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Structural Longevity, Vol.9, No.3, pp. 143-151, 2013, DOI:10.3970/sl.2013.009.143
Abstract Several water control agents, including pre-linked gel particles, emulsion microspheres, continuous chromium gel with different viscosity and underground starch graft copolymer gel were evaluated in lab. The properties such as gelation time and gel strength of gel, and expansion of particles and microspheres were tested at high temperature. Also, the injection pressure, plugging strength and resistance factor were measured using the artificial low permeability cores with fractures.
It was shown that, for the particle type water control (pre-linked gel particles and emulsion microspheres), the particle size and distribution are crucial characters for the plugging property. The… More >

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Structural Longevity, Vol.9, No.3, pp. 153-168, 2013, DOI:10.3970/sl.2013.009.153
Abstract Coalbed methane (CBM) is an important natural gas resource, and appropriate well completion method is very important to increase productivity. At present there are many CBM well completion methods, including fractured vertical well, open-hole cavity well, U-shape well, V-shape well and pinnate horizontal well. Aim at the diversity of CBM well completion methods, multi-objective decision-making method is used to evaluate these completion methods and select the best completion to maximize economic benefit. Firstly implements production prediction and economic evaluation for each completion method, and then chooses multi-objective decision-making method to evaluate five indexes: cumulative gas… More >

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Structural Longevity, Vol.9, No.3, pp. 169-180, 2013, DOI:10.3970/sl.2013.009.169
Abstract In long horizontal wells, the production rate at the heel is typically higher than that at the toe. The resulting imbalanced production profile may cause early water or gas breakthrough into the wellbore. Once coning occurs, well production may severely decrease due to limited flow contribution from the toe. To eliminate this imbalance, inflow control devices (ICDs) are placed in each screen joint to balance the production influx profile across the entire lateral length and to compensate for permeability variation.
Currently, there are four different Passive ICD designs in the industry: nozzlebased, helical channel, tube-type and… More >

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Structural Longevity, Vol.9, No.3, pp. 181-196, 2013, DOI:10.3970/sl.2013.009.181
Abstract On the basis of describing the nonlinear seepage characteristics in lowpermeability reservoirs and the conductivity varying law of hydraulic fracture, a nonlinear mathematics model which couples low-permeability reservoirs and hydraulic fracture is established. The model takes nonlinear and quasi-linear flow stages in the reservoirs system, and emerging Darcy and non-Darcy flow in the fracture system into account. Finite difference equation set is derived with Taylor expansion method, and stability condition of the scheme is presented; On that basis the computer model is formed. The impact of starting pressure gradient, varying conductivity of the hydraulic fracture More >

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Structural Longevity, Vol.9, No.3, pp. 197-205, 2013, DOI:10.3970/sl.2013.009.197
Abstract The LD5-2N block is a typical heavy oil reservoir in Bohai offshore oilfield, and the viscosity of crude oil for this block at reservoir condition is about 10000mPa.s. Therefore, the conventional exploitation method of water flooding or chemical flooding will be not suitable for this block, and the thermal recovery should be considered. Using the method of numerical simulation, the steam assisted gravity drainage (SAGD) process for this block is investigated in this paper. Firstly, a sensitivity analysis process of reservoir properties and fluid parameters is conducted, e.g., reservoir thickness, oil viscosity, permeability, the vertical-horizontal… More >

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