Evidence map›Paper›PMID 42730072›Full record

ReviewACS omega2026

Enhancement Mechanisms of Multi-Scale Huff-and-Puff in Horizontal Wells for Tight Sandstone Reservoirs‑A Case Study of the Chang 6

Xiaohui Zhang, Yi Shi, Yanli Ma, Yicheng Wang, Juan Zhang

Abstract readReview
In one paragraph

Review in ACS omega, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Xiaohui ZhangExploration and Development Research Institute, Changqing Oilfield Company PetroChina, Xi'an, Shaanxi 710000, China.
Yi ShiExploration and Development Research Institute, Changqing Oilfield Company PetroChina, Xi'an, Shaanxi 710000, China.
Yanli MaExploration and Development Research Institute, Changqing Oilfield Company PetroChina, Xi'an, Shaanxi 710000, China.
Yicheng WangExploration and Development Research Institute, Changqing Oilfield Company PetroChina, Xi'an, Shaanxi 710000, China.
Juan ZhangEarth Science and Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710000, China.ORCID https://orcid.org/0000-0001-5277-1147

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Hydraulic fracturing is the primary method for developing tight sandstone reservoirs. In particular, horizontal well staged fracturing huff-n-puff is the main technique for enhancing oil recovery in tight sandstones. To clarify the remaining oil distribution and oil displacement mechanism under this technological background, this paper starts from the microscopic seepage mechanism and conducts systematic research by combining microscopic experiments, macroscopic displacement analysis, and numerical simulation. The simple capillary number model is improved for tight reservoirs, revealing that the core mechanism of imbibition is capillary force. To study the coupled imbibition-displacement mechanism in tight reservoirs, visualization oil displacement experiments using glass etching models were carried out, and the oil-water migration under coupled imbibition-displacement was analyzed. The results show that the sweep range of imbibition is much smaller than that of displacement, and the higher the water-wetness, the less the remaining oil during displacement and imbibition replacement. Based on this, conventional imbibition experiments were conducted using real oil-wet thin cores (0.5 cm), confirming that gravity is the main driving force for imbibition in real oil-wet cores, and the larger the contact area between the core and the liquid, the higher the imbibition rate. To eliminate the influence of gravity and analyze the effect of imbibition area, end-face imbibition and full-surface imbibition experiments were performed using thin cores (0.5 cm) and long cores (7.5 cm). The results indicate that imbibition in horizontal cores is mainly horizontal, and the relationship between contact area and imbibition rate was quantified. To analyze the displacement-imbibition oil enhancement in mixed-wet cores from multiple angles and by multiple means, digital rock technology was used to simulate the imbibition experiments on real cores. The main controlling factor for imbibition was identified as displacement pressure: under capillary imbibition and low-pressure drive, the oil displacement efficiency by imbibition is low, but the flowback ratio is high; under higher injection pressure, the imbibition efficiency increases while the flowback ratio decreases. Guided by the microscopic experimental mechanisms, a macroscopic model of horizontal well multistage fracturing was established using numerical simulation to analyze the factors influencing huff-n-puff and imbibition oil enhancement. The results show that after fracturing and well soaking in the study area, high-pressure drive is the main mechanism for oil-water replacement; the optimal well soaking time is 3-4 months; for reservoirs with relatively low oil saturation, imbibition replacement during well soaking is the main means to enhance oil recovery.

Identifiers

PMID42730072
PMCPMC13563634

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.