined. The compressive strength of the material was stable at about 4.6 MPa, and the plugging agent had good temperature and salt resistance. Through the physical simulation experiment of fracture core flow, the plugging effect of different plugging agent injection volume on plugging agent is discussed. When the injection volume is 0.3 PV, the liquid phase plugging rate is 86.69 %, and the gas phase plugging rate is 26.18 %, which has good water resistance and gas permeability.