RU2229019C2 - Method for producing gas influx from horizontal portion of well shaft - Google Patents

Abstract

FIELD: gas extracting industry. SUBSTANCE: method includes lowering of tubing string into casing strings to depth of beginning of filter portion of layer, and well completion with lowering of its level to necessary depth. According to the method, well completion is performed by exchanging boring compound with water. Into operating shaft by a tubing string flexible pipes are lowered into horizontal portion of shaft down to bottom-hole. Through said flexible pipes, washing of well by water and blasting of well by inert gas. After each washing and blasting debit is measured and graph of gas debit change is created. This graph is used for determining maximum gas debit when its value on the graph is close to horizontal line. Consecutive washing and blasting are performed up to closing of graph curve to a horizontal line. EFFECT: increased debit of horizontal portion of well after its driving. 1 ex, 1 dwg

Description

The present invention relates to the field of production, in particular to methods for causing gas to flow from a horizontal section of a well.

Known methods of causing gas inflow, including lowering the tubing to the depth of the beginning of the filter part and replacing the drilling fluid with liquid (water, oil), lowering the level of the fluid in the well, swabbing, aeration, the use of two-phase foams, etc. / 1 /.

However, all of these methods apply only to vertical or directional wells. As for the wells with horizontal completion, the above methods are ineffective due to the fact that the drilling fluid is left in the horizontal filter portion of the bore (or in the open horizontal section of the bore if the borehole is operated by open bottom).

The closest in technical essence and the achieved result is a method of inducing gas inflow from the horizontal section of the well table, including lowering the tubing string into the casing to the depth of the beginning of the filter portion of the formation and developing the well with lowering it to the required depth (2).

The disadvantage of this method is that after development in a horizontal section of the wellbore remains drilling fluid, the displacement of the entire volume of which to the surface during the operation of the well is difficult, which does not increase its flow rate.

The technical result of the invention is to increase the flow rate of the horizontal section of the wellbore after its development.

The necessary technical result is achieved by the fact that in the known method of causing gas inflow from a horizontal section of the wellbore, including lowering into the casing pipes of the tubing string to the depth of the beginning of the filter portion of the formation and developing the well with lowering its level to the required depth, according to the invention, the well’s development carried out by replacing the drilling fluid with water, and into the working well along the string of tubing are lowered into the horizontal part of the trunk to the bottom of the flexible pipe and they flush the well with water and purge it with inert gas, and, after each flush and purge, measure the gas flow rate from the well and build a graph of the change in gas flow rate, which determines the maximum gas flow rate when its value approaches the horizontal line, while successive flushing and purging of the well is carried out until the graph curve approaches the horizontal line.

The essence of the method lies in the fact that after the well has been developed in one of the traditional ways, for example, by replacing the drilling fluid with water and then lowering its level to the required depth, or using: an air cushion, or using jet devices, or swabbing, or aeration, or biphasic foams, etc., into a working well (without killing it) along the string of tubing to the bottom at the farthest point from the wellhead from the wellhead, flexible pipes are lowered, for example, using the AP unit T. Through them, the drilling fluid remaining in the horizontal section is washed with water, then flushed with an inert gas.

In this case, the flow rate is measured and the first point (flow rate value) is plotted on the graph, in the drawing, which shows the dependence of the gas flow rate on the number of purges.

Next, water is again pumped into the well, it is possible with the addition of a surfactant, which is purged with an inert gas. Measure the flow rate and put the second point on the graph.

Alternately flushing with water, then flushing with an inert gas, taking measurements of the flow rate in each case and constructing at the same time a graph of the change in flow rate, they lead until the curve of the graph approaches the horizontal line.

Example. Alternately washing with water and gas purging the well in the sequence: water-gas, water-gas. After each washing, the gas flow rate was also measured:

Q ₁ = 154 thousand m ³ / day.

Q ₂ = 169 thousand m ³ / day.

Q ₃ = 171 thousand m ³ / day.

Q ₄ = 171.5 thousand m ³ / day.

and on the received measurements of the debit build a graph (drawing).

The curve in the drawing shows that Q ₄ = Q max, with this value of the flow rate, the graph curve begins to approach the horizontal line.

Using the proposed invention will increase the flow rate of the horizontal section of the wellbore after its development.

Sources of information

1. Bulatov A.I. et al. Well development, Moscow, Nedra, 1998, pp. 218-245.

2. RU 2111348 C1, 05.20.1998.

Claims (1)

A method of causing a gas inflow from a horizontal section of a wellbore, including lowering into the casing pipes of the tubing string to the depth of the start of the filter portion of the formation and developing the well with lowering it to the required depth, characterized in that the well is drilled by replacing the drilling fluid with water and into the working well, along the string of tubing pipes, the flexible pipes are lowered into the horizontal part of the trunk to the bottom and they are flushed through them alternately with water and purging it with inert gas, and after each flushing and purging, the gas production rate from the well is measured and a gas production rate is plotted, according to which the maximum gas production rate is determined when its value approaches the horizontal line on the graph, and the washing and purging of the well are carried out until the graph curve approaches horizontal line.