SU1320384A1 - Method of producing wells in salt-anhydrite deposits embedding a brine manifestation zone - Google Patents

Abstract

The invention relates to mining and M. b. used in drilling for oil and gas. The purpose of the invention is to increase the drilling efficiency by eliminating the appearance of brine. In the southern zone, an anticlinal structure is revealed and drilling is carried out to the top of salt deposits. Overlap with a column of salted section. Wells are laid outside the lock of the saline deposits. The column is tested for pressure calculated in the rapes zone. A rapine zone, bounded by a cone, is determined, the base of which passes on the last closed isohypse along the basement of the sediments, and the top is in the lock of the salt-bearing arch. Then, the value of the reservoir pressure abnormality coefficient (CAPD) for the section to be opened on the subsalt structural plan is determined by interpolation from the KAND set values to its values by the last closed isohypsum. Subsequent drilling is carried out to the zone bounded by a cone, in solution, with a density corresponding to the parameters of the sediment to be opened, and in the zone of the cone with a density established in accordance with the CAPD of the section to be opened. This method ensures the completion of drilling wells in the zones of reproduction without complications. 2 il. 2 tab. & (L oo o oo 00

Description

The invention relates to mining and can be used in drilling for oil and gas.

The aim of the invention is to increase the drilling efficiency by eliminating the appearance of brine.

 FIG. 1 shows a plot of objects to open brine from their position in the area of the local structure but subsalt deposits; in fig. 2 - diagram of salt-anhydrite deposits with a distribution zone and a projected well, section.

The following designations are used on the drywall: I - clay, 2 - aquiferous limestones; 3 - AOjro.vmrbi aquifers; 4 - anhydrite, 5 - salt; 6 - contact boundary: o - reference seismic horizon,

b lithological packs; 7 is the anomalous coefficient of the nlastic pressure in the reservoir; x; 8 - test interval {flow rate, water density, mineralization

water); 9 zone: numbers

on the side, the percentage of the opening of the salt-anhydrite deposits, the figures but the basics --- the predicted values of KAFIZL

The proposed method is carried out in the following manner.

In the region you are in. They are local and local, prepared for prospecting drilling for gas but bloody and nodal salt-anhydrite from beddings. Evaluate one of the forecast methods, or, by analogy of the geological structure of the stream section of a given area with the same footprint — the presence of long-lasting deposits of lenses in the section. A well is laid in optimal conditions, but outside the lock. of the vault, and drill it to the top of the sediments in accordance with the geological conditions of the section. The entire supra-slit section of the tehnical column is cased and compressed at a pressure depending on the value of the anomaly coefficient of the reservoir pressure, calculated for the section to reveal the rapids in the salt-bearing section.

It was assumed that this pressure is comparable with geostatic pressure. However, this trend, as reported by the results of the test of raporn wells, is not universal. The pressure recovery curves, taken at the Baigushli, Karaulkuy, Dzhuramergen, Seyrab, Bagadzh, Sama}) areas, etc., show that the coefficient of abnormal formation pressure (CAPD) in the lens. The ramps vary from 1.1 to 2.2. At the same time, within a single area, the CAPD varies in (and a wide range. For example, in South. Iolotani from 1.73-1.74 (well 4) to 2.07 (well b), in Dzhuramergei from 1.60- i, 6J (SLE. 5) up to 2.1 (well 6). In all examples, the coefficient of anomaly of the reservoir pressure of Lenin brine lenses in the distribution zone is uniformly differentiated from the sub-geostatic on the arch to its values

salt deposits, which corresponds to the epure of stresses generated in unstable plastic rocks.

In tab. 1 shows the values of K. APD on the areas of Juramergen and Samantepe.

FIG. Figure 2 shows the information on the compliance of the calculated CAPD and the mud density in the zone of operation.

Rapids in wells appeared only in those cases when the mud density was lower than the calculated CAPD value. The calculated CAPD value was obtained by interpolation in the area of the subsalt structural plan between the value 2.2 at the arch and its value in

5 subsalt deposits on the contour of the last closed isohypses of local antikotinal structure. Of the nineteen examples given, only well 3 (Saman- tepe) produced a zone of replenishment on the solution, the density of which was lower than the calculated CAPD value. This is due to the fact that the well is a salt-anhydrite layer outside the sphere of influence of the brine lens. The predicted values of ADP in subsalt debris .x are usually determined by inter, area correlation or by its dependence on the thickness of their salt-andes deposits and the position of the local area to the gas generation zone and contour} of the area of the evaporite formation.

0 Subsequent drilling is carried out in a lightweight solution. In the presence of reservoir formations in the saline section, drilling is carried out on the solution, the parameters of which are selected in accordance with the fluid pressure in them. Such a solution is used to drill to the rapids, the surface of which, as the drilling results have found, has the shape of a cone, rather than a cylinder. For example, by drilling an I-shaped ploil, hell, x, it was established that, in the anticlinal structure of the lens, replenishment lenses can

0 to open at its various levels. But between the position of the well on the structural plan and the depth of the opening, a dependence is observed (Fig. 1). According to the talk of drilling at the Sakar, Sundukli, Samanteni and other deposits, it was revealed that the source and,,: the wound are grouped in the volume described by the surface of the cone with the base in the bottom . Moreover, the cone back is predicted from the vault of the node-salt structure and is located in the vault of the vault, and the base is worn on the last closed isoghysis along the sole from the south. By drilling to the rapids zone (to the cone), further drilling in the zone is oswestled on the solution with a density that corresponds to the calculated anomalous coefficient of the net pressure at the site of opening the site.

Example. Plonkhad Bayra.mali (Eastern Turkmenistan) prepared for deeply exploratory drilling for oil and gas but above - and node 5

salt deposits m. This is the brachyanticline of the submeridian strike. The area is located in a region with a known perception. The presence in her incision focal lens brine installed SLE. 10 and was predisposed by similar geological conditions of the salt-bearing section with neighboring working areas (Mary, Uchadzhi, Seyrab, etc.). The thickness of the salt-anhydride (salt-bearing) stratum from a comparison of the structural plans for over- and subsalt sediments is 850 m. Within an area of 8.5 km south of the arch, it is planned to drill the hard currency. 11. Before opening the roof of the salt-bearing deposits, occurring at a depth of 3260 m (-3100 m), it is surrounded by technical column 5. The technical column should be tested for reservoir pressure from a CAPD calculation of 1.6, since the well opens the rapids in the section with CAPD not exceeding this pressure (Fig. 2). It was obtained by interpolation on the subsalt 20 structural plan from 2.2 (maximum density of salt-bearing rocks) on the arch to the value of the predicted CAPD in the subsalt ones. deposits of 1.1 on the last closed iso-gypsum (-4000 m), i.e., within the boundaries of the base of the cone. Drilling in a salt-bearing section, due to the presence of reservoirs with a CAPD of 1.5, is carried out to the zone of penetration on a solution with a density calculated for this value. The rapes zone according to the results of building a n cone (the base passes on the last closed isohypse of subsalt deposits –4000 m, and the cone vertex is restored from the arch of these deviations to the roof

25

Plot it 1.6 open. This completes the construction of the well in the salt anhydrite deposits.

The proposed method is implemented with the help of standard equipment and ensures the completion of the drilling of wells in the distribution zones without complications and at lower costs.

Claims (1)

Invention Formula The method of well construction in the salt-anhydrite deposits, which include the zone of penetration, includes the detection of an anticlinal structure within the flow region, drilling to the top of the salt deposit, blocking the supersal column with a column, testing it and subsequent drilling below the roof, characterized by that, in order to increase the drilling efficiency due to the exclusion of the occurrence of brine, the wells lay outside the vault lock, salt-bearing sediments and, depending on their location on the structural plan of subsalt sediments The test of the column is made on the pressure calculated in the rapes zone, the rapes zone is defined, bounded by a cone, the base of which passes on the last closed isohypse along the base of the sediments, and the top is in the lock of the saliferous sediment, after which the value of the coefficient reservoir pressure anomaly (CAPD) for the section to be opened on the subsalt structural plan by interpolation from CAPD values of the arch to its values for the last closed sulfate-halogen deposits) reveals 55% of the thickness of the isohypsis, while drilling is carried out before the zosulphate-halogen deposits, i.e., bounded by the specified cone, ng Lfs depth 3710 (-3550 m). The depth of the opening of the zone is determined on the outer side of the cone, which on the profile represents the sides of the triangle (Fig. 2). In the drilling zone, the density of the drilling fluid is applied in accordance with the CAPD on on solutions with a density corresponding to the parameters of the deposits being opened, and in the zone of the cone - with solutions with a density established in accordance with the factor 40 of the anomalous formation pressure of the section being opened. squash Hypsometric mark of the sole of the salt-bearing formation, m Djuramergen 6 2 5 Samantepe 4D 7 P five Plot it 1.6 open. This solution completes the construction of the well in salt-anhydrite deposits. The proposed method is implemented using standard equipment and ensures the completion of drilling of wells in the distribution zones without complications and at lower costs. Invention Formula A method for constructing wells in salt-anhydrite deposits that enclose a zone of rapids, including the detection of an anticlinal structure within the turnaround region, drilling to the top of the salt-bearing deposits, blocking the over-cut with a column, testing it and then drilling below the roof, differing from the fact that, in order to increase the drilling efficiency due to the elimination of brine occurrence, the wells are laid outside the vault lock, salt-bearing sediments and, depending on their location, in the subsurface structural plan test, the column is made on the pressure calculated in the rapes zone, the rapes zone is defined, bounded by a cone, the base of which passes on the last closed isohypse along the base of the sediments, and the top is in the lock of the saliferous sediment, after which the value of the coefficient reservoir pressure anomalies (CAPD) for the section to be opened on the subsalt structural plan by interpolation from CAPD values of the code to its last closed values limited by the specified cone, ng on solutions with a density corresponding to the parameters of the deposits being opened, and in the zone of the cone - with solutions with a density established in accordance with the factor 40 of the anomalous formation pressure of the section being opened. Table 1 Values CAPD 2.1 1.74-1.75 1.63 1.97-1.99 1.34 table 2 Reproduction Without complic. No complications No complications No complications Rapoprovenlenie Drainage Rapopropenia No complications Rapor implantation Rapolation Rapalization No complications. Rapography. Rapography. No complications Rapology No complications Rapography About 10 20 30 40 50 60 70 80 90 WO / L DEPRECIATION aSwftmapano- PROVENESS From cSodff,% Vue.j 30003100-3100 -3200 -3300  -3WO --3500 --3600 --3700 -3SOO -39OO -WOO 50 T 1 50 3oT i i i i f with W 2.2 1.6 Compiled by E. .Molchanova Editor L. PovhanTehred I. VeresKorrektor .M. Sharoshi Order 2625/30 Circulation 532 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 1 13035, Moscow, Zh-35. Raushsk nab., D. -J / B Production and ilegraphic enterprise, Uzhgorod, st. Projects four