Sleeving-back of Horizontal Wells to Control Downstream Oil Saturation and Improve Oil Recovery

Gréaves, M.; Saghr, A. M.

doi:10.2118/50428-ms

Cited by 7 publications

(5 citation statements)

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“…The downstream-half of the well, a conventional fully-perforated section very similar to Design 2, is shut in when the upstream sleeve-back is operating and later opened after the combustion front reaches the mid-way position in the sandpack. Full details of the sleeve-back technique are reported in an earlier paper (10) . Temperature regulation of the combustion cell surface was achieved by means of three tape heaters, which were wound around the cell.…”

Section: Methodsmentioning

confidence: 99%

THAI-New Air Injection Technology for Heavy Oil Recovery and In Situ Upgrading

Gréaves

Saghr

Xia

et al. 2001

Journal of Canadian Petroleum Technology

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THAI-"Toe-to-Heel" Air Injection, is a new EOR process, which integrates advanced technology and horizontal well concepts, to achieve a potentially very high recovery of heavy oil. It can also realize very substantial in situ upgrading by thermal cracking, producing upgraded oil to the surface. The process operates in a gravity stabilized manner by restricting drainage to a narrow mobile zone. This causes the flow of mobilized fluids to enter directly into the exposed section of a horizontal production well. The process can be operated on primary production, asnew technology, as a follow-up to existing technologies, or asa co-process where the advantages of high thermal efficiency are equired. This is achieved by concentrating the energy required for oil mobilization, recovery and thermal upgrading in the reservoir. Combined with clean technology design, THAI offerspathway, to future economic success for the heavy oil industry. Three-dimensional, semi-scaled experimental tests on light "Forties Mix" oil (30.7 °CDATA[API), Clair, West of Shetlands medium heavy oil (20.8 °CDATA[API), and heavy Wolf Lake oil (10.95 °CDATA[API) show that a well-controlled, narrow mobile oil zone is created just ahead of the combustion front. The width of this narrow zone depends on the characteristics of the heavy oil at reservoir conditions and the degree to which the very high viscosity of the cold oil seals the horizontal producer well. Well sealing can be augmented by a novel sleeve-back technique, which allows perforated downstream sections of the well to be shut-in. The application of this technique enabled the light oil test to mimic the operation of a heavy oil reservoir using THAI. Very high oil recoveries were achieved in the tests, up to 85﹪ OOIP. During wet in situ combustion (ISC), Wolf Lake oil was upgraded to 20 °CDATA[API, achieving a reduction in the cold oil viscosity from 100,000 mPas to around 50 mPas. Introduction Horizontal and multi-lateral wells are being introduced in ever increasing numbers to achieve further gains in reservoir productivity. Two hundred horizontal wells were drilled a decade ago. Now, one company has reported drilling more than 2,100 horizontalwells in North America(1). Advances have also been achieved in the depths drilled, reaching 8,761m(2) and lengths now reaching up to 11 km. Multi-lateral wells, with four or more side-tracks, are not uncommon and offer further optimization gains. Moreover, this technology will accommodate reservoir faults and problems of structural geology as regular design factors so that strategic placement of the well path is achieved. More recently, a new technique to control gas and water production rates by varying the fluid entry points has been successfully tested(3). The most important advantage of horizontal wells is the increase in the reservoir contact area compared to a vertical well. Horizontal wells have created new possibilities for the implementation of advanced IOR methods, especially in thermal recovery.

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Section: Methodsmentioning

confidence: 99%

THAI-New Air Injection Technology for Heavy Oil Recovery and In Situ Upgrading

Gréaves

Saghr

Xia

et al. 2001

Journal of Canadian Petroleum Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…The downstream-half of the well, a conventional fully-perforated section very similar to Design 2, is shut in when the upstream sleeve-back section is operating and later opened after the combustion front reaches the mid-way position in the sandpack. Full details of the sleeve-back technique are reported in an earlier paper (13).…”

Section: Methodsmentioning

confidence: 99%

New Air Injection Technology for IOR Operations in Light and Heavy Oil Reservoirs

1999

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“…While in the THAI process the gas channelling through the horizontal producer is negligible because of a natural seal off by a coke-like residue plug (1) , in TTH steamflooding this mechanism does not exist and a similar/equivalent mechanism has to be developed by the operator. For instance, the blocking of the upstream portion, close to the toe region, can be achieved (15) . Also, a certain chemical blocking agent, to progressively block the toe region, could be contemplated, similarly to the case of the TTHW process (16) .…”

Section: Developing a Self-healing Feature For The Tth Steamfloodingmentioning

confidence: 99%

Preliminary Considerations on Application of Steamflooding in a Toe-to-Heel Configuration

Turta¹,

Singhal²,

Xia

et al. 2009

Journal of Canadian Petroleum Technology

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With the advent of horizontal wells, a distinct change is tacitly taking place in our approach to the improved recovery of heavy oil-from displacing mobilized oil in a flood pattern from injector to producers over long distances on the order of hundreds of metres to short-distance oil displacement (SDOD) processes (typically over a few tens of metres).SDOD processes comprise Steam Assisted Gravity Drainage (SAGD), Cyclic Steam Stimulation (CSS) and Toe-to-Heel (TTH) Displacement Processes, which comprise Toe-to-Heel Air Injection (THAI), with its variant catalytic THAI (CAPRI), and Toe-to-Heel Waterflooding (TTHW). Presently SAGD is commercially used, while THAI has been under field testing for 3 years; testing of CAPRI is scheduled to start in 2010. TTHW has been under field testing both in the US and Canada for more than 4 years.Steamflooding in a TTH configuration (TTH steamflooding) uses vertical wells as injectors and horizontal wells as producers, arranged in a staggered line drive, with producers having their toes close to the shoes of vertical injectors; the horizontal section of producers is located at the base of the pay. The vertical wells are used for initiating the steam front, which subsequently is anchored at the toe of the horizontal producer; it is then propagated towards the producer's heel. In TTH steamflooding, the existing deficiency of conventional steamflooding schemes in terms of low vertical sweep is overcome by the beneficial use of gravity.To investigate the potential of TTH steamflooding, some laboratory tests were conducted. The objective was to assess the feasibility of TTH steam and thermo-solvent flooding (steam+propane co-injection) by carrying out 3D model experiments using heavy oil with a viscosity of 15,000 cP.Laboratory results showed that the concepts of TTH steamflooding and TTH steamflooding with solvent are feasible. All in all, stability of TTH steamflooding was relatively good, while the stability of TTH steamflooding with the addition of nitrogen or propane was much better. Significant improvements in design and operation of these processes were needed in order to promote override during the early phase, and obtain a stable and efficient process. The improvements included a cold (gas fingering) and a hot (steam-based) communication phase; and controlling lateral spread of steam by using two additional vertical control wells (positioned laterally but close to the heel of the horizontal producer) for conducting a limited steamflood. Nitrogen was injected along with steam in the conventional steamflood; propane replaced nitrogen in TTH steamflooding with solvent. With these improvements, rise of steam chamber to the top occurred much earlier, and a favourable tilt-forward-angle of the thermal front was quickly obtained. TTH steamflooding with solvent proved superior to the TTH steamflooding, as the channeling of steam

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Sleeving-back of Horizontal Wells to Control Downstream Oil Saturation and Improve Oil Recovery

Abstract: This paper was prepared for presentation at the 1998 SPE International Conference on Horizontal Well Technology held in Calgary, Alberta, Canada, 1-4 November 1998.

Cited by 7 publications

References 4 publications

THAI-New Air Injection Technology for Heavy Oil Recovery and In Situ Upgrading

THAI-New Air Injection Technology for Heavy Oil Recovery and In Situ Upgrading

New Air Injection Technology for IOR Operations in Light and Heavy Oil Reservoirs

Preliminary Considerations on Application of Steamflooding in a Toe-to-Heel Configuration

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