Hydrocarbon filled fracture formation testing before shale fracturing
First Claim
1. A method of determining a presence of hydrocarbon-filled natural fractures in a well in which stimulation by hydraulic fracturing is to be carried out by a method comprising steps of:
- (a) completing the well;
(b) selecting a first interval at a far end of a drain length of the well;
(c) perforating the first interval to expose a formation to provide access between the formation and inside of a completion tubing;
(d) carrying out a frac job at the first interval;
(e) plugging the first interval to block access to the formation;
(f) selecting a further interval spaced apart from a previous interval;
(g) perforating the further interval to expose the formation to provide access between a shale formation and the inside of the completion tubing;
(h) carrying out the frac job at the further interval;
(i) plugging the further interval to block access to the formation;
(j) repeating steps (f) to (i) along the drain length of the well; and
(k) opening the well up to production;
characterised in that;
at steps (c) and (g), comprising the additional steps of;
(i) exposing the formation at the first interval and the further interval, respectively;
(ii) pumping a first fluid at a first rate into the well, the first rate being lower than a pump rate of the frac job;
(iii) collecting a pressure response trace of pressure versus time at a first data collection rate measured at a gauge located at a wellhead of the well, the first data collection rate being higher than a data collection rate of the frac job;
(iv) from the pressure response trace determining the presence of hydrocarbon-filled natural fractures at the first interval and the further interval, respectively; and
(v) omitting step (d) and (h), respectively, when the presence of hydrocarbon-filled natural fractures are not identified.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of determining the presence of hydrocarbon-filled natural fractures with sufficient lateral extension in a well in which stimulation by hydraulic fracturing is intended to be carried out. Following perforation of an interval, a fluid is pumped into the well and a pressure response trace is collected. The fluid is pumped at a rate which is lower than the pump rate for the intended frac job and the data collection rate is higher than the data collection rate for the intended frac job. Characteristic elements are identified in the pressure response trace whose value and combination indicate the presence or absence of hydrocarbon-filled natural fractures with sufficient lateral extension in the interval.
-
Citations
16 Claims
-
1. A method of determining a presence of hydrocarbon-filled natural fractures in a well in which stimulation by hydraulic fracturing is to be carried out by a method comprising steps of:
-
(a) completing the well; (b) selecting a first interval at a far end of a drain length of the well; (c) perforating the first interval to expose a formation to provide access between the formation and inside of a completion tubing; (d) carrying out a frac job at the first interval; (e) plugging the first interval to block access to the formation; (f) selecting a further interval spaced apart from a previous interval; (g) perforating the further interval to expose the formation to provide access between a shale formation and the inside of the completion tubing; (h) carrying out the frac job at the further interval; (i) plugging the further interval to block access to the formation; (j) repeating steps (f) to (i) along the drain length of the well; and (k) opening the well up to production; characterised in that; at steps (c) and (g), comprising the additional steps of; (i) exposing the formation at the first interval and the further interval, respectively; (ii) pumping a first fluid at a first rate into the well, the first rate being lower than a pump rate of the frac job; (iii) collecting a pressure response trace of pressure versus time at a first data collection rate measured at a gauge located at a wellhead of the well, the first data collection rate being higher than a data collection rate of the frac job; (iv) from the pressure response trace determining the presence of hydrocarbon-filled natural fractures at the first interval and the further interval, respectively; and (v) omitting step (d) and (h), respectively, when the presence of hydrocarbon-filled natural fractures are not identified. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
Specification