Re-digging oil in the remaining oil - a record of the oil enhancement technology of the second oil production plant in Daqing Oilfield

"This well is near a small fault, although the potential layer is small, but the oil saturation is not low, and there is still potential for exploitation
.
" On December 22, 2022, when analyzing the sedimentary phase map of the western block of the South 4th District managed by the plant, scientists and technicians from the Institute of Geology of the No.
2 Oil Production Plant in Daqing Oilfield said that they plan to apply the ultra-short radius side drilling horizontal well digging technology to drill two new test wells in this block to further excavate the remaining oil
near the fault.

In the past two years, the plant has accelerated the pace of technical research, explored and implemented three technologies: moderate scale fracturing, reverse pressure flooding of oil wells, and horizontal well diving of ultra-short radius side drilling, and the average annual decreasing output of water flooding has decreased by 60,000 tons compared with the "13th Five-Year Plan" period; The measures increase oil by an average of 82,000 tons per year, 1.
8 times
that of the "13th Five-Year Plan" period.

Moderate-scale fracturing technology: cumulative oil increase of 205,600 tons

After 58 years of efficient development, the conventional fracturing effect of the second oil production plant of Daqing Oilfield has gradually decreased, and the contribution to oil production has gradually weakened
.

In the face of difficulties, the plant took a different approach, preferred the two types of residual oil that were not extracted due to unpressed and small fracturing scale, accurately measured the economic and technical boundaries of sand amount, crack parameters and construction costs in the process of designing the measure plan, appropriately increased the scale of transformation, increased the amount of liquid increase, and ensured the fracturing effect
.

"Well 4-30-642 in South is poorly developed in Sa II.
1 unit and has relatively poor communication with surrounding water injection wells, and we optimize the amount of sand in a single layer by 19 cubic meters through simulation calculations, thereby increasing the radius of oil displacement
.
At the same time, we gave full play to the development advantages of the well in Sa II.
2 unit, and carried out moderate scale fracturing on the well, and the fracture and sand body were optimally matched, and the daily oil increase after fracturing was 4.
6 tons
.
Cai Xiaofeng, director of the dynamic room of the geological research institute of the plant, said
.

Since its implementation, the plant has carried out a total of 158 wells on a moderate scale, with a cumulative oil increase of 205,600 tons
.

Oil well reverse pressure drive technology: cumulative oil increase of 254,200 tons

Through reservoir numerical simulation and other methods, the plant clarifies the technical boundaries of well selection, layer selection, fracture and well simmering, and supports the development of two tracking and adjustment methods of skid-mounted pump secondary replenishment and proximal pressure remote end, and establishes a complete set of reverse pressure driving technical standards for oil wells, which makes up for the inherent disadvantages of fracturing target reservoirs and well groups, and opens up effective displacement channels
.

"We have selected 'three low and one high' reservoirs with low liquid strength, low production degree, low formation pressure and high oil saturation, and implemented reverse pressure flooding technology to expand the potential space
of measures.
Among them, the implementation effect of South 8-21-C 614 well is the most obvious, the sand body of the well is well developed, the remaining oil is relatively rich, but it is in the fault edge of the injection and production connection is poor, there are reserves and no energy
.
Through the pressure flooding transformation of the well, the synergistic effect of the oil displacement agent and the crack was brought into play to effectively supplement the formation energy, and the initial daily oil increase reached 19.
7 tons
.
Cai Xiaofeng introduced
.

Since the implementation of the oil well reverse pressure drive technology, the plant has carried out a total of 53 oil well reverse pressure driving wells, with a cumulative oil increase of 254,200 tons
.

Ultra-short radius side drilling horizontal well digging technology: cumulative oil increase of 2204 tons

By using MWD ultra-short radius horizontal well technology and stepped side drilling horizontal well technology, the plant targets the single-layer, one-direction residual oil-enriched wells to further activate the residual potential
of the reservoirs near the edges of large faults and small faults.

In 2022, the plant successfully tested 1 well in the field, with an initial average daily oil increase of 7.
3 tons, a comprehensive water cut of more than 10 percentage points, and a cumulative oil increase of 2,204 tons
.

Faced with the problem of increasing the difficulty of selecting wells and layers in the stage of water flooding and ultra-high water cut, and the deterioration of oil increase effect, the plant will further optimize the potential mining process of supporting measures, expand the potential of measures, and continuously improve the oil increase effect
of measures.