Phase behavior of heavy oil–solvent mixture systems under reservoir conditions

Abstract

A novel experimental procedure was proposed to investigate the phase behavior of a solvent mixture (SM) (64 mol% CH4, 8 mol% CO2, and 28 mol% C3H8) with heavy oil. Then, a theoretical methodology was employed to estimate the phase behavior of the heavy oil–solvent mixture (HO–SM) systems with various mole fractions of SM. The experimental results show that as the mole fraction of SM increases, the saturation pressures and swelling factors of the HO–SM systems considerably increase, and the viscosities and densities of the HO–SM systems decrease. The heavy oil is upgraded in situ via asphaltene precipitation and SM dissolution. Therefore, the solvent-enriched oil phase at the top layer of reservoirs can easily be produced from the reservoir. The aforementioned results indicate that the SM has promising application potential for enhanced heavy oil recovery via solvent-based processes. The theoretical methodology can accurately predict the saturation pressures, swelling factors, and densities of HO–SM systems with various mole fractions of SM, with average error percentages of 1.77% for saturation pressures, 0.07% for swelling factors, and 0.07% for densities.

A Numerical Model for Investigating the Steam Conformance along the Dual-String Horizontal Wells in SAGD Operations

“…The oil phase difference equation is taken as an example to illustrate the linearization process of the equations. 1 The first two terms on the left side of the oil phase difference Equation (A44) can be derived as follows:…”

“…Heavy oil is an important energy source [1][2][3][4], and Steam-assisted gravity drainage (SAGD) is an effective technology for the economic recovery of heavy oil [5][6][7][8]. The SAGD process usually employs two parallel horizontal wells.…”

“…δP l oi, j,k+1 − δP l oi, j,k + ∂T ho ∂P o δP o + ∂T ho ∂T δT + ∂T ho ∂S w δS w + ∂T ho , j,k−1 − Φ l oi,j,k + T l hoi, j,k− 1 2 δP l oi, j,k−1 − δP l oi, j,k + ∂T ho ∂P o δP o + ∂T ho ∂T δT + ∂T ho ∂S w δS w + ∂T ho ,k − Φ l wi, j,k + T l hwi+ 1 2 , j,k δP l oi+1, j,k − δP l oi, j,k − T l hwi+ 1 2 , j,k δP l cowi+1, j,k − δP l cowi, j,k + ∂T hw ∂P o δP o + ∂T hw ∂T δT + ∂T hw ∂S w δS w i+ 1 2 , j,k Φ l wi+1, j,k − Φ l wi, j,k + T l hwi− 1 2 , j,k Φ l wi−1, j,k − Φ l wi, j,k + T l hwi− 1 2 , j,k δP l oi−1,j,k − δP l oi, j,k − T l hwi− 1 2 , j,k δP l cowi−1, j,k − δP l cowi, j,k + ∂T hw ∂P o δP o + ∂T hw ∂T δT + ∂T hw ∂S w δS w i− 1 2 , j,k Φ l wi−1, j,k − Φ l wi, j,k + T l hwi,j+ 1 2 ,k Φ l wi, j+1,k − Φ l wi, j,k + T l hwi, j+ 1 2 ,k δP l oi, j+1,k − δP l oi, j,k − T l hwi, j+ 1 2 ,k δP l cowi, j+1,k − δP l cowi, j,k + ∂T hw ∂P o δP o + ∂T hw ∂T δT + ∂T hw ∂S w δS w i,j+ 1 2 ,k Φ l wi, j+1,k − Φ l wi, j,k + T l hwi,j− 1 2 ,k Φ l wi, j−1,k − Φ l wi, j,k + T l hwi, j− 1 2 ,k δP l oi, j−1,k − δP l oi, j,k − T l hwi, j− 1 2 ,k δP l cowi, j−1,k − δP l cowi, j,k + ∂T hw ∂P o δP o + ∂T hw ∂T δT + ∂T hw ∂S w δS w i,j− 1 2 ,k Φ l wi, j−1,k − Φ l wi, j,k + T l hwi,j,k+ 1 2 Φ l wi, j,k+1 − Φ l wi, j,k + T l hwi, j,k+ 1 2 δP l oi, j,k+1 − δP l oi, j,k − T l hwi, j,k+ 1 2 δP l cowi, j,k+1 − δP l cowi, j,k + ∂T hw ∂P o δP o + ∂T hw ∂T δT + ∂T hw ∂S w δS w i,j,k+ 1 l wi, j,k+1 − Φ l wi, j,k + T l hwi,j,k− 1 2 Φ l wi, j,k−1 − Φ l wi, j,k + T l hwi, j,k− 1 2 δP l oi, j,k−1 − δP l oi, j,k − T l hwi, j,k− 1 2 δP l cowi, j,k−1 − δP l cowi, j,k + ∂T hw ∂P o δP o + ∂T hw ∂T δT + ∂T hw ∂S w δS w i,j,k− 1 l wi, j,k−1 − Φ l wi, j,k + T l hgi+ 1 2 ,j,k Φ l gi+1,j,k − Φ l gi, j,k + T l hgi+ 1 2 , j,k δP l oi+1, j,k − δP l oi, j,k + T l hgi+ 1 2 , j,k δP l cgoi+1, j,k − δP l cgoi, j,k + ∂T hg ∂T δT + ∂T hg ∂S g δS g i+ 1 2 , j,k Φ l gi+1, j,k − Φ l gi, j,k + j,k − Φ l gi,j,k + T l hgi−1 2 ,j,k δP l oi−1,j,k − δP l oi, j,k + T l ,k−1 − Φ l gi,j,k + T l hgi, j,k− 1 2 δP l oi,j,k−1 − δP l oi, j,k + T l hgi,j,k− 1 2 δP l cgoi,j,k−1 − δP l cgoi,j,k + ∂T hg…”

The Supercritical Multithermal Fluid Flooding Investigation: Experiments and Numerical Simulation for Deep Offshore Heavy Oil Reservoirs

“…The decline of light oil production and the exhaustion of onshore heavy oil resources lead to an increasing demand of offshore heavy oil [1,2]. Due to high but the temperature-dependent viscosity, the development regimes of offshore heavy oil, especially for oil with viscosity exceeding 350 mPa•s, can only be effectively extracted by thermal methods [3,4].…”

“…The generation of SCMTF is realized by the gasification of produced waste water and combustion of gasification product in SCW [8]. In contrast of steam, SCMTF has the following advantages: (1) the produced waste water is utilized as feedstock for SCMTF generation, which reduces the disposal cost of waste water, and the fuel cost for steam generation; (2) the SCMTF generator occupies small areas of land, which is more convenient than the large-scale steam generator considering the narrow space of offshore platforms; and (3) the temperature and dryness fraction of SCMTF is much higher than that of steam. Therefore, it is inferred that the SCMTF is superior to steam in enhancing deep offshore heavy oil recovery.…”