Northeast Oil & Gas Longfengshan No. 1 Horizontal Well Obtains New Breakthrough in Productivity

Sinopec News Network News North 217-4HF well is the first horizontal well drilled since the establishment of the Longfengshan Gas Field High-Efficiency Development Project Department at the end of 2020.
They have carried out joint research on gas reservoir geology, drilling, fracturing, and gas production.
This well has created multiple records of "the longest horizontal section, the highest rate of gas formations, and the highest post-compression productivity" in the Longfengshan intermediate-basic volcanic gas reservoir
.

"Five-step method" for gas reservoirs to stabilize reservoirs with high-efficiency drilling

Well Bei217-4HF adopts the “five-step method” of combining well-seismic "fixed frame", "fine inside story" of lithofacies phases, "optimal sweet spot" of multiple methods, "recalculation" of risk reduction, and "strong tracking" of high-efficiency adjustment.
Carry out scientific research, well location deployment and implementation
.

When deploying well sections in the well site, they first established the overall framework of the volcanic rock strata of the Huoshiling Formation in the Longfengshan Gas Field based on the principle of "cycle-phase-volcanic structure"; then they finely portrayed the boundary of the structure to determine the spatial distribution characteristics of the volcanic structure; The physical properties and gas-bearing control factors of the reservoir in the Bei217 well area were further clarified, and the Bei217-4HF well was deployed in the optimal sweet spot in the eastern part of the Bei217 well area
.

Before the implementation of the well location, considering the diversities of effective reservoir lateral distribution, vertical thickness, time-depth conversion differences in the well location design, they used desktop deduction to analyze the existence of “Drilling through effective reservoir before target A, The extension speed and the actual formation speed differ greatly at the toe end of the horizontal section.
There are two risks, and measures have been formulated for targeted increase in inclination adjustment and real-time adjustment of actual drilling trajectory
.

In the tracking while drilling stage, they used cuttings logging, gamma while drilling, gas logging and other real-time parameters to perform time-depth corrections on the main seismic reflection interface and correct the effective reservoir thickness.
The integration of geological and engineering research was carried out at the horizontal level.
Perform two trajectory adjustments in the section to ensure that the well trajectory is continuously located inside the reservoir
.

Drilling "three optimizations" to achieve the goal of geological protection

Through on-site field surveys, they found that the actual logging wellhead of Well Bei217-4HF is quite different from the designed wellhead.
In order not to adjust the well trajectory to affect the geological purpose, they carried out three aspects of "well trajectory, drilling tool selection, and drilling fluid performance".
Fine optimization
.

First, the original five-stage three-dimensional trajectory twisting position 53° is optimized to a "double two-dimensional" well trajectory, which avoids the situation that the geological adjustment target point affects the drilling encounter, and the single well increases the control reserve by 21 million cubic meters; the second is the use of high efficiency PDC+1.
5° high torque without screw, three-opening design saves two drilling trips; thirdly, materials such as calcium carbonate, bamboo fiber, plugging agent while drilling and high-efficiency environmentally friendly lubricants are selected, which effectively solves the problem of lost circulation and large friction At the same time, the mud-carrying and inhibiting properties are improved to ensure the safety of the wellbore
.
The actual drilling cycle of this well increased by 30.

Fracturing "fine iteration" helps the economic release of production capacity

They started with the link of "optimizing points, subdividing, and reiterating", and iteratively optimized the reservoir reconstruction plan
.

The principle of fracturing point selection for Well Bei217-4HF has changed from the past "geological fixed point, engineering fine-tuning" to an iterative optimization model of "geological and engineering back-to-back selection of points, integrated and then optimized", with "productivity release, engineering feasible" as the The “difference points” were fine-tuned in principle, and the well eventually formed 83 “dual sweet spots” in geological engineering
.

　　After the sweet spot was determined, they combined the control of the reserve range and the pore-throat connectivity of the reservoir to quantitatively describe and classify the sweet spot reformation demand, and formulated the high-yield "multi-stage multi-cluster cutting, few-segment multi-cluster cutting, and few-segment few clusters".
, Relatively high-yield, conventional three main programs
.
The gas reservoir builds a "geology + fracture" numerical model, predicts the development indicators such as the initial production capacity and stable production capacity of each program, combines the internal rate of return, the investment payback period and other economic evaluation results, evaluates the feasibility of the program, and then selects the sweet spot, Re-optimize the program design

　　The North 217-4HF well finally determined the high-yield plan, divided into 28 sections and 83 clusters for fracturing, using casing + pumping bridge plug fracturing method, supporting integrated fracturing fluid system, rope knot temporary plugging technology, and temporary plugging in fractures Turning to technology, continuous construction for 24 hours, cumulative sand addition of 4296 cubic meters, net liquid consumption of 36342 cubic meters, construction displacement 8-18 cubic meters per minute, comprehensive sand ratio 11.
82%, an increase of 30% compared with adjacent wells in the same area
.
It is the horizontal well with the largest number of construction sections, the largest construction scale and the largest displacement in the Northeast Branch

　　After the North 217-4HF is compressed, a high-yield gas stream with a daily output of 11.

　(Ren Xianjun)