LOGO INFLOW PERFORMANCE RELATIONSHIP COMPOSITE IPR LOGO
Composite IPR (1) 2 Nearly all producing formations are stratified
to some extent. This means that the vertical borehole in the
production zone has different layers having different reservoir
pressures, permeabilities, and producing fluids. If it is assumed
that there are no other communication between these formations
(other than the wellbore), the production will come mainly from the
higher permeability layers. Pr1, k1,.. Pr2, k2,.. Pr3, k3,.. q1 q2
q3 q1+q2+q3 LOGO Composite IPR (2) 3 As the wells rate of
production is gradually increased, the less consolidated layers
will begin to produce one by one (at progressively lower GOR), and
so the overall ratio of production (q1 : q2 : q3) will fall as the
rate is increased. q1 q2 q3 (q1+q2+q3)>>> Pwf > GOR
total >> LOGO Composite IPR (4) 5 Thus, it is to be expected
that a well producing from a stratified formation will exhibit a
minimum GOR as the rate of production is increased.
q1q2q3q1+q2+q3>>GORtotal >>LOGO Composite IPR (5)6 One
of the major concerns in a multiplayer system is that interlayer
cross-flow may occur if reservoir fluids are produced from
commingled layers that have unequal initial pressures. This
cross-flow greatly affects the composite IPR of the well, which may
result in an optimistic estimate of production rate from the
commingled layers. q 1 q 2 q 3 q 1 +q 2 +q 3 >> GORtotal
>> LOGO Composite IPR (6) 7 El-Banbi and Wattenbarger (1996,
1997) investigated productivity of commingled gas reservoirs based
on history matching to production data. However, no information was
given in the papers regarding generation of IPR curves. LOGO
CompositeIPR (7) Pseudosteady-state flow prevails in all the
reservoir layers. Fluids from/into all the layers have similar
properties. Pressure losses in the wellbore sections between layers
are negligible (these pressure losses are considered in Chapter 6
where multilateral wells are addressed). The IPR of individual
layers is known. 8 q1q2q3q1+q2+q3>>GORtotal >>LOGO 9 On
the basis of Assumption 1, under steady-flow conditions, the
principle of material balance dictates net mass flow rate from
layers to the well =mass flow rate at well head or
PENGEMBANGANPERSAMAAN COMPOSITE IPR LOGO 10 Fluid flow from
wellbore to reservoir is indicated by negative qi UsingAssumption 2
and ignoring density change from bottom hole to well head, Eq.
(3.36) degenerates to PENGEMBANGANPERSAMAAN COMPOSITE IPR LOGO
Single-Phase Liquid Flow 11 The reservoir Pressure is above the
Bubble Point Pressure The flowing bottom hole pressure also above
the Bubble Point pressure J*i is the productivity index of layer I
IPR Equation for composite reservoirs and single phase LOGO Maximum
Production Rate 12 For a single layer formation, Qmax is determine
at Pwf = 0 It is different for composite formations Each formation
has different values of Qmax, but should have the same bottom hole
pressure It should be borne in mind that Pwfo is a dynamic
bottomhole pressure because of cross-flow between layers. LOGO
Two-Phase Flow Composite IPR 13 Developed based on Vogels IPR Curve
Composite Two-Phase IPR Curve Wells Maximum Flow Rate The flowing
bottom hole pressure at Qmax
LOGO Two Phase IPR Pr > Pb 14 LOGO Case Study (1) 15 LOGO
Case Study (2) 16 LOGO Case Study (3) 17 The composite IPR for
Group 1 (D3 and D4) is the same as shown in Fig. 3.15 because these
two layers were the commingle-tested.Composite IPRs of Group 2 and
Group 3 are plotted in Figs. 3.17 and 3.18. Table 3.2 compares
production rates read from Figs. 3.16, 3.17, and 3.18 at some
pressures. This comparison indicates that significant production
from Group 1 can be achieved at bottom-hole pressures higher than
2658 psi, while Group 2 and Group 3 are shut-in.A significant
production from Group 1 and Group 2 can be achieved at bottomhole
pressures higher than 2,625 psi while Group 3 is shutin. The
grouped-layer production will remain beneficial until bottom-hole
pressure is dropped to below 2,335 psi where Group 3 can be open
for production. LOGO FUTURE IPR CURVES PERAMALAN KURVA IPRNp
meningkat, P-r turun, maka Productivity Index turun (?) 18 LOGO
Persamaan Aliran Dua Fasa Dinyatakan sebagai Fungsi tekanan Kro
sebagai fungsi saturasi minyak So = f(P) Berubah thd Waktu Dan
Tekanan J dipengaruhi oleh kro/oBo 19 LOGO Persamaan Aliran Dua
Fasa Perubahan Kurva IPR di waktu mendatang ditunjukkan oleh
perubahan slope, yang ditunjukkan olehperubahan productivity index,
J. Untuk kondisi aliran 2 fasa, untuk setiap kurva IPR harga
productivity index dinyatakan sebagai dq/dPwf = J 20 LOGO Perubahan
Productivity Index (1) 21 LOGO Perubahan Productivity Index (2)
Muskat menyatakan bahwa perbandingan Productiviy Index pada dua
waktu produksi yang berbeda dapat dinyatakan sebagai perbandingan:
Productivity Index didefinisikan sebagai slope dari kurva IPR
2121||.|
\|||.|
\|=o oroo oroBkBkJJwfdPdqJ =22 LOGO Peramalan IPR rmax o*pPQ 8 .
1J =Productivity Index, (dq/dPwf) yang merupakan turunandari
persamaan Vogel adalah sebagai berikut: Subscript p menyatakan
kondisi saat ini (presentcondition) Berdasarkan persamaan aliran 2
fasa, perbandingan productivity index padakondisi saat ini dan
yangakan datang, dinyatakan: 23 LOGO Peramalan IPR Berdasarkan
hasil turunan productivity index, maka dapat ditentukan Laju
Produksi Minyak Maksimum untuk waktu produksi mendatang : 24 LOGO
Persamaan Fetkovich Asumsi bahwa hubungan antara kro/oBo terhadap
tekanan adalah linier, sehingga perbandingan kro/oBo pada dua harga
tekanan sama dengan perbandingan tekanannya Dengan demikian
perbandingan productivity index dapat dinyatakan sebagai rirPo
oroPo oroPPBkBkrir=||.|
\|||.|
\|2 r1 r21PPJJ=25 LOGO Persamaan Fetkovich
rfriPrPrPPJJfi=n2wf2rf Pr oP P J qf =n2wf2rfrirfi Pr oP PPPJ q
=rirfPr PrPPJ Ji f=Harga JPri dan n diperoleh dari data test
isochronal pada Pri Dengan anggapan bahwa J dan n tidak berubah 26
LOGO Persamaan Fetkovich Jika harga n pada persamaan Fetkovich
dianggap berharga 1.0, maka perbandingan antara laju produksi
maksimum pada dua harga tekanan reservoir yang berbeda dapat
dinyatakan sebagai:31 r2 r1 max o2 max oPPQQ||.|
\|=3rirfi max o f max oPPQ Q||.|
\|=27 LOGO Persamaan Peramalan IPR - PS ( ) ( ) { }wf rwe3oP m P
mS 5 . 0rrlnkh 10 08 . 7q + ||.|
\|=( )rwe3max oP mS 5 . 0rrlnkh 10 08 . 7Q+ ||.|
\|=( )( )rirfi max of max oP mP mQQ=Pada Pwf = 0 maka Qo,max:
Perbandingan Qomax awal terhadap Qomax yang akan datang: 28 LOGO
Persamaan Peramalan IPR - PS ( )( )||.|
\|=rirfrirfPP429922 . 3 exp 033210 . 0P mP m( )( )||.|
\|=rirfrirfPP152343 . 4 exp 015215 . 0P mP mAPI > 40 API <
40 ( )( )rirfi max o f max oP mP mQ Q =Persamaan IPR PS 29 LOGO
Persamaan IPR PS S c3S c1 n4 2e c e c a + =anc1c2c3c4
a10.1829220-0.36443800.8145410-0.0558730
a2-1.4769500-0.45663201.6462460-0.4423060
a3-2.1492740-0.19597602.2892420-0.2203330
a4-0.02178310.0882860-0.2603850-0.2108010
a5-0.5524470-0.0324490-0.5832420-0.3069620 rwfDPPP =30 LOGO 31
