Spontaneous imbibition measurement method based on electric potential

Abstract

The invention discloses a spontaneous imbibition measurement method based on electric potential. The spontaneous imbibition measurement method comprises the following steps: drying a rock core to a state without free water and putting the rock core into a rubber cylinder; applying confining pressure on the rubber cylinder; switching on a constant-voltage power supply and recording an electric potential difference between adjacent measurement probes; adjusting a hand pump to enable a water surface in a water storage space to be right in contact with the bottom end of the rock core and recording the change of the electric potential of each measurement probe along with time; unloading the confining pressure of the rock core and putting the rock core into a water pool until the rock core reaches a saturated state, and then putting into the rubber cylinder and applying the confining pressure on the rock core; switching on the constant-voltage power supply and recording an electric potential difference between the adjacent measurement probes; analyzing data; and evaluating a spontaneous imbibition rule of the rock core. According to the measurement method, the electric potential difference is applied to the rock core through a spontaneous imbibition measurement device based on the electric potential and the electric potential of each point on the surface of the rock core is measured; and the spontaneous imbibition interface height of the rock core to each type of liquid including fracturing fluid and the like is monitored and the change of liquid saturation degree on the rock core along the time is monitored, so that parameters including water absorption speed, capillary force, water absorption quality and the like of a tested sample can be grasped in real time.

Description

technical field

[0001] The invention belongs to the technical field of petroleum engineering and relates to a rock core spontaneous imbibition measurement technology, in particular to a potential-based spontaneous imbibition measurement method. Background technique

[0002] At present, unconventional reservoirs represented by shale gas are characterized by tightness, and their development requires large-scale hydraulic fracturing, and a large amount of water is injected into the formation. Therefore, evaluating the spontaneous imbibition law of reservoir rocks is the most important aspect of unconventional oil and gas development research. one of the key issues. This is mainly due to the following reasons: First, because the pore throats of tight reservoirs are small, and the distribution of throats is mostly at the micro-nano level, the spontaneous imbibition phenomenon caused by capillary force is more obvious than that of conventional reservoirs, which has a great impact ...

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