FIELD: oil industry.
SUBSTANCE: invention relates to oil industry and can be used in cementing of casing strings in oil and gas wells during multistage cementing. Method is characterised by that casing string is equipped with first and second cementing couplings mounted at a distance from each other corresponding to distance between abnormal zones of well. Casing string is lowered to specified depth with intermediate washing. Design volume of cement grout of first stage of cementing is pumped. Bottom plug is pressed to fit in stop-pipe casing. First plug-bomb adapted for free fall to fit into lower seat of first cementing of coupling is lowered. In tube space is created excess pressure to specified value to open cementing window of first cementing of coupling. Excess cement grout first stage is cut off and a pause is held in expectation of setting of cement solution of first stage. Design volume of cement grout of second stage of cementing is pumped. Cement plug is lowered, press-fit in upper seat of first cementing coupling. In tube space is created excess pressure to specified value for cementing windows of first cementing coupling. Second plug-bomb to lowered to fit into lower seat of second cementing coupling. In tube space is created excess pressure to specified value to open cementing windows of second cementing coupling. Excess cement grout of second stage is cut off and pause is made in expectation setting of cement grout of second stage. Design volume of cement grout of third stage is then pumped. Upper plug is lowered and its squeezed to fit in upper seat of second cementing coupling. In tube space is created excess pressure to specified value for cementing windows of second cementing coupling and pause is held in expectation of setting of cement grout of third stage.
EFFECT: technical result is improved reliability of preventing behind-casing gas, oil and water showings of weak layers.
5 cl, 10 dwg
| Title | Year | Author | Number |
|---|---|---|---|
| METHOD FOR MULTI-STAGE CUFF CEMENTING OF WELLS | 2020 |
|
RU2741882C1 |
| STEP CEMENTING SLEEVE | 2022 |
|
RU2787674C1 |
| DEVICE FOR STEPWISE CEMENTING OF TAIL PIECE | 2007 |
|
RU2344271C1 |
| METHOD OF SECURING A HIDDEN CASING STRING OF A BOREHOLE WITH ROTATION AND CEMENTING OF THE ZONE ABOVE THE PRODUCTIVE FORMATION | 2020 |
|
RU2745147C1 |
| DEVICE FOR STAGE CEMENTING OF WELLS | 0 |
|
SU1707187A1 |
| METHOD OF STAGE-WISE CEMENTING OF CASINGS | 0 |
|
SU947390A1 |
| COMPLETION OF DIRECT-CEMENTING CASING STRING WITH RETURN VALVE | 2014 |
|
RU2571469C1 |
| METHOD AND APPARATUS FOR STEPWISE CEMENTING OF CASING | 0 |
|
SU823557A1 |
| CEMENTING PLUG | 0 |
|
SU1705548A1 |
| DEVICE FOR STAGE CEMENTING OF CASING PIPE | 2009 |
|
RU2400618C1 |
