Title: Proppant flowback control in coal bed methane wells: experimental study and field application

Authors: Kai Zhu; Dali Guo; Xiaohui Zeng; Shuguang Li; Chuanqing Liu

Addresses: State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, School of Sciences, Southwest Petroleum University, Xindu Avenue 8#, Xindu District, Chengdu City, Sichuan, 610500, China ' State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, School of Sciences, Southwest Petroleum University, Xindu Avenue 8#, Xindu District, Chengdu City, Sichuan, 610500, China ' State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, School of Petroleum Engineering, Southwest Petroleum University, Xindu Avenue 8#, Xindu District, Chengdu City, Sichuan, 610500, China ' Coal Bed Methane Company, China National Petroleum Corporation, Fung Woo Building, Chaoyang District, Beijing, 100028, China ' Coal Bed Methane Company, China National Petroleum Corporation, Fung Woo Building, Chaoyang District, Beijing, 100028, China

Abstract: Proppant flowback after fracturing coal bed methane (CBM) wells is a very common challenge which results in fracture pinching out, noticeable well productivity decrease, downhole and surface facility damage, etc. In this paper, fibre was studied as a low-cost and environmentally friendly additive to control proppant flowback in CBM well fracturing operation. Two kinds of glass fibre (short fibre and long fibre) are selected. Extensive experimental studies have been conducted to test the effects of fibre concentration and fibre control length exerting on the critical proppant flowback rate. The optimal fibre combination is 1:2 as the mass ratio of long fibre to short fibre. And fibre control length is 225 mm in a 300 mm tube. An optimisation model is also presented to optimise the fibre concentration and fibre control length in the field application. So the in-situ fracturing design can be conducted by repeating fracture propagation and proppant transport simulations and parameters optimisations. The experimental results and the optimisation model were applied in CBM well fracturing in Hancheng area in China. 23 tested wells have achieved a significant increase of gas production and decrease of workover times than the 9 offset ones without fibre-added sand. [Received: 22 October 2012; Accepted: 3 April 2013]

Keywords: coal bed methane wells; hydraulic fracturing; fracking; proppant flowback; experiment study; critical flowback rate; flowback control; glass fibre additives; CBM well fracturing; China; fracturing design; fracture propagation; proppant transport simulation; parameter optimisation.

DOI: 10.1504/IJOGCT.2014.059279

International Journal of Oil, Gas and Coal Technology, 2014 Vol.7 No.2, pp.189 - 202

Received: 23 Oct 2012
Accepted: 03 Apr 2013

Published online: 24 May 2014 *

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