RU2019689C1 - Method for well testing - Google Patents

Abstract

FIELD: oil producing industry. SUBSTANCE: installed preliminary in well is permeable cement plug closing producing formations. Then, inflow of formation fluid is induced by reducing hydrostatic pressure exerted on producing formations, and well is tested under needed conditions. EFFECT: cut down costs and reduced terms of well testing due to prevention of tubing clogging.

Description

 The invention relates to the oil and gas industry, in particular to well development. A known method of well development by reducing the back pressure on the reservoir [1].

 A disadvantage of the known methods is the destruction of the borehole zone of productive formations and blockage by rock particles of tubing.

 The closest technical solution (prototype) is a method of testing wells using an in-line filter [2]. According to the prototype in the perforation interval 2-4 m above the upper holes of the filter create a gravel-sand plug, which serves as a filter. Such filters limit or prevent the entry of sand into the well, create a zone of increased permeability and strengthen the formation. The disadvantage of the prototype is the clogging of the filter particles (gravel, sand) of the tubing (well) when testing wells.

 The aim of the present invention is to prevent clogging of the filter particles of the tubing (flow pipe).

 This goal is achieved by the fact that first a permeable cement bridge is installed in the wellbore, overlapping productive formations for 4 m, and then an inflow of formation fluid is caused by reducing hydrostatic pressure on the productive formations, after which the wells are examined in regimes.

 The method is as follows.

 Pumping (fountain) pipes are lowered into the well. The bare end of the pipes is installed at the bottom of the reservoir. According to a pre-selected recipe, a cement mortar is prepared in a container. Using a cementing unit, cement mortar is pumped into the trunk, overlapping productive formations by 10-25 m. Raise the tubing string 5 m above the top of the reservoir. The excess cement mortar is washed out of the well and the well is left in the bcc. After the cement mortar has set in the well, the presence of a cement bridge in the wellbore is checked, and then the flow of formation fluid is caused by reducing hydrostatic pressure on the productive formations, after which the well is examined in regimes.

PRI me R. Well data
⌀ 426 mm 426 mm conductor - 221 m;
⌀ 299 mm 299 mm technical column - 3100 m;
⌀ 219 mm 210 mm production casing - 3500 m;
filter part of 219 mm production casing - 3250-3450 m
the interval of productive strata is 3250-3450 m.

In the well, 102 m tubing (fountain) pipes are lowered to a depth of 3450 m. 0.25 m ^{3 of} buffer solution (5% CMC solution) is pumped into the pipe, then 1.25 m ^{3 of} grouting mortar, then 0 again. 25 m ^{3 of} buffer solution and 21 m ^{3 of} drilling fluid.

 After the cement slurry is pumped into the interval of the productive formations, the tubing string is raised to a depth of 3246 m, the excess cement slurry is washed off, after which the pipe string is lifted another 10-15 m and the well is left on the baffle. After the cement mortar has set in the well, the presence of a cement bridge in the well is checked, and then the flow of formation fluid is caused by reducing hydrostatic pressure on the productive formations, after which the well is examined in regimes.

 The implementation of the proposed method in production will significantly reduce the cost and timing of testing wells.

Claims (1)

 WELL TEST METHOD, which includes installing a filter in the wellbore that overlaps productive formations, causing formation fluid to flow through the filter by reducing hydrostatic pressure on the productive formations and examining the well in regimes, characterized in that, in order to prevent clogging of the tubing, as The filter uses a permeable cement bridge.