川西须家河组页岩气水基钻井液技术

油基钻井液是页岩气开发常用的钻井液体系，但存在污染大、费用高等问题，通过改进水基钻井液体系开发页岩气藏可以有效地解决上述问题。对川西须家河组五段泥页岩的工程地质特征进行分析发现，该层属硬脆性泥页岩，膨胀性矿物体积分数低，微裂缝发育，井壁失稳是影响水基钻井液使用的主要因素。通过室内实验优选了抑制剂、封堵剂和降失水剂，形成强抑制强封堵的聚胺仿油基水基钻井液体系。该体系具有较强的抑制封堵性、抗污染性、润滑性和优良的流变性，同时具有较低的中压失水和高温高压失水，在川西XYHF￣1井页岩层现场进行了应用。结果表明，该体系能有效防止页岩层吸水膨胀、缩径垮塌，确保钻井施工安全，在川西页岩气藏开发过程中具有广泛的应用前景。

The oil-based drilling fluid is commonly used in shale gas exploitation, but there are issues of pollution, high costs and so on. Through improving the water-based drilling fluid, the above problems can be solved. The experimental study on engineering geology of T3x5 in western Sichuan shows that this layer is a hard brittle shale, the content of expansive minerals is low and microfractures develop. Borehole instability is the main factor affecting the application of water-based drilling fluid. Through laboratory experiment, the inhibitors, blocking agent and fluid loss additive are selected, forming a polyamine pseudo oil-based drilling fluid system with strong blocking resistance, pollution resistance, lubricity, good rheological property, low middle pressure water loss, high temperature and high pressure water loss, which applies in the shale formation of Well XYHF-1. Results show that this system can effectively provent water from swelling, reducing diameter and sloughing to ensure the safety of drilling construction. This polyamine water-based drilling fluid has a wide application prospect in the shale gas exploitation of western Sichuan.

10.6056/dkyqt201406028