HU198776B - Method for opening hydrocarbon-producing well drillings by blasting perforators - Google Patents

Abstract

Field of the Invention The present invention relates to the opening of hydrocarbon production wells with explosive perforators. According to the invention, the perforation is provided at an opening hydrostatic pressure in the range of the difference between the overpressure (S) and rock flow (6 "" f) and the value of the pore pressure (p) reduced by 1 MPa. description range: 3 pages without drawing -1-

Description

The present invention relates to the effective opening of hydrocarbon deep wells with explosive perforators.

The commonly used method for the production of exploration-containing formations is:

All required information on drilled levels is obtained through drilling observations, geophysical hole tracing, and sampling. With all the necessary knowledge, the hole is guided into the lining tube and the liner tube is cemented, thereby restoring hydrodynamic closure between the layers. Opening a layer is an operation in which the liner and cement sheath are punched in a well-defined depth by a suitable method. The most commonly used method of this punching is through the use of hollow, so-called .jet cartridges, commonly known as jet perforation. A perforator equipped with such hollow charges is lowered to a designated depth using a mechanically supported electric cable and then electrically triggered and fired from the surface. (For this known method of jet perforation, see, e.g., Allen,

T.O.Roberts, A.P .: Production operations c. Oil and Gas Consultants, Inc., Tulsa, Oklahoma, USA, 1970).

During the perforation operation, there is fluid in the well, depending on the specific gravity and level, the hydrostatic pressure at the perforation site may be greater than the pore pressure of the container to be opened (this is called overweight) or less (underweight or underpressure). Of course, there may also be an equilibrium situation where the hydrostatic pressure is the pore pressure of the reservoir.

Thus, at the moment of perforation, the separation between the interior of the lining tube and the pores of the reservoir is eliminated, as the shots pierce the lining tube and the surrounding cement sheath. The pressures of the two spaces of different pressures immediately seek to equalize. In an overbalanced situation, flow from the well to the reservoir will begin to trap contaminants in the fuel fluid and punch debris into the open firing canal, severely reducing the permeability of the firing canal. However, in an unbalanced situation, the flow from the storage tank to the well will obviously have a cleaning effect. The risk of contamination is particularly high when perforating in an overbalanced state because, due to the greater compressibility of the gas, much more liquid from the well can flow into the reservoir until the pressure differential is equalized or the permeability of the opening is lost.

However, opening in an unbalanced or reduced counterpressure position may also have the disadvantages of having too little hydrostatic pressure in the well. In this case, no contamination occurs, but still the fluid pressure in the pores; Due to the sudden drop in the rock skeleton, the compressive shear may increase to such an extent that this skeleton cannot withstand the overhead pressure and rock pressure without fracture. And such collapse of the rock skeleton results in a significant reduction or complete loss of permeability.

The present invention provides a method of effectively opening hydrocarbon-producing deep wells with explosive perforators, wherein the rock pressure of β rock, the pore pressure of the rock to be opened, and the flow rate of the rock skeleton at the open are measured and determined by known by appropriately selecting the density and / or level of the fluid, hydrostatic pressure at the depth of the bullet is adjusted so that the unbalance of the shot can be maintained to avoid contamination, but the unbalance, i.e., the depression upon opening, does not reach rope rail collapses due to overload. The well-known Terzaghi-Peck model should be used to determine the correct hydrostatic pressure. On this basis, the following relationship was deduced:

S = 6 * v + p, where: S is the total pressure of rock at a given level (at the level of perforation in the practice of the invention), i.e., the overpressure of the formations above the level, ζ va is the vertical rock skeleton stress, pa called pore pressure.

(See, e.g., Hottmyn, C.E. - Johnson, R.K .: Estimation of Formate from Pressed Shale Properties. Journal of Petroleum Technology, 6, 1965, p. 717).

The pressure active load on a roof S at a given level depends on the depth of that level and the average density of the covering rocks. With this β load, two reaction pressures are equilibrated according to the quoted L model and equation: p pore pressure and ff v vertical skeletal stress. If one of these two reaction pressures changes, the other necessarily changes according to the above equation, since S is constant: rock pressure exists. If pore pressure p drops abruptly during unbalanced perforation, then 5 v must increase. When this vertical stress Θ '* reaches the rock flow limit, the skeleton will collapse. However, no fracture can occur if the hydrostatic pressure at the level of the perforation is

GB 198776 By appropriately selecting the density and level of the dean, adjust it so that it does not fall

P <ii = S - 6v.

However, the requirement for low equilibrium is the experience of Pu hydrostatic pressure. According to the present invention, in the case of under-balanced depression perforations, the prevailing hydrostatic pressure at the level of the perforation must be adjusted to define 1, within the following equation:

S - & t <Pu <p - 1 aho] all quantities are in MPa,

The fracture yield limit tf f of each formation is known by direct proximity measurements or by geophysical measurements (hairs us and density .V'-kbc.l) calculated by calculation (see, for example, by Jescb Aladár:

Range (.volume, near siliceous bay, deep main hour geophysics. Hungarian geophysics, no. 1975,

Page 147).

When perforating in accordance with the present invention, locking devices are dimensioned for expected pressure to provide reliable opening. (remote-controlled lubricant, cable breakout, Gland box) must be mounted on the well head. Make sure that the cable and the cable end are pressurized wells! It should also be possible to disassemble the well and, if necessary, to suppress the well. The tools and procedures required for all these works are generally known.

Claims (1)

Patent Claim Point A method for effectively opening hydrocarbon-producing deep wells with explosive perforators, wherein the top pressure of the rock, the pore pressure of the opening to be opened, and the flow limit of the rock vase at the opening are measured or determined. S - £? adjusting the density and / or level of the well filling liquid according to the conditions of f <Pt, <p - 1, where: 15 S - the rock pressure at the given depth, tf í - the flowing fish of the rock to be opened, Ph is the value of the hydrostatic pressure, p-1, the value of the pore pressure in the pores of the rock to be opened, reduced by 1 MPa.