CN1059010C - Method for integrally profile-controlling and water-plugging block - Google Patents

Abstract

A method for overall profile control and water shutoff of the block, which mainly measures the pressure index PI of all injection wells in the block, and then uses the value of the pressure index PI as the relevant problem of profile control and water shutoff decision parameters. This method has strong operability, wide decision-making scope and rapid decision-making, and can make multiple decisions on the block's overall profile control and water plugging repeated construction.

Description

A method for overall profile control and water plugging of blocks

The invention relates to a method for overall profile control and water shutoff of blocks, which belongs to an effective decision-making method for formulating and implementing oilfield profile control and water shutoff schemes in oil and gas field development projects. It mainly uses the pressure index method to determine the major issues related to the block's overall profile control and water shutoff.

In oil and gas field development projects, profile control and water shutoff technology is an important means and measure to enhance oil recovery. The profile control and water shutoff technology has gradually developed from the single oil well water shutoff stage, the water well single well profile control stage, the oil and water wells of the well group corresponding to the profile control and water shutoff stage to the block overall profile control and water shutoff stage. So far, there is no particularly effective method to solve the problem of overall profile control and water shutoff in oilfield blocks. In order to make profile control and water shutoff an important measure to enhance oil recovery, it must be carried out in the block as a whole. Therefore, in order to make profile control and water shutoff reflect the overall concept and form the center of other comprehensive management, there must be a decision A set of methods for major problems of profile control and water shutoff, which must be able to solve six aspects of the overall profile control and water shutoff of the block: ① determine the necessity of profile control in the block; well; ③select the appropriate plugging agent for profile control and water shutoff; ④calculate the dosage of plugging agent; ⑤evaluate the effect; ⑥determine the time for repeated construction.

The purpose of the present invention is to solve the above six practical problems in the prior art and provide a brand-new method for overall profile control and water plugging of the block. When cutting and plugging water, its operation should specifically include the following steps: (1). First, measure the pressure drop curves of the wellheads of all the water injection wells in the block, and use the measured pressure drop curves of each water injection well

The curve is calculated according to the following definition of PI value and the specified shut-in time for each water injection well

PI value: $\mathrm{P.I.}=\frac{{\∫}_0^{t}p\left(t\right)\mathrm{dt}}{t},$

In the formula, PI is the pressure index of the water injection well (Mpa); p(t) is the tubing pressure (Mpa) after the water injection well shut-in time t; t is the well shut-in time; (2). Judging the necessity of profile adjustment:

①. Block average PI value: the smaller the block average PI value, the more profile control is needed. If the block average PI

If the value is lower than 10Mpa, the block needs profile control;

②. PI value range of block water injection wells: PI value range refers to the maximum value of PI value of block water injection wells

The difference between the minimum value and the larger the value is, the more the profile control is required. If the PI value range exceeds 5Mpa, the area

The block needs profile adjustment;

Profile control is required for blocks that meet any of the above criteria or two criteria at the same time; (3). Select profile control wells and water injection wells according to the average PI value of the block and the PI value of the water injection well.

The water injection well with average PI value is the profile control well, and the water injection well with higher than the average PI value of the block is selected as the injection well

Wells, water injection wells near the average PI value of the block, slightly higher or slightly lower than the average PI value are not located

Well management; (4). Select the type of profile control agent for profile control; (5). Select the time for repeated profile control and water plugging construction.

In the above-mentioned method for overall profile control and water plugging of the block, the pressure index PI value has the following relationship with the physical parameters of the formation and fluid:

In the formula, q is the daily injection rate of the water injection well; μ is the hydrodynamic viscosity; k is the formation permeability; h is the formation thickness; r _e is the control radius of the water injection well;  is the formation porosity; Shut-in time.

In the above-mentioned method described above, the consumption of its profile control agent depends on the predetermined increase value of water injection well pressure index value, the consumption coefficient and formation thickness, and the consumption coefficient of its profile control agent is to be calculated by the following formula of test injection result: $\mathrm{\β}=\frac{W}{h_f\mathrm{\ΔP}{I}^{\′}}$

In the formula, β is the dosage coefficient; W is the dosage of profile control agent; h _f is the thickness of water injection layer; ΔPI′ is the change of PI value before and after trial injection of profile control agent.

The technical characteristics of the present invention will be described in detail below in conjunction with the embodiments.

In actual operation and implementation, the designer of the present invention realizes the overall profile control and water plugging decision of the block according to the following steps, namely: 1. The acquisition of the decision parameter PI value

Measure the wellhead pressure drop curve of all water injection wells on the block, and calculate the PI value of the water injection well according to the following PI value definition formula and the specified well shut-in time from this curve: $\mathrm{P.I.}=\frac{{\∫}_0^{t}p\left(t\right)\mathrm{dt}}{t}$ In the formula, PI is the pressure index (Mpa) of the water injection well; p(t) is the tubing pressure (Mpa) after the water injection well shut-in time t; t is the well shut-in time. 2. Judgment on the necessity of block profile control

The necessity of block profile control is judged according to two criteria ①Block average PI value: the smaller the block average PI value, the more profile control is needed. Generally, the block with an average PI value lower than 10Mpa needs profile control. ②The extreme difference of PI value of water injection wells in the block: the extreme difference of PI value refers to the difference between the maximum value and the minimum value of PI value of water injection wells in the block. The block needs profile adjustment.

Usually, the blocks that meet one or both standards are necessary for profile control. 3. Selection of profile control wells

Selected according to the average PI value of the block and the PI value of the water injection well. Usually, the water injection wells lower than the average PI value of the block are profile control wells, the water injection wells higher than the average PI value of the block are injection wells, and the water injection wells are near, slightly higher or slightly lower than the average PI value of the block The water injection wells are untreated wells. 4. Selection of profile control agent

The selection of profile control agent for water injection wells is carried out according to four conventional standards, namely formation temperature, salinity of formation water, PI value and cost of water injection wells. 5. Calculation of profile control agent dosage:

Calculate the dosage of the profile control agent through the following three steps, that is, ① determine the formula of the profile control agent. ② The dosage coefficient defined by the following formula is calculated from the profile control agent test injection: $\mathrm{\β}=\frac{W}{h_f\mathrm{\Δ}{\mathrm{P.I.}}^{\′}}$ In the formula, β is the dosage coefficient; W is the dosage of profile control agent; h _f is the thickness of water injection layer; ΔPI′ is the change of PI value before and after trial injection of profile control agent. ③Calculate the formal construction dosage of profile control agent by the dosage coefficient:

W=βh _f ΔPI

In the formula, ΔPI is the predetermined increase value (MPa) of the PI value of the water injection well before and after profile control 6. Evaluation of profile control effect

The evaluation is mainly based on ① wellhead pressure drop curve of water injection well; ② indicating curve of water injection well; ③ water absorption profile of water injection well; ④ water drive curve; Curves (daily liquid production, comprehensive water cut and daily oil production). 7. Decision to repeat construction time

Because the profile control agent moves into the formation, the plugging effect on the near-wellbore area is reduced, and the curve decreases. The curve falls, that is, the PI value decreases. When the PI value decreases to the PI value before profile control or a reasonable specified value, it is time for repeated construction. 8. Decision-making for oil well water plugging ① Selection of water plugging oil wells: Water plugging oil wells are based on production capacity, high water cut, and low PI value area (from the area

Block PI value contour map to find out) and other conditions are selected. ②Selection of water shutoff agent: water shutoff agent according to formation temperature, salinity of formation water, PI value of oil well

The selection of conditions such as the region and cost. ③ Determination of the amount of water blocking agent: calculated by w = β′h _t . In the formula, β' is the dosage coefficient of water blocking agent,

Its value is in the range of 2-20m ³ /m (formation). The specific value of β' should refer to the construction under the same conditions

Selection of oil wells. ④Evaluation of water shutoff effect: It can be evaluated by the change of fluid production profile and oil production curve of the oil well before and after water shutoff.

price. ⑤ Determination of repeated construction time: determined by the change of oil production curve.

The decision-making method adopted by the present invention has been implemented to blocks (20) in some oil fields, and all have achieved good results. Compared with the existing profile control and water plugging methods, this technology has strong operability, wide decision-making area, and rapid decision-making, and can make multiple decisions on the block’s overall profile control and water plugging repeated construction, so this technology is especially suitable for Make decisions on the overall profile control and water plugging of the block.

Claims (3)

1. method that is used for block is carried out the integral profile control water blockoff, it is characterized in that this method comprises the following steps: (1). at first measure the falloff curve of the well head of the whole water injection wells of block, and calculate the PI value of each mouthful water injection well by the every mouthful of water injection well falloff curve that records by closed-in time of the definition of following PI value and appointment: $\mathrm{PI}=\frac{{\∫}_0^{t}p\left(t\right)\mathrm{dt}}{t},$

In the formula, PI is the pressure index (Mpa) of water injection well; P (t) is the tubing pressure (Mpa) behind the water injection well closed-in time t; T is the closed-in time; (2). by two standards the necessity of block profile control to be judged: 1.. block mean P I value: block mean P I value is more little to need profile control more, if block mean P I value is lower than 10Mpa, then this block needs profile control; 2.. the PI value extreme difference of block water injection well: PI value extreme difference is meant the poor of the maximum value of block water injection well PI value and minimum value, the big more profile control that needs more of its value, PI value extreme difference surpasses 5Mpa, and then this block needs profile control;

The block that meets above-mentioned any one standard or meet two standards simultaneously all must carry out profile control; (3). press block mean P I value and water injection well PI value and select profile control well and water injection well, select to be lower than block

The water injection well of mean P I value is a profile control well, selects to be higher than the water injection well of block mean P I value for increasing

Annotate well, near block mean P I value, a little more than or a little less than the water injection well of mean P I value be

Do not handle well; (4). select the type of profile control agent to carry out profile control; (5). select to repeat the time of profile control and water plugging construction.

2. the method that is used for block is carried out the integral profile control water blockoff according to claim 1 is characterized in that the physical parameter of pressure index PI value and stratum and fluid has following relation:

In the formula, q is a water injection well day fluence; μ is a fluid dynamic viscosity; K is an in-place permeability; H is a formation thickness; r _eIt is the water injection well Control Radius; is a formation porosity; C is a system compressibility; T is the closed-in time.

3. the method that is used for block is carried out the integral profile control water blockoff according to claim 1, the consumption that it is characterized in that profile control agent depends on the predetermined improvement value of water injection well pressure index value, with flow factor and formation thickness, its profile control agent be to calculate by following formula with flow factor by the injection test result: $\mathrm{\β}=\frac{W}{h_f\mathrm{\ΔP}{I}^{\′}}$

In the formula, β uses flow factor; W is the profile control agent consumption; h _fIt is the water filling layer thickness; Δ PI ' is the variation of PI value before and after the injection test profile control agent.