1. A page buffer, comprising:
a bit line selection unit to selectively connect an even bit line or an odd bit line, which is connected to a memory cell array and to a sensing node according to a bit line selection signal;
a first switch to precharge the even bit line or the odd bit line by supplying a predetermined voltage to the sensing node according to a precharge signal;
a main register to store state data of the selected cell according to a voltage level of the sensing node and a main latch signal; a second switch to output an erase-verify signal according to a voltage level of a first terminal of the main register; a third switch to output a program-verify signal according to a voltage level of a second terminal of the main register; a cache register to store program data according to a control signal in a program operation; a fourth switch to transfer data stored in the cache register to the main register; and
a fifth switch to program the program data stored in the main register into the selected memory cell according to a program signal.
2. The page buffer as claimed in claim 1, wherein the bit line selection unit includes:
first and second NMOS transistors to discharge memory cells connected to the even bit line and the odd bit line, respectively, according to first and second discharge signals; and
third and fourth NMOS transistors to connect the even bit line or the odd bit line and the node, respectively, according to first and second bit line selection signals.
3. The page buffer as claimed in claim 1, wherein the first switch includes a PMOS transistor to supply a power supply voltage to the sensing node according to the precharge signal.
4. The page buffer as claimed in claim 1, wherein the main register includes:
a latch to store data depending upon a status of a selected cell of the memory cell array;
a first NMOS transistor driven according to a voltage level of the sensing node; and
a second NMOS transistor driven according to the main latch signal.
5. The page buffer as claimed in claim 4, wherein the main register further includes a NMOS transistor to initialize the latch according to an initialization signal.
6. The page buffer as claimed in claim 1, wherein the second switch includes a PMOS transistor that outputs a source voltage level or the erase-verify signal of a floating state according to the voltage level of the first terminal of the main register.
7. The page buffer as claimed in claim 1, wherein the third switch includes a PMOS transistor that outputs a source voltage level or the program-verify signal of a floating state according to the voltage level of the second terminal of the main register.
8. A verify method of a flash memory device, comprising the steps of:
discharging a selected bit line for program or erase verification, and then initializing a main latch;
precharging the selected bit line with a predetermined voltage level, and then evaluating a selected cell connected to the selected bit line;
storing data depending upon the state of the selected memory cell in the main latch;
outputting an erase-verify signal according to a voltage level of a first terminal of the main latch; and
outputting a program-verify signal according to a voltage level of a second terminal of the main latch.
9. The verify method as claimed in claim 8, wherein state data of the selected cell maintains a low level if the selected cell is in an erased state, and a high level if the selected cell is in a programmed state.
10. The verify method as claimed in claim 8, wherein the erase-verify signal maintains a floating state if the selected cell is in an erased state, and a high level if the selected cell is not in an erased state.
11. The verify method as claimed in claim 8, wherein the program-verify signal maintains a high level if the selected cell is in a programmed state, and a floating state if the selected cell is not in a programmed state.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for estimating a model of a formation, the formation having a wellbore extending therethrough, comprising:
obtaining a first resistivity measurement associated with the formation from a logging-while-drilling (LWD) senor, utilizing a computer;
obtaining a second resistivity measurement and a third invaded zone resistivity measurement associated with the formation from a second sensor, after obtaining the first resistivity measurement, utilizing the computer;
calculating an invaded zone thickness value for the wellbore using a first inversion technique, based on the first resistivity measurement, the second resistivity measurement, and the third invaded zone resistivity measurement, utilizing the computer; and
storing the invaded zone thickness value in a database, utilizing the computer.
2. The method of claim 1, wherein the model comprises an isotropic model of the formation.
3. The method of claim 1, wherein the invaded zone resistivity value is associated with an invaded zone of the formation proximate the wellbore.
4. The method of claim 1, wherein the first inversion technique comprises a least-squares inversion technique.
5. The method of claim 1, wherein the invaded zone resistivity value is associated with a predetermined layer in the formation.
6. The method of claim 5, wherein the invaded zone thickness value is associated with a predetermined layer in the formation.
7. The method of claim 1, wherein the second sensor comprises a wireline (WL) sensor, the method further comprising:
obtaining multi-component induction measurement obtained from an x-axis coil, a y-axis, and an z-axis coil in the WL sensor, utilizing the computer;
calculating a vertical resistivity value associated with the formation by utilizing a second inversion technique, based on the multi-component induction measurement from the WL sensor, utilizing the computer; and
storing the vertical resistivity value in the database, utilizing the computer.
8. The method of claim 1, wherein the second sensor comprises a wireline (WL) sensor, the third invaded zone resistivity measurement being obtained utilizing a micro-resistivity measurement device in the WL sensor.
9. The method of claim 1, further comprising calculating a horizontal resistivity value associated with the formation by utilizing the first inversion technique, based on the first resistivity measurement, utilizing the computer.
10. The method of claim 9, wherein the horizontal resistivity value is associated with a predetermined layer in the formation.
11. The method of claim 10, wherein the invaded zone thickness value, the third invaded zone resistivity measurement, and the horizontal resistivity value comprise a first model of the formation.
12. A system for estimating a model of a formation, the formation having a wellbore extending therethrough, comprising:
a database configured to store a first resistivity measurement from a logging-while-drilling (LWD) sensor associated with the formation, the database further configured to later store a second resistivity measurement and a third invaded zone resistivity measurement associated with the formation from a second sensor; and
a computer operably coupled to the database, the computer configured to calculate an invaded zone thickness value for the wellbore using a first inversion technique, based on the first resistivity measurement, the second resistivity measurement, and the third invaded zone resistivity measurement, the computer being further configured to store the invaded zone thickness value for the wellbore in the database.
13. The system of claim 12, wherein the second sensor comprises a wireless (WL) sensor, the database being further configured to stores at least one multi-component induction measurement obtained from an x-axis coil, a y-axis, and an z-axis coil in the WL sensor, the computer being further configured to calculate a vertical resistivity value associated with the formation by utilizing a second inversion technique, based on the multi-component induction measurement, the computer being further configured to store the vertical resistivity value associated with the formation in the database.
14. A method for estimating a model of a formation, the formation having a wellbore extending therethrough, comprising:
obtaining a first resistivity measurement associated with the formation from a logging-while-drilling (LWD) sensor, utilizing a computer;
obtaining a second resistivity measurement associated with the formation from a second sensor, after obtaining the first resistivity measurement, utilizing the computer;
calculating an invaded zone resistivity value and an invaded zone thickness value for the wellbore by utilizing an inversion technique, based on the second resistivity measurement, utilizing the computer; and
storing the invaded zone resistivity value and the invaded zone thickness value for the wellbore in a database, utilizing the computer.
15. The method of claim 14, wherein the model comprises an isotropic model of the formation.
16. The method of claim 15, wherein the inversion technique comprises a least-squares inversion technique.
17. The method of claim 14, wherein the invaded zone resistivity value is associated with an invaded zone of the formation proximate the wellbore.
18. The method of claim 14, wherein the invaded zone resistivity value is associated with a predetermined layer in the formation.
19. The method of claim 18, wherein the invaded zone thickness value is associated with the predetermined layer in the formation.
20. The method of claim 14, further comprising calculating a horizontal resistivity value utilizing the inversion technique, based on the first resistivity measurement, utilizing the computer.
21. The method of claim 20, wherein the horizontal resistivity value is associated with a predetermined layer in the formation.
22. The method of claim 21, wherein the invaded zone thickness value, the invaded zone resistivity value, and the horizontal resistivity value comprise a first model of the formation.
23. A system for estimating a model of a formation, the formation having a wellbore extending therethrough, comprising:
a database configured to store a first resistivity measurement associated with the formation from a logging-while-drilling (LWD) sensor, the database is further configured to later store a second resistivity measurement associated with the formation from a second sensor; and
a computer operably coupled to the database, the computer configured to calculate an invaded zone resistivity value and an invaded zone thickness value for the wellbore by utilizing an inversion technique, based on the second resistivity measurement, the computer being further configured to store the invaded zone resistivity value and the invaded zone thickness value for the wellbore in the database.
24. The system of claim 23, wherein the model comprises an isotropic model of the formation.