RU2518585C1 - Multihole well construction method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: construction of multihole wells involves drilling of bores in productive formations and well development. Initially, the first bore is drilled in formation of lower productivity. The drilled bore without development is filled with fluid on a hydrocarbon basis forming filter cake not more than 0.5 mm thick. After that, the second bore is drilled in formation with higher productivity, using drill mud. The well is developed by simultaneous stimulation of both formations. At that, fluid on a hydrocarbon basis is used with density not less than density of drill mud used at drilling of the second bore.

EFFECT: decrease of well formation clogging and increase of its productivity.

1 ex

Description

The invention relates to the oil industry and may find application in the construction of a multilateral well.

A known method of holding and attaching a multilateral well (RF patent No. 2074944, publ. March 10, 1997), which consists in drilling the main trunk to the last depth of branching, fixing the main trunk with pipes, drilling additional trunks with their subsequent attachment by shanks from the main trunk.

Closest to the proposed invention in technical essence is a method for conducting, securing and developing a multilateral well, which includes drilling the main trunk to the last branching depth, securing it with pipes, drilling additional trunks with their subsequent attachment with shanks from the main trunk. The main trunk is first drilled to the roof of the upper productive formation with a set of zenith angle and fastened, then deepened it to accommodate in the thickness of the most productive formation with fastened pipes with packers placed on them if necessary, cutting off the productive layers from each other, and carry out its development . Then, sequential drilling, fastening and development of additional trunks from the bottom to the roof of the upper productive formation with the placement of the faces of additional trunks in various productive formations is carried out from the main trunk. Previously drilled and mastered shafts are isolated from the next additional trunk in the process of its drilling, fastening and development. Provides an increase in production capabilities of the well, reduction of time, labor and material costs for conducting, fixing and development of a multilateral well (RF Patent No. 2386006, publ. 10.04.2010 - prototype).

A disadvantage of the known methods is the high colmatation of the productive wellbores and, as a consequence, the low productivity of the well.

The proposed invention solves the problem of reducing the mud bore of multilateral wells and increasing its productivity.

The problem is solved in that in the method of constructing a multilateral well, including drilling the wells into productive formations and developing the well, according to the invention, the first well is first drilled into the formation with lower productivity, the drilled well is not mastered, it is filled with a hydrocarbon-based liquid forming a filter cake with a thickness not more than 0.5 mm, then drill the second wellbore into the formation with greater productivity using drilling fluid, develop the well by acting on both formations simultaneously, while the fluid on coal Hydrogen is used based on a density of not less than the density of the drilling mud used during the drilling of the second bore.

SUMMARY OF THE INVENTION

When drilling the second wellbore of a multilateral well, the first already drilled well is bogged. At the same time, when drilling the first wellbore into the most productive formation, subsequently, when drilling the wellbore into less productive formations, the first most productive formation becomes colmatized and the entire well production rate decreases. The more productive the formation, the more its clogging occurs during the drilling of subsequent layers. At the same time, neither the consistent development of the formations, the cutting off of formations from each other, or other measures aimed at eliminating the formations does not save from the mudding of the most productive trunk. The proposed invention solves the problem of reducing the mud bore of multilateral wells and increasing its productivity. The problem is solved as follows.

When constructing a multilateral well, the first well is first drilled into the formation with lower productivity, the drilled well is not mastered, it is filled with hydrocarbon-based liquid forming a filter cake no more than 0.5 mm thick, then the second well is drilled into the formation with higher productivity using drilling fluid , drill a well by acting on both layers simultaneously, while a hydrocarbon-based fluid is used with a density not less than the density of the drilling fluid used when drilling the second well la

Well development is most rationally carried out by swabbing the tubing string with the installation of a packer in the shoe area of the production string in the vertical section of the well and subsequent hydrochloric acid treatment of the trunks.

As a hydrocarbon-based liquid, liquids are used in which a hydrocarbon liquid, for example, oil, kerosene, diesel fuel and the like, is used as a base. A hydrocarbon-based liquid may contain thickeners, fillers, surfactants, antifoam agents, bactericides, etc. Such a liquid practically does not clump the near-wellbore zone, and during well operation it dissolves in oil and is removed from the well.

The use of a hydrocarbon-based fluid in the first wellbore with a density not less than the density of the drilling fluid used when drilling the second wellbore helps to minimize penetration of the drilling fluid into the drilled wellbore while drilling the second wellbore and minimizes rock formation in the near-wellbore zone of the first wellbore.

The same effect of minimizing the mudding of the near-wellbore zone of the drilled formation is provided when using hydrocarbon-based fluid, forming a filter cake with a thickness of not more than 0.5 mm.

As a result of minimal mudding, the production rate of the well increases.

Concrete example

Build a multilateral well oil well. The productivity of the lower layer is 4.05 t / day _* MPa, the productivity of the upper layer is 2.00 t / day _* MPa.

The strata are located at depths, the upper one is 1138 m and the lower one is 1162 m. First, the first well is drilled 150 m long in the upper stratum with lower productivity, the drilled well is not mastered, it is filled with hydrocarbon-based fluid in accordance with TU 2413-003-52412574-01 and which is a 40% solution of complex zfirs of higher unsaturated fatty acids (linoleic, oleic, linolenic, etc.) and resin acids in diesel fuel with the addition of an organosilicon stabilizer, 2% alkyldimethylamine oxide and nonionic surfactant EU ETS. In appearance it is an oily viscous liquid from light brown to black in color, has an acid number in the range from 2 to 4 mg KOH / g and a pour point of no higher than minus 35 ° C.

Properties of the used hydrocarbon liquid: density 1.14 g / cm ³ , viscosity 30-50 sec, filtration rate (water loss) ≤6 ml / 30 min according to VM-6, filter cake thickness ≤0.5 mm, sand content ≤1 % vol., SNA 1 \ 10 (static shear stress after 1 and ten minutes) up to 7 \ 10.5 dPa, BPS 1 \ 10 (dynamic shear stress after 1 and ten minutes) up to 36 dPa, electrical resistance ≥0.8 Ohm * m, plastic viscosity 5-19 MPa _* s.

A second well 200 m long is drilled in the lower layer with higher productivity using a biopolymer-carbonate clay-free mud with a density varying from 1 to 1.08 g / cm ³ as a drilling fluid (drilling fluid). Drilled trunks do not plant. A vertical wellbore is cased. A column of tubing with a packer is lowered into a vertical wellbore in the area of the casing shoe. Both layers are mastered simultaneously by swabbing and with subsequent hydrochloric acid treatment of the trunks.

As a result, the well productivity is 5.65 t / day _* MPa. The well productivity of the prototype is 4.76 tons / day _* MPa.

The application of the proposed method will allow to solve the problem of reducing the mud bore of multilateral wells and increasing productivity.

Claims (1)

A method of constructing a multilateral well, including drilling wells into productive formations and developing a well, characterized in that the first well is drilled into the formation with lower productivity, the drilled well is not mastered, it is filled with a hydrocarbon-based liquid forming a filter cake of a thickness of not more than 0.5 mm, then drill the second wellbore into the formation with greater productivity using drilling fluid, drill the well by acting on both formations at the same time, while the hydrocarbon-based fluid is used dissolved at a density of not less than the density of the drilling mud used during the drilling of the second bore.