SU1463905A1 - Method of casing and cementing wells - Google Patents

Abstract

The invention relates to the field of well drilling and m. used to fix and cement them. The goal is to improve the quality of cementing by increasing the completeness of filling the well space with cement mortar and reducing the time of cementing. Before the casing is lowered in the well above the reservoir, the rocks are fractured and the wellhead pressure in the annulus is recorded. After the casing is lowered, clay-alumina and cement slurries are sequentially pumped with the latter being pushed into the well interval against the productive formation, and the first one - into the productive formation. During the pushing of the alumina cement solution, the annular space at the mouth is periodically blocked until the pressure of the slip is close to that of the fracture of the rocks. This makes it possible to cement all weakened zones of rocks in a single step. W SP

Description

one

The invention relates to the drilling of wells, in particular to methods for their fastening and cementing.

The purpose of the invention is to improve the quality of cementing by increasing the completeness of filling the well space with cement mortar and reducing the time of cementing.

The method is carried out as follows.

The column is descended to a predetermined depth. Then the alumina-cement and cement mortars are sequentially pumped with the latter being pushed.

in the squiggle interval against the productive formation, and the first - above the productive formation. In this case, before the casing is lowered, the rocks are fractured over the producing formation and the pressure at the wellhead in the annulus is fixed, and the annular space at the wellhead is periodically closed during the displacement of the alumina cement solution. The operations of overlapping the annular space on the mouth are stopped after an increase in the pressure of the sales is noted at the next overlap, the annular space is up to 4 O)

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nor close to fracture pressure.

Such a sequence and volume of operations allows one to cement all weakened ones; zones, which allows cementing to be done in a single step, and also reduce the time of well fixing.

II p im. A conductor with a diameter of 324 mm is lowered to a depth of 400 m, cemented to the ust, a technical column with a diameter of 219 mm is lowered to a depth of 1300 m, and cemented to the ust. The operational column with a diameter of 146 mm is lowered to a depth of 3200 m. The cementing interval is 3200 m to the mouth. Cement mortar with a density of 1.78 g / cm is forced into intellar 3200-2400 m, Potassium mortar with a density of 1, 55 g / cm is forced into an interval of 2400 - mouth Drilling mud density of 1.2 g / cm Additional pressure of rocks in the interval 1300-3200 m in a solution with a density of 1.2 g / cm is 97 kgf / cm. The fracturing pressure at the bottom of the well P t. P 481 kgf / cm. Fracture gradient К g, р 0.150 (kgf / cm2) / m.

After a portion of 2.5 m of the clay-cement mixture is finished, the operation-. The column is fractured by closing the preventer plates and pressurizing it into the absorption volume in an amount of 1.0 m. Then the preventer plates are opened. In order to prevent hydraulic udgar, each closing of the preventer is carried out with the choke battery open, the valves of which are then closed. Injection operations with closed prehepter tshashka repeated five times. The pressure on the PA manometer is constant and equal to 77 kgf / cm. With the next, sixth, closing of the preventer, the pressure on the pressure gauge, the pressure gauge, increases even with the achievement of 130 kgf / cm. preventer open. An increase in pressure indicates that absorption cracks are tamped down,

 The whole process consumes 38 m of alumina-cement solution, including 5 m of absorbing cracks, for the formation of core holes.

foot ring 33 m.

The technological process of pumping and pressing the plugging mixture to receive a Stop signal during multiple operations of opening and closing the preventer plates is carried out continuously. After the completion of punching and receiving the Stop signal, the well is left on the PCR.

Claims (1)

0 claims The way of laziness and cementing-. no wells, including descent, sequential injection 5 clay-cement and cement mortars with the latter being pushed into the well interval against the productive formation, and the former above the productive formation, characterized in that, in order to improve the cementing quality by increasing the completeness of filling the annular cKBajioiH cement solution and reducing the cementing time, before descending the casing string is fractured above the reservoir and pressure is recorded at the wellhead in the annulus while 40 of the alumina cement solution is periodically blocked behind the annular space at the mouth, and the overlap of the annular space at the mouth is stopped after the increase in selling pressure at the next blocking of the annular space to a pressure close to the fracture pressure of the rocks. 0