Vertical Interference Test in Wells With Downhole Water Sink Completions

Key L ab o ra to ry o f E xp lo ra tio n T e ch n olo gie s fo r O il and Gas Resources, M in is try o f Education, Yangtze U nive rsity, W u h an , H ubei 4 3 0 1 0 0 , C hina; P e tro le u m E n g in e erin g C ollege, Yangtze U nive rsity, W uhan, H ubei 4 3 0 1 0 0 , C hina e -m a il: m adong @ ya n g tze u .e du .cn C hangw ei Liu S c h o o l o f Energy, C hin a U n iv e rs ity o f G eosciences (B e ijin g ), B e ijin g 4 3 0 1 0 0 , C hina e -m a il: c h a n g w e iliu @ o u tlo o k .c o m Changhui Cheng S in o p e c J ia n g h a n O il Field, W u h an , H ubei 4 3 0 1 0 0 , C hina e -m a il: c c h je n n y @ 1 6 3 .c o m New Relationship Between Resistivity Index and Relative PermeabilityRelative permeability as an important petrophysical parameter is often measured directly in the laboratory or obtained indirectly from the capillary pressure data. However, the literature on relationship between relative permeability and resistivity is lacking. To this end, a new model o f inferring two-phase relative permeability from resistivity index data wav derived on the basis o f Poiseuille's law and Darcy's law. The wetting phase tortuos ity ratio was included in the proposed model. The relative permeabilities computed from the capillary pressure data, as well as the experimental data measured in gas-water and oil-water flow condition, were compared with the proposed model. Both results demon strated that the two-phase permeability obtained by proposed model were generally in good agreement with the data computed from capillary pressure and measured in the lab oratory. The comparison also showed that our model was much better than Li model at matching the relative permeability data.Darcy's law and Ohm's law are used to describe quantitatively the fluid flow in a porous medium and the electric flow in a con ductive body, respectively. The similarity theory between the two Journal of Energy Resources Technology

Section: Introductionmentioning

confidence: 99%

New Relationship Between Resistivity Index and Relative Permeability

Liu

Cheng

2015

Numerical Modeling of the Effects of Disproportionate Permeability Reduction Water-Shutoff Treatments on Water Coning

Bekbauov¹,

Kаltayev

Wojtanowicz

et al. 2012

In the present paper, we analyze numerically the disproportionate permeability reduction (DPR) water-shutoff (WSO) treatments in oil production well, i.e., the ability to reduce relative permeability (RP) to water more than to oil. The technique consists of bullhead injection of polymer solutions (gelant) into the near-wellbore formation without zone isolation. By assuming the low dissolution of polymer in oil and the low mobility of the gel in porous medium, we reduced the compositional model of the process to a simple two-phase model, with RP and capillary pressure (PC) dependent on the water and gel saturation. We proposed the extension of the LET correlations used to calculate RP and PC for the case of three phases (oil–water–gel). The problem is divided into two stages: the polymer injection and the post-treatment production. Both of these processes are described by the same formal mathematical model, which results from incompressible two-phase flow equations formulated in terms of normalized saturation and global pressure. The thermal effects caused by the injection of a relatively cold aqueous solution are taken into account. The numerical solution shows favorable results for the DPR WSO treatments. Other techniques, such as the creation of impermeable barrier and downhole water sink (DWS) technology, are also tested in order to check the validity of the developed numerical model with experimental data.

Determination and Implication of Ultimate Water Cut in Well-Spacing Design for Developed Reservoirs With Water Coning

Prasun

Wojtanowicz

2018

Theoretically, ultimate water-cut (WCult) defines stabilized well's oil and water production rates for uncontained oil pay underlain with water. However, in a real multiwell reservoir, the well's drainage area is contained by a no-flow boundary (NFB) that would control water coning, so the WCult concept should be qualified and related to the well-spacing size. Also, the presently used WCult formula derives from several simplifying assumptions, so its validity needs to be verified. The study shows that in multiwell bottom-water reservoirs, the production water-cut would never stabilize (after initial rapid increase) but would continue increasing at slow rate dependent on the production rate and well-spacing size. At each production rate, there is a minimum well-spacing size above which water-cut becomes practically constant at the value defined here as pseudoWCult. A new formula—developed in this study—correlates the minimum well-spacing with reservoir properties. Further, formula for pseudoWCult is derived by considering radial flow distortion effects in the oil and water zones. It is found that for well-spacing larger than the minimum well-spacing, the two effects-when combined-do not change the water-cut value. Thus, in practical applications, for sufficiently large well-spacing, the pseudoWCult values can be computed from the presently used WCult formula. The pseudoWCult concept has potential practical use in well-spacing design for ultimate recovery determined by the water cut economic limit, WCec. When the water-cut economic margin (WCec–WCult) is large, well-spacing has little effect on the ultimate recovery, so large well-spacing could be designed. However, when the water-cut economic margin is small, reservoir development decision should consider increase of final recovery by reducing well-spacing below the minimum well-spacing.