The process of development and subsequent maintenance of the working condition of the well is a complex of technological operations aimed at extracting the target material. The formation of the drilling tunnel is carried out in different ways, differing both in technical support and in the configuration of the use of aggregates and devices. The choice of the method by which gas well development is planned to a large extent depends on the conditions of work. Engineers pre-calculate the load on the bottom-hole zone and, based on the data obtained, develop a work plan.
Preparation for mastering
Before the start of development, mounting reinforcement is supplied to the wellhead , with the help of which the technical organization of the development process will be possible. Regardless of the chosen development method, a valve with a high pressure is installed on the flange of the mounted casing string. It will be required if a decision is made to close the trunk. As part of the preparation, perforation of the working out and installation of the face is carried out, after which it is possible to begin immersion in the well formed of the pumping and compression equipment. Mandatory development of the well provides for the possibility of removing inflows from the reservoirs. This operation is also included in the list of preventive measures in case of accident prevention or exposure to undesirable load on the equipment.
Well analysis
To clarify or correct the development method, research is carried out. By dividing the mud products of the well through water flows, specialists identify reservoir characteristics. At the same stage, surface finishing with dry ice can be carried out. Further, bypassing the working cavity, the workers clean the filters. Flushing the annulus through the filter shoe. Then the final project is prepared, in accordance with which the development of wells is carried out. The development methods presented below are selected based on the fixed parameters of the well and the external conditions for the operation of the equipment.
Tartania
In accordance with this technique, a liquid is extracted, which is lowered by means of a winch and bailer on a thin rope with a thickness of about 16 mm. The flap is an 8-meter pipe circuit, the lower part of which is provided with a valve with a stem. At the moment of persistent action on the stem, the valve will open. On the back of the bobbin is a rope mount - usually a hardware fixture. The pipe typically has a diameter of not more than 70% of the thickness of the casing. For one trigger approach, it must carry out liquid in a volume of up to 0.06 m3. As practice shows, tartany well development is a labor-intensive process with low productivity. The main disadvantage of this method is the limited possibilities of its use. This is due to the fact that the valve cannot be closed during the extraction of the baffle in the case of fountain manifestations. On the other hand, workers are able to efficiently recover sludge while fully monitoring the fluid level in the well.
Pistoning method
This technique is also called swabbing, as both a piston and a swab can be used as a working unit. Both devices descend into the tubing using a rope. The piston can have a diameter of 25 to 35 mm on average, and by design it is a small pipe with a valve that opens the top of the device. A reinforcing harness over external surfaces is especially important for this fixture. As reinforcement elements, rubber cuffs or wire mesh can be used. As drilling progresses, well development by pistoning is implemented as water intake. The valve opens under fluid pressure and moves to the upper level. On the contrary, during the lifting of the unit, the valve closes, the water drops, and the harness tightens the pipe walls more. One descent makes it possible to extract exactly the volume of liquid that was absorbed into the cavity above the level of the valve during immersion. In terms of productivity, the pistoning method is about 10 times higher than that of tartania.
Well fluid replacement method
The technology also involves working with tubing installations, but subject to complete sealing of the mouth. The creation of a damper on the surface helps to prevent fountain manifestations and discharges from the well, which increases the reliability of the method. Upon exiting the drilling process, the well is filled with clay mass, and after flushing operations with degassed oil or water, the bottomhole pressure coefficient can be significantly reduced. This method effectively shows itself in the development of wells, characterized by high pressure reservoir pressure . Actually, this is beneficial for well development by replacing the fluid and cleaning the field. Updating can be done with the help of tubing units, and through drilling rigs. Sometimes, if there is confidence in the safety of the well from the point of view of exerting high loads on the equipment, an additional piston mechanism for extracting fluid is also used.
Gas injection development method
In this case, the development technology is implemented, similar to the substitution of liquid mixtures. As a working filling, a combination of gas and oil liquid is used. The resulting mixture fills the space between the immersed pipes. As a result, a tension is created between the supplied mixture and the well fluid, under the conditions of which it becomes possible to regulate the development process. This method is optimally suited for work at great depths, but its implementation involves the use of pipes and compressor installations of high pressure. As well development takes place under constant temperature fluctuations, equipment surfaces must also have enhanced external protection. In addition, work with gaseous mixtures makes high demands on safety measures during work, and this increases the cost of the event.
Development methods for injection wells
Work with injection wells is not much different from similar activities with production wells. Methods are also used to obtain the target inflow from the strata through drainage with the cleaning of the bottomhole section. But there are certain differences. The main one is to use the soft start method. This means that during the sampling process, a slow increase in speed occurs, at which a larger volume of liquid is serviced at peak power. Also, methods of developing wells of injection type are guided by a high degree of openness of channels with increasing injectivity rates. That is, the absorption capacity of the downhole support is growing, which also affects the increase in productivity.
Use of compressor units
Most field development methods involve connecting compressor stations. Typically, mobile units of various designs with a feed volume of about 8 m 3 / min are involved. The most productive units with a caterpillar undercarriage are capable of servicing wells with a pumping potential of 16 m 3 / min, but they are highly specialized tools capable of operating under high pressure. The most technologically advanced compressors include diesel free piston stations. Such units for well development are launched from cylinders with compressed air without the need for preheating. The choice of compressor technology for a particular field depends on the characteristics of the well. Moreover, the power supply does not always play a key role in the choice. So, in deep and narrow wells, it is more advisable to use compact, accurate and at the same time functional units.
Mastering Flexible Pipes of a Compressor Unit
Some projects exploring the potential of an undeveloped field include some kind of exploration using flexible pumping equipment. This activity precedes the implementation of actions related to the inflow call. At this stage of the well development work, the following operations are usually performed:
- Preparing for perforation.
- Directly perforating.
- Preparing to call tributaries.
Perforation is understood as drilling a well in order to increase the volume of inflows. That is, at this stage, an inflow in certain volumes should not be organized, but at least efforts are made to increase the productivity of this part of the process in the future.
Well repair work
Repair measures are understood as a complex of measures aimed at maintaining or improving the operability of a cement ring, casing strings and other elements of a well structure. The emergency remedial actions include the elimination of collapses - especially on descents and ascents. More often, well repair is carried out, during which specialists can restore equipment, change configurations and schemes of its installation, carry out cleaning operations, etc.
Well overhaul, in turn, sets the goal of full or partial restoration of the bottomhole zone. As a result of the implementation of such measures, the yield of the layers should be improved against the background of strengthening their structure. In each case, the wells are repaired according to the project prepared in advance and supervised by the team leader. After its completion, an acceptance certificate is drawn up.
Well development safety
Only persons who have undergone special training are allowed to work. In addition, prior to the start of work activities, a briefing is conducted in order to familiarize oneself with the nuances of performing operations at a specific facility. At the site should be present only the necessary technical means, equipment and devices. The equipment must receive special approval, indicating the serviceability of all functional parts. Fire safety during well development is especially important in working with oil and gas fields. Extinguishing media should be present at the facility in the event of a gaseous zone fire. Local communications for temporary storage of oil and its transportation (barns, pipelines) must have reliable fire insulation.
Conclusion
The technical organization of field development requires serious training in a wide range of different aspects. In some cases, the emphasis is on the power of the equipment, when you need to get large volumes in a short time. In others, stringent safety standards are taken into account. By the way, the same development of oil wells is characterized by increased requirements not only in terms of safety, but also in terms of technological support. Petroleum products, by virtue of their physicochemical qualities, limit the use of certain methods, which often forces engineers to modify them specifically for specific conditions. Of course, in such cases, the cost of development also increases - but, provided that the work is done qualitatively, the invested resources and efforts justify themselves.